/* * linux/fs/ext4/inode.c * * Copyright (C) 1992, 1993, 1994, 1995 * Remy Card (card@masi.ibp.fr) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * * from * * linux/fs/minix/inode.c * * Copyright (C) 1991, 1992 Linus Torvalds * * Goal-directed block allocation by Stephen Tweedie * (sct@redhat.com), 1993, 1998 * Big-endian to little-endian byte-swapping/bitmaps by * David S. Miller (davem@caip.rutgers.edu), 1995 * 64-bit file support on 64-bit platforms by Jakub Jelinek * (jj@sunsite.ms.mff.cuni.cz) * * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ext4_jbd2.h" #include "xattr.h" #include "acl.h" #include "ext4_extents.h" #include #define MPAGE_DA_EXTENT_TAIL 0x01 static inline int ext4_begin_ordered_truncate(struct inode *inode, loff_t new_size) { trace_ext4_begin_ordered_truncate(inode, new_size); /* * If jinode is zero, then we never opened the file for * writing, so there's no need to call * jbd2_journal_begin_ordered_truncate() since there's no * outstanding writes we need to flush. */ if (!EXT4_I(inode)->jinode) return 0; return jbd2_journal_begin_ordered_truncate(EXT4_JOURNAL(inode), EXT4_I(inode)->jinode, new_size); } static void ext4_invalidatepage(struct page *page, unsigned long offset); static int noalloc_get_block_write(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create); static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode); static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate); static int __ext4_journalled_writepage(struct page *page, unsigned int len); static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh); /* * Test whether an inode is a fast symlink. */ static int ext4_inode_is_fast_symlink(struct inode *inode) { int ea_blocks = EXT4_I(inode)->i_file_acl ? (inode->i_sb->s_blocksize >> 9) : 0; return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0); } /* * Work out how many blocks we need to proceed with the next chunk of a * truncate transaction. */ static unsigned long blocks_for_truncate(struct inode *inode) { ext4_lblk_t needed; needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); /* Give ourselves just enough room to cope with inodes in which * i_blocks is corrupt: we've seen disk corruptions in the past * which resulted in random data in an inode which looked enough * like a regular file for ext4 to try to delete it. Things * will go a bit crazy if that happens, but at least we should * try not to panic the whole kernel. */ if (needed < 2) needed = 2; /* But we need to bound the transaction so we don't overflow the * journal. */ if (needed > EXT4_MAX_TRANS_DATA) needed = EXT4_MAX_TRANS_DATA; return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; } /* * Truncate transactions can be complex and absolutely huge. So we need to * be able to restart the transaction at a conventient checkpoint to make * sure we don't overflow the journal. * * start_transaction gets us a new handle for a truncate transaction, * and extend_transaction tries to extend the existing one a bit. If * extend fails, we need to propagate the failure up and restart the * transaction in the top-level truncate loop. --sct */ static handle_t *start_transaction(struct inode *inode) { handle_t *result; result = ext4_journal_start(inode, blocks_for_truncate(inode)); if (!IS_ERR(result)) return result; ext4_std_error(inode->i_sb, PTR_ERR(result)); return result; } /* * Try to extend this transaction for the purposes of truncation. * * Returns 0 if we managed to create more room. If we can't create more * room, and the transaction must be restarted we return 1. */ static int try_to_extend_transaction(handle_t *handle, struct inode *inode) { if (!ext4_handle_valid(handle)) return 0; if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1)) return 0; if (!ext4_journal_extend(handle, blocks_for_truncate(inode))) return 0; return 1; } /* * Restart the transaction associated with *handle. This does a commit, * so before we call here everything must be consistently dirtied against * this transaction. */ int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode, int nblocks) { int ret; /* * Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this * moment, get_block can be called only for blocks inside i_size since * page cache has been already dropped and writes are blocked by * i_mutex. So we can safely drop the i_data_sem here. */ BUG_ON(EXT4_JOURNAL(inode) == NULL); jbd_debug(2, "restarting handle %p\n", handle); up_write(&EXT4_I(inode)->i_data_sem); ret = ext4_journal_restart(handle, nblocks); down_write(&EXT4_I(inode)->i_data_sem); ext4_discard_preallocations(inode); return ret; } /* * Called at the last iput() if i_nlink is zero. */ void ext4_evict_inode(struct inode *inode) { handle_t *handle; int err; trace_ext4_evict_inode(inode); if (inode->i_nlink) { truncate_inode_pages(&inode->i_data, 0); goto no_delete; } if (!is_bad_inode(inode)) dquot_initialize(inode); if (ext4_should_order_data(inode)) ext4_begin_ordered_truncate(inode, 0); truncate_inode_pages(&inode->i_data, 0); if (is_bad_inode(inode)) goto no_delete; handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3); if (IS_ERR(handle)) { ext4_std_error(inode->i_sb, PTR_ERR(handle)); /* * If we're going to skip the normal cleanup, we still need to * make sure that the in-core orphan linked list is properly * cleaned up. */ ext4_orphan_del(NULL, inode); goto no_delete; } if (IS_SYNC(inode)) ext4_handle_sync(handle); inode->i_size = 0; err = ext4_mark_inode_dirty(handle, inode); if (err) { ext4_warning(inode->i_sb, "couldn't mark inode dirty (err %d)", err); goto stop_handle; } if (inode->i_blocks) ext4_truncate(inode); /* * ext4_ext_truncate() doesn't reserve any slop when it * restarts journal transactions; therefore there may not be * enough credits left in the handle to remove the inode from * the orphan list and set the dtime field. */ if (!ext4_handle_has_enough_credits(handle, 3)) { err = ext4_journal_extend(handle, 3); if (err > 0) err = ext4_journal_restart(handle, 3); if (err != 0) { ext4_warning(inode->i_sb, "couldn't extend journal (err %d)", err); stop_handle: ext4_journal_stop(handle); ext4_orphan_del(NULL, inode); goto no_delete; } } /* * Kill off the orphan record which ext4_truncate created. * AKPM: I think this can be inside the above `if'. * Note that ext4_orphan_del() has to be able to cope with the * deletion of a non-existent orphan - this is because we don't * know if ext4_truncate() actually created an orphan record. * (Well, we could do this if we need to, but heck - it works) */ ext4_orphan_del(handle, inode); EXT4_I(inode)->i_dtime = get_seconds(); /* * One subtle ordering requirement: if anything has gone wrong * (transaction abort, IO errors, whatever), then we can still * do these next steps (the fs will already have been marked as * having errors), but we can't free the inode if the mark_dirty * fails. */ if (ext4_mark_inode_dirty(handle, inode)) /* If that failed, just do the required in-core inode clear. */ ext4_clear_inode(inode); else ext4_free_inode(handle, inode); ext4_journal_stop(handle); return; no_delete: ext4_clear_inode(inode); /* We must guarantee clearing of inode... */ } typedef struct { __le32 *p; __le32 key; struct buffer_head *bh; } Indirect; static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v) { p->key = *(p->p = v); p->bh = bh; } /** * ext4_block_to_path - parse the block number into array of offsets * @inode: inode in question (we are only interested in its superblock) * @i_block: block number to be parsed * @offsets: array to store the offsets in * @boundary: set this non-zero if the referred-to block is likely to be * followed (on disk) by an indirect block. * * To store the locations of file's data ext4 uses a data structure common * for UNIX filesystems - tree of pointers anchored in the inode, with * data blocks at leaves and indirect blocks in intermediate nodes. * This function translates the block number into path in that tree - * return value is the path length and @offsets[n] is the offset of * pointer to (n+1)th node in the nth one. If @block is out of range * (negative or too large) warning is printed and zero returned. * * Note: function doesn't find node addresses, so no IO is needed. All * we need to know is the capacity of indirect blocks (taken from the * inode->i_sb). */ /* * Portability note: the last comparison (check that we fit into triple * indirect block) is spelled differently, because otherwise on an * architecture with 32-bit longs and 8Kb pages we might get into trouble * if our filesystem had 8Kb blocks. We might use long long, but that would * kill us on x86. Oh, well, at least the sign propagation does not matter - * i_block would have to be negative in the very beginning, so we would not * get there at all. */ static int ext4_block_to_path(struct inode *inode, ext4_lblk_t i_block, ext4_lblk_t offsets[4], int *boundary) { int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb); int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb); const long direct_blocks = EXT4_NDIR_BLOCKS, indirect_blocks = ptrs, double_blocks = (1 << (ptrs_bits * 2)); int n = 0; int final = 0; if (i_block < direct_blocks) { offsets[n++] = i_block; final = direct_blocks; } else if ((i_block -= direct_blocks) < indirect_blocks) { offsets[n++] = EXT4_IND_BLOCK; offsets[n++] = i_block; final = ptrs; } else if ((i_block -= indirect_blocks) < double_blocks) { offsets[n++] = EXT4_DIND_BLOCK; offsets[n++] = i_block >> ptrs_bits; offsets[n++] = i_block & (ptrs - 1); final = ptrs; } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) { offsets[n++] = EXT4_TIND_BLOCK; offsets[n++] = i_block >> (ptrs_bits * 2); offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1); offsets[n++] = i_block & (ptrs - 1); final = ptrs; } else { ext4_warning(inode->i_sb, "block %lu > max in inode %lu", i_block + direct_blocks + indirect_blocks + double_blocks, inode->i_ino); } if (boundary) *boundary = final - 1 - (i_block & (ptrs - 1)); return n; } static int __ext4_check_blockref(const char *function, unsigned int line, struct inode *inode, __le32 *p, unsigned int max) { struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es; __le32 *bref = p; unsigned int blk; while (bref < p+max) { blk = le32_to_cpu(*bref++); if (blk && unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb), blk, 1))) { es->s_last_error_block = cpu_to_le64(blk); ext4_error_inode(inode, function, line, blk, "invalid block"); return -EIO; } } return 0; } #define ext4_check_indirect_blockref(inode, bh) \ __ext4_check_blockref(__func__, __LINE__, inode, \ (__le32 *)(bh)->b_data, \ EXT4_ADDR_PER_BLOCK((inode)->i_sb)) #define ext4_check_inode_blockref(inode) \ __ext4_check_blockref(__func__, __LINE__, inode, \ EXT4_I(inode)->i_data, \ EXT4_NDIR_BLOCKS) /** * ext4_get_branch - read the chain of indirect blocks leading to data * @inode: inode in question * @depth: depth of the chain (1 - direct pointer, etc.) * @offsets: offsets of pointers in inode/indirect blocks * @chain: place to store the result * @err: here we store the error value * * Function fills the array of triples and returns %NULL * if everything went OK or the pointer to the last filled triple * (incomplete one) otherwise. Upon the return chain[i].key contains * the number of (i+1)-th block in the chain (as it is stored in memory, * i.e. little-endian 32-bit), chain[i].p contains the address of that * number (it points into struct inode for i==0 and into the bh->b_data * for i>0) and chain[i].bh points to the buffer_head of i-th indirect * block for i>0 and NULL for i==0. In other words, it holds the block * numbers of the chain, addresses they were taken from (and where we can * verify that chain did not change) and buffer_heads hosting these * numbers. * * Function stops when it stumbles upon zero pointer (absent block) * (pointer to last triple returned, *@err == 0) * or when it gets an IO error reading an indirect block * (ditto, *@err == -EIO) * or when it reads all @depth-1 indirect blocks successfully and finds * the whole chain, all way to the data (returns %NULL, *err == 0). * * Need to be called with * down_read(&EXT4_I(inode)->i_data_sem) */ static Indirect *ext4_get_branch(struct inode *inode, int depth, ext4_lblk_t *offsets, Indirect chain[4], int *err) { struct super_block *sb = inode->i_sb; Indirect *p = chain; struct buffer_head *bh; *err = 0; /* i_data is not going away, no lock needed */ add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets); if (!p->key) goto no_block; while (--depth) { bh = sb_getblk(sb, le32_to_cpu(p->key)); if (unlikely(!bh)) goto failure; if (!bh_uptodate_or_lock(bh)) { if (bh_submit_read(bh) < 0) { put_bh(bh); goto failure; } /* validate block references */ if (ext4_check_indirect_blockref(inode, bh)) { put_bh(bh); goto failure; } } add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets); /* Reader: end */ if (!p->key) goto no_block; } return NULL; failure: *err = -EIO; no_block: return p; } /** * ext4_find_near - find a place for allocation with sufficient locality * @inode: owner * @ind: descriptor of indirect block. * * This function returns the preferred place for block allocation. * It is used when heuristic for sequential allocation fails. * Rules are: * + if there is a block to the left of our position - allocate near it. * + if pointer will live in indirect block - allocate near that block. * + if pointer will live in inode - allocate in the same * cylinder group. * * In the latter case we colour the starting block by the callers PID to * prevent it from clashing with concurrent allocations for a different inode * in the same block group. The PID is used here so that functionally related * files will be close-by on-disk. * * Caller must make sure that @ind is valid and will stay that way. */ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind) { struct ext4_inode_info *ei = EXT4_I(inode); __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data; __le32 *p; ext4_fsblk_t bg_start; ext4_fsblk_t last_block; ext4_grpblk_t colour; ext4_group_t block_group; int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); /* Try to find previous block */ for (p = ind->p - 1; p >= start; p--) { if (*p) return le32_to_cpu(*p); } /* No such thing, so let's try location of indirect block */ if (ind->bh) return ind->bh->b_blocknr; /* * It is going to be referred to from the inode itself? OK, just put it * into the same cylinder group then. */ block_group = ei->i_block_group; if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { block_group &= ~(flex_size-1); if (S_ISREG(inode->i_mode)) block_group++; } bg_start = ext4_group_first_block_no(inode->i_sb, block_group); last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; /* * If we are doing delayed allocation, we don't need take * colour into account. */ if (test_opt(inode->i_sb, DELALLOC)) return bg_start; if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) colour = (current->pid % 16) * (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); else colour = (current->pid % 16) * ((last_block - bg_start) / 16); return bg_start + colour; } /** * ext4_find_goal - find a preferred place for allocation. * @inode: owner * @block: block we want * @partial: pointer to the last triple within a chain * * Normally this function find the preferred place for block allocation, * returns it. * Because this is only used for non-extent files, we limit the block nr * to 32 bits. */ static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block, Indirect *partial) { ext4_fsblk_t goal; /* * XXX need to get goal block from mballoc's data structures */ goal = ext4_find_near(inode, partial); goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; return goal; } /** * ext4_blks_to_allocate - Look up the block map and count the number * of direct blocks need to be allocated for the given branch. * * @branch: chain of indirect blocks * @k: number of blocks need for indirect blocks * @blks: number of data blocks to be mapped. * @blocks_to_boundary: the offset in the indirect block * * return the total number of blocks to be allocate, including the * direct and indirect blocks. */ static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks, int blocks_to_boundary) { unsigned int count = 0; /* * Simple case, [t,d]Indirect block(s) has not allocated yet * then it's clear blocks on that path have not allocated */ if (k > 0) { /* right now we don't handle cross boundary allocation */ if (blks < blocks_to_boundary + 1) count += blks; else count += blocks_to_boundary + 1; return count; } count++; while (count < blks && count <= blocks_to_boundary && le32_to_cpu(*(branch[0].p + count)) == 0) { count++; } return count; } /** * ext4_alloc_blocks: multiple allocate blocks needed for a branch * @handle: handle for this transaction * @inode: inode which needs allocated blocks * @iblock: the logical block to start allocated at * @goal: preferred physical block of allocation * @indirect_blks: the number of blocks need to allocate for indirect * blocks * @blks: number of desired blocks * @new_blocks: on return it will store the new block numbers for * the indirect blocks(if needed) and the first direct block, * @err: on return it will store the error code * * This function will return the number of blocks allocated as * requested by the passed-in parameters. */ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, ext4_lblk_t iblock, ext4_fsblk_t goal, int indirect_blks, int blks, ext4_fsblk_t new_blocks[4], int *err) { struct ext4_allocation_request ar; int target, i; unsigned long count = 0, blk_allocated = 0; int index = 0; ext4_fsblk_t current_block = 0; int ret = 0; /* * Here we try to allocate the requested multiple blocks at once, * on a best-effort basis. * To build a branch, we should allocate blocks for * the indirect blocks(if not allocated yet), and at least * the first direct block of this branch. That's the * minimum number of blocks need to allocate(required) */ /* first we try to allocate the indirect blocks */ target = indirect_blks; while (target > 0) { count = target; /* allocating blocks for indirect blocks and direct blocks */ current_block = ext4_new_meta_blocks(handle, inode, goal, &count, err); if (*err) goto failed_out; if (unlikely(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS)) { EXT4_ERROR_INODE(inode, "current_block %llu + count %lu > %d!", current_block, count, EXT4_MAX_BLOCK_FILE_PHYS); *err = -EIO; goto failed_out; } target -= count; /* allocate blocks for indirect blocks */ while (index < indirect_blks && count) { new_blocks[index++] = current_block++; count--; } if (count > 0) { /* * save the new block number * for the first direct block */ new_blocks[index] = current_block; printk(KERN_INFO "%s returned more blocks than " "requested\n", __func__); WARN_ON(1); break; } } target = blks - count ; blk_allocated = count; if (!target) goto allocated; /* Now allocate data blocks */ memset(&ar, 0, sizeof(ar)); ar.inode = inode; ar.goal = goal; ar.len = target; ar.logical = iblock; if (S_ISREG(inode->i_mode)) /* enable in-core preallocation only for regular files */ ar.flags = EXT4_MB_HINT_DATA; current_block = ext4_mb_new_blocks(handle, &ar, err); if (unlikely(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS)) { EXT4_ERROR_INODE(inode, "current_block %llu + ar.len %d > %d!", current_block, ar.len, EXT4_MAX_BLOCK_FILE_PHYS); *err = -EIO; goto failed_out; } if (*err && (target == blks)) { /* * if the allocation failed and we didn't allocate * any blocks before */ goto failed_out; } if (!*err) { if (target == blks) { /* * save the new block number * for the first direct block */ new_blocks[index] = current_block; } blk_allocated += ar.len; } allocated: /* total number of blocks allocated for direct blocks */ ret = blk_allocated; *err = 0; return ret; failed_out: for (i = 0; i < index; i++) ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0); return ret; } /** * ext4_alloc_branch - allocate and set up a chain of blocks. * @handle: handle for this transaction * @inode: owner * @indirect_blks: number of allocated indirect blocks * @blks: number of allocated direct blocks * @goal: preferred place for allocation * @offsets: offsets (in the blocks) to store the pointers to next. * @branch: place to store the chain in. * * This function allocates blocks, zeroes out all but the last one, * links them into chain and (if we are synchronous) writes them to disk. * In other words, it prepares a branch that can be spliced onto the * inode. It stores the information about that chain in the branch[], in * the same format as ext4_get_branch() would do. We are calling it after * we had read the existing part of chain and partial points to the last * triple of that (one with zero ->key). Upon the exit we have the same * picture as after the successful ext4_get_block(), except that in one * place chain is disconnected - *branch->p is still zero (we did not * set the last link), but branch->key contains the number that should * be placed into *branch->p to fill that gap. * * If allocation fails we free all blocks we've allocated (and forget * their buffer_heads) and return the error value the from failed * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain * as described above and return 0. */ static int ext4_alloc_branch(handle_t *handle, struct inode *inode, ext4_lblk_t iblock, int indirect_blks, int *blks, ext4_fsblk_t goal, ext4_lblk_t *offsets, Indirect *branch) { int blocksize = inode->i_sb->s_blocksize; int i, n = 0; int err = 0; struct buffer_head *bh; int num; ext4_fsblk_t new_blocks[4]; ext4_fsblk_t current_block; num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks, *blks, new_blocks, &err); if (err) return err; branch[0].key = cpu_to_le32(new_blocks[0]); /* * metadata blocks and data blocks are allocated. */ for (n = 1; n <= indirect_blks; n++) { /* * Get buffer_head for parent block, zero it out * and set the pointer to new one, then send * parent to disk. */ bh = sb_getblk(inode->i_sb, new_blocks[n-1]); if (unlikely(!bh)) { err = -EIO; goto failed; } branch[n].bh = bh; lock_buffer(bh); BUFFER_TRACE(bh, "call get_create_access"); err = ext4_journal_get_create_access(handle, bh); if (err) { /* Don't brelse(bh) here; it's done in * ext4_journal_forget() below */ unlock_buffer(bh); goto failed; } memset(bh->b_data, 0, blocksize); branch[n].p = (__le32 *) bh->b_data + offsets[n]; branch[n].key = cpu_to_le32(new_blocks[n]); *branch[n].p = branch[n].key; if (n == indirect_blks) { current_block = new_blocks[n]; /* * End of chain, update the last new metablock of * the chain to point to the new allocated * data blocks numbers */ for (i = 1; i < num; i++) *(branch[n].p + i) = cpu_to_le32(++current_block); } BUFFER_TRACE(bh, "marking uptodate"); set_buffer_uptodate(bh); unlock_buffer(bh); BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); err = ext4_handle_dirty_metadata(handle, inode, bh); if (err) goto failed; } *blks = num; return err; failed: /* Allocation failed, free what we already allocated */ ext4_free_blocks(handle, inode, NULL, new_blocks[0], 1, 0); for (i = 1; i <= n ; i++) { /* * branch[i].bh is newly allocated, so there is no * need to revoke the block, which is why we don't * need to set EXT4_FREE_BLOCKS_METADATA. */ ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, EXT4_FREE_BLOCKS_FORGET); } for (i = n+1; i < indirect_blks; i++) ext4_free_blocks(handle, inode, NULL, new_blocks[i], 1, 0); ext4_free_blocks(handle, inode, NULL, new_blocks[i], num, 0); return err; } /** * ext4_splice_branch - splice the allocated branch onto inode. * @handle: handle for this transaction * @inode: owner * @block: (logical) number of block we are adding * @chain: chain of indirect blocks (with a missing link - see * ext4_alloc_branch) * @where: location of missing link * @num: number of indirect blocks we are adding * @blks: number of direct blocks we are adding * * This function fills the missing link and does all housekeeping needed in * inode (->i_blocks, etc.). In case of success we end up with the full * chain to new block and return 0. */ static int ext4_splice_branch(handle_t *handle, struct inode *inode, ext4_lblk_t block, Indirect *where, int num, int blks) { int i; int err = 0; ext4_fsblk_t current_block; /* * If we're splicing into a [td]indirect block (as opposed to the * inode) then we need to get write access to the [td]indirect block * before the splice. */ if (where->bh) { BUFFER_TRACE(where->bh, "get_write_access"); err = ext4_journal_get_write_access(handle, where->bh); if (err) goto err_out; } /* That's it */ *where->p = where->key; /* * Update the host buffer_head or inode to point to more just allocated * direct blocks blocks */ if (num == 0 && blks > 1) { current_block = le32_to_cpu(where->key) + 1; for (i = 1; i < blks; i++) *(where->p + i) = cpu_to_le32(current_block++); } /* We are done with atomic stuff, now do the rest of housekeeping */ /* had we spliced it onto indirect block? */ if (where->bh) { /* * If we spliced it onto an indirect block, we haven't * altered the inode. Note however that if it is being spliced * onto an indirect block at the very end of the file (the * file is growing) then we *will* alter the inode to reflect * the new i_size. But that is not done here - it is done in * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode. */ jbd_debug(5, "splicing indirect only\n"); BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata"); err = ext4_handle_dirty_metadata(handle, inode, where->bh); if (err) goto err_out; } else { /* * OK, we spliced it into the inode itself on a direct block. */ ext4_mark_inode_dirty(handle, inode); jbd_debug(5, "splicing direct\n"); } return err; err_out: for (i = 1; i <= num; i++) { /* * branch[i].bh is newly allocated, so there is no * need to revoke the block, which is why we don't * need to set EXT4_FREE_BLOCKS_METADATA. */ ext4_free_blocks(handle, inode, where[i].bh, 0, 1, EXT4_FREE_BLOCKS_FORGET); } ext4_free_blocks(handle, inode, NULL, le32_to_cpu(where[num].key), blks, 0); return err; } /* * The ext4_ind_map_blocks() function handles non-extents inodes * (i.e., using the traditional indirect/double-indirect i_blocks * scheme) for ext4_map_blocks(). * * Allocation strategy is simple: if we have to allocate something, we will * have to go the whole way to leaf. So let's do it before attaching anything * to tree, set linkage between the newborn blocks, write them if sync is * required, recheck the path, free and repeat if check fails, otherwise * set the last missing link (that will protect us from any truncate-generated * removals - all blocks on the path are immune now) and possibly force the * write on the parent block. * That has a nice additional property: no special recovery from the failed * allocations is needed - we simply release blocks and do not touch anything * reachable from inode. * * `handle' can be NULL if create == 0. * * return > 0, # of blocks mapped or allocated. * return = 0, if plain lookup failed. * return < 0, error case. * * The ext4_ind_get_blocks() function should be called with * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system * blocks. */ static int ext4_ind_map_blocks(handle_t *handle, struct inode *inode, struct ext4_map_blocks *map, int flags) { int err = -EIO; ext4_lblk_t offsets[4]; Indirect chain[4]; Indirect *partial; ext4_fsblk_t goal; int indirect_blks; int blocks_to_boundary = 0; int depth; int count = 0; ext4_fsblk_t first_block = 0; trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags); J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))); J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0); depth = ext4_block_to_path(inode, map->m_lblk, offsets, &blocks_to_boundary); if (depth == 0) goto out; partial = ext4_get_branch(inode, depth, offsets, chain, &err); /* Simplest case - block found, no allocation needed */ if (!partial) { first_block = le32_to_cpu(chain[depth - 1].key); count++; /*map more blocks*/ while (count < map->m_len && count <= blocks_to_boundary) { ext4_fsblk_t blk; blk = le32_to_cpu(*(chain[depth-1].p + count)); if (blk == first_block + count) count++; else break; } goto got_it; } /* Next simple case - plain lookup or failed read of indirect block */ if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO) goto cleanup; /* * Okay, we need to do block allocation. */ goal = ext4_find_goal(inode, map->m_lblk, partial); /* the number of blocks need to allocate for [d,t]indirect blocks */ indirect_blks = (chain + depth) - partial - 1; /* * Next look up the indirect map to count the totoal number of * direct blocks to allocate for this branch. */ count = ext4_blks_to_allocate(partial, indirect_blks, map->m_len, blocks_to_boundary); /* * Block out ext4_truncate while we alter the tree */ err = ext4_alloc_branch(handle, inode, map->m_lblk, indirect_blks, &count, goal, offsets + (partial - chain), partial); /* * The ext4_splice_branch call will free and forget any buffers * on the new chain if there is a failure, but that risks using * up transaction credits, especially for bitmaps where the * credits cannot be returned. Can we handle this somehow? We * may need to return -EAGAIN upwards in the worst case. --sct */ if (!err) err = ext4_splice_branch(handle, inode, map->m_lblk, partial, indirect_blks, count); if (err) goto cleanup; map->m_flags |= EXT4_MAP_NEW; ext4_update_inode_fsync_trans(handle, inode, 1); got_it: map->m_flags |= EXT4_MAP_MAPPED; map->m_pblk = le32_to_cpu(chain[depth-1].key); map->m_len = count; if (count > blocks_to_boundary) map->m_flags |= EXT4_MAP_BOUNDARY; err = count; /* Clean up and exit */ partial = chain + depth - 1; /* the whole chain */ cleanup: while (partial > chain) { BUFFER_TRACE(partial->bh, "call brelse"); brelse(partial->bh); partial--; } out: trace_ext4_ind_map_blocks_exit(inode, map->m_lblk, map->m_pblk, map->m_len, err); return err; } #ifdef CONFIG_QUOTA qsize_t *ext4_get_reserved_space(struct inode *inode) { return &EXT4_I(inode)->i_reserved_quota; } #endif /* * Calculate the number of metadata blocks need to reserve * to allocate a new block at @lblocks for non extent file based file */ static int ext4_indirect_calc_metadata_amount(struct inode *inode, sector_t lblock) { struct ext4_inode_info *ei = EXT4_I(inode); sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1); int blk_bits; if (lblock < EXT4_NDIR_BLOCKS) return 0; lblock -= EXT4_NDIR_BLOCKS; if (ei->i_da_metadata_calc_len && (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) { ei->i_da_metadata_calc_len++; return 0; } ei->i_da_metadata_calc_last_lblock = lblock & dind_mask; ei->i_da_metadata_calc_len = 1; blk_bits = order_base_2(lblock); return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1; } /* * Calculate the number of metadata blocks need to reserve * to allocate a block located at @lblock */ static int ext4_calc_metadata_amount(struct inode *inode, ext4_lblk_t lblock) { if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) return ext4_ext_calc_metadata_amount(inode, lblock); return ext4_indirect_calc_metadata_amount(inode, lblock); } /* * Called with i_data_sem down, which is important since we can call * ext4_discard_preallocations() from here. */ void ext4_da_update_reserve_space(struct inode *inode, int used, int quota_claim) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); struct ext4_inode_info *ei = EXT4_I(inode); spin_lock(&ei->i_block_reservation_lock); trace_ext4_da_update_reserve_space(inode, used); if (unlikely(used > ei->i_reserved_data_blocks)) { ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d " "with only %d reserved data blocks\n", __func__, inode->i_ino, used, ei->i_reserved_data_blocks); WARN_ON(1); used = ei->i_reserved_data_blocks; } /* Update per-inode reservations */ ei->i_reserved_data_blocks -= used; ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks; percpu_counter_sub(&sbi->s_dirtyblocks_counter, used + ei->i_allocated_meta_blocks); ei->i_allocated_meta_blocks = 0; if (ei->i_reserved_data_blocks == 0) { /* * We can release all of the reserved metadata blocks * only when we have written all of the delayed * allocation blocks. */ percpu_counter_sub(&sbi->s_dirtyblocks_counter, ei->i_reserved_meta_blocks); ei->i_reserved_meta_blocks = 0; ei->i_da_metadata_calc_len = 0; } spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); /* Update quota subsystem for data blocks */ if (quota_claim) dquot_claim_block(inode, used); else { /* * We did fallocate with an offset that is already delayed * allocated. So on delayed allocated writeback we should * not re-claim the quota for fallocated blocks. */ dquot_release_reservation_block(inode, used); } /* * If we have done all the pending block allocations and if * there aren't any writers on the inode, we can discard the * inode's preallocations. */ if ((ei->i_reserved_data_blocks == 0) && (atomic_read(&inode->i_writecount) == 0)) ext4_discard_preallocations(inode); } static int __check_block_validity(struct inode *inode, const char *func, unsigned int line, struct ext4_map_blocks *map) { if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk, map->m_len)) { ext4_error_inode(inode, func, line, map->m_pblk, "lblock %lu mapped to illegal pblock " "(length %d)", (unsigned long) map->m_lblk, map->m_len); return -EIO; } return 0; } #define check_block_validity(inode, map) \ __check_block_validity((inode), __func__, __LINE__, (map)) /* * Return the number of contiguous dirty pages in a given inode * starting at page frame idx. */ static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx, unsigned int max_pages) { struct address_space *mapping = inode->i_mapping; pgoff_t index; struct pagevec pvec; pgoff_t num = 0; int i, nr_pages, done = 0; if (max_pages == 0) return 0; pagevec_init(&pvec, 0); while (!done) { index = idx; nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_DIRTY, (pgoff_t)PAGEVEC_SIZE); if (nr_pages == 0) break; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; struct buffer_head *bh, *head; lock_page(page); if (unlikely(page->mapping != mapping) || !PageDirty(page) || PageWriteback(page) || page->index != idx) { done = 1; unlock_page(page); break; } if (page_has_buffers(page)) { bh = head = page_buffers(page); do { if (!buffer_delay(bh) && !buffer_unwritten(bh)) done = 1; bh = bh->b_this_page; } while (!done && (bh != head)); } unlock_page(page); if (done) break; idx++; num++; if (num >= max_pages) { done = 1; break; } } pagevec_release(&pvec); } return num; } /* * The ext4_map_blocks() function tries to look up the requested blocks, * and returns if the blocks are already mapped. * * Otherwise it takes the write lock of the i_data_sem and allocate blocks * and store the allocated blocks in the result buffer head and mark it * mapped. * * If file type is extents based, it will call ext4_ext_map_blocks(), * Otherwise, call with ext4_ind_map_blocks() to handle indirect mapping * based files * * On success, it returns the number of blocks being mapped or allocate. * if create==0 and the blocks are pre-allocated and uninitialized block, * the result buffer head is unmapped. If the create ==1, it will make sure * the buffer head is mapped. * * It returns 0 if plain look up failed (blocks have not been allocated), in * that casem, buffer head is unmapped * * It returns the error in case of allocation failure. */ int ext4_map_blocks(handle_t *handle, struct inode *inode, struct ext4_map_blocks *map, int flags) { int retval; map->m_flags = 0; ext_debug("ext4_map_blocks(): inode %lu, flag %d, max_blocks %u," "logical block %lu\n", inode->i_ino, flags, map->m_len, (unsigned long) map->m_lblk); /* * Try to see if we can get the block without requesting a new * file system block. */ down_read((&EXT4_I(inode)->i_data_sem)); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { retval = ext4_ext_map_blocks(handle, inode, map, 0); } else { retval = ext4_ind_map_blocks(handle, inode, map, 0); } up_read((&EXT4_I(inode)->i_data_sem)); if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { int ret = check_block_validity(inode, map); if (ret != 0) return ret; } /* If it is only a block(s) look up */ if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) return retval; /* * Returns if the blocks have already allocated * * Note that if blocks have been preallocated * ext4_ext_get_block() returns th create = 0 * with buffer head unmapped. */ if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) return retval; /* * When we call get_blocks without the create flag, the * BH_Unwritten flag could have gotten set if the blocks * requested were part of a uninitialized extent. We need to * clear this flag now that we are committed to convert all or * part of the uninitialized extent to be an initialized * extent. This is because we need to avoid the combination * of BH_Unwritten and BH_Mapped flags being simultaneously * set on the buffer_head. */ map->m_flags &= ~EXT4_MAP_UNWRITTEN; /* * New blocks allocate and/or writing to uninitialized extent * will possibly result in updating i_data, so we take * the write lock of i_data_sem, and call get_blocks() * with create == 1 flag. */ down_write((&EXT4_I(inode)->i_data_sem)); /* * if the caller is from delayed allocation writeout path * we have already reserved fs blocks for allocation * let the underlying get_block() function know to * avoid double accounting */ if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) ext4_set_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED); /* * We need to check for EXT4 here because migrate * could have changed the inode type in between */ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { retval = ext4_ext_map_blocks(handle, inode, map, flags); } else { retval = ext4_ind_map_blocks(handle, inode, map, flags); if (retval > 0 && map->m_flags & EXT4_MAP_NEW) { /* * We allocated new blocks which will result in * i_data's format changing. Force the migrate * to fail by clearing migrate flags */ ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE); } /* * Update reserved blocks/metadata blocks after successful * block allocation which had been deferred till now. We don't * support fallocate for non extent files. So we can update * reserve space here. */ if ((retval > 0) && (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)) ext4_da_update_reserve_space(inode, retval, 1); } if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED); up_write((&EXT4_I(inode)->i_data_sem)); if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) { int ret = check_block_validity(inode, map); if (ret != 0) return ret; } return retval; } /* Maximum number of blocks we map for direct IO at once. */ #define DIO_MAX_BLOCKS 4096 static int _ext4_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh, int flags) { handle_t *handle = ext4_journal_current_handle(); struct ext4_map_blocks map; int ret = 0, started = 0; int dio_credits; map.m_lblk = iblock; map.m_len = bh->b_size >> inode->i_blkbits; if (flags && !handle) { /* Direct IO write... */ if (map.m_len > DIO_MAX_BLOCKS) map.m_len = DIO_MAX_BLOCKS; dio_credits = ext4_chunk_trans_blocks(inode, map.m_len); handle = ext4_journal_start(inode, dio_credits); if (IS_ERR(handle)) { ret = PTR_ERR(handle); return ret; } started = 1; } ret = ext4_map_blocks(handle, inode, &map, flags); if (ret > 0) { map_bh(bh, inode->i_sb, map.m_pblk); bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags; bh->b_size = inode->i_sb->s_blocksize * map.m_len; ret = 0; } if (started) ext4_journal_stop(handle); return ret; } int ext4_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh, int create) { return _ext4_get_block(inode, iblock, bh, create ? EXT4_GET_BLOCKS_CREATE : 0); } /* * `handle' can be NULL if create is zero */ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode, ext4_lblk_t block, int create, int *errp) { struct ext4_map_blocks map; struct buffer_head *bh; int fatal = 0, err; J_ASSERT(handle != NULL || create == 0); map.m_lblk = block; map.m_len = 1; err = ext4_map_blocks(handle, inode, &map, create ? EXT4_GET_BLOCKS_CREATE : 0); if (err < 0) *errp = err; if (err <= 0) return NULL; *errp = 0; bh = sb_getblk(inode->i_sb, map.m_pblk); if (!bh) { *errp = -EIO; return NULL; } if (map.m_flags & EXT4_MAP_NEW) { J_ASSERT(create != 0); J_ASSERT(handle != NULL); /* * Now that we do not always journal data, we should * keep in mind whether this should always journal the * new buffer as metadata. For now, regular file * writes use ext4_get_block instead, so it's not a * problem. */ lock_buffer(bh); BUFFER_TRACE(bh, "call get_create_access"); fatal = ext4_journal_get_create_access(handle, bh); if (!fatal && !buffer_uptodate(bh)) { memset(bh->b_data, 0, inode->i_sb->s_blocksize); set_buffer_uptodate(bh); } unlock_buffer(bh); BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); err = ext4_handle_dirty_metadata(handle, inode, bh); if (!fatal) fatal = err; } else { BUFFER_TRACE(bh, "not a new buffer"); } if (fatal) { *errp = fatal; brelse(bh); bh = NULL; } return bh; } struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode, ext4_lblk_t block, int create, int *err) { struct buffer_head *bh; bh = ext4_getblk(handle, inode, block, create, err); if (!bh) return bh; if (buffer_uptodate(bh)) return bh; ll_rw_block(READ_META, 1, &bh); wait_on_buffer(bh); if (buffer_uptodate(bh)) return bh; put_bh(bh); *err = -EIO; return NULL; } static int walk_page_buffers(handle_t *handle, struct buffer_head *head, unsigned from, unsigned to, int *partial, int (*fn)(handle_t *handle, struct buffer_head *bh)) { struct buffer_head *bh; unsigned block_start, block_end; unsigned blocksize = head->b_size; int err, ret = 0; struct buffer_head *next; for (bh = head, block_start = 0; ret == 0 && (bh != head || !block_start); block_start = block_end, bh = next) { next = bh->b_this_page; block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { if (partial && !buffer_uptodate(bh)) *partial = 1; continue; } err = (*fn)(handle, bh); if (!ret) ret = err; } return ret; } /* * To preserve ordering, it is essential that the hole instantiation and * the data write be encapsulated in a single transaction. We cannot * close off a transaction and start a new one between the ext4_get_block() * and the commit_write(). So doing the jbd2_journal_start at the start of * prepare_write() is the right place. * * Also, this function can nest inside ext4_writepage() -> * block_write_full_page(). In that case, we *know* that ext4_writepage() * has generated enough buffer credits to do the whole page. So we won't * block on the journal in that case, which is good, because the caller may * be PF_MEMALLOC. * * By accident, ext4 can be reentered when a transaction is open via * quota file writes. If we were to commit the transaction while thus * reentered, there can be a deadlock - we would be holding a quota * lock, and the commit would never complete if another thread had a * transaction open and was blocking on the quota lock - a ranking * violation. * * So what we do is to rely on the fact that jbd2_journal_stop/journal_start * will _not_ run commit under these circumstances because handle->h_ref * is elevated. We'll still have enough credits for the tiny quotafile * write. */ static int do_journal_get_write_access(handle_t *handle, struct buffer_head *bh) { int dirty = buffer_dirty(bh); int ret; if (!buffer_mapped(bh) || buffer_freed(bh)) return 0; /* * __block_write_begin() could have dirtied some buffers. Clean * the dirty bit as jbd2_journal_get_write_access() could complain * otherwise about fs integrity issues. Setting of the dirty bit * by __block_write_begin() isn't a real problem here as we clear * the bit before releasing a page lock and thus writeback cannot * ever write the buffer. */ if (dirty) clear_buffer_dirty(bh); ret = ext4_journal_get_write_access(handle, bh); if (!ret && dirty) ret = ext4_handle_dirty_metadata(handle, NULL, bh); return ret; } /* * Truncate blocks that were not used by write. We have to truncate the * pagecache as well so that corresponding buffers get properly unmapped. */ static void ext4_truncate_failed_write(struct inode *inode) { truncate_inode_pages(inode->i_mapping, inode->i_size); ext4_truncate(inode); } static int ext4_get_block_write(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create); static int ext4_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { struct inode *inode = mapping->host; int ret, needed_blocks; handle_t *handle; int retries = 0; struct page *page; pgoff_t index; unsigned from, to; trace_ext4_write_begin(inode, pos, len, flags); /* * Reserve one block more for addition to orphan list in case * we allocate blocks but write fails for some reason */ needed_blocks = ext4_writepage_trans_blocks(inode) + 1; index = pos >> PAGE_CACHE_SHIFT; from = pos & (PAGE_CACHE_SIZE - 1); to = from + len; retry: handle = ext4_journal_start(inode, needed_blocks); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } /* We cannot recurse into the filesystem as the transaction is already * started */ flags |= AOP_FLAG_NOFS; page = grab_cache_page_write_begin(mapping, index, flags); if (!page) { ext4_journal_stop(handle); ret = -ENOMEM; goto out; } *pagep = page; if (ext4_should_dioread_nolock(inode)) ret = __block_write_begin(page, pos, len, ext4_get_block_write); else ret = __block_write_begin(page, pos, len, ext4_get_block); if (!ret && ext4_should_journal_data(inode)) { ret = walk_page_buffers(handle, page_buffers(page), from, to, NULL, do_journal_get_write_access); } if (ret) { unlock_page(page); page_cache_release(page); /* * __block_write_begin may have instantiated a few blocks * outside i_size. Trim these off again. Don't need * i_size_read because we hold i_mutex. * * Add inode to orphan list in case we crash before * truncate finishes */ if (pos + len > inode->i_size && ext4_can_truncate(inode)) ext4_orphan_add(handle, inode); ext4_journal_stop(handle); if (pos + len > inode->i_size) { ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might * still be on the orphan list; we need to * make sure the inode is removed from the * orphan list in that case. */ if (inode->i_nlink) ext4_orphan_del(NULL, inode); } } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; out: return ret; } /* For write_end() in data=journal mode */ static int write_end_fn(handle_t *handle, struct buffer_head *bh) { if (!buffer_mapped(bh) || buffer_freed(bh)) return 0; set_buffer_uptodate(bh); return ext4_handle_dirty_metadata(handle, NULL, bh); } static int ext4_generic_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { int i_size_changed = 0; struct inode *inode = mapping->host; handle_t *handle = ext4_journal_current_handle(); copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); /* * No need to use i_size_read() here, the i_size * cannot change under us because we hold i_mutex. * * But it's important to update i_size while still holding page lock: * page writeout could otherwise come in and zero beyond i_size. */ if (pos + copied > inode->i_size) { i_size_write(inode, pos + copied); i_size_changed = 1; } if (pos + copied > EXT4_I(inode)->i_disksize) { /* We need to mark inode dirty even if * new_i_size is less that inode->i_size * bu greater than i_disksize.(hint delalloc) */ ext4_update_i_disksize(inode, (pos + copied)); i_size_changed = 1; } unlock_page(page); page_cache_release(page); /* * Don't mark the inode dirty under page lock. First, it unnecessarily * makes the holding time of page lock longer. Second, it forces lock * ordering of page lock and transaction start for journaling * filesystems. */ if (i_size_changed) ext4_mark_inode_dirty(handle, inode); return copied; } /* * We need to pick up the new inode size which generic_commit_write gave us * `file' can be NULL - eg, when called from page_symlink(). * * ext4 never places buffers on inode->i_mapping->private_list. metadata * buffers are managed internally. */ static int ext4_ordered_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = mapping->host; int ret = 0, ret2; trace_ext4_ordered_write_end(inode, pos, len, copied); ret = ext4_jbd2_file_inode(handle, inode); if (ret == 0) { ret2 = ext4_generic_write_end(file, mapping, pos, len, copied, page, fsdata); copied = ret2; if (pos + len > inode->i_size && ext4_can_truncate(inode)) /* if we have allocated more blocks and copied * less. We will have blocks allocated outside * inode->i_size. So truncate them */ ext4_orphan_add(handle, inode); if (ret2 < 0) ret = ret2; } ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; if (pos + len > inode->i_size) { ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be * on the orphan list; we need to make sure the inode * is removed from the orphan list in that case. */ if (inode->i_nlink) ext4_orphan_del(NULL, inode); } return ret ? ret : copied; } static int ext4_writeback_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = mapping->host; int ret = 0, ret2; trace_ext4_writeback_write_end(inode, pos, len, copied); ret2 = ext4_generic_write_end(file, mapping, pos, len, copied, page, fsdata); copied = ret2; if (pos + len > inode->i_size && ext4_can_truncate(inode)) /* if we have allocated more blocks and copied * less. We will have blocks allocated outside * inode->i_size. So truncate them */ ext4_orphan_add(handle, inode); if (ret2 < 0) ret = ret2; ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; if (pos + len > inode->i_size) { ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be * on the orphan list; we need to make sure the inode * is removed from the orphan list in that case. */ if (inode->i_nlink) ext4_orphan_del(NULL, inode); } return ret ? ret : copied; } static int ext4_journalled_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = mapping->host; int ret = 0, ret2; int partial = 0; unsigned from, to; loff_t new_i_size; trace_ext4_journalled_write_end(inode, pos, len, copied); from = pos & (PAGE_CACHE_SIZE - 1); to = from + len; if (copied < len) { if (!PageUptodate(page)) copied = 0; page_zero_new_buffers(page, from+copied, to); } ret = walk_page_buffers(handle, page_buffers(page), from, to, &partial, write_end_fn); if (!partial) SetPageUptodate(page); new_i_size = pos + copied; if (new_i_size > inode->i_size) i_size_write(inode, pos+copied); ext4_set_inode_state(inode, EXT4_STATE_JDATA); if (new_i_size > EXT4_I(inode)->i_disksize) { ext4_update_i_disksize(inode, new_i_size); ret2 = ext4_mark_inode_dirty(handle, inode); if (!ret) ret = ret2; } unlock_page(page); page_cache_release(page); if (pos + len > inode->i_size && ext4_can_truncate(inode)) /* if we have allocated more blocks and copied * less. We will have blocks allocated outside * inode->i_size. So truncate them */ ext4_orphan_add(handle, inode); ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; if (pos + len > inode->i_size) { ext4_truncate_failed_write(inode); /* * If truncate failed early the inode might still be * on the orphan list; we need to make sure the inode * is removed from the orphan list in that case. */ if (inode->i_nlink) ext4_orphan_del(NULL, inode); } return ret ? ret : copied; } /* * Reserve a single block located at lblock */ static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock) { int retries = 0; struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); struct ext4_inode_info *ei = EXT4_I(inode); unsigned long md_needed; int ret; /* * recalculate the amount of metadata blocks to reserve * in order to allocate nrblocks * worse case is one extent per block */ repeat: spin_lock(&ei->i_block_reservation_lock); md_needed = ext4_calc_metadata_amount(inode, lblock); trace_ext4_da_reserve_space(inode, md_needed); spin_unlock(&ei->i_block_reservation_lock); /* * We will charge metadata quota at writeout time; this saves * us from metadata over-estimation, though we may go over by * a small amount in the end. Here we just reserve for data. */ ret = dquot_reserve_block(inode, 1); if (ret) return ret; /* * We do still charge estimated metadata to the sb though; * we cannot afford to run out of free blocks. */ if (ext4_claim_free_blocks(sbi, md_needed + 1)) { dquot_release_reservation_block(inode, 1); if (ext4_should_retry_alloc(inode->i_sb, &retries)) { yield(); goto repeat; } return -ENOSPC; } spin_lock(&ei->i_block_reservation_lock); ei->i_reserved_data_blocks++; ei->i_reserved_meta_blocks += md_needed; spin_unlock(&ei->i_block_reservation_lock); return 0; /* success */ } static void ext4_da_release_space(struct inode *inode, int to_free) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); struct ext4_inode_info *ei = EXT4_I(inode); if (!to_free) return; /* Nothing to release, exit */ spin_lock(&EXT4_I(inode)->i_block_reservation_lock); trace_ext4_da_release_space(inode, to_free); if (unlikely(to_free > ei->i_reserved_data_blocks)) { /* * if there aren't enough reserved blocks, then the * counter is messed up somewhere. Since this * function is called from invalidate page, it's * harmless to return without any action. */ ext4_msg(inode->i_sb, KERN_NOTICE, "ext4_da_release_space: " "ino %lu, to_free %d with only %d reserved " "data blocks\n", inode->i_ino, to_free, ei->i_reserved_data_blocks); WARN_ON(1); to_free = ei->i_reserved_data_blocks; } ei->i_reserved_data_blocks -= to_free; if (ei->i_reserved_data_blocks == 0) { /* * We can release all of the reserved metadata blocks * only when we have written all of the delayed * allocation blocks. */ percpu_counter_sub(&sbi->s_dirtyblocks_counter, ei->i_reserved_meta_blocks); ei->i_reserved_meta_blocks = 0; ei->i_da_metadata_calc_len = 0; } /* update fs dirty data blocks counter */ percpu_counter_sub(&sbi->s_dirtyblocks_counter, to_free); spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); dquot_release_reservation_block(inode, to_free); } static void ext4_da_page_release_reservation(struct page *page, unsigned long offset) { int to_release = 0; struct buffer_head *head, *bh; unsigned int curr_off = 0; head = page_buffers(page); bh = head; do { unsigned int next_off = curr_off + bh->b_size; if ((offset <= curr_off) && (buffer_delay(bh))) { to_release++; clear_buffer_delay(bh); } curr_off = next_off; } while ((bh = bh->b_this_page) != head); ext4_da_release_space(page->mapping->host, to_release); } /* * Delayed allocation stuff */ /* * mpage_da_submit_io - walks through extent of pages and try to write * them with writepage() call back * * @mpd->inode: inode * @mpd->first_page: first page of the extent * @mpd->next_page: page after the last page of the extent * * By the time mpage_da_submit_io() is called we expect all blocks * to be allocated. this may be wrong if allocation failed. * * As pages are already locked by write_cache_pages(), we can't use it */ static int mpage_da_submit_io(struct mpage_da_data *mpd, struct ext4_map_blocks *map) { struct pagevec pvec; unsigned long index, end; int ret = 0, err, nr_pages, i; struct inode *inode = mpd->inode; struct address_space *mapping = inode->i_mapping; loff_t size = i_size_read(inode); unsigned int len, block_start; struct buffer_head *bh, *page_bufs = NULL; int journal_data = ext4_should_journal_data(inode); sector_t pblock = 0, cur_logical = 0; struct ext4_io_submit io_submit; BUG_ON(mpd->next_page <= mpd->first_page); memset(&io_submit, 0, sizeof(io_submit)); /* * We need to start from the first_page to the next_page - 1 * to make sure we also write the mapped dirty buffer_heads. * If we look at mpd->b_blocknr we would only be looking * at the currently mapped buffer_heads. */ index = mpd->first_page; end = mpd->next_page - 1; pagevec_init(&pvec, 0); while (index <= end) { nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); if (nr_pages == 0) break; for (i = 0; i < nr_pages; i++) { int commit_write = 0, skip_page = 0; struct page *page = pvec.pages[i]; index = page->index; if (index > end) break; if (index == size >> PAGE_CACHE_SHIFT) len = size & ~PAGE_CACHE_MASK; else len = PAGE_CACHE_SIZE; if (map) { cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); pblock = map->m_pblk + (cur_logical - map->m_lblk); } index++; BUG_ON(!PageLocked(page)); BUG_ON(PageWriteback(page)); /* * If the page does not have buffers (for * whatever reason), try to create them using * __block_write_begin. If this fails, * skip the page and move on. */ if (!page_has_buffers(page)) { if (__block_write_begin(page, 0, len, noalloc_get_block_write)) { skip_page: unlock_page(page); continue; } commit_write = 1; } bh = page_bufs = page_buffers(page); block_start = 0; do { if (!bh) goto skip_page; if (map && (cur_logical >= map->m_lblk) && (cur_logical <= (map->m_lblk + (map->m_len - 1)))) { if (buffer_delay(bh)) { clear_buffer_delay(bh); bh->b_blocknr = pblock; } if (buffer_unwritten(bh) || buffer_mapped(bh)) BUG_ON(bh->b_blocknr != pblock); if (map->m_flags & EXT4_MAP_UNINIT) set_buffer_uninit(bh); clear_buffer_unwritten(bh); } /* skip page if block allocation undone */ if (buffer_delay(bh) || buffer_unwritten(bh)) skip_page = 1; bh = bh->b_this_page; block_start += bh->b_size; cur_logical++; pblock++; } while (bh != page_bufs); if (skip_page) goto skip_page; if (commit_write) /* mark the buffer_heads as dirty & uptodate */ block_commit_write(page, 0, len); clear_page_dirty_for_io(page); /* * Delalloc doesn't support data journalling, * but eventually maybe we'll lift this * restriction. */ if (unlikely(journal_data && PageChecked(page))) err = __ext4_journalled_writepage(page, len); else if (test_opt(inode->i_sb, MBLK_IO_SUBMIT)) err = ext4_bio_write_page(&io_submit, page, len, mpd->wbc); else err = block_write_full_page(page, noalloc_get_block_write, mpd->wbc); if (!err) mpd->pages_written++; /* * In error case, we have to continue because * remaining pages are still locked */ if (ret == 0) ret = err; } pagevec_release(&pvec); } ext4_io_submit(&io_submit); return ret; } static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd) { int nr_pages, i; pgoff_t index, end; struct pagevec pvec; struct inode *inode = mpd->inode; struct address_space *mapping = inode->i_mapping; index = mpd->first_page; end = mpd->next_page - 1; while (index <= end) { nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); if (nr_pages == 0) break; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; if (page->index > end) break; BUG_ON(!PageLocked(page)); BUG_ON(PageWriteback(page)); block_invalidatepage(page, 0); ClearPageUptodate(page); unlock_page(page); } index = pvec.pages[nr_pages - 1]->index + 1; pagevec_release(&pvec); } return; } static void ext4_print_free_blocks(struct inode *inode) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); printk(KERN_CRIT "Total free blocks count %lld\n", ext4_count_free_blocks(inode->i_sb)); printk(KERN_CRIT "Free/Dirty block details\n"); printk(KERN_CRIT "free_blocks=%lld\n", (long long) percpu_counter_sum(&sbi->s_freeblocks_counter)); printk(KERN_CRIT "dirty_blocks=%lld\n", (long long) percpu_counter_sum(&sbi->s_dirtyblocks_counter)); printk(KERN_CRIT "Block reservation details\n"); printk(KERN_CRIT "i_reserved_data_blocks=%u\n", EXT4_I(inode)->i_reserved_data_blocks); printk(KERN_CRIT "i_reserved_meta_blocks=%u\n", EXT4_I(inode)->i_reserved_meta_blocks); return; } /* * mpage_da_map_and_submit - go through given space, map them * if necessary, and then submit them for I/O * * @mpd - bh describing space * * The function skips space we know is already mapped to disk blocks. * */ static void mpage_da_map_and_submit(struct mpage_da_data *mpd) { int err, blks, get_blocks_flags; struct ext4_map_blocks map, *mapp = NULL; sector_t next = mpd->b_blocknr; unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits; loff_t disksize = EXT4_I(mpd->inode)->i_disksize; handle_t *handle = NULL; /* * If the blocks are mapped already, or we couldn't accumulate * any blocks, then proceed immediately to the submission stage. */ if ((mpd->b_size == 0) || ((mpd->b_state & (1 << BH_Mapped)) && !(mpd->b_state & (1 << BH_Delay)) && !(mpd->b_state & (1 << BH_Unwritten)))) goto submit_io; handle = ext4_journal_current_handle(); BUG_ON(!handle); /* * Call ext4_map_blocks() to allocate any delayed allocation * blocks, or to convert an uninitialized extent to be * initialized (in the case where we have written into * one or more preallocated blocks). * * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to * indicate that we are on the delayed allocation path. This * affects functions in many different parts of the allocation * call path. This flag exists primarily because we don't * want to change *many* call functions, so ext4_map_blocks() * will set the EXT4_STATE_DELALLOC_RESERVED flag once the * inode's allocation semaphore is taken. * * If the blocks in questions were delalloc blocks, set * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting * variables are updated after the blocks have been allocated. */ map.m_lblk = next; map.m_len = max_blocks; get_blocks_flags = EXT4_GET_BLOCKS_CREATE; if (ext4_should_dioread_nolock(mpd->inode)) get_blocks_flags |= EXT4_GET_BLOCKS_IO_CREATE_EXT; if (mpd->b_state & (1 << BH_Delay)) get_blocks_flags |= EXT4_GET_BLOCKS_DELALLOC_RESERVE; blks = ext4_map_blocks(handle, mpd->inode, &map, get_blocks_flags); if (blks < 0) { struct super_block *sb = mpd->inode->i_sb; err = blks; /* * If get block returns EAGAIN or ENOSPC and there * appears to be free blocks we will just let * mpage_da_submit_io() unlock all of the pages. */ if (err == -EAGAIN) goto submit_io; if (err == -ENOSPC && ext4_count_free_blocks(sb)) { mpd->retval = err; goto submit_io; } /* * get block failure will cause us to loop in * writepages, because a_ops->writepage won't be able * to make progress. The page will be redirtied by * writepage and writepages will again try to write * the same. */ if (!(EXT4_SB(sb)->s_mount_flags & EXT4_MF_FS_ABORTED)) { ext4_msg(sb, KERN_CRIT, "delayed block allocation failed for inode %lu " "at logical offset %llu with max blocks %zd " "with error %d", mpd->inode->i_ino, (unsigned long long) next, mpd->b_size >> mpd->inode->i_blkbits, err); ext4_msg(sb, KERN_CRIT, "This should not happen!! Data will be lost\n"); if (err == -ENOSPC) ext4_print_free_blocks(mpd->inode); } /* invalidate all the pages */ ext4_da_block_invalidatepages(mpd); /* Mark this page range as having been completed */ mpd->io_done = 1; return; } BUG_ON(blks == 0); mapp = ↦ if (map.m_flags & EXT4_MAP_NEW) { struct block_device *bdev = mpd->inode->i_sb->s_bdev; int i; for (i = 0; i < map.m_len; i++) unmap_underlying_metadata(bdev, map.m_pblk + i); } if (ext4_should_order_data(mpd->inode)) { err = ext4_jbd2_file_inode(handle, mpd->inode); if (err) /* This only happens if the journal is aborted */ return; } /* * Update on-disk size along with block allocation. */ disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits; if (disksize > i_size_read(mpd->inode)) disksize = i_size_read(mpd->inode); if (disksize > EXT4_I(mpd->inode)->i_disksize) { ext4_update_i_disksize(mpd->inode, disksize); err = ext4_mark_inode_dirty(handle, mpd->inode); if (err) ext4_error(mpd->inode->i_sb, "Failed to mark inode %lu dirty", mpd->inode->i_ino); } submit_io: mpage_da_submit_io(mpd, mapp); mpd->io_done = 1; } #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \ (1 << BH_Delay) | (1 << BH_Unwritten)) /* * mpage_add_bh_to_extent - try to add one more block to extent of blocks * * @mpd->lbh - extent of blocks * @logical - logical number of the block in the file * @bh - bh of the block (used to access block's state) * * the function is used to collect contig. blocks in same state */ static void mpage_add_bh_to_extent(struct mpage_da_data *mpd, sector_t logical, size_t b_size, unsigned long b_state) { sector_t next; int nrblocks = mpd->b_size >> mpd->inode->i_blkbits; /* * XXX Don't go larger than mballoc is willing to allocate * This is a stopgap solution. We eventually need to fold * mpage_da_submit_io() into this function and then call * ext4_map_blocks() multiple times in a loop */ if (nrblocks >= 8*1024*1024/mpd->inode->i_sb->s_blocksize) goto flush_it; /* check if thereserved journal credits might overflow */ if (!(ext4_test_inode_flag(mpd->inode, EXT4_INODE_EXTENTS))) { if (nrblocks >= EXT4_MAX_TRANS_DATA) { /* * With non-extent format we are limited by the journal * credit available. Total credit needed to insert * nrblocks contiguous blocks is dependent on the * nrblocks. So limit nrblocks. */ goto flush_it; } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) > EXT4_MAX_TRANS_DATA) { /* * Adding the new buffer_head would make it cross the * allowed limit for which we have journal credit * reserved. So limit the new bh->b_size */ b_size = (EXT4_MAX_TRANS_DATA - nrblocks) << mpd->inode->i_blkbits; /* we will do mpage_da_submit_io in the next loop */ } } /* * First block in the extent */ if (mpd->b_size == 0) { mpd->b_blocknr = logical; mpd->b_size = b_size; mpd->b_state = b_state & BH_FLAGS; return; } next = mpd->b_blocknr + nrblocks; /* * Can we merge the block to our big extent? */ if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) { mpd->b_size += b_size; return; } flush_it: /* * We couldn't merge the block to our extent, so we * need to flush current extent and start new one */ mpage_da_map_and_submit(mpd); return; } static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh) { return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh); } /* * This is a special get_blocks_t callback which is used by * ext4_da_write_begin(). It will either return mapped block or * reserve space for a single block. * * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set. * We also have b_blocknr = -1 and b_bdev initialized properly * * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set. * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev * initialized properly. */ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock, struct buffer_head *bh, int create) { struct ext4_map_blocks map; int ret = 0; sector_t invalid_block = ~((sector_t) 0xffff); if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es)) invalid_block = ~0; BUG_ON(create == 0); BUG_ON(bh->b_size != inode->i_sb->s_blocksize); map.m_lblk = iblock; map.m_len = 1; /* * first, we need to know whether the block is allocated already * preallocated blocks are unmapped but should treated * the same as allocated blocks. */ ret = ext4_map_blocks(NULL, inode, &map, 0); if (ret < 0) return ret; if (ret == 0) { if (buffer_delay(bh)) return 0; /* Not sure this could or should happen */ /* * XXX: __block_write_begin() unmaps passed block, is it OK? */ ret = ext4_da_reserve_space(inode, iblock); if (ret) /* not enough space to reserve */ return ret; map_bh(bh, inode->i_sb, invalid_block); set_buffer_new(bh); set_buffer_delay(bh); return 0; } map_bh(bh, inode->i_sb, map.m_pblk); bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags; if (buffer_unwritten(bh)) { /* A delayed write to unwritten bh should be marked * new and mapped. Mapped ensures that we don't do * get_block multiple times when we write to the same * offset and new ensures that we do proper zero out * for partial write. */ set_buffer_new(bh); set_buffer_mapped(bh); } return 0; } /* * This function is used as a standard get_block_t calback function * when there is no desire to allocate any blocks. It is used as a * callback function for block_write_begin() and block_write_full_page(). * These functions should only try to map a single block at a time. * * Since this function doesn't do block allocations even if the caller * requests it by passing in create=1, it is critically important that * any caller checks to make sure that any buffer heads are returned * by this function are either all already mapped or marked for * delayed allocation before calling block_write_full_page(). Otherwise, * b_blocknr could be left unitialized, and the page write functions will * be taken by surprise. */ static int noalloc_get_block_write(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize); return _ext4_get_block(inode, iblock, bh_result, 0); } static int bget_one(handle_t *handle, struct buffer_head *bh) { get_bh(bh); return 0; } static int bput_one(handle_t *handle, struct buffer_head *bh) { put_bh(bh); return 0; } static int __ext4_journalled_writepage(struct page *page, unsigned int len) { struct address_space *mapping = page->mapping; struct inode *inode = mapping->host; struct buffer_head *page_bufs; handle_t *handle = NULL; int ret = 0; int err; ClearPageChecked(page); page_bufs = page_buffers(page); BUG_ON(!page_bufs); walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one); /* As soon as we unlock the page, it can go away, but we have * references to buffers so we are safe */ unlock_page(page); handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } ret = walk_page_buffers(handle, page_bufs, 0, len, NULL, do_journal_get_write_access); err = walk_page_buffers(handle, page_bufs, 0, len, NULL, write_end_fn); if (ret == 0) ret = err; err = ext4_journal_stop(handle); if (!ret) ret = err; walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one); ext4_set_inode_state(inode, EXT4_STATE_JDATA); out: return ret; } static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode); static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate); /* * Note that we don't need to start a transaction unless we're journaling data * because we should have holes filled from ext4_page_mkwrite(). We even don't * need to file the inode to the transaction's list in ordered mode because if * we are writing back data added by write(), the inode is already there and if * we are writing back data modified via mmap(), no one guarantees in which * transaction the data will hit the disk. In case we are journaling data, we * cannot start transaction directly because transaction start ranks above page * lock so we have to do some magic. * * This function can get called via... * - ext4_da_writepages after taking page lock (have journal handle) * - journal_submit_inode_data_buffers (no journal handle) * - shrink_page_list via pdflush (no journal handle) * - grab_page_cache when doing write_begin (have journal handle) * * We don't do any block allocation in this function. If we have page with * multiple blocks we need to write those buffer_heads that are mapped. This * is important for mmaped based write. So if we do with blocksize 1K * truncate(f, 1024); * a = mmap(f, 0, 4096); * a[0] = 'a'; * truncate(f, 4096); * we have in the page first buffer_head mapped via page_mkwrite call back * but other bufer_heads would be unmapped but dirty(dirty done via the * do_wp_page). So writepage should write the first block. If we modify * the mmap area beyond 1024 we will again get a page_fault and the * page_mkwrite callback will do the block allocation and mark the * buffer_heads mapped. * * We redirty the page if we have any buffer_heads that is either delay or * unwritten in the page. * * We can get recursively called as show below. * * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() -> * ext4_writepage() * * But since we don't do any block allocation we should not deadlock. * Page also have the dirty flag cleared so we don't get recurive page_lock. */ static int ext4_writepage(struct page *page, struct writeback_control *wbc) { int ret = 0, commit_write = 0; loff_t size; unsigned int len; struct buffer_head *page_bufs = NULL; struct inode *inode = page->mapping->host; trace_ext4_writepage(inode, page); size = i_size_read(inode); if (page->index == size >> PAGE_CACHE_SHIFT) len = size & ~PAGE_CACHE_MASK; else len = PAGE_CACHE_SIZE; /* * If the page does not have buffers (for whatever reason), * try to create them using __block_write_begin. If this * fails, redirty the page and move on. */ if (!page_has_buffers(page)) { if (__block_write_begin(page, 0, len, noalloc_get_block_write)) { redirty_page: redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } commit_write = 1; } page_bufs = page_buffers(page); if (walk_page_buffers(NULL, page_bufs, 0, len, NULL, ext4_bh_delay_or_unwritten)) { /* * We don't want to do block allocation, so redirty * the page and return. We may reach here when we do * a journal commit via journal_submit_inode_data_buffers. * We can also reach here via shrink_page_list */ goto redirty_page; } if (commit_write) /* now mark the buffer_heads as dirty and uptodate */ block_commit_write(page, 0, len); if (PageChecked(page) && ext4_should_journal_data(inode)) /* * It's mmapped pagecache. Add buffers and journal it. There * doesn't seem much point in redirtying the page here. */ return __ext4_journalled_writepage(page, len); if (buffer_uninit(page_bufs)) { ext4_set_bh_endio(page_bufs, inode); ret = block_write_full_page_endio(page, noalloc_get_block_write, wbc, ext4_end_io_buffer_write); } else ret = block_write_full_page(page, noalloc_get_block_write, wbc); return ret; } /* * This is called via ext4_da_writepages() to * calculate the total number of credits to reserve to fit * a single extent allocation into a single transaction, * ext4_da_writpeages() will loop calling this before * the block allocation. */ static int ext4_da_writepages_trans_blocks(struct inode *inode) { int max_blocks = EXT4_I(inode)->i_reserved_data_blocks; /* * With non-extent format the journal credit needed to * insert nrblocks contiguous block is dependent on * number of contiguous block. So we will limit * number of contiguous block to a sane value */ if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) && (max_blocks > EXT4_MAX_TRANS_DATA)) max_blocks = EXT4_MAX_TRANS_DATA; return ext4_chunk_trans_blocks(inode, max_blocks); } /* * write_cache_pages_da - walk the list of dirty pages of the given * address space and accumulate pages that need writing, and call * mpage_da_map_and_submit to map a single contiguous memory region * and then write them. */ static int write_cache_pages_da(struct address_space *mapping, struct writeback_control *wbc, struct mpage_da_data *mpd, pgoff_t *done_index) { struct buffer_head *bh, *head; struct inode *inode = mapping->host; struct pagevec pvec; unsigned int nr_pages; sector_t logical; pgoff_t index, end; long nr_to_write = wbc->nr_to_write; int i, tag, ret = 0; memset(mpd, 0, sizeof(struct mpage_da_data)); mpd->wbc = wbc; mpd->inode = inode; pagevec_init(&pvec, 0); index = wbc->range_start >> PAGE_CACHE_SHIFT; end = wbc->range_end >> PAGE_CACHE_SHIFT; if (wbc->sync_mode == WB_SYNC_ALL) tag = PAGECACHE_TAG_TOWRITE; else tag = PAGECACHE_TAG_DIRTY; *done_index = index; while (index <= end) { nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag, min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1); if (nr_pages == 0) return 0; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; /* * At this point, the page may be truncated or * invalidated (changing page->mapping to NULL), or * even swizzled back from swapper_space to tmpfs file * mapping. However, page->index will not change * because we have a reference on the page. */ if (page->index > end) goto out; *done_index = page->index + 1; /* * If we can't merge this page, and we have * accumulated an contiguous region, write it */ if ((mpd->next_page != page->index) && (mpd->next_page != mpd->first_page)) { mpage_da_map_and_submit(mpd); goto ret_extent_tail; } lock_page(page); /* * If the page is no longer dirty, or its * mapping no longer corresponds to inode we * are writing (which means it has been * truncated or invalidated), or the page is * already under writeback and we are not * doing a data integrity writeback, skip the page */ if (!PageDirty(page) || (PageWriteback(page) && (wbc->sync_mode == WB_SYNC_NONE)) || unlikely(page->mapping != mapping)) { unlock_page(page); continue; } wait_on_page_writeback(page); BUG_ON(PageWriteback(page)); if (mpd->next_page != page->index) mpd->first_page = page->index; mpd->next_page = page->index + 1; logical = (sector_t) page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); if (!page_has_buffers(page)) { mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE, (1 << BH_Dirty) | (1 << BH_Uptodate)); if (mpd->io_done) goto ret_extent_tail; } else { /* * Page with regular buffer heads, * just add all dirty ones */ head = page_buffers(page); bh = head; do { BUG_ON(buffer_locked(bh)); /* * We need to try to allocate * unmapped blocks in the same page. * Otherwise we won't make progress * with the page in ext4_writepage */ if (ext4_bh_delay_or_unwritten(NULL, bh)) { mpage_add_bh_to_extent(mpd, logical, bh->b_size, bh->b_state); if (mpd->io_done) goto ret_extent_tail; } else if (buffer_dirty(bh) && (buffer_mapped(bh))) { /* * mapped dirty buffer. We need * to update the b_state * because we look at b_state * in mpage_da_map_blocks. We * don't update b_size because * if we find an unmapped * buffer_head later we need to * use the b_state flag of that * buffer_head. */ if (mpd->b_size == 0) mpd->b_state = bh->b_state & BH_FLAGS; } logical++; } while ((bh = bh->b_this_page) != head); } if (nr_to_write > 0) { nr_to_write--; if (nr_to_write == 0 && wbc->sync_mode == WB_SYNC_NONE) /* * We stop writing back only if we are * not doing integrity sync. In case of * integrity sync we have to keep going * because someone may be concurrently * dirtying pages, and we might have * synced a lot of newly appeared dirty * pages, but have not synced all of the * old dirty pages. */ goto out; } } pagevec_release(&pvec); cond_resched(); } return 0; ret_extent_tail: ret = MPAGE_DA_EXTENT_TAIL; out: pagevec_release(&pvec); cond_resched(); return ret; } static int ext4_da_writepages(struct address_space *mapping, struct writeback_control *wbc) { pgoff_t index; int range_whole = 0; handle_t *handle = NULL; struct mpage_da_data mpd; struct inode *inode = mapping->host; int pages_written = 0; unsigned int max_pages; int range_cyclic, cycled = 1, io_done = 0; int needed_blocks, ret = 0; long desired_nr_to_write, nr_to_writebump = 0; loff_t range_start = wbc->range_start; struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); pgoff_t done_index = 0; pgoff_t end; trace_ext4_da_writepages(inode, wbc); /* * No pages to write? This is mainly a kludge to avoid starting * a transaction for special inodes like journal inode on last iput() * because that could violate lock ordering on umount */ if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) return 0; /* * If the filesystem has aborted, it is read-only, so return * right away instead of dumping stack traces later on that * will obscure the real source of the problem. We test * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because * the latter could be true if the filesystem is mounted * read-only, and in that case, ext4_da_writepages should * *never* be called, so if that ever happens, we would want * the stack trace. */ if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) return -EROFS; if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) range_whole = 1; range_cyclic = wbc->range_cyclic; if (wbc->range_cyclic) { index = mapping->writeback_index; if (index) cycled = 0; wbc->range_start = index << PAGE_CACHE_SHIFT; wbc->range_end = LLONG_MAX; wbc->range_cyclic = 0; end = -1; } else { index = wbc->range_start >> PAGE_CACHE_SHIFT; end = wbc->range_end >> PAGE_CACHE_SHIFT; } /* * This works around two forms of stupidity. The first is in * the writeback code, which caps the maximum number of pages * written to be 1024 pages. This is wrong on multiple * levels; different architectues have a different page size, * which changes the maximum amount of data which gets * written. Secondly, 4 megabytes is way too small. XFS * forces this value to be 16 megabytes by multiplying * nr_to_write parameter by four, and then relies on its * allocator to allocate larger extents to make them * contiguous. Unfortunately this brings us to the second * stupidity, which is that ext4's mballoc code only allocates * at most 2048 blocks. So we force contiguous writes up to * the number of dirty blocks in the inode, or * sbi->max_writeback_mb_bump whichever is smaller. */ max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT); if (!range_cyclic && range_whole) { if (wbc->nr_to_write == LONG_MAX) desired_nr_to_write = wbc->nr_to_write; else desired_nr_to_write = wbc->nr_to_write * 8; } else desired_nr_to_write = ext4_num_dirty_pages(inode, index, max_pages); if (desired_nr_to_write > max_pages) desired_nr_to_write = max_pages; if (wbc->nr_to_write < desired_nr_to_write) { nr_to_writebump = desired_nr_to_write - wbc->nr_to_write; wbc->nr_to_write = desired_nr_to_write; } retry: if (wbc->sync_mode == WB_SYNC_ALL) tag_pages_for_writeback(mapping, index, end); while (!ret && wbc->nr_to_write > 0) { /* * we insert one extent at a time. So we need * credit needed for single extent allocation. * journalled mode is currently not supported * by delalloc */ BUG_ON(ext4_should_journal_data(inode)); needed_blocks = ext4_da_writepages_trans_blocks(inode); /* start a new transaction*/ handle = ext4_journal_start(inode, needed_blocks); if (IS_ERR(handle)) { ret = PTR_ERR(handle); ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: " "%ld pages, ino %lu; err %d", __func__, wbc->nr_to_write, inode->i_ino, ret); goto out_writepages; } /* * Now call write_cache_pages_da() to find the next * contiguous region of logical blocks that need * blocks to be allocated by ext4 and submit them. */ ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index); /* * If we have a contiguous extent of pages and we * haven't done the I/O yet, map the blocks and submit * them for I/O. */ if (!mpd.io_done && mpd.next_page != mpd.first_page) { mpage_da_map_and_submit(&mpd); ret = MPAGE_DA_EXTENT_TAIL; } trace_ext4_da_write_pages(inode, &mpd); wbc->nr_to_write -= mpd.pages_written; ext4_journal_stop(handle); if ((mpd.retval == -ENOSPC) && sbi->s_journal) { /* commit the transaction which would * free blocks released in the transaction * and try again */ jbd2_journal_force_commit_nested(sbi->s_journal); ret = 0; } else if (ret == MPAGE_DA_EXTENT_TAIL) { /* * got one extent now try with * rest of the pages */ pages_written += mpd.pages_written; ret = 0; io_done = 1; } else if (wbc->nr_to_write) /* * There is no more writeout needed * or we requested for a noblocking writeout * and we found the device congested */ break; } if (!io_done && !cycled) { cycled = 1; index = 0; wbc->range_start = index << PAGE_CACHE_SHIFT; wbc->range_end = mapping->writeback_index - 1; goto retry; } /* Update index */ wbc->range_cyclic = range_cyclic; if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) /* * set the writeback_index so that range_cyclic * mode will write it back later */ mapping->writeback_index = done_index; out_writepages: wbc->nr_to_write -= nr_to_writebump; wbc->range_start = range_start; trace_ext4_da_writepages_result(inode, wbc, ret, pages_written); return ret; } #define FALL_BACK_TO_NONDELALLOC 1 static int ext4_nonda_switch(struct super_block *sb) { s64 free_blocks, dirty_blocks; struct ext4_sb_info *sbi = EXT4_SB(sb); /* * switch to non delalloc mode if we are running low * on free block. The free block accounting via percpu * counters can get slightly wrong with percpu_counter_batch getting * accumulated on each CPU without updating global counters * Delalloc need an accurate free block accounting. So switch * to non delalloc when we are near to error range. */ free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter); dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter); if (2 * free_blocks < 3 * dirty_blocks || free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) { /* * free block count is less than 150% of dirty blocks * or free blocks is less than watermark */ return 1; } /* * Even if we don't switch but are nearing capacity, * start pushing delalloc when 1/2 of free blocks are dirty. */ if (free_blocks < 2 * dirty_blocks) writeback_inodes_sb_if_idle(sb); return 0; } static int ext4_da_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { int ret, retries = 0; struct page *page; pgoff_t index; struct inode *inode = mapping->host; handle_t *handle; index = pos >> PAGE_CACHE_SHIFT; if (ext4_nonda_switch(inode->i_sb)) { *fsdata = (void *)FALL_BACK_TO_NONDELALLOC; return ext4_write_begin(file, mapping, pos, len, flags, pagep, fsdata); } *fsdata = (void *)0; trace_ext4_da_write_begin(inode, pos, len, flags); retry: /* * With delayed allocation, we don't log the i_disksize update * if there is delayed block allocation. But we still need * to journalling the i_disksize update if writes to the end * of file which has an already mapped buffer. */ handle = ext4_journal_start(inode, 1); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } /* We cannot recurse into the filesystem as the transaction is already * started */ flags |= AOP_FLAG_NOFS; page = grab_cache_page_write_begin(mapping, index, flags); if (!page) { ext4_journal_stop(handle); ret = -ENOMEM; goto out; } *pagep = page; ret = __block_write_begin(page, pos, len, ext4_da_get_block_prep); if (ret < 0) { unlock_page(page); ext4_journal_stop(handle); page_cache_release(page); /* * block_write_begin may have instantiated a few blocks * outside i_size. Trim these off again. Don't need * i_size_read because we hold i_mutex. */ if (pos + len > inode->i_size) ext4_truncate_failed_write(inode); } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; out: return ret; } /* * Check if we should update i_disksize * when write to the end of file but not require block allocation */ static int ext4_da_should_update_i_disksize(struct page *page, unsigned long offset) { struct buffer_head *bh; struct inode *inode = page->mapping->host; unsigned int idx; int i; bh = page_buffers(page); idx = offset >> inode->i_blkbits; for (i = 0; i < idx; i++) bh = bh->b_this_page; if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh)) return 0; return 1; } static int ext4_da_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = mapping->host; int ret = 0, ret2; handle_t *handle = ext4_journal_current_handle(); loff_t new_i_size; unsigned long start, end; int write_mode = (int)(unsigned long)fsdata; if (write_mode == FALL_BACK_TO_NONDELALLOC) { if (ext4_should_order_data(inode)) { return ext4_ordered_write_end(file, mapping, pos, len, copied, page, fsdata); } else if (ext4_should_writeback_data(inode)) { return ext4_writeback_write_end(file, mapping, pos, len, copied, page, fsdata); } else { BUG(); } } trace_ext4_da_write_end(inode, pos, len, copied); start = pos & (PAGE_CACHE_SIZE - 1); end = start + copied - 1; /* * generic_write_end() will run mark_inode_dirty() if i_size * changes. So let's piggyback the i_disksize mark_inode_dirty * into that. */ new_i_size = pos + copied; if (new_i_size > EXT4_I(inode)->i_disksize) { if (ext4_da_should_update_i_disksize(page, end)) { down_write(&EXT4_I(inode)->i_data_sem); if (new_i_size > EXT4_I(inode)->i_disksize) { /* * Updating i_disksize when extending file * without needing block allocation */ if (ext4_should_order_data(inode)) ret = ext4_jbd2_file_inode(handle, inode); EXT4_I(inode)->i_disksize = new_i_size; } up_write(&EXT4_I(inode)->i_data_sem); /* We need to mark inode dirty even if * new_i_size is less that inode->i_size * bu greater than i_disksize.(hint delalloc) */ ext4_mark_inode_dirty(handle, inode); } } ret2 = generic_write_end(file, mapping, pos, len, copied, page, fsdata); copied = ret2; if (ret2 < 0) ret = ret2; ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; return ret ? ret : copied; } static void ext4_da_invalidatepage(struct page *page, unsigned long offset) { /* * Drop reserved blocks */ BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) goto out; ext4_da_page_release_reservation(page, offset); out: ext4_invalidatepage(page, offset); return; } /* * Force all delayed allocation blocks to be allocated for a given inode. */ int ext4_alloc_da_blocks(struct inode *inode) { trace_ext4_alloc_da_blocks(inode); if (!EXT4_I(inode)->i_reserved_data_blocks && !EXT4_I(inode)->i_reserved_meta_blocks) return 0; /* * We do something simple for now. The filemap_flush() will * also start triggering a write of the data blocks, which is * not strictly speaking necessary (and for users of * laptop_mode, not even desirable). However, to do otherwise * would require replicating code paths in: * * ext4_da_writepages() -> * write_cache_pages() ---> (via passed in callback function) * __mpage_da_writepage() --> * mpage_add_bh_to_extent() * mpage_da_map_blocks() * * The problem is that write_cache_pages(), located in * mm/page-writeback.c, marks pages clean in preparation for * doing I/O, which is not desirable if we're not planning on * doing I/O at all. * * We could call write_cache_pages(), and then redirty all of * the pages by calling redirty_page_for_writepage() but that * would be ugly in the extreme. So instead we would need to * replicate parts of the code in the above functions, * simplifying them because we wouldn't actually intend to * write out the pages, but rather only collect contiguous * logical block extents, call the multi-block allocator, and * then update the buffer heads with the block allocations. * * For now, though, we'll cheat by calling filemap_flush(), * which will map the blocks, and start the I/O, but not * actually wait for the I/O to complete. */ return filemap_flush(inode->i_mapping); } /* * bmap() is special. It gets used by applications such as lilo and by * the swapper to find the on-disk block of a specific piece of data. * * Naturally, this is dangerous if the block concerned is still in the * journal. If somebody makes a swapfile on an ext4 data-journaling * filesystem and enables swap, then they may get a nasty shock when the * data getting swapped to that swapfile suddenly gets overwritten by * the original zero's written out previously to the journal and * awaiting writeback in the kernel's buffer cache. * * So, if we see any bmap calls here on a modified, data-journaled file, * take extra steps to flush any blocks which might be in the cache. */ static sector_t ext4_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; journal_t *journal; int err; if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && test_opt(inode->i_sb, DELALLOC)) { /* * With delalloc we want to sync the file * so that we can make sure we allocate * blocks for file */ filemap_write_and_wait(mapping); } if (EXT4_JOURNAL(inode) && ext4_test_inode_state(inode, EXT4_STATE_JDATA)) { /* * This is a REALLY heavyweight approach, but the use of * bmap on dirty files is expected to be extremely rare: * only if we run lilo or swapon on a freshly made file * do we expect this to happen. * * (bmap requires CAP_SYS_RAWIO so this does not * represent an unprivileged user DOS attack --- we'd be * in trouble if mortal users could trigger this path at * will.) * * NB. EXT4_STATE_JDATA is not set on files other than * regular files. If somebody wants to bmap a directory * or symlink and gets confused because the buffer * hasn't yet been flushed to disk, they deserve * everything they get. */ ext4_clear_inode_state(inode, EXT4_STATE_JDATA); journal = EXT4_JOURNAL(inode); jbd2_journal_lock_updates(journal); err = jbd2_journal_flush(journal); jbd2_journal_unlock_updates(journal); if (err) return 0; } return generic_block_bmap(mapping, block, ext4_get_block); } static int ext4_readpage(struct file *file, struct page *page) { trace_ext4_readpage(page); return mpage_readpage(page, ext4_get_block); } static int ext4_readpages(struct file *file, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { return mpage_readpages(mapping, pages, nr_pages, ext4_get_block); } static void ext4_invalidatepage_free_endio(struct page *page, unsigned long offset) { struct buffer_head *head, *bh; unsigned int curr_off = 0; if (!page_has_buffers(page)) return; head = bh = page_buffers(page); do { if (offset <= curr_off && test_clear_buffer_uninit(bh) && bh->b_private) { ext4_free_io_end(bh->b_private); bh->b_private = NULL; bh->b_end_io = NULL; } curr_off = curr_off + bh->b_size; bh = bh->b_this_page; } while (bh != head); } static void ext4_invalidatepage(struct page *page, unsigned long offset) { journal_t *journal = EXT4_JOURNAL(page->mapping->host); trace_ext4_invalidatepage(page, offset); /* * free any io_end structure allocated for buffers to be discarded */ if (ext4_should_dioread_nolock(page->mapping->host)) ext4_invalidatepage_free_endio(page, offset); /* * If it's a full truncate we just forget about the pending dirtying */ if (offset == 0) ClearPageChecked(page); if (journal) jbd2_journal_invalidatepage(journal, page, offset); else block_invalidatepage(page, offset); } static int ext4_releasepage(struct page *page, gfp_t wait) { journal_t *journal = EXT4_JOURNAL(page->mapping->host); trace_ext4_releasepage(page); WARN_ON(PageChecked(page)); if (!page_has_buffers(page)) return 0; if (journal) return jbd2_journal_try_to_free_buffers(journal, page, wait); else return try_to_free_buffers(page); } /* * O_DIRECT for ext3 (or indirect map) based files * * If the O_DIRECT write will extend the file then add this inode to the * orphan list. So recovery will truncate it back to the original size * if the machine crashes during the write. * * If the O_DIRECT write is intantiating holes inside i_size and the machine * crashes then stale disk data _may_ be exposed inside the file. But current * VFS code falls back into buffered path in that case so we are safe. */ static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t offset, unsigned long nr_segs) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct ext4_inode_info *ei = EXT4_I(inode); handle_t *handle; ssize_t ret; int orphan = 0; size_t count = iov_length(iov, nr_segs); int retries = 0; if (rw == WRITE) { loff_t final_size = offset + count; if (final_size > inode->i_size) { /* Credits for sb + inode write */ handle = ext4_journal_start(inode, 2); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } ret = ext4_orphan_add(handle, inode); if (ret) { ext4_journal_stop(handle); goto out; } orphan = 1; ei->i_disksize = inode->i_size; ext4_journal_stop(handle); } } retry: if (rw == READ && ext4_should_dioread_nolock(inode)) ret = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ext4_get_block, NULL, NULL, 0); else { ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ext4_get_block, NULL); if (unlikely((rw & WRITE) && ret < 0)) { loff_t isize = i_size_read(inode); loff_t end = offset + iov_length(iov, nr_segs); if (end > isize) vmtruncate(inode, isize); } } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; if (orphan) { int err; /* Credits for sb + inode write */ handle = ext4_journal_start(inode, 2); if (IS_ERR(handle)) { /* This is really bad luck. We've written the data * but cannot extend i_size. Bail out and pretend * the write failed... */ ret = PTR_ERR(handle); if (inode->i_nlink) ext4_orphan_del(NULL, inode); goto out; } if (inode->i_nlink) ext4_orphan_del(handle, inode); if (ret > 0) { loff_t end = offset + ret; if (end > inode->i_size) { ei->i_disksize = end; i_size_write(inode, end); /* * We're going to return a positive `ret' * here due to non-zero-length I/O, so there's * no way of reporting error returns from * ext4_mark_inode_dirty() to userspace. So * ignore it. */ ext4_mark_inode_dirty(handle, inode); } } err = ext4_journal_stop(handle); if (ret == 0) ret = err; } out: return ret; } /* * ext4_get_block used when preparing for a DIO write or buffer write. * We allocate an uinitialized extent if blocks haven't been allocated. * The extent will be converted to initialized after the IO is complete. */ static int ext4_get_block_write(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n", inode->i_ino, create); return _ext4_get_block(inode, iblock, bh_result, EXT4_GET_BLOCKS_IO_CREATE_EXT); } static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset, ssize_t size, void *private, int ret, bool is_async) { ext4_io_end_t *io_end = iocb->private; struct workqueue_struct *wq; unsigned long flags; struct ext4_inode_info *ei; /* if not async direct IO or dio with 0 bytes write, just return */ if (!io_end || !size) goto out; ext_debug("ext4_end_io_dio(): io_end 0x%p" "for inode %lu, iocb 0x%p, offset %llu, size %llu\n", iocb->private, io_end->inode->i_ino, iocb, offset, size); /* if not aio dio with unwritten extents, just free io and return */ if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { ext4_free_io_end(io_end); iocb->private = NULL; out: if (is_async) aio_complete(iocb, ret, 0); return; } io_end->offset = offset; io_end->size = size; if (is_async) { io_end->iocb = iocb; io_end->result = ret; } wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq; /* Add the io_end to per-inode completed aio dio list*/ ei = EXT4_I(io_end->inode); spin_lock_irqsave(&ei->i_completed_io_lock, flags); list_add_tail(&io_end->list, &ei->i_completed_io_list); spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); /* queue the work to convert unwritten extents to written */ queue_work(wq, &io_end->work); iocb->private = NULL; } static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate) { ext4_io_end_t *io_end = bh->b_private; struct workqueue_struct *wq; struct inode *inode; unsigned long flags; if (!test_clear_buffer_uninit(bh) || !io_end) goto out; if (!(io_end->inode->i_sb->s_flags & MS_ACTIVE)) { printk("sb umounted, discard end_io request for inode %lu\n", io_end->inode->i_ino); ext4_free_io_end(io_end); goto out; } io_end->flag = EXT4_IO_END_UNWRITTEN; inode = io_end->inode; /* Add the io_end to per-inode completed io list*/ spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags); wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq; /* queue the work to convert unwritten extents to written */ queue_work(wq, &io_end->work); out: bh->b_private = NULL; bh->b_end_io = NULL; clear_buffer_uninit(bh); end_buffer_async_write(bh, uptodate); } static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode) { ext4_io_end_t *io_end; struct page *page = bh->b_page; loff_t offset = (sector_t)page->index << PAGE_CACHE_SHIFT; size_t size = bh->b_size; retry: io_end = ext4_init_io_end(inode, GFP_ATOMIC); if (!io_end) { pr_warn_ratelimited("%s: allocation fail\n", __func__); schedule(); goto retry; } io_end->offset = offset; io_end->size = size; /* * We need to hold a reference to the page to make sure it * doesn't get evicted before ext4_end_io_work() has a chance * to convert the extent from written to unwritten. */ io_end->page = page; get_page(io_end->page); bh->b_private = io_end; bh->b_end_io = ext4_end_io_buffer_write; return 0; } /* * For ext4 extent files, ext4 will do direct-io write to holes, * preallocated extents, and those write extend the file, no need to * fall back to buffered IO. * * For holes, we fallocate those blocks, mark them as uninitialized * If those blocks were preallocated, we mark sure they are splited, but * still keep the range to write as uninitialized. * * The unwrritten extents will be converted to written when DIO is completed. * For async direct IO, since the IO may still pending when return, we * set up an end_io call back function, which will do the conversion * when async direct IO completed. * * If the O_DIRECT write will extend the file then add this inode to the * orphan list. So recovery will truncate it back to the original size * if the machine crashes during the write. * */ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t offset, unsigned long nr_segs) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; ssize_t ret; size_t count = iov_length(iov, nr_segs); loff_t final_size = offset + count; if (rw == WRITE && final_size <= inode->i_size) { /* * We could direct write to holes and fallocate. * * Allocated blocks to fill the hole are marked as uninitialized * to prevent parallel buffered read to expose the stale data * before DIO complete the data IO. * * As to previously fallocated extents, ext4 get_block * will just simply mark the buffer mapped but still * keep the extents uninitialized. * * for non AIO case, we will convert those unwritten extents * to written after return back from blockdev_direct_IO. * * for async DIO, the conversion needs to be defered when * the IO is completed. The ext4 end_io callback function * will be called to take care of the conversion work. * Here for async case, we allocate an io_end structure to * hook to the iocb. */ iocb->private = NULL; EXT4_I(inode)->cur_aio_dio = NULL; if (!is_sync_kiocb(iocb)) { iocb->private = ext4_init_io_end(inode, GFP_NOFS); if (!iocb->private) return -ENOMEM; /* * we save the io structure for current async * direct IO, so that later ext4_map_blocks() * could flag the io structure whether there * is a unwritten extents needs to be converted * when IO is completed. */ EXT4_I(inode)->cur_aio_dio = iocb->private; } ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ext4_get_block_write, ext4_end_io_dio); if (iocb->private) EXT4_I(inode)->cur_aio_dio = NULL; /* * The io_end structure takes a reference to the inode, * that structure needs to be destroyed and the * reference to the inode need to be dropped, when IO is * complete, even with 0 byte write, or failed. * * In the successful AIO DIO case, the io_end structure will be * desctroyed and the reference to the inode will be dropped * after the end_io call back function is called. * * In the case there is 0 byte write, or error case, since * VFS direct IO won't invoke the end_io call back function, * we need to free the end_io structure here. */ if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) { ext4_free_io_end(iocb->private); iocb->private = NULL; } else if (ret > 0 && ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN)) { int err; /* * for non AIO case, since the IO is already * completed, we could do the conversion right here */ err = ext4_convert_unwritten_extents(inode, offset, ret); if (err < 0) ret = err; ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); } return ret; } /* for write the the end of file case, we fall back to old way */ return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs); } static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t offset, unsigned long nr_segs) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; ssize_t ret; trace_ext4_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) ret = ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs); else ret = ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs); trace_ext4_direct_IO_exit(inode, offset, iov_length(iov, nr_segs), rw, ret); return ret; } /* * Pages can be marked dirty completely asynchronously from ext4's journalling * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do * much here because ->set_page_dirty is called under VFS locks. The page is * not necessarily locked. * * We cannot just dirty the page and leave attached buffers clean, because the * buffers' dirty state is "definitive". We cannot just set the buffers dirty * or jbddirty because all the journalling code will explode. * * So what we do is to mark the page "pending dirty" and next time writepage * is called, propagate that into the buffers appropriately. */ static int ext4_journalled_set_page_dirty(struct page *page) { SetPageChecked(page); return __set_page_dirty_nobuffers(page); } static const struct address_space_operations ext4_ordered_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_writepage, .write_begin = ext4_write_begin, .write_end = ext4_ordered_write_end, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; static const struct address_space_operations ext4_writeback_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_writepage, .write_begin = ext4_write_begin, .write_end = ext4_writeback_write_end, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; static const struct address_space_operations ext4_journalled_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_writepage, .write_begin = ext4_write_begin, .write_end = ext4_journalled_write_end, .set_page_dirty = ext4_journalled_set_page_dirty, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; static const struct address_space_operations ext4_da_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_writepage, .writepages = ext4_da_writepages, .write_begin = ext4_da_write_begin, .write_end = ext4_da_write_end, .bmap = ext4_bmap, .invalidatepage = ext4_da_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; void ext4_set_aops(struct inode *inode) { if (ext4_should_order_data(inode) && test_opt(inode->i_sb, DELALLOC)) inode->i_mapping->a_ops = &ext4_da_aops; else if (ext4_should_order_data(inode)) inode->i_mapping->a_ops = &ext4_ordered_aops; else if (ext4_should_writeback_data(inode) && test_opt(inode->i_sb, DELALLOC)) inode->i_mapping->a_ops = &ext4_da_aops; else if (ext4_should_writeback_data(inode)) inode->i_mapping->a_ops = &ext4_writeback_aops; else inode->i_mapping->a_ops = &ext4_journalled_aops; } /* * ext4_block_truncate_page() zeroes out a mapping from file offset `from' * up to the end of the block which corresponds to `from'. * This required during truncate. We need to physically zero the tail end * of that block so it doesn't yield old data if the file is later grown. */ int ext4_block_truncate_page(handle_t *handle, struct address_space *mapping, loff_t from) { ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); unsigned blocksize, length, pos; ext4_lblk_t iblock; struct inode *inode = mapping->host; struct buffer_head *bh; struct page *page; int err = 0; page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT, mapping_gfp_mask(mapping) & ~__GFP_FS); if (!page) return -EINVAL; blocksize = inode->i_sb->s_blocksize; length = blocksize - (offset & (blocksize - 1)); iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); if (!page_has_buffers(page)) create_empty_buffers(page, blocksize, 0); /* Find the buffer that contains "offset" */ bh = page_buffers(page); pos = blocksize; while (offset >= pos) { bh = bh->b_this_page; iblock++; pos += blocksize; } err = 0; if (buffer_freed(bh)) { BUFFER_TRACE(bh, "freed: skip"); goto unlock; } if (!buffer_mapped(bh)) { BUFFER_TRACE(bh, "unmapped"); ext4_get_block(inode, iblock, bh, 0); /* unmapped? It's a hole - nothing to do */ if (!buffer_mapped(bh)) { BUFFER_TRACE(bh, "still unmapped"); goto unlock; } } /* Ok, it's mapped. Make sure it's up-to-date */ if (PageUptodate(page)) set_buffer_uptodate(bh); if (!buffer_uptodate(bh)) { err = -EIO; ll_rw_block(READ, 1, &bh); wait_on_buffer(bh); /* Uhhuh. Read error. Complain and punt. */ if (!buffer_uptodate(bh)) goto unlock; } if (ext4_should_journal_data(inode)) { BUFFER_TRACE(bh, "get write access"); err = ext4_journal_get_write_access(handle, bh); if (err) goto unlock; } zero_user(page, offset, length); BUFFER_TRACE(bh, "zeroed end of block"); err = 0; if (ext4_should_journal_data(inode)) { err = ext4_handle_dirty_metadata(handle, inode, bh); } else { if (ext4_should_order_data(inode) && EXT4_I(inode)->jinode) err = ext4_jbd2_file_inode(handle, inode); mark_buffer_dirty(bh); } unlock: unlock_page(page); page_cache_release(page); return err; } /* * Probably it should be a library function... search for first non-zero word * or memcmp with zero_page, whatever is better for particular architecture. * Linus? */ static inline int all_zeroes(__le32 *p, __le32 *q) { while (p < q) if (*p++) return 0; return 1; } /** * ext4_find_shared - find the indirect blocks for partial truncation. * @inode: inode in question * @depth: depth of the affected branch * @offsets: offsets of pointers in that branch (see ext4_block_to_path) * @chain: place to store the pointers to partial indirect blocks * @top: place to the (detached) top of branch * * This is a helper function used by ext4_truncate(). * * When we do truncate() we may have to clean the ends of several * indirect blocks but leave the blocks themselves alive. Block is * partially truncated if some data below the new i_size is referred * from it (and it is on the path to the first completely truncated * data block, indeed). We have to free the top of that path along * with everything to the right of the path. Since no allocation * past the truncation point is possible until ext4_truncate() * finishes, we may safely do the latter, but top of branch may * require special attention - pageout below the truncation point * might try to populate it. * * We atomically detach the top of branch from the tree, store the * block number of its root in *@top, pointers to buffer_heads of * partially truncated blocks - in @chain[].bh and pointers to * their last elements that should not be removed - in * @chain[].p. Return value is the pointer to last filled element * of @chain. * * The work left to caller to do the actual freeing of subtrees: * a) free the subtree starting from *@top * b) free the subtrees whose roots are stored in * (@chain[i].p+1 .. end of @chain[i].bh->b_data) * c) free the subtrees growing from the inode past the @chain[0]. * (no partially truncated stuff there). */ static Indirect *ext4_find_shared(struct inode *inode, int depth, ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top) { Indirect *partial, *p; int k, err; *top = 0; /* Make k index the deepest non-null offset + 1 */ for (k = depth; k > 1 && !offsets[k-1]; k--) ; partial = ext4_get_branch(inode, k, offsets, chain, &err); /* Writer: pointers */ if (!partial) partial = chain + k-1; /* * If the branch acquired continuation since we've looked at it - * fine, it should all survive and (new) top doesn't belong to us. */ if (!partial->key && *partial->p) /* Writer: end */ goto no_top; for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--) ; /* * OK, we've found the last block that must survive. The rest of our * branch should be detached before unlocking. However, if that rest * of branch is all ours and does not grow immediately from the inode * it's easier to cheat and just decrement partial->p. */ if (p == chain + k - 1 && p > chain) { p->p--; } else { *top = *p->p; /* Nope, don't do this in ext4. Must leave the tree intact */ #if 0 *p->p = 0; #endif } /* Writer: end */ while (partial > p) { brelse(partial->bh); partial--; } no_top: return partial; } /* * Zero a number of block pointers in either an inode or an indirect block. * If we restart the transaction we must again get write access to the * indirect block for further modification. * * We release `count' blocks on disk, but (last - first) may be greater * than `count' because there can be holes in there. * * Return 0 on success, 1 on invalid block range * and < 0 on fatal error. */ static int ext4_clear_blocks(handle_t *handle, struct inode *inode, struct buffer_head *bh, ext4_fsblk_t block_to_free, unsigned long count, __le32 *first, __le32 *last) { __le32 *p; int flags = EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_VALIDATED; int err; if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) flags |= EXT4_FREE_BLOCKS_METADATA; if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free, count)) { EXT4_ERROR_INODE(inode, "attempt to clear invalid " "blocks %llu len %lu", (unsigned long long) block_to_free, count); return 1; } if (try_to_extend_transaction(handle, inode)) { if (bh) { BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); err = ext4_handle_dirty_metadata(handle, inode, bh); if (unlikely(err)) goto out_err; } err = ext4_mark_inode_dirty(handle, inode); if (unlikely(err)) goto out_err; err = ext4_truncate_restart_trans(handle, inode, blocks_for_truncate(inode)); if (unlikely(err)) goto out_err; if (bh) { BUFFER_TRACE(bh, "retaking write access"); err = ext4_journal_get_write_access(handle, bh); if (unlikely(err)) goto out_err; } } for (p = first; p < last; p++) *p = 0; ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags); return 0; out_err: ext4_std_error(inode->i_sb, err); return err; } /** * ext4_free_data - free a list of data blocks * @handle: handle for this transaction * @inode: inode we are dealing with * @this_bh: indirect buffer_head which contains *@first and *@last * @first: array of block numbers * @last: points immediately past the end of array * * We are freeing all blocks referred from that array (numbers are stored as * little-endian 32-bit) and updating @inode->i_blocks appropriately. * * We accumulate contiguous runs of blocks to free. Conveniently, if these * blocks are contiguous then releasing them at one time will only affect one * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't * actually use a lot of journal space. * * @this_bh will be %NULL if @first and @last point into the inode's direct * block pointers. */ static void ext4_free_data(handle_t *handle, struct inode *inode, struct buffer_head *this_bh, __le32 *first, __le32 *last) { ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */ unsigned long count = 0; /* Number of blocks in the run */ __le32 *block_to_free_p = NULL; /* Pointer into inode/ind corresponding to block_to_free */ ext4_fsblk_t nr; /* Current block # */ __le32 *p; /* Pointer into inode/ind for current block */ int err = 0; if (this_bh) { /* For indirect block */ BUFFER_TRACE(this_bh, "get_write_access"); err = ext4_journal_get_write_access(handle, this_bh); /* Important: if we can't update the indirect pointers * to the blocks, we can't free them. */ if (err) return; } for (p = first; p < last; p++) { nr = le32_to_cpu(*p); if (nr) { /* accumulate blocks to free if they're contiguous */ if (count == 0) { block_to_free = nr; block_to_free_p = p; count = 1; } else if (nr == block_to_free + count) { count++; } else { err = ext4_clear_blocks(handle, inode, this_bh, block_to_free, count, block_to_free_p, p); if (err) break; block_to_free = nr; block_to_free_p = p; count = 1; } } } if (!err && count > 0) err = ext4_clear_blocks(handle, inode, this_bh, block_to_free, count, block_to_free_p, p); if (err < 0) /* fatal error */ return; if (this_bh) { BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata"); /* * The buffer head should have an attached journal head at this * point. However, if the data is corrupted and an indirect * block pointed to itself, it would have been detached when * the block was cleared. Check for this instead of OOPSing. */ if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh)) ext4_handle_dirty_metadata(handle, inode, this_bh); else EXT4_ERROR_INODE(inode, "circular indirect block detected at " "block %llu", (unsigned long long) this_bh->b_blocknr); } } /** * ext4_free_branches - free an array of branches * @handle: JBD handle for this transaction * @inode: inode we are dealing with * @parent_bh: the buffer_head which contains *@first and *@last * @first: array of block numbers * @last: pointer immediately past the end of array * @depth: depth of the branches to free * * We are freeing all blocks referred from these branches (numbers are * stored as little-endian 32-bit) and updating @inode->i_blocks * appropriately. */ static void ext4_free_branches(handle_t *handle, struct inode *inode, struct buffer_head *parent_bh, __le32 *first, __le32 *last, int depth) { ext4_fsblk_t nr; __le32 *p; if (ext4_handle_is_aborted(handle)) return; if (depth--) { struct buffer_head *bh; int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); p = last; while (--p >= first) { nr = le32_to_cpu(*p); if (!nr) continue; /* A hole */ if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), nr, 1)) { EXT4_ERROR_INODE(inode, "invalid indirect mapped " "block %lu (level %d)", (unsigned long) nr, depth); break; } /* Go read the buffer for the next level down */ bh = sb_bread(inode->i_sb, nr); /* * A read failure? Report error and clear slot * (should be rare). */ if (!bh) { EXT4_ERROR_INODE_BLOCK(inode, nr, "Read failure"); continue; } /* This zaps the entire block. Bottom up. */ BUFFER_TRACE(bh, "free child branches"); ext4_free_branches(handle, inode, bh, (__le32 *) bh->b_data, (__le32 *) bh->b_data + addr_per_block, depth); brelse(bh); /* * Everything below this this pointer has been * released. Now let this top-of-subtree go. * * We want the freeing of this indirect block to be * atomic in the journal with the updating of the * bitmap block which owns it. So make some room in * the journal. * * We zero the parent pointer *after* freeing its * pointee in the bitmaps, so if extend_transaction() * for some reason fails to put the bitmap changes and * the release into the same transaction, recovery * will merely complain about releasing a free block, * rather than leaking blocks. */ if (ext4_handle_is_aborted(handle)) return; if (try_to_extend_transaction(handle, inode)) { ext4_mark_inode_dirty(handle, inode); ext4_truncate_restart_trans(handle, inode, blocks_for_truncate(inode)); } /* * The forget flag here is critical because if * we are journaling (and not doing data * journaling), we have to make sure a revoke * record is written to prevent the journal * replay from overwriting the (former) * indirect block if it gets reallocated as a * data block. This must happen in the same * transaction where the data blocks are * actually freed. */ ext4_free_blocks(handle, inode, NULL, nr, 1, EXT4_FREE_BLOCKS_METADATA| EXT4_FREE_BLOCKS_FORGET); if (parent_bh) { /* * The block which we have just freed is * pointed to by an indirect block: journal it */ BUFFER_TRACE(parent_bh, "get_write_access"); if (!ext4_journal_get_write_access(handle, parent_bh)){ *p = 0; BUFFER_TRACE(parent_bh, "call ext4_handle_dirty_metadata"); ext4_handle_dirty_metadata(handle, inode, parent_bh); } } } } else { /* We have reached the bottom of the tree. */ BUFFER_TRACE(parent_bh, "free data blocks"); ext4_free_data(handle, inode, parent_bh, first, last); } } int ext4_can_truncate(struct inode *inode) { if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) return 0; if (S_ISREG(inode->i_mode)) return 1; if (S_ISDIR(inode->i_mode)) return 1; if (S_ISLNK(inode->i_mode)) return !ext4_inode_is_fast_symlink(inode); return 0; } /* * ext4_truncate() * * We block out ext4_get_block() block instantiations across the entire * transaction, and VFS/VM ensures that ext4_truncate() cannot run * simultaneously on behalf of the same inode. * * As we work through the truncate and commmit bits of it to the journal there * is one core, guiding principle: the file's tree must always be consistent on * disk. We must be able to restart the truncate after a crash. * * The file's tree may be transiently inconsistent in memory (although it * probably isn't), but whenever we close off and commit a journal transaction, * the contents of (the filesystem + the journal) must be consistent and * restartable. It's pretty simple, really: bottom up, right to left (although * left-to-right works OK too). * * Note that at recovery time, journal replay occurs *before* the restart of * truncate against the orphan inode list. * * The committed inode has the new, desired i_size (which is the same as * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see * that this inode's truncate did not complete and it will again call * ext4_truncate() to have another go. So there will be instantiated blocks * to the right of the truncation point in a crashed ext4 filesystem. But * that's fine - as long as they are linked from the inode, the post-crash * ext4_truncate() run will find them and release them. */ void ext4_truncate(struct inode *inode) { handle_t *handle; struct ext4_inode_info *ei = EXT4_I(inode); __le32 *i_data = ei->i_data; int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); struct address_space *mapping = inode->i_mapping; ext4_lblk_t offsets[4]; Indirect chain[4]; Indirect *partial; __le32 nr = 0; int n = 0; ext4_lblk_t last_block, max_block; unsigned blocksize = inode->i_sb->s_blocksize; trace_ext4_truncate_enter(inode); if (!ext4_can_truncate(inode)) return; ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS); if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC)) ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE); if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { ext4_ext_truncate(inode); trace_ext4_truncate_exit(inode); return; } handle = start_transaction(inode); if (IS_ERR(handle)) return; /* AKPM: return what? */ last_block = (inode->i_size + blocksize-1) >> EXT4_BLOCK_SIZE_BITS(inode->i_sb); max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1) >> EXT4_BLOCK_SIZE_BITS(inode->i_sb); if (inode->i_size & (blocksize - 1)) if (ext4_block_truncate_page(handle, mapping, inode->i_size)) goto out_stop; if (last_block != max_block) { n = ext4_block_to_path(inode, last_block, offsets, NULL); if (n == 0) goto out_stop; /* error */ } /* * OK. This truncate is going to happen. We add the inode to the * orphan list, so that if this truncate spans multiple transactions, * and we crash, we will resume the truncate when the filesystem * recovers. It also marks the inode dirty, to catch the new size. * * Implication: the file must always be in a sane, consistent * truncatable state while each transaction commits. */ if (ext4_orphan_add(handle, inode)) goto out_stop; /* * From here we block out all ext4_get_block() callers who want to * modify the block allocation tree. */ down_write(&ei->i_data_sem); ext4_discard_preallocations(inode); /* * The orphan list entry will now protect us from any crash which * occurs before the truncate completes, so it is now safe to propagate * the new, shorter inode size (held for now in i_size) into the * on-disk inode. We do this via i_disksize, which is the value which * ext4 *really* writes onto the disk inode. */ ei->i_disksize = inode->i_size; if (last_block == max_block) { /* * It is unnecessary to free any data blocks if last_block is * equal to the indirect block limit. */ goto out_unlock; } else if (n == 1) { /* direct blocks */ ext4_free_data(handle, inode, NULL, i_data+offsets[0], i_data + EXT4_NDIR_BLOCKS); goto do_indirects; } partial = ext4_find_shared(inode, n, offsets, chain, &nr); /* Kill the top of shared branch (not detached) */ if (nr) { if (partial == chain) { /* Shared branch grows from the inode */ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, (chain+n-1) - partial); *partial->p = 0; /* * We mark the inode dirty prior to restart, * and prior to stop. No need for it here. */ } else { /* Shared branch grows from an indirect block */ BUFFER_TRACE(partial->bh, "get_write_access"); ext4_free_branches(handle, inode, partial->bh, partial->p, partial->p+1, (chain+n-1) - partial); } } /* Clear the ends of indirect blocks on the shared branch */ while (partial > chain) { ext4_free_branches(handle, inode, partial->bh, partial->p + 1, (__le32*)partial->bh->b_data+addr_per_block, (chain+n-1) - partial); BUFFER_TRACE(partial->bh, "call brelse"); brelse(partial->bh); partial--; } do_indirects: /* Kill the remaining (whole) subtrees */ switch (offsets[0]) { default: nr = i_data[EXT4_IND_BLOCK]; if (nr) { ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1); i_data[EXT4_IND_BLOCK] = 0; } case EXT4_IND_BLOCK: nr = i_data[EXT4_DIND_BLOCK]; if (nr) { ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2); i_data[EXT4_DIND_BLOCK] = 0; } case EXT4_DIND_BLOCK: nr = i_data[EXT4_TIND_BLOCK]; if (nr) { ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3); i_data[EXT4_TIND_BLOCK] = 0; } case EXT4_TIND_BLOCK: ; } out_unlock: up_write(&ei->i_data_sem); inode->i_mtime = inode->i_ctime = ext4_current_time(inode); ext4_mark_inode_dirty(handle, inode); /* * In a multi-transaction truncate, we only make the final transaction * synchronous */ if (IS_SYNC(inode)) ext4_handle_sync(handle); out_stop: /* * If this was a simple ftruncate(), and the file will remain alive * then we need to clear up the orphan record which we created above. * However, if this was a real unlink then we were called by * ext4_delete_inode(), and we allow that function to clean up the * orphan info for us. */ if (inode->i_nlink) ext4_orphan_del(handle, inode); ext4_journal_stop(handle); trace_ext4_truncate_exit(inode); } /* * ext4_get_inode_loc returns with an extra refcount against the inode's * underlying buffer_head on success. If 'in_mem' is true, we have all * data in memory that is needed to recreate the on-disk version of this * inode. */ static int __ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc, int in_mem) { struct ext4_group_desc *gdp; struct buffer_head *bh; struct super_block *sb = inode->i_sb; ext4_fsblk_t block; int inodes_per_block, inode_offset; iloc->bh = NULL; if (!ext4_valid_inum(sb, inode->i_ino)) return -EIO; iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb); gdp = ext4_get_group_desc(sb, iloc->block_group, NULL); if (!gdp) return -EIO; /* * Figure out the offset within the block group inode table */ inodes_per_block = EXT4_SB(sb)->s_inodes_per_block; inode_offset = ((inode->i_ino - 1) % EXT4_INODES_PER_GROUP(sb)); block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block); iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb); bh = sb_getblk(sb, block); if (!bh) { EXT4_ERROR_INODE_BLOCK(inode, block, "unable to read itable block"); return -EIO; } if (!buffer_uptodate(bh)) { lock_buffer(bh); /* * If the buffer has the write error flag, we have failed * to write out another inode in the same block. In this * case, we don't have to read the block because we may * read the old inode data successfully. */ if (buffer_write_io_error(bh) && !buffer_uptodate(bh)) set_buffer_uptodate(bh); if (buffer_uptodate(bh)) { /* someone brought it uptodate while we waited */ unlock_buffer(bh); goto has_buffer; } /* * If we have all information of the inode in memory and this * is the only valid inode in the block, we need not read the * block. */ if (in_mem) { struct buffer_head *bitmap_bh; int i, start; start = inode_offset & ~(inodes_per_block - 1); /* Is the inode bitmap in cache? */ bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp)); if (!bitmap_bh) goto make_io; /* * If the inode bitmap isn't in cache then the * optimisation may end up performing two reads instead * of one, so skip it. */ if (!buffer_uptodate(bitmap_bh)) { brelse(bitmap_bh); goto make_io; } for (i = start; i < start + inodes_per_block; i++) { if (i == inode_offset) continue; if (ext4_test_bit(i, bitmap_bh->b_data)) break; } brelse(bitmap_bh); if (i == start + inodes_per_block) { /* all other inodes are free, so skip I/O */ memset(bh->b_data, 0, bh->b_size); set_buffer_uptodate(bh); unlock_buffer(bh); goto has_buffer; } } make_io: /* * If we need to do any I/O, try to pre-readahead extra * blocks from the inode table. */ if (EXT4_SB(sb)->s_inode_readahead_blks) { ext4_fsblk_t b, end, table; unsigned num; table = ext4_inode_table(sb, gdp); /* s_inode_readahead_blks is always a power of 2 */ b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1); if (table > b) b = table; end = b + EXT4_SB(sb)->s_inode_readahead_blks; num = EXT4_INODES_PER_GROUP(sb); if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) num -= ext4_itable_unused_count(sb, gdp); table += num / inodes_per_block; if (end > table) end = table; while (b <= end) sb_breadahead(sb, b++); } /* * There are other valid inodes in the buffer, this inode * has in-inode xattrs, or we don't have this inode in memory. * Read the block from disk. */ trace_ext4_load_inode(inode); get_bh(bh); bh->b_end_io = end_buffer_read_sync; submit_bh(READ_META, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) { EXT4_ERROR_INODE_BLOCK(inode, block, "unable to read itable block"); brelse(bh); return -EIO; } } has_buffer: iloc->bh = bh; return 0; } int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) { /* We have all inode data except xattrs in memory here. */ return __ext4_get_inode_loc(inode, iloc, !ext4_test_inode_state(inode, EXT4_STATE_XATTR)); } void ext4_set_inode_flags(struct inode *inode) { unsigned int flags = EXT4_I(inode)->i_flags; inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); if (flags & EXT4_SYNC_FL) inode->i_flags |= S_SYNC; if (flags & EXT4_APPEND_FL) inode->i_flags |= S_APPEND; if (flags & EXT4_IMMUTABLE_FL) inode->i_flags |= S_IMMUTABLE; if (flags & EXT4_NOATIME_FL) inode->i_flags |= S_NOATIME; if (flags & EXT4_DIRSYNC_FL) inode->i_flags |= S_DIRSYNC; } /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */ void ext4_get_inode_flags(struct ext4_inode_info *ei) { unsigned int vfs_fl; unsigned long old_fl, new_fl; do { vfs_fl = ei->vfs_inode.i_flags; old_fl = ei->i_flags; new_fl = old_fl & ~(EXT4_SYNC_FL|EXT4_APPEND_FL| EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL| EXT4_DIRSYNC_FL); if (vfs_fl & S_SYNC) new_fl |= EXT4_SYNC_FL; if (vfs_fl & S_APPEND) new_fl |= EXT4_APPEND_FL; if (vfs_fl & S_IMMUTABLE) new_fl |= EXT4_IMMUTABLE_FL; if (vfs_fl & S_NOATIME) new_fl |= EXT4_NOATIME_FL; if (vfs_fl & S_DIRSYNC) new_fl |= EXT4_DIRSYNC_FL; } while (cmpxchg(&ei->i_flags, old_fl, new_fl) != old_fl); } static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode, struct ext4_inode_info *ei) { blkcnt_t i_blocks ; struct inode *inode = &(ei->vfs_inode); struct super_block *sb = inode->i_sb; if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) { /* we are using combined 48 bit field */ i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 | le32_to_cpu(raw_inode->i_blocks_lo); if (ext4_test_inode_flag(inode, EXT4_INODE_HUGE_FILE)) { /* i_blocks represent file system block size */ return i_blocks << (inode->i_blkbits - 9); } else { return i_blocks; } } else { return le32_to_cpu(raw_inode->i_blocks_lo); } } struct inode *ext4_iget(struct super_block *sb, unsigned long ino) { struct ext4_iloc iloc; struct ext4_inode *raw_inode; struct ext4_inode_info *ei; struct inode *inode; journal_t *journal = EXT4_SB(sb)->s_journal; long ret; int block; inode = iget_locked(sb, ino); if (!inode) return ERR_PTR(-ENOMEM); if (!(inode->i_state & I_NEW)) return inode; ei = EXT4_I(inode); iloc.bh = NULL; ret = __ext4_get_inode_loc(inode, &iloc, 0); if (ret < 0) goto bad_inode; raw_inode = ext4_raw_inode(&iloc); inode->i_mode = le16_to_cpu(raw_inode->i_mode); inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low); inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low); if (!(test_opt(inode->i_sb, NO_UID32))) { inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16; inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16; } inode->i_nlink = le16_to_cpu(raw_inode->i_links_count); ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */ ei->i_dir_start_lookup = 0; ei->i_dtime = le32_to_cpu(raw_inode->i_dtime); /* We now have enough fields to check if the inode was active or not. * This is needed because nfsd might try to access dead inodes * the test is that same one that e2fsck uses * NeilBrown 1999oct15 */ if (inode->i_nlink == 0) { if (inode->i_mode == 0 || !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) { /* this inode is deleted */ ret = -ESTALE; goto bad_inode; } /* The only unlinked inodes we let through here have * valid i_mode and are being read by the orphan * recovery code: that's fine, we're about to complete * the process of deleting those. */ } ei->i_flags = le32_to_cpu(raw_inode->i_flags); inode->i_blocks = ext4_inode_blocks(raw_inode, ei); ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo); if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) ei->i_file_acl |= ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32; inode->i_size = ext4_isize(raw_inode); ei->i_disksize = inode->i_size; #ifdef CONFIG_QUOTA ei->i_reserved_quota = 0; #endif inode->i_generation = le32_to_cpu(raw_inode->i_generation); ei->i_block_group = iloc.block_group; ei->i_last_alloc_group = ~0; /* * NOTE! The in-memory inode i_data array is in little-endian order * even on big-endian machines: we do NOT byteswap the block numbers! */ for (block = 0; block < EXT4_N_BLOCKS; block++) ei->i_data[block] = raw_inode->i_block[block]; INIT_LIST_HEAD(&ei->i_orphan); /* * Set transaction id's of transactions that have to be committed * to finish f[data]sync. We set them to currently running transaction * as we cannot be sure that the inode or some of its metadata isn't * part of the transaction - the inode could have been reclaimed and * now it is reread from disk. */ if (journal) { transaction_t *transaction; tid_t tid; read_lock(&journal->j_state_lock); if (journal->j_running_transaction) transaction = journal->j_running_transaction; else transaction = journal->j_committing_transaction; if (transaction) tid = transaction->t_tid; else tid = journal->j_commit_sequence; read_unlock(&journal->j_state_lock); ei->i_sync_tid = tid; ei->i_datasync_tid = tid; } if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize); if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > EXT4_INODE_SIZE(inode->i_sb)) { ret = -EIO; goto bad_inode; } if (ei->i_extra_isize == 0) { /* The extra space is currently unused. Use it. */ ei->i_extra_isize = sizeof(struct ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE; } else { __le32 *magic = (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize; if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) ext4_set_inode_state(inode, EXT4_STATE_XATTR); } } else ei->i_extra_isize = 0; EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode); EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode); EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode); EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode); inode->i_version = le32_to_cpu(raw_inode->i_disk_version); if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) inode->i_version |= (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32; } ret = 0; if (ei->i_file_acl && !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) { EXT4_ERROR_INODE(inode, "bad extended attribute block %llu", ei->i_file_acl); ret = -EIO; goto bad_inode; } else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || (S_ISLNK(inode->i_mode) && !ext4_inode_is_fast_symlink(inode))) /* Validate extent which is part of inode */ ret = ext4_ext_check_inode(inode); } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || (S_ISLNK(inode->i_mode) && !ext4_inode_is_fast_symlink(inode))) { /* Validate block references which are part of inode */ ret = ext4_check_inode_blockref(inode); } if (ret) goto bad_inode; if (S_ISREG(inode->i_mode)) { inode->i_op = &ext4_file_inode_operations; inode->i_fop = &ext4_file_operations; ext4_set_aops(inode); } else if (S_ISDIR(inode->i_mode)) { inode->i_op = &ext4_dir_inode_operations; inode->i_fop = &ext4_dir_operations; } else if (S_ISLNK(inode->i_mode)) { if (ext4_inode_is_fast_symlink(inode)) { inode->i_op = &ext4_fast_symlink_inode_operations; nd_terminate_link(ei->i_data, inode->i_size, sizeof(ei->i_data) - 1); } else { inode->i_op = &ext4_symlink_inode_operations; ext4_set_aops(inode); } } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) || S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { inode->i_op = &ext4_special_inode_operations; if (raw_inode->i_block[0]) init_special_inode(inode, inode->i_mode, old_decode_dev(le32_to_cpu(raw_inode->i_block[0]))); else init_special_inode(inode, inode->i_mode, new_decode_dev(le32_to_cpu(raw_inode->i_block[1]))); } else { ret = -EIO; EXT4_ERROR_INODE(inode, "bogus i_mode (%o)", inode->i_mode); goto bad_inode; } brelse(iloc.bh); ext4_set_inode_flags(inode); unlock_new_inode(inode); return inode; bad_inode: brelse(iloc.bh); iget_failed(inode); return ERR_PTR(ret); } static int ext4_inode_blocks_set(handle_t *handle, struct ext4_inode *raw_inode, struct ext4_inode_info *ei) { struct inode *inode = &(ei->vfs_inode); u64 i_blocks = inode->i_blocks; struct super_block *sb = inode->i_sb; if (i_blocks <= ~0U) { /* * i_blocks can be represnted in a 32 bit variable * as multiple of 512 bytes */ raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); raw_inode->i_blocks_high = 0; ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE); return 0; } if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) return -EFBIG; if (i_blocks <= 0xffffffffffffULL) { /* * i_blocks can be represented in a 48 bit variable * as multiple of 512 bytes */ raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); ext4_clear_inode_flag(inode, EXT4_INODE_HUGE_FILE); } else { ext4_set_inode_flag(inode, EXT4_INODE_HUGE_FILE); /* i_block is stored in file system block size */ i_blocks = i_blocks >> (inode->i_blkbits - 9); raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); } return 0; } /* * Post the struct inode info into an on-disk inode location in the * buffer-cache. This gobbles the caller's reference to the * buffer_head in the inode location struct. * * The caller must have write access to iloc->bh. */ static int ext4_do_update_inode(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { struct ext4_inode *raw_inode = ext4_raw_inode(iloc); struct ext4_inode_info *ei = EXT4_I(inode); struct buffer_head *bh = iloc->bh; int err = 0, rc, block; /* For fields not not tracking in the in-memory inode, * initialise them to zero for new inodes. */ if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); ext4_get_inode_flags(ei); raw_inode->i_mode = cpu_to_le16(inode->i_mode); if (!(test_opt(inode->i_sb, NO_UID32))) { raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid)); raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid)); /* * Fix up interoperability with old kernels. Otherwise, old inodes get * re-used with the upper 16 bits of the uid/gid intact */ if (!ei->i_dtime) { raw_inode->i_uid_high = cpu_to_le16(high_16_bits(inode->i_uid)); raw_inode->i_gid_high = cpu_to_le16(high_16_bits(inode->i_gid)); } else { raw_inode->i_uid_high = 0; raw_inode->i_gid_high = 0; } } else { raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(inode->i_uid)); raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(inode->i_gid)); raw_inode->i_uid_high = 0; raw_inode->i_gid_high = 0; } raw_inode->i_links_count = cpu_to_le16(inode->i_nlink); EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode); EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode); EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode); EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode); if (ext4_inode_blocks_set(handle, raw_inode, ei)) goto out_brelse; raw_inode->i_dtime = cpu_to_le32(ei->i_dtime); raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF); if (EXT4_SB(inode->i_sb)->s_es->s_creator_os != cpu_to_le32(EXT4_OS_HURD)) raw_inode->i_file_acl_high = cpu_to_le16(ei->i_file_acl >> 32); raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl); ext4_isize_set(raw_inode, ei->i_disksize); if (ei->i_disksize > 0x7fffffffULL) { struct super_block *sb = inode->i_sb; if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_LARGE_FILE) || EXT4_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT4_GOOD_OLD_REV)) { /* If this is the first large file * created, add a flag to the superblock. */ err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh); if (err) goto out_brelse; ext4_update_dynamic_rev(sb); EXT4_SET_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_LARGE_FILE); sb->s_dirt = 1; ext4_handle_sync(handle); err = ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); } } raw_inode->i_generation = cpu_to_le32(inode->i_generation); if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) { if (old_valid_dev(inode->i_rdev)) { raw_inode->i_block[0] = cpu_to_le32(old_encode_dev(inode->i_rdev)); raw_inode->i_block[1] = 0; } else { raw_inode->i_block[0] = 0; raw_inode->i_block[1] = cpu_to_le32(new_encode_dev(inode->i_rdev)); raw_inode->i_block[2] = 0; } } else for (block = 0; block < EXT4_N_BLOCKS; block++) raw_inode->i_block[block] = ei->i_data[block]; raw_inode->i_disk_version = cpu_to_le32(inode->i_version); if (ei->i_extra_isize) { if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) raw_inode->i_version_hi = cpu_to_le32(inode->i_version >> 32); raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize); } BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata"); rc = ext4_handle_dirty_metadata(handle, NULL, bh); if (!err) err = rc; ext4_clear_inode_state(inode, EXT4_STATE_NEW); ext4_update_inode_fsync_trans(handle, inode, 0); out_brelse: brelse(bh); ext4_std_error(inode->i_sb, err); return err; } /* * ext4_write_inode() * * We are called from a few places: * * - Within generic_file_write() for O_SYNC files. * Here, there will be no transaction running. We wait for any running * trasnaction to commit. * * - Within sys_sync(), kupdate and such. * We wait on commit, if tol to. * * - Within prune_icache() (PF_MEMALLOC == true) * Here we simply return. We can't afford to block kswapd on the * journal commit. * * In all cases it is actually safe for us to return without doing anything, * because the inode has been copied into a raw inode buffer in * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for * knfsd. * * Note that we are absolutely dependent upon all inode dirtiers doing the * right thing: they *must* call mark_inode_dirty() after dirtying info in * which we are interested. * * It would be a bug for them to not do this. The code: * * mark_inode_dirty(inode) * stuff(); * inode->i_size = expr; * * is in error because a kswapd-driven write_inode() could occur while * `stuff()' is running, and the new i_size will be lost. Plus the inode * will no longer be on the superblock's dirty inode list. */ int ext4_write_inode(struct inode *inode, struct writeback_control *wbc) { int err; if (current->flags & PF_MEMALLOC) return 0; if (EXT4_SB(inode->i_sb)->s_journal) { if (ext4_journal_current_handle()) { jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n"); dump_stack(); return -EIO; } if (wbc->sync_mode != WB_SYNC_ALL) return 0; err = ext4_force_commit(inode->i_sb); } else { struct ext4_iloc iloc; err = __ext4_get_inode_loc(inode, &iloc, 0); if (err) return err; if (wbc->sync_mode == WB_SYNC_ALL) sync_dirty_buffer(iloc.bh); if (buffer_req(iloc.bh) && !buffer_uptodate(iloc.bh)) { EXT4_ERROR_INODE_BLOCK(inode, iloc.bh->b_blocknr, "IO error syncing inode"); err = -EIO; } brelse(iloc.bh); } return err; } /* * ext4_setattr() * * Called from notify_change. * * We want to trap VFS attempts to truncate the file as soon as * possible. In particular, we want to make sure that when the VFS * shrinks i_size, we put the inode on the orphan list and modify * i_disksize immediately, so that during the subsequent flushing of * dirty pages and freeing of disk blocks, we can guarantee that any * commit will leave the blocks being flushed in an unused state on * disk. (On recovery, the inode will get truncated and the blocks will * be freed, so we have a strong guarantee that no future commit will * leave these blocks visible to the user.) * * Another thing we have to assure is that if we are in ordered mode * and inode is still attached to the committing transaction, we must * we start writeout of all the dirty pages which are being truncated. * This way we are sure that all the data written in the previous * transaction are already on disk (truncate waits for pages under * writeback). * * Called with inode->i_mutex down. */ int ext4_setattr(struct dentry *dentry, struct iattr *attr) { struct inode *inode = dentry->d_inode; int error, rc = 0; int orphan = 0; const unsigned int ia_valid = attr->ia_valid; error = inode_change_ok(inode, attr); if (error) return error; if (is_quota_modification(inode, attr)) dquot_initialize(inode); if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) || (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) { handle_t *handle; /* (user+group)*(old+new) structure, inode write (sb, * inode block, ? - but truncate inode update has it) */ handle = ext4_journal_start(inode, (EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+ EXT4_MAXQUOTAS_DEL_BLOCKS(inode->i_sb))+3); if (IS_ERR(handle)) { error = PTR_ERR(handle); goto err_out; } error = dquot_transfer(inode, attr); if (error) { ext4_journal_stop(handle); return error; } /* Update corresponding info in inode so that everything is in * one transaction */ if (attr->ia_valid & ATTR_UID) inode->i_uid = attr->ia_uid; if (attr->ia_valid & ATTR_GID) inode->i_gid = attr->ia_gid; error = ext4_mark_inode_dirty(handle, inode); ext4_journal_stop(handle); } if (attr->ia_valid & ATTR_SIZE) { if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); if (attr->ia_size > sbi->s_bitmap_maxbytes) return -EFBIG; } } if (S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE && (attr->ia_size < inode->i_size || (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))) { handle_t *handle; handle = ext4_journal_start(inode, 3); if (IS_ERR(handle)) { error = PTR_ERR(handle); goto err_out; } if (ext4_handle_valid(handle)) { error = ext4_orphan_add(handle, inode); orphan = 1; } EXT4_I(inode)->i_disksize = attr->ia_size; rc = ext4_mark_inode_dirty(handle, inode); if (!error) error = rc; ext4_journal_stop(handle); if (ext4_should_order_data(inode)) { error = ext4_begin_ordered_truncate(inode, attr->ia_size); if (error) { /* Do as much error cleanup as possible */ handle = ext4_journal_start(inode, 3); if (IS_ERR(handle)) { ext4_orphan_del(NULL, inode); goto err_out; } ext4_orphan_del(handle, inode); orphan = 0; ext4_journal_stop(handle); goto err_out; } } /* ext4_truncate will clear the flag */ if ((ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))) ext4_truncate(inode); } if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size != i_size_read(inode)) rc = vmtruncate(inode, attr->ia_size); if (!rc) { setattr_copy(inode, attr); mark_inode_dirty(inode); } /* * If the call to ext4_truncate failed to get a transaction handle at * all, we need to clean up the in-core orphan list manually. */ if (orphan && inode->i_nlink) ext4_orphan_del(NULL, inode); if (!rc && (ia_valid & ATTR_MODE)) rc = ext4_acl_chmod(inode); err_out: ext4_std_error(inode->i_sb, error); if (!error) error = rc; return error; } int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct inode *inode; unsigned long delalloc_blocks; inode = dentry->d_inode; generic_fillattr(inode, stat); /* * We can't update i_blocks if the block allocation is delayed * otherwise in the case of system crash before the real block * allocation is done, we will have i_blocks inconsistent with * on-disk file blocks. * We always keep i_blocks updated together with real * allocation. But to not confuse with user, stat * will return the blocks that include the delayed allocation * blocks for this file. */ delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks; stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9; return 0; } static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks, int chunk) { int indirects; /* if nrblocks are contiguous */ if (chunk) { /* * With N contiguous data blocks, we need at most * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks, * 2 dindirect blocks, and 1 tindirect block */ return DIV_ROUND_UP(nrblocks, EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4; } /* * if nrblocks are not contiguous, worse case, each block touch * a indirect block, and each indirect block touch a double indirect * block, plus a triple indirect block */ indirects = nrblocks * 2 + 1; return indirects; } static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk) { if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) return ext4_indirect_trans_blocks(inode, nrblocks, chunk); return ext4_ext_index_trans_blocks(inode, nrblocks, chunk); } /* * Account for index blocks, block groups bitmaps and block group * descriptor blocks if modify datablocks and index blocks * worse case, the indexs blocks spread over different block groups * * If datablocks are discontiguous, they are possible to spread over * different block groups too. If they are contiuguous, with flexbg, * they could still across block group boundary. * * Also account for superblock, inode, quota and xattr blocks */ static int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk) { ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb); int gdpblocks; int idxblocks; int ret = 0; /* * How many index blocks need to touch to modify nrblocks? * The "Chunk" flag indicating whether the nrblocks is * physically contiguous on disk * * For Direct IO and fallocate, they calls get_block to allocate * one single extent at a time, so they could set the "Chunk" flag */ idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk); ret = idxblocks; /* * Now let's see how many group bitmaps and group descriptors need * to account */ groups = idxblocks; if (chunk) groups += 1; else groups += nrblocks; gdpblocks = groups; if (groups > ngroups) groups = ngroups; if (groups > EXT4_SB(inode->i_sb)->s_gdb_count) gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count; /* bitmaps and block group descriptor blocks */ ret += groups + gdpblocks; /* Blocks for super block, inode, quota and xattr blocks */ ret += EXT4_META_TRANS_BLOCKS(inode->i_sb); return ret; } /* * Calculate the total number of credits to reserve to fit * the modification of a single pages into a single transaction, * which may include multiple chunks of block allocations. * * This could be called via ext4_write_begin() * * We need to consider the worse case, when * one new block per extent. */ int ext4_writepage_trans_blocks(struct inode *inode) { int bpp = ext4_journal_blocks_per_page(inode); int ret; ret = ext4_meta_trans_blocks(inode, bpp, 0); /* Account for data blocks for journalled mode */ if (ext4_should_journal_data(inode)) ret += bpp; return ret; } /* * Calculate the journal credits for a chunk of data modification. * * This is called from DIO, fallocate or whoever calling * ext4_map_blocks() to map/allocate a chunk of contiguous disk blocks. * * journal buffers for data blocks are not included here, as DIO * and fallocate do no need to journal data buffers. */ int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks) { return ext4_meta_trans_blocks(inode, nrblocks, 1); } /* * The caller must have previously called ext4_reserve_inode_write(). * Give this, we know that the caller already has write access to iloc->bh. */ int ext4_mark_iloc_dirty(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { int err = 0; if (test_opt(inode->i_sb, I_VERSION)) inode_inc_iversion(inode); /* the do_update_inode consumes one bh->b_count */ get_bh(iloc->bh); /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */ err = ext4_do_update_inode(handle, inode, iloc); put_bh(iloc->bh); return err; } /* * On success, We end up with an outstanding reference count against * iloc->bh. This _must_ be cleaned up later. */ int ext4_reserve_inode_write(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { int err; err = ext4_get_inode_loc(inode, iloc); if (!err) { BUFFER_TRACE(iloc->bh, "get_write_access"); err = ext4_journal_get_write_access(handle, iloc->bh); if (err) { brelse(iloc->bh); iloc->bh = NULL; } } ext4_std_error(inode->i_sb, err); return err; } /* * Expand an inode by new_extra_isize bytes. * Returns 0 on success or negative error number on failure. */ static int ext4_expand_extra_isize(struct inode *inode, unsigned int new_extra_isize, struct ext4_iloc iloc, handle_t *handle) { struct ext4_inode *raw_inode; struct ext4_xattr_ibody_header *header; if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) return 0; raw_inode = ext4_raw_inode(&iloc); header = IHDR(inode, raw_inode); /* No extended attributes present */ if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR) || header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) { memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0, new_extra_isize); EXT4_I(inode)->i_extra_isize = new_extra_isize; return 0; } /* try to expand with EAs present */ return ext4_expand_extra_isize_ea(inode, new_extra_isize, raw_inode, handle); } /* * What we do here is to mark the in-core inode as clean with respect to inode * dirtiness (it may still be data-dirty). * This means that the in-core inode may be reaped by prune_icache * without having to perform any I/O. This is a very good thing, * because *any* task may call prune_icache - even ones which * have a transaction open against a different journal. * * Is this cheating? Not really. Sure, we haven't written the * inode out, but prune_icache isn't a user-visible syncing function. * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync) * we start and wait on commits. * * Is this efficient/effective? Well, we're being nice to the system * by cleaning up our inodes proactively so they can be reaped * without I/O. But we are potentially leaving up to five seconds' * worth of inodes floating about which prune_icache wants us to * write out. One way to fix that would be to get prune_icache() * to do a write_super() to free up some memory. It has the desired * effect. */ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) { struct ext4_iloc iloc; struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); static unsigned int mnt_count; int err, ret; might_sleep(); trace_ext4_mark_inode_dirty(inode, _RET_IP_); err = ext4_reserve_inode_write(handle, inode, &iloc); if (ext4_handle_valid(handle) && EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize && !ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) { /* * We need extra buffer credits since we may write into EA block * with this same handle. If journal_extend fails, then it will * only result in a minor loss of functionality for that inode. * If this is felt to be critical, then e2fsck should be run to * force a large enough s_min_extra_isize. */ if ((jbd2_journal_extend(handle, EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) { ret = ext4_expand_extra_isize(inode, sbi->s_want_extra_isize, iloc, handle); if (ret) { ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); if (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count)) { ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete" " some EAs or run e2fsck.", inode->i_ino); mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count); } } } } if (!err) err = ext4_mark_iloc_dirty(handle, inode, &iloc); return err; } /* * ext4_dirty_inode() is called from __mark_inode_dirty() * * We're really interested in the case where a file is being extended. * i_size has been changed by generic_commit_write() and we thus need * to include the updated inode in the current transaction. * * Also, dquot_alloc_block() will always dirty the inode when blocks * are allocated to the file. * * If the inode is marked synchronous, we don't honour that here - doing * so would cause a commit on atime updates, which we don't bother doing. * We handle synchronous inodes at the highest possible level. */ void ext4_dirty_inode(struct inode *inode) { handle_t *handle; handle = ext4_journal_start(inode, 2); if (IS_ERR(handle)) goto out; ext4_mark_inode_dirty(handle, inode); ext4_journal_stop(handle); out: return; } #if 0 /* * Bind an inode's backing buffer_head into this transaction, to prevent * it from being flushed to disk early. Unlike * ext4_reserve_inode_write, this leaves behind no bh reference and * returns no iloc structure, so the caller needs to repeat the iloc * lookup to mark the inode dirty later. */ static int ext4_pin_inode(handle_t *handle, struct inode *inode) { struct ext4_iloc iloc; int err = 0; if (handle) { err = ext4_get_inode_loc(inode, &iloc); if (!err) { BUFFER_TRACE(iloc.bh, "get_write_access"); err = jbd2_journal_get_write_access(handle, iloc.bh); if (!err) err = ext4_handle_dirty_metadata(handle, NULL, iloc.bh); brelse(iloc.bh); } } ext4_std_error(inode->i_sb, err); return err; } #endif int ext4_change_inode_journal_flag(struct inode *inode, int val) { journal_t *journal; handle_t *handle; int err; /* * We have to be very careful here: changing a data block's * journaling status dynamically is dangerous. If we write a * data block to the journal, change the status and then delete * that block, we risk forgetting to revoke the old log record * from the journal and so a subsequent replay can corrupt data. * So, first we make sure that the journal is empty and that * nobody is changing anything. */ journal = EXT4_JOURNAL(inode); if (!journal) return 0; if (is_journal_aborted(journal)) return -EROFS; jbd2_journal_lock_updates(journal); jbd2_journal_flush(journal); /* * OK, there are no updates running now, and all cached data is * synced to disk. We are now in a completely consistent state * which doesn't have anything in the journal, and we know that * no filesystem updates are running, so it is safe to modify * the inode's in-core data-journaling state flag now. */ if (val) ext4_set_inode_flag(inode, EXT4_INODE_JOURNAL_DATA); else ext4_clear_inode_flag(inode, EXT4_INODE_JOURNAL_DATA); ext4_set_aops(inode); jbd2_journal_unlock_updates(journal); /* Finally we can mark the inode as dirty. */ handle = ext4_journal_start(inode, 1); if (IS_ERR(handle)) return PTR_ERR(handle); err = ext4_mark_inode_dirty(handle, inode); ext4_handle_sync(handle); ext4_journal_stop(handle); ext4_std_error(inode->i_sb, err); return err; } static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh) { return !buffer_mapped(bh); } int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) { struct page *page = vmf->page; loff_t size; unsigned long len; int ret = -EINVAL; void *fsdata; struct file *file = vma->vm_file; struct inode *inode = file->f_path.dentry->d_inode; struct address_space *mapping = inode->i_mapping; /* * Get i_alloc_sem to stop truncates messing with the inode. We cannot * get i_mutex because we are already holding mmap_sem. */ down_read(&inode->i_alloc_sem); size = i_size_read(inode); if (page->mapping != mapping || size <= page_offset(page) || !PageUptodate(page)) { /* page got truncated from under us? */ goto out_unlock; } ret = 0; if (PageMappedToDisk(page)) goto out_unlock; if (page->index == size >> PAGE_CACHE_SHIFT) len = size & ~PAGE_CACHE_MASK; else len = PAGE_CACHE_SIZE; lock_page(page); /* * return if we have all the buffers mapped. This avoid * the need to call write_begin/write_end which does a * journal_start/journal_stop which can block and take * long time */ if (page_has_buffers(page)) { if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, ext4_bh_unmapped)) { unlock_page(page); goto out_unlock; } } unlock_page(page); /* * OK, we need to fill the hole... Do write_begin write_end * to do block allocation/reservation.We are not holding * inode.i__mutex here. That allow * parallel write_begin, * write_end call. lock_page prevent this from happening * on the same page though */ ret = mapping->a_ops->write_begin(file, mapping, page_offset(page), len, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); if (ret < 0) goto out_unlock; ret = mapping->a_ops->write_end(file, mapping, page_offset(page), len, len, page, fsdata); if (ret < 0) goto out_unlock; ret = 0; out_unlock: if (ret) ret = VM_FAULT_SIGBUS; up_read(&inode->i_alloc_sem); return ret; }