/* * linux/fs/ext2/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@dcs.ed.ac.uk), 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 ext2_get_block() by Al Viro, 2000 */ #include #include #include #include #include #include #include #include #include #include #include "ext2.h" #include "acl.h" #include "xip.h" MODULE_AUTHOR("Remy Card and others"); MODULE_DESCRIPTION("Second Extended Filesystem"); MODULE_LICENSE("GPL"); static int __ext2_write_inode(struct inode *inode, int do_sync); /* * Test whether an inode is a fast symlink. */ static inline int ext2_inode_is_fast_symlink(struct inode *inode) { int ea_blocks = EXT2_I(inode)->i_file_acl ? (inode->i_sb->s_blocksize >> 9) : 0; return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0); } static void ext2_truncate_blocks(struct inode *inode, loff_t offset); static void ext2_write_failed(struct address_space *mapping, loff_t to) { struct inode *inode = mapping->host; if (to > inode->i_size) { truncate_pagecache(inode, to, inode->i_size); ext2_truncate_blocks(inode, inode->i_size); } } /* * Called at the last iput() if i_nlink is zero. */ void ext2_delete_inode (struct inode * inode) { if (!is_bad_inode(inode)) dquot_initialize(inode); truncate_inode_pages(&inode->i_data, 0); if (is_bad_inode(inode)) goto no_delete; EXT2_I(inode)->i_dtime = get_seconds(); mark_inode_dirty(inode); __ext2_write_inode(inode, inode_needs_sync(inode)); inode->i_size = 0; if (inode->i_blocks) ext2_truncate_blocks(inode, 0); ext2_free_inode (inode); return; no_delete: 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; } static inline int verify_chain(Indirect *from, Indirect *to) { while (from <= to && from->key == *from->p) from++; return (from > to); } /** * ext2_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 ext2 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 ext2_block_to_path(struct inode *inode, long i_block, int offsets[4], int *boundary) { int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb); int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb); const long direct_blocks = EXT2_NDIR_BLOCKS, indirect_blocks = ptrs, double_blocks = (1 << (ptrs_bits * 2)); int n = 0; int final = 0; if (i_block < 0) { ext2_msg(inode->i_sb, KERN_WARNING, "warning: %s: block < 0", __func__); } else if (i_block < direct_blocks) { offsets[n++] = i_block; final = direct_blocks; } else if ( (i_block -= direct_blocks) < indirect_blocks) { offsets[n++] = EXT2_IND_BLOCK; offsets[n++] = i_block; final = ptrs; } else if ((i_block -= indirect_blocks) < double_blocks) { offsets[n++] = EXT2_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++] = EXT2_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 { ext2_msg(inode->i_sb, KERN_WARNING, "warning: %s: block is too big", __func__); } if (boundary) *boundary = final - 1 - (i_block & (ptrs - 1)); return n; } /** * ext2_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 notices that chain had been changed while it was reading * (ditto, *@err == -EAGAIN) * or when it reads all @depth-1 indirect blocks successfully and finds * the whole chain, all way to the data (returns %NULL, *err == 0). */ static Indirect *ext2_get_branch(struct inode *inode, int depth, int *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, EXT2_I(inode)->i_data + *offsets); if (!p->key) goto no_block; while (--depth) { bh = sb_bread(sb, le32_to_cpu(p->key)); if (!bh) goto failure; read_lock(&EXT2_I(inode)->i_meta_lock); if (!verify_chain(chain, p)) goto changed; add_chain(++p, bh, (__le32*)bh->b_data + *++offsets); read_unlock(&EXT2_I(inode)->i_meta_lock); if (!p->key) goto no_block; } return NULL; changed: read_unlock(&EXT2_I(inode)->i_meta_lock); brelse(bh); *err = -EAGAIN; goto no_block; failure: *err = -EIO; no_block: return p; } /** * ext2_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 ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind) { struct ext2_inode_info *ei = EXT2_I(inode); __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data; __le32 *p; ext2_fsblk_t bg_start; ext2_fsblk_t colour; /* 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 refered from inode itself? OK, just put it into * the same cylinder group then. */ bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group); colour = (current->pid % 16) * (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16); return bg_start + colour; } /** * ext2_find_goal - find a preferred place for allocation. * @inode: owner * @block: block we want * @partial: pointer to the last triple within a chain * * Returns preferred place for a block (the goal). */ static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block, Indirect *partial) { struct ext2_block_alloc_info *block_i; block_i = EXT2_I(inode)->i_block_alloc_info; /* * try the heuristic for sequential allocation, * failing that at least try to get decent locality. */ if (block_i && (block == block_i->last_alloc_logical_block + 1) && (block_i->last_alloc_physical_block != 0)) { return block_i->last_alloc_physical_block + 1; } return ext2_find_near(inode, partial); } /** * ext2_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 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks, int blocks_to_boundary) { unsigned long 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 don't hanel 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; } /** * ext2_alloc_blocks: multiple allocate blocks needed for a branch * @indirect_blks: the number of blocks need to allocate for indirect * blocks * * @new_blocks: on return it will store the new block numbers for * the indirect blocks(if needed) and the first direct block, * @blks: on return it will store the total number of allocated * direct blocks */ static int ext2_alloc_blocks(struct inode *inode, ext2_fsblk_t goal, int indirect_blks, int blks, ext2_fsblk_t new_blocks[4], int *err) { int target, i; unsigned long count = 0; int index = 0; ext2_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) */ target = blks + indirect_blks; while (1) { count = target; /* allocating blocks for indirect blocks and direct blocks */ current_block = ext2_new_blocks(inode,goal,&count,err); if (*err) goto failed_out; target -= count; /* allocate blocks for indirect blocks */ while (index < indirect_blks && count) { new_blocks[index++] = current_block++; count--; } if (count > 0) break; } /* save the new block number for the first direct block */ new_blocks[index] = current_block; /* total number of blocks allocated for direct blocks */ ret = count; *err = 0; return ret; failed_out: for (i = 0; i key). Upon the exit we have the same * picture as after the successful ext2_get_block(), excpet 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 * ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain * as described above and return 0. */ static int ext2_alloc_branch(struct inode *inode, int indirect_blks, int *blks, ext2_fsblk_t goal, int *offsets, Indirect *branch) { int blocksize = inode->i_sb->s_blocksize; int i, n = 0; int err = 0; struct buffer_head *bh; int num; ext2_fsblk_t new_blocks[4]; ext2_fsblk_t current_block; num = ext2_alloc_blocks(inode, 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]); branch[n].bh = bh; lock_buffer(bh); 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); } set_buffer_uptodate(bh); unlock_buffer(bh); mark_buffer_dirty_inode(bh, inode); /* We used to sync bh here if IS_SYNC(inode). * But we now rely upon generic_write_sync() * and b_inode_buffers. But not for directories. */ if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) sync_dirty_buffer(bh); } *blks = num; return err; } /** * ext2_splice_branch - splice the allocated branch onto inode. * @inode: owner * @block: (logical) number of block we are adding * @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 void ext2_splice_branch(struct inode *inode, long block, Indirect *where, int num, int blks) { int i; struct ext2_block_alloc_info *block_i; ext2_fsblk_t current_block; block_i = EXT2_I(inode)->i_block_alloc_info; /* XXX LOCKING probably should have i_meta_lock ?*/ /* 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++); } /* * update the most recently allocated logical & physical block * in i_block_alloc_info, to assist find the proper goal block for next * allocation */ if (block_i) { block_i->last_alloc_logical_block = block + blks - 1; block_i->last_alloc_physical_block = le32_to_cpu(where[num].key) + blks - 1; } /* We are done with atomic stuff, now do the rest of housekeeping */ /* had we spliced it onto indirect block? */ if (where->bh) mark_buffer_dirty_inode(where->bh, inode); inode->i_ctime = CURRENT_TIME_SEC; mark_inode_dirty(inode); } /* * 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. */ static int ext2_get_blocks(struct inode *inode, sector_t iblock, unsigned long maxblocks, struct buffer_head *bh_result, int create) { int err = -EIO; int offsets[4]; Indirect chain[4]; Indirect *partial; ext2_fsblk_t goal; int indirect_blks; int blocks_to_boundary = 0; int depth; struct ext2_inode_info *ei = EXT2_I(inode); int count = 0; ext2_fsblk_t first_block = 0; depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary); if (depth == 0) return (err); partial = ext2_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); clear_buffer_new(bh_result); /* What's this do? */ count++; /*map more blocks*/ while (count < maxblocks && count <= blocks_to_boundary) { ext2_fsblk_t blk; if (!verify_chain(chain, chain + depth - 1)) { /* * Indirect block might be removed by * truncate while we were reading it. * Handling of that case: forget what we've * got now, go to reread. */ err = -EAGAIN; count = 0; break; } blk = le32_to_cpu(*(chain[depth-1].p + count)); if (blk == first_block + count) count++; else break; } if (err != -EAGAIN) goto got_it; } /* Next simple case - plain lookup or failed read of indirect block */ if (!create || err == -EIO) goto cleanup; mutex_lock(&ei->truncate_mutex); /* * If the indirect block is missing while we are reading * the chain(ext3_get_branch() returns -EAGAIN err), or * if the chain has been changed after we grab the semaphore, * (either because another process truncated this branch, or * another get_block allocated this branch) re-grab the chain to see if * the request block has been allocated or not. * * Since we already block the truncate/other get_block * at this point, we will have the current copy of the chain when we * splice the branch into the tree. */ if (err == -EAGAIN || !verify_chain(chain, partial)) { while (partial > chain) { brelse(partial->bh); partial--; } partial = ext2_get_branch(inode, depth, offsets, chain, &err); if (!partial) { count++; mutex_unlock(&ei->truncate_mutex); if (err) goto cleanup; clear_buffer_new(bh_result); goto got_it; } } /* * Okay, we need to do block allocation. Lazily initialize the block * allocation info here if necessary */ if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info)) ext2_init_block_alloc_info(inode); goal = ext2_find_goal(inode, iblock, 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 = ext2_blks_to_allocate(partial, indirect_blks, maxblocks, blocks_to_boundary); /* * XXX ???? Block out ext2_truncate while we alter the tree */ err = ext2_alloc_branch(inode, indirect_blks, &count, goal, offsets + (partial - chain), partial); if (err) { mutex_unlock(&ei->truncate_mutex); goto cleanup; } if (ext2_use_xip(inode->i_sb)) { /* * we need to clear the block */ err = ext2_clear_xip_target (inode, le32_to_cpu(chain[depth-1].key)); if (err) { mutex_unlock(&ei->truncate_mutex); goto cleanup; } } ext2_splice_branch(inode, iblock, partial, indirect_blks, count); mutex_unlock(&ei->truncate_mutex); set_buffer_new(bh_result); got_it: map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key)); if (count > blocks_to_boundary) set_buffer_boundary(bh_result); err = count; /* Clean up and exit */ partial = chain + depth - 1; /* the whole chain */ cleanup: while (partial > chain) { brelse(partial->bh); partial--; } return err; } int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { unsigned max_blocks = bh_result->b_size >> inode->i_blkbits; int ret = ext2_get_blocks(inode, iblock, max_blocks, bh_result, create); if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); ret = 0; } return ret; } int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len) { return generic_block_fiemap(inode, fieinfo, start, len, ext2_get_block); } static int ext2_writepage(struct page *page, struct writeback_control *wbc) { return block_write_full_page(page, ext2_get_block, wbc); } static int ext2_readpage(struct file *file, struct page *page) { return mpage_readpage(page, ext2_get_block); } static int ext2_readpages(struct file *file, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { return mpage_readpages(mapping, pages, nr_pages, ext2_get_block); } int __ext2_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { return block_write_begin_newtrunc(file, mapping, pos, len, flags, pagep, fsdata, ext2_get_block); } static int ext2_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { int ret; *pagep = NULL; ret = __ext2_write_begin(file, mapping, pos, len, flags, pagep, fsdata); if (ret < 0) ext2_write_failed(mapping, pos + len); return ret; } static int ext2_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { int ret; ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata); if (ret < len) ext2_write_failed(mapping, pos + len); return ret; } static int ext2_nobh_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { int ret; ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata, ext2_get_block); if (ret < 0) ext2_write_failed(mapping, pos + len); return ret; } static int ext2_nobh_writepage(struct page *page, struct writeback_control *wbc) { return nobh_writepage(page, ext2_get_block, wbc); } static sector_t ext2_bmap(struct address_space *mapping, sector_t block) { return generic_block_bmap(mapping,block,ext2_get_block); } static ssize_t ext2_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 address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; ssize_t ret; ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ext2_get_block, NULL); if (ret < 0 && (rw & WRITE)) ext2_write_failed(mapping, offset + iov_length(iov, nr_segs)); return ret; } static int ext2_writepages(struct address_space *mapping, struct writeback_control *wbc) { return mpage_writepages(mapping, wbc, ext2_get_block); } const struct address_space_operations ext2_aops = { .readpage = ext2_readpage, .readpages = ext2_readpages, .writepage = ext2_writepage, .sync_page = block_sync_page, .write_begin = ext2_write_begin, .write_end = ext2_write_end, .bmap = ext2_bmap, .direct_IO = ext2_direct_IO, .writepages = ext2_writepages, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; const struct address_space_operations ext2_aops_xip = { .bmap = ext2_bmap, .get_xip_mem = ext2_get_xip_mem, }; const struct address_space_operations ext2_nobh_aops = { .readpage = ext2_readpage, .readpages = ext2_readpages, .writepage = ext2_nobh_writepage, .sync_page = block_sync_page, .write_begin = ext2_nobh_write_begin, .write_end = nobh_write_end, .bmap = ext2_bmap, .direct_IO = ext2_direct_IO, .writepages = ext2_writepages, .migratepage = buffer_migrate_page, .error_remove_page = generic_error_remove_page, }; /* * 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; } /** * ext2_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 ext2_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 ext2_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 refered 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 ext2_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].p * (no partially truncated stuff there). */ static Indirect *ext2_find_shared(struct inode *inode, int depth, int offsets[4], Indirect chain[4], __le32 *top) { Indirect *partial, *p; int k, err; *top = 0; for (k = depth; k > 1 && !offsets[k-1]; k--) ; partial = ext2_get_branch(inode, k, offsets, chain, &err); 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. */ write_lock(&EXT2_I(inode)->i_meta_lock); if (!partial->key && *partial->p) { write_unlock(&EXT2_I(inode)->i_meta_lock); 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; *p->p = 0; } write_unlock(&EXT2_I(inode)->i_meta_lock); while(partial > p) { brelse(partial->bh); partial--; } no_top: return partial; } /** * ext2_free_data - free a list of data blocks * @inode: inode we are dealing with * @p: array of block numbers * @q: points immediately past the end of array * * We are freeing all blocks refered from that array (numbers are * stored as little-endian 32-bit) and updating @inode->i_blocks * appropriately. */ static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q) { unsigned long block_to_free = 0, count = 0; unsigned long nr; for ( ; p < q ; p++) { nr = le32_to_cpu(*p); if (nr) { *p = 0; /* accumulate blocks to free if they're contiguous */ if (count == 0) goto free_this; else if (block_to_free == nr - count) count++; else { mark_inode_dirty(inode); ext2_free_blocks (inode, block_to_free, count); free_this: block_to_free = nr; count = 1; } } } if (count > 0) { mark_inode_dirty(inode); ext2_free_blocks (inode, block_to_free, count); } } /** * ext2_free_branches - free an array of branches * @inode: inode we are dealing with * @p: array of block numbers * @q: pointer immediately past the end of array * @depth: depth of the branches to free * * We are freeing all blocks refered from these branches (numbers are * stored as little-endian 32-bit) and updating @inode->i_blocks * appropriately. */ static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth) { struct buffer_head * bh; unsigned long nr; if (depth--) { int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb); for ( ; p < q ; p++) { nr = le32_to_cpu(*p); if (!nr) continue; *p = 0; bh = sb_bread(inode->i_sb, nr); /* * A read failure? Report error and clear slot * (should be rare). */ if (!bh) { ext2_error(inode->i_sb, "ext2_free_branches", "Read failure, inode=%ld, block=%ld", inode->i_ino, nr); continue; } ext2_free_branches(inode, (__le32*)bh->b_data, (__le32*)bh->b_data + addr_per_block, depth); bforget(bh); ext2_free_blocks(inode, nr, 1); mark_inode_dirty(inode); } } else ext2_free_data(inode, p, q); } static void __ext2_truncate_blocks(struct inode *inode, loff_t offset) { __le32 *i_data = EXT2_I(inode)->i_data; struct ext2_inode_info *ei = EXT2_I(inode); int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb); int offsets[4]; Indirect chain[4]; Indirect *partial; __le32 nr = 0; int n; long iblock; unsigned blocksize; blocksize = inode->i_sb->s_blocksize; iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb); n = ext2_block_to_path(inode, iblock, offsets, NULL); if (n == 0) return; /* * From here we block out all ext2_get_block() callers who want to * modify the block allocation tree. */ mutex_lock(&ei->truncate_mutex); if (n == 1) { ext2_free_data(inode, i_data+offsets[0], i_data + EXT2_NDIR_BLOCKS); goto do_indirects; } partial = ext2_find_shared(inode, n, offsets, chain, &nr); /* Kill the top of shared branch (already detached) */ if (nr) { if (partial == chain) mark_inode_dirty(inode); else mark_buffer_dirty_inode(partial->bh, inode); ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial); } /* Clear the ends of indirect blocks on the shared branch */ while (partial > chain) { ext2_free_branches(inode, partial->p + 1, (__le32*)partial->bh->b_data+addr_per_block, (chain+n-1) - partial); mark_buffer_dirty_inode(partial->bh, inode); brelse (partial->bh); partial--; } do_indirects: /* Kill the remaining (whole) subtrees */ switch (offsets[0]) { default: nr = i_data[EXT2_IND_BLOCK]; if (nr) { i_data[EXT2_IND_BLOCK] = 0; mark_inode_dirty(inode); ext2_free_branches(inode, &nr, &nr+1, 1); } case EXT2_IND_BLOCK: nr = i_data[EXT2_DIND_BLOCK]; if (nr) { i_data[EXT2_DIND_BLOCK] = 0; mark_inode_dirty(inode); ext2_free_branches(inode, &nr, &nr+1, 2); } case EXT2_DIND_BLOCK: nr = i_data[EXT2_TIND_BLOCK]; if (nr) { i_data[EXT2_TIND_BLOCK] = 0; mark_inode_dirty(inode); ext2_free_branches(inode, &nr, &nr+1, 3); } case EXT2_TIND_BLOCK: ; } ext2_discard_reservation(inode); mutex_unlock(&ei->truncate_mutex); } static void ext2_truncate_blocks(struct inode *inode, loff_t offset) { /* * XXX: it seems like a bug here that we don't allow * IS_APPEND inode to have blocks-past-i_size trimmed off. * review and fix this. * * Also would be nice to be able to handle IO errors and such, * but that's probably too much to ask. */ if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) return; if (ext2_inode_is_fast_symlink(inode)) return; if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) return; __ext2_truncate_blocks(inode, offset); } int ext2_setsize(struct inode *inode, loff_t newsize) { loff_t oldsize; int error; error = inode_newsize_ok(inode, newsize); if (error) return error; if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))) return -EINVAL; if (ext2_inode_is_fast_symlink(inode)) return -EINVAL; if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) return -EPERM; if (mapping_is_xip(inode->i_mapping)) error = xip_truncate_page(inode->i_mapping, newsize); else if (test_opt(inode->i_sb, NOBH)) error = nobh_truncate_page(inode->i_mapping, newsize, ext2_get_block); else error = block_truncate_page(inode->i_mapping, newsize, ext2_get_block); if (error) return error; oldsize = inode->i_size; i_size_write(inode, newsize); truncate_pagecache(inode, oldsize, newsize); __ext2_truncate_blocks(inode, newsize); inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC; if (inode_needs_sync(inode)) { sync_mapping_buffers(inode->i_mapping); ext2_sync_inode (inode); } else { mark_inode_dirty(inode); } return 0; } static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino, struct buffer_head **p) { struct buffer_head * bh; unsigned long block_group; unsigned long block; unsigned long offset; struct ext2_group_desc * gdp; *p = NULL; if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) || ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count)) goto Einval; block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb); gdp = ext2_get_group_desc(sb, block_group, NULL); if (!gdp) goto Egdp; /* * Figure out the offset within the block group inode table */ offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb); block = le32_to_cpu(gdp->bg_inode_table) + (offset >> EXT2_BLOCK_SIZE_BITS(sb)); if (!(bh = sb_bread(sb, block))) goto Eio; *p = bh; offset &= (EXT2_BLOCK_SIZE(sb) - 1); return (struct ext2_inode *) (bh->b_data + offset); Einval: ext2_error(sb, "ext2_get_inode", "bad inode number: %lu", (unsigned long) ino); return ERR_PTR(-EINVAL); Eio: ext2_error(sb, "ext2_get_inode", "unable to read inode block - inode=%lu, block=%lu", (unsigned long) ino, block); Egdp: return ERR_PTR(-EIO); } void ext2_set_inode_flags(struct inode *inode) { unsigned int flags = EXT2_I(inode)->i_flags; inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); if (flags & EXT2_SYNC_FL) inode->i_flags |= S_SYNC; if (flags & EXT2_APPEND_FL) inode->i_flags |= S_APPEND; if (flags & EXT2_IMMUTABLE_FL) inode->i_flags |= S_IMMUTABLE; if (flags & EXT2_NOATIME_FL) inode->i_flags |= S_NOATIME; if (flags & EXT2_DIRSYNC_FL) inode->i_flags |= S_DIRSYNC; } /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */ void ext2_get_inode_flags(struct ext2_inode_info *ei) { unsigned int flags = ei->vfs_inode.i_flags; ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL| EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL); if (flags & S_SYNC) ei->i_flags |= EXT2_SYNC_FL; if (flags & S_APPEND) ei->i_flags |= EXT2_APPEND_FL; if (flags & S_IMMUTABLE) ei->i_flags |= EXT2_IMMUTABLE_FL; if (flags & S_NOATIME) ei->i_flags |= EXT2_NOATIME_FL; if (flags & S_DIRSYNC) ei->i_flags |= EXT2_DIRSYNC_FL; } struct inode *ext2_iget (struct super_block *sb, unsigned long ino) { struct ext2_inode_info *ei; struct buffer_head * bh; struct ext2_inode *raw_inode; struct inode *inode; long ret = -EIO; int n; inode = iget_locked(sb, ino); if (!inode) return ERR_PTR(-ENOMEM); if (!(inode->i_state & I_NEW)) return inode; ei = EXT2_I(inode); ei->i_block_alloc_info = NULL; raw_inode = ext2_get_inode(inode->i_sb, ino, &bh); if (IS_ERR(raw_inode)) { ret = PTR_ERR(raw_inode); goto bad_inode; } 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); inode->i_size = le32_to_cpu(raw_inode->i_size); inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime); inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime); inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime); inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 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 && (inode->i_mode == 0 || ei->i_dtime)) { /* this inode is deleted */ brelse (bh); ret = -ESTALE; goto bad_inode; } inode->i_blocks = le32_to_cpu(raw_inode->i_blocks); ei->i_flags = le32_to_cpu(raw_inode->i_flags); ei->i_faddr = le32_to_cpu(raw_inode->i_faddr); ei->i_frag_no = raw_inode->i_frag; ei->i_frag_size = raw_inode->i_fsize; ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl); ei->i_dir_acl = 0; if (S_ISREG(inode->i_mode)) inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32; else ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl); ei->i_dtime = 0; inode->i_generation = le32_to_cpu(raw_inode->i_generation); ei->i_state = 0; ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb); ei->i_dir_start_lookup = 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 (n = 0; n < EXT2_N_BLOCKS; n++) ei->i_data[n] = raw_inode->i_block[n]; if (S_ISREG(inode->i_mode)) { inode->i_op = &ext2_file_inode_operations; if (ext2_use_xip(inode->i_sb)) { inode->i_mapping->a_ops = &ext2_aops_xip; inode->i_fop = &ext2_xip_file_operations; } else if (test_opt(inode->i_sb, NOBH)) { inode->i_mapping->a_ops = &ext2_nobh_aops; inode->i_fop = &ext2_file_operations; } else { inode->i_mapping->a_ops = &ext2_aops; inode->i_fop = &ext2_file_operations; } } else if (S_ISDIR(inode->i_mode)) { inode->i_op = &ext2_dir_inode_operations; inode->i_fop = &ext2_dir_operations; if (test_opt(inode->i_sb, NOBH)) inode->i_mapping->a_ops = &ext2_nobh_aops; else inode->i_mapping->a_ops = &ext2_aops; } else if (S_ISLNK(inode->i_mode)) { if (ext2_inode_is_fast_symlink(inode)) { inode->i_op = &ext2_fast_symlink_inode_operations; nd_terminate_link(ei->i_data, inode->i_size, sizeof(ei->i_data) - 1); } else { inode->i_op = &ext2_symlink_inode_operations; if (test_opt(inode->i_sb, NOBH)) inode->i_mapping->a_ops = &ext2_nobh_aops; else inode->i_mapping->a_ops = &ext2_aops; } } else { inode->i_op = &ext2_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]))); } brelse (bh); ext2_set_inode_flags(inode); unlock_new_inode(inode); return inode; bad_inode: iget_failed(inode); return ERR_PTR(ret); } static int __ext2_write_inode(struct inode *inode, int do_sync) { struct ext2_inode_info *ei = EXT2_I(inode); struct super_block *sb = inode->i_sb; ino_t ino = inode->i_ino; uid_t uid = inode->i_uid; gid_t gid = inode->i_gid; struct buffer_head * bh; struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh); int n; int err = 0; if (IS_ERR(raw_inode)) return -EIO; /* For fields not not tracking in the in-memory inode, * initialise them to zero for new inodes. */ if (ei->i_state & EXT2_STATE_NEW) memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size); ext2_get_inode_flags(ei); raw_inode->i_mode = cpu_to_le16(inode->i_mode); if (!(test_opt(sb, NO_UID32))) { raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid)); raw_inode->i_gid_low = cpu_to_le16(low_16_bits(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(uid)); raw_inode->i_gid_high = cpu_to_le16(high_16_bits(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(uid)); raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid)); raw_inode->i_uid_high = 0; raw_inode->i_gid_high = 0; } raw_inode->i_links_count = cpu_to_le16(inode->i_nlink); raw_inode->i_size = cpu_to_le32(inode->i_size); raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec); raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec); raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec); raw_inode->i_blocks = cpu_to_le32(inode->i_blocks); raw_inode->i_dtime = cpu_to_le32(ei->i_dtime); raw_inode->i_flags = cpu_to_le32(ei->i_flags); raw_inode->i_faddr = cpu_to_le32(ei->i_faddr); raw_inode->i_frag = ei->i_frag_no; raw_inode->i_fsize = ei->i_frag_size; raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl); if (!S_ISREG(inode->i_mode)) raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl); else { raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32); if (inode->i_size > 0x7fffffffULL) { if (!EXT2_HAS_RO_COMPAT_FEATURE(sb, EXT2_FEATURE_RO_COMPAT_LARGE_FILE) || EXT2_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT2_GOOD_OLD_REV)) { /* If this is the first large file * created, add a flag to the superblock. */ spin_lock(&EXT2_SB(sb)->s_lock); ext2_update_dynamic_rev(sb); EXT2_SET_RO_COMPAT_FEATURE(sb, EXT2_FEATURE_RO_COMPAT_LARGE_FILE); spin_unlock(&EXT2_SB(sb)->s_lock); ext2_write_super(sb); } } } 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 (n = 0; n < EXT2_N_BLOCKS; n++) raw_inode->i_block[n] = ei->i_data[n]; mark_buffer_dirty(bh); if (do_sync) { sync_dirty_buffer(bh); if (buffer_req(bh) && !buffer_uptodate(bh)) { printk ("IO error syncing ext2 inode [%s:%08lx]\n", sb->s_id, (unsigned long) ino); err = -EIO; } } ei->i_state &= ~EXT2_STATE_NEW; brelse (bh); return err; } int ext2_write_inode(struct inode *inode, struct writeback_control *wbc) { return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL); } int ext2_sync_inode(struct inode *inode) { struct writeback_control wbc = { .sync_mode = WB_SYNC_ALL, .nr_to_write = 0, /* sys_fsync did this */ }; return sync_inode(inode, &wbc); } int ext2_setattr(struct dentry *dentry, struct iattr *iattr) { struct inode *inode = dentry->d_inode; int error; error = inode_change_ok(inode, iattr); if (error) return error; if (is_quota_modification(inode, iattr)) dquot_initialize(inode); if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) || (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) { error = dquot_transfer(inode, iattr); if (error) return error; } if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) { error = ext2_setsize(inode, iattr->ia_size); if (error) return error; } generic_setattr(inode, iattr); if (iattr->ia_valid & ATTR_MODE) error = ext2_acl_chmod(inode); mark_inode_dirty(inode); return error; }