diff options
Diffstat (limited to 'fs/ext4/extents.c')
| -rw-r--r-- | fs/ext4/extents.c | 2075 |
1 files changed, 2075 insertions, 0 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c new file mode 100644 index 000000000000..f67b2ef6a71f --- /dev/null +++ b/fs/ext4/extents.c @@ -0,0 +1,2075 @@ +/* + * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com + * Written by Alex Tomas <alex@clusterfs.com> + * + * Architecture independence: + * Copyright (c) 2005, Bull S.A. + * Written by Pierre Peiffer <pierre.peiffer@bull.net> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public Licens + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- + */ + +/* + * Extents support for EXT4 + * + * TODO: + * - ext4*_error() should be used in some situations + * - analyze all BUG()/BUG_ON(), use -EIO where appropriate + * - smart tree reduction + */ + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/time.h> +#include <linux/ext4_jbd2.h> +#include <linux/jbd.h> +#include <linux/smp_lock.h> +#include <linux/highuid.h> +#include <linux/pagemap.h> +#include <linux/quotaops.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/ext4_fs_extents.h> +#include <asm/uaccess.h> + + +static int ext4_ext_check_header(const char *function, struct inode *inode, + struct ext4_extent_header *eh) +{ + const char *error_msg = NULL; + + if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { + error_msg = "invalid magic"; + goto corrupted; + } + if (unlikely(eh->eh_max == 0)) { + error_msg = "invalid eh_max"; + goto corrupted; + } + if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { + error_msg = "invalid eh_entries"; + goto corrupted; + } + return 0; + +corrupted: + ext4_error(inode->i_sb, function, + "bad header in inode #%lu: %s - magic %x, " + "entries %u, max %u, depth %u", + inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic), + le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max), + le16_to_cpu(eh->eh_depth)); + + return -EIO; +} + +static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed) +{ + int err; + + if (handle->h_buffer_credits > needed) + return handle; + if (!ext4_journal_extend(handle, needed)) + return handle; + err = ext4_journal_restart(handle, needed); + + return handle; +} + +/* + * could return: + * - EROFS + * - ENOMEM + */ +static int ext4_ext_get_access(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path) +{ + if (path->p_bh) { + /* path points to block */ + return ext4_journal_get_write_access(handle, path->p_bh); + } + /* path points to leaf/index in inode body */ + /* we use in-core data, no need to protect them */ + return 0; +} + +/* + * could return: + * - EROFS + * - ENOMEM + * - EIO + */ +static int ext4_ext_dirty(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path) +{ + int err; + if (path->p_bh) { + /* path points to block */ + err = ext4_journal_dirty_metadata(handle, path->p_bh); + } else { + /* path points to leaf/index in inode body */ + err = ext4_mark_inode_dirty(handle, inode); + } + return err; +} + +static int ext4_ext_find_goal(struct inode *inode, + struct ext4_ext_path *path, + unsigned long block) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + unsigned long bg_start; + unsigned long colour; + int depth; + + if (path) { + struct ext4_extent *ex; + depth = path->p_depth; + + /* try to predict block placement */ + if ((ex = path[depth].p_ext)) + return le32_to_cpu(ex->ee_start) + + (block - le32_to_cpu(ex->ee_block)); + + /* it looks index is empty + * try to find starting from index itself */ + if (path[depth].p_bh) + return path[depth].p_bh->b_blocknr; + } + + /* OK. use inode's group */ + bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) + + le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block); + colour = (current->pid % 16) * + (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); + return bg_start + colour + block; +} + +static int +ext4_ext_new_block(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path, + struct ext4_extent *ex, int *err) +{ + int goal, newblock; + + goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block)); + newblock = ext4_new_block(handle, inode, goal, err); + return newblock; +} + +static inline int ext4_ext_space_block(struct inode *inode) +{ + int size; + + size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) + / sizeof(struct ext4_extent); +#ifdef AGRESSIVE_TEST + if (size > 6) + size = 6; +#endif + return size; +} + +static inline int ext4_ext_space_block_idx(struct inode *inode) +{ + int size; + + size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header)) + / sizeof(struct ext4_extent_idx); +#ifdef AGRESSIVE_TEST + if (size > 5) + size = 5; +#endif + return size; +} + +static inline int ext4_ext_space_root(struct inode *inode) +{ + int size; + + size = sizeof(EXT4_I(inode)->i_data); + size -= sizeof(struct ext4_extent_header); + size /= sizeof(struct ext4_extent); +#ifdef AGRESSIVE_TEST + if (size > 3) + size = 3; +#endif + return size; +} + +static inline int ext4_ext_space_root_idx(struct inode *inode) +{ + int size; + + size = sizeof(EXT4_I(inode)->i_data); + size -= sizeof(struct ext4_extent_header); + size /= sizeof(struct ext4_extent_idx); +#ifdef AGRESSIVE_TEST + if (size > 4) + size = 4; +#endif + return size; +} + +#ifdef EXT_DEBUG +static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) +{ + int k, l = path->p_depth; + + ext_debug("path:"); + for (k = 0; k <= l; k++, path++) { + if (path->p_idx) { + ext_debug(" %d->%d", le32_to_cpu(path->p_idx->ei_block), + le32_to_cpu(path->p_idx->ei_leaf)); + } else if (path->p_ext) { + ext_debug(" %d:%d:%d", + le32_to_cpu(path->p_ext->ee_block), + le16_to_cpu(path->p_ext->ee_len), + le32_to_cpu(path->p_ext->ee_start)); + } else + ext_debug(" []"); + } + ext_debug("\n"); +} + +static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path) +{ + int depth = ext_depth(inode); + struct ext4_extent_header *eh; + struct ext4_extent *ex; + int i; + + if (!path) + return; + + eh = path[depth].p_hdr; + ex = EXT_FIRST_EXTENT(eh); + + for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) { + ext_debug("%d:%d:%d ", le32_to_cpu(ex->ee_block), + le16_to_cpu(ex->ee_len), + le32_to_cpu(ex->ee_start)); + } + ext_debug("\n"); +} +#else +#define ext4_ext_show_path(inode,path) +#define ext4_ext_show_leaf(inode,path) +#endif + +static void ext4_ext_drop_refs(struct ext4_ext_path *path) +{ + int depth = path->p_depth; + int i; + + for (i = 0; i <= depth; i++, path++) + if (path->p_bh) { + brelse(path->p_bh); + path->p_bh = NULL; + } +} + +/* + * binary search for closest index by given block + */ +static void +ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block) +{ + struct ext4_extent_header *eh = path->p_hdr; + struct ext4_extent_idx *r, *l, *m; + + BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC); + BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max)); + BUG_ON(le16_to_cpu(eh->eh_entries) <= 0); + + ext_debug("binsearch for %d(idx): ", block); + + l = EXT_FIRST_INDEX(eh) + 1; + r = EXT_FIRST_INDEX(eh) + le16_to_cpu(eh->eh_entries) - 1; + while (l <= r) { + m = l + (r - l) / 2; + if (block < le32_to_cpu(m->ei_block)) + r = m - 1; + else + l = m + 1; + ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ei_block, + m, m->ei_block, r, r->ei_block); + } + + path->p_idx = l - 1; + ext_debug(" -> %d->%d ", le32_to_cpu(path->p_idx->ei_block), + le32_to_cpu(path->p_idx->ei_leaf)); + +#ifdef CHECK_BINSEARCH + { + struct ext4_extent_idx *chix, *ix; + int k; + + chix = ix = EXT_FIRST_INDEX(eh); + for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) { + if (k != 0 && + le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) { + printk("k=%d, ix=0x%p, first=0x%p\n", k, + ix, EXT_FIRST_INDEX(eh)); + printk("%u <= %u\n", + le32_to_cpu(ix->ei_block), + le32_to_cpu(ix[-1].ei_block)); + } + BUG_ON(k && le32_to_cpu(ix->ei_block) + <= le32_to_cpu(ix[-1].ei_block)); + if (block < le32_to_cpu(ix->ei_block)) + break; + chix = ix; + } + BUG_ON(chix != path->p_idx); + } +#endif + +} + +/* + * binary search for closest extent by given block + */ +static void +ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block) +{ + struct ext4_extent_header *eh = path->p_hdr; + struct ext4_extent *r, *l, *m; + + BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC); + BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max)); + + if (eh->eh_entries == 0) { + /* + * this leaf is empty yet: + * we get such a leaf in split/add case + */ + return; + } + + ext_debug("binsearch for %d: ", block); + + l = EXT_FIRST_EXTENT(eh) + 1; + r = EXT_FIRST_EXTENT(eh) + le16_to_cpu(eh->eh_entries) - 1; + + while (l <= r) { + m = l + (r - l) / 2; + if (block < le32_to_cpu(m->ee_block)) + r = m - 1; + else + l = m + 1; + ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ee_block, + m, m->ee_block, r, r->ee_block); + } + + path->p_ext = l - 1; + ext_debug(" -> %d:%d:%d ", + le32_to_cpu(path->p_ext->ee_block), + le32_to_cpu(path->p_ext->ee_start), + le16_to_cpu(path->p_ext->ee_len)); + +#ifdef CHECK_BINSEARCH + { + struct ext4_extent *chex, *ex; + int k; + + chex = ex = EXT_FIRST_EXTENT(eh); + for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) { + BUG_ON(k && le32_to_cpu(ex->ee_block) + <= le32_to_cpu(ex[-1].ee_block)); + if (block < le32_to_cpu(ex->ee_block)) + break; + chex = ex; + } + BUG_ON(chex != path->p_ext); + } +#endif + +} + +int ext4_ext_tree_init(handle_t *handle, struct inode *inode) +{ + struct ext4_extent_header *eh; + + eh = ext_inode_hdr(inode); + eh->eh_depth = 0; + eh->eh_entries = 0; + eh->eh_magic = EXT4_EXT_MAGIC; + eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode)); + ext4_mark_inode_dirty(handle, inode); + ext4_ext_invalidate_cache(inode); + return 0; +} + +struct ext4_ext_path * +ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path) +{ + struct ext4_extent_header *eh; + struct buffer_head *bh; + short int depth, i, ppos = 0, alloc = 0; + + eh = ext_inode_hdr(inode); + BUG_ON(eh == NULL); + if (ext4_ext_check_header(__FUNCTION__, inode, eh)) + return ERR_PTR(-EIO); + + i = depth = ext_depth(inode); + + /* account possible depth increase */ + if (!path) { + path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 2), + GFP_NOFS); + if (!path) + return ERR_PTR(-ENOMEM); + alloc = 1; + } + memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1)); + path[0].p_hdr = eh; + + /* walk through the tree */ + while (i) { + ext_debug("depth %d: num %d, max %d\n", + ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); + ext4_ext_binsearch_idx(inode, path + ppos, block); + path[ppos].p_block = le32_to_cpu(path[ppos].p_idx->ei_leaf); + path[ppos].p_depth = i; + path[ppos].p_ext = NULL; + + bh = sb_bread(inode->i_sb, path[ppos].p_block); + if (!bh) + goto err; + + eh = ext_block_hdr(bh); + ppos++; + BUG_ON(ppos > depth); + path[ppos].p_bh = bh; + path[ppos].p_hdr = eh; + i--; + + if (ext4_ext_check_header(__FUNCTION__, inode, eh)) + goto err; + } + + path[ppos].p_depth = i; + path[ppos].p_hdr = eh; + path[ppos].p_ext = NULL; + path[ppos].p_idx = NULL; + + if (ext4_ext_check_header(__FUNCTION__, inode, eh)) + goto err; + + /* find extent */ + ext4_ext_binsearch(inode, path + ppos, block); + + ext4_ext_show_path(inode, path); + + return path; + +err: + ext4_ext_drop_refs(path); + if (alloc) + kfree(path); + return ERR_PTR(-EIO); +} + +/* + * insert new index [logical;ptr] into the block at cupr + * it check where to insert: before curp or after curp + */ +static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, + struct ext4_ext_path *curp, + int logical, int ptr) +{ + struct ext4_extent_idx *ix; + int len, err; + + if ((err = ext4_ext_get_access(handle, inode, curp))) + return err; + + BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block)); + len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx; + if (logical > le32_to_cpu(curp->p_idx->ei_block)) { + /* insert after */ + if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) { + len = (len - 1) * sizeof(struct ext4_extent_idx); + len = len < 0 ? 0 : len; + ext_debug("insert new index %d after: %d. " + "move %d from 0x%p to 0x%p\n", + logical, ptr, len, + (curp->p_idx + 1), (curp->p_idx + 2)); + memmove(curp->p_idx + 2, curp->p_idx + 1, len); + } + ix = curp->p_idx + 1; + } else { + /* insert before */ + len = len * sizeof(struct ext4_extent_idx); + len = len < 0 ? 0 : len; + ext_debug("insert new index %d before: %d. " + "move %d from 0x%p to 0x%p\n", + logical, ptr, len, + curp->p_idx, (curp->p_idx + 1)); + memmove(curp->p_idx + 1, curp->p_idx, len); + ix = curp->p_idx; + } + + ix->ei_block = cpu_to_le32(logical); + ix->ei_leaf = cpu_to_le32(ptr); + curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1); + + BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries) + > le16_to_cpu(curp->p_hdr->eh_max)); + BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr)); + + err = ext4_ext_dirty(handle, inode, curp); + ext4_std_error(inode->i_sb, err); + + return err; +} + +/* + * routine inserts new subtree into the path, using free index entry + * at depth 'at: + * - allocates all needed blocks (new leaf and all intermediate index blocks) + * - makes decision where to split + * - moves remaining extens and index entries (right to the split point) + * into the newly allocated blocks + * - initialize subtree + */ +static int ext4_ext_split(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path, + struct ext4_extent *newext, int at) +{ + struct buffer_head *bh = NULL; + int depth = ext_depth(inode); + struct ext4_extent_header *neh; + struct ext4_extent_idx *fidx; + struct ext4_extent *ex; + int i = at, k, m, a; + unsigned long newblock, oldblock; + __le32 border; + int *ablocks = NULL; /* array of allocated blocks */ + int err = 0; + + /* make decision: where to split? */ + /* FIXME: now desicion is simplest: at current extent */ + + /* if current leaf will be splitted, then we should use + * border from split point */ + BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr)); + if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) { + border = path[depth].p_ext[1].ee_block; + ext_debug("leaf will be splitted." + " next leaf starts at %d\n", + le32_to_cpu(border)); + } else { + border = newext->ee_block; + ext_debug("leaf will be added." + " next leaf starts at %d\n", + le32_to_cpu(border)); + } + + /* + * if error occurs, then we break processing + * and turn filesystem read-only. so, index won't + * be inserted and tree will be in consistent + * state. next mount will repair buffers too + */ + + /* + * get array to track all allocated blocks + * we need this to handle errors and free blocks + * upon them + */ + ablocks = kmalloc(sizeof(unsigned long) * depth, GFP_NOFS); + if (!ablocks) + return -ENOMEM; + memset(ablocks, 0, sizeof(unsigned long) * depth); + + /* allocate all needed blocks */ + ext_debug("allocate %d blocks for indexes/leaf\n", depth - at); + for (a = 0; a < depth - at; a++) { + newblock = ext4_ext_new_block(handle, inode, path, newext, &err); + if (newblock == 0) + goto cleanup; + ablocks[a] = newblock; + } + + /* initialize new leaf */ + newblock = ablocks[--a]; + BUG_ON(newblock == 0); + bh = sb_getblk(inode->i_sb, newblock); + if (!bh) { + err = -EIO; + goto cleanup; + } + lock_buffer(bh); + + if ((err = ext4_journal_get_create_access(handle, bh))) + goto cleanup; + + neh = ext_block_hdr(bh); + neh->eh_entries = 0; + neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); + neh->eh_magic = EXT4_EXT_MAGIC; + neh->eh_depth = 0; + ex = EXT_FIRST_EXTENT(neh); + + /* move remain of path[depth] to the new leaf */ + BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max); + /* start copy from next extent */ + /* TODO: we could do it by single memmove */ + m = 0; + path[depth].p_ext++; + while (path[depth].p_ext <= + EXT_MAX_EXTENT(path[depth].p_hdr)) { + ext_debug("move %d:%d:%d in new leaf %lu\n", + le32_to_cpu(path[depth].p_ext->ee_block), + le32_to_cpu(path[depth].p_ext->ee_start), + le16_to_cpu(path[depth].p_ext->ee_len), + newblock); + /*memmove(ex++, path[depth].p_ext++, + sizeof(struct ext4_extent)); + neh->eh_entries++;*/ + path[depth].p_ext++; + m++; + } + if (m) { + memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m); + neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m); + } + + set_buffer_uptodate(bh); + unlock_buffer(bh); + + if ((err = ext4_journal_dirty_metadata(handle, bh))) + goto cleanup; + brelse(bh); + bh = NULL; + + /* correct old leaf */ + if (m) { + if ((err = ext4_ext_get_access(handle, inode, path + depth))) + goto cleanup; + path[depth].p_hdr->eh_entries = + cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m); + if ((err = ext4_ext_dirty(handle, inode, path + depth))) + goto cleanup; + + } + + /* create intermediate indexes */ + k = depth - at - 1; + BUG_ON(k < 0); + if (k) + ext_debug("create %d intermediate indices\n", k); + /* insert new index into current index block */ + /* current depth stored in i var */ + i = depth - 1; + while (k--) { + oldblock = newblock; + newblock = ablocks[--a]; + bh = sb_getblk(inode->i_sb, newblock); + if (!bh) { + err = -EIO; + goto cleanup; + } + lock_buffer(bh); + + if ((err = ext4_journal_get_create_access(handle, bh))) + goto cleanup; + + neh = ext_block_hdr(bh); + neh->eh_entries = cpu_to_le16(1); + neh->eh_magic = EXT4_EXT_MAGIC; + neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); + neh->eh_depth = cpu_to_le16(depth - i); + fidx = EXT_FIRST_INDEX(neh); + fidx->ei_block = border; + fidx->ei_leaf = cpu_to_le32(oldblock); + + ext_debug("int.index at %d (block %lu): %lu -> %lu\n", i, + newblock, (unsigned long) le32_to_cpu(border), + oldblock); + /* copy indexes */ + m = 0; + path[i].p_idx++; + + ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx, + EXT_MAX_INDEX(path[i].p_hdr)); + BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) != + EXT_LAST_INDEX(path[i].p_hdr)); + while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) { + ext_debug("%d: move %d:%d in new index %lu\n", i, + le32_to_cpu(path[i].p_idx->ei_block), + le32_to_cpu(path[i].p_idx->ei_leaf), + newblock); + /*memmove(++fidx, path[i].p_idx++, + sizeof(struct ext4_extent_idx)); + neh->eh_entries++; + BUG_ON(neh->eh_entries > neh->eh_max);*/ + path[i].p_idx++; + m++; + } + if (m) { + memmove(++fidx, path[i].p_idx - m, + sizeof(struct ext4_extent_idx) * m); + neh->eh_entries = + cpu_to_le16(le16_to_cpu(neh->eh_entries) + m); + } + set_buffer_uptodate(bh); + unlock_buffer(bh); + + if ((err = ext4_journal_dirty_metadata(handle, bh))) + goto cleanup; + brelse(bh); + bh = NULL; + + /* correct old index */ + if (m) { + err = ext4_ext_get_access(handle, inode, path + i); + if (err) + goto cleanup; + path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m); + err = ext4_ext_dirty(handle, inode, path + i); + if (err) + goto cleanup; + } + + i--; + } + + /* insert new index */ + if (err) + goto cleanup; + + err = ext4_ext_insert_index(handle, inode, path + at, + le32_to_cpu(border), newblock); + +cleanup: + if (bh) { + if (buffer_locked(bh)) + unlock_buffer(bh); + brelse(bh); + } + + if (err) { + /* free all allocated blocks in error case */ + for (i = 0; i < depth; i++) { + if (!ablocks[i]) + continue; + ext4_free_blocks(handle, inode, ablocks[i], 1); + } + } + kfree(ablocks); + + return err; +} + +/* + * routine implements tree growing procedure: + * - allocates new block + * - moves top-level data (index block or leaf) into the new block + * - initialize new top-level, creating index that points to the + * just created block + */ +static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path, + struct ext4_extent *newext) +{ + struct ext4_ext_path *curp = path; + struct ext4_extent_header *neh; + struct ext4_extent_idx *fidx; + struct buffer_head *bh; + unsigned long newblock; + int err = 0; + + newblock = ext4_ext_new_block(handle, inode, path, newext, &err); + if (newblock == 0) + return err; + + bh = sb_getblk(inode->i_sb, newblock); + if (!bh) { + err = -EIO; + ext4_std_error(inode->i_sb, err); + return err; + } + lock_buffer(bh); + + if ((err = ext4_journal_get_create_access(handle, bh))) { + unlock_buffer(bh); + goto out; + } + + /* move top-level index/leaf into new block */ + memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data)); + + /* set size of new block */ + neh = ext_block_hdr(bh); + /* old root could have indexes or leaves + * so calculate e_max right way */ + if (ext_depth(inode)) + neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode)); + else + neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode)); + neh->eh_magic = EXT4_EXT_MAGIC; + set_buffer_uptodate(bh); + unlock_buffer(bh); + + if ((err = ext4_journal_dirty_metadata(handle, bh))) + goto out; + + /* create index in new top-level index: num,max,pointer */ + if ((err = ext4_ext_get_access(handle, inode, curp))) + goto out; + + curp->p_hdr->eh_magic = EXT4_EXT_MAGIC; + curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode)); + curp->p_hdr->eh_entries = cpu_to_le16(1); + curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr); + /* FIXME: it works, but actually path[0] can be index */ + curp->p_idx->ei_block = EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block; + curp->p_idx->ei_leaf = cpu_to_le32(newblock); + + neh = ext_inode_hdr(inode); + fidx = EXT_FIRST_INDEX(neh); + ext_debug("new root: num %d(%d), lblock %d, ptr %d\n", + le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), + le32_to_cpu(fidx->ei_block), le32_to_cpu(fidx->ei_leaf)); + + neh->eh_depth = cpu_to_le16(path->p_depth + 1); + err = ext4_ext_dirty(handle, inode, curp); +out: + brelse(bh); + + return err; +} + +/* + * routine finds empty index and adds new leaf. if no free index found + * then it requests in-depth growing + */ +static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path, + struct ext4_extent *newext) +{ + struct ext4_ext_path *curp; + int depth, i, err = 0; + +repeat: + i = depth = ext_depth(inode); + + /* walk up to the tree and look for free index entry */ + curp = path + depth; + while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) { + i--; + curp--; + } + + /* we use already allocated block for index block + * so, subsequent data blocks should be contigoues */ + if (EXT_HAS_FREE_INDEX(curp)) { + /* if we found index with free entry, then use that + * entry: create all needed subtree and add new leaf */ + err = ext4_ext_split(handle, inode, path, newext, i); + + /* refill path */ + ext4_ext_drop_refs(path); + path = ext4_ext_find_extent(inode, + le32_to_cpu(newext->ee_block), + path); + if (IS_ERR(path)) + err = PTR_ERR(path); + } else { + /* tree is full, time to grow in depth */ + err = ext4_ext_grow_indepth(handle, inode, path, newext); + if (err) + goto out; + + /* refill path */ + ext4_ext_drop_refs(path); + path = ext4_ext_find_extent(inode, + le32_to_cpu(newext->ee_block), + path); + if (IS_ERR(path)) { + err = PTR_ERR(path); + goto out; + } + + /* + * only first (depth 0 -> 1) produces free space + * in all other cases we have to split growed tree + */ + depth = ext_depth(inode); + if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { + /* now we need split */ + goto repeat; + } + } + +out: + return err; +} + +/* + * returns allocated block in subsequent extent or EXT_MAX_BLOCK + * NOTE: it consider block number from index entry as + * allocated block. thus, index entries have to be consistent + * with leafs + */ +static unsigned long +ext4_ext_next_allocated_block(struct ext4_ext_path *path) +{ + int depth; + + BUG_ON(path == NULL); + depth = path->p_depth; + + if (depth == 0 && path->p_ext == NULL) + return EXT_MAX_BLOCK; + + while (depth >= 0) { + if (depth == path->p_depth) { + /* leaf */ + if (path[depth].p_ext != + EXT_LAST_EXTENT(path[depth].p_hdr)) + return le32_to_cpu(path[depth].p_ext[1].ee_block); + } else { + /* index */ + if (path[depth].p_idx != + EXT_LAST_INDEX(path[depth].p_hdr)) + return le32_to_cpu(path[depth].p_idx[1].ei_block); + } + depth--; + } + + return EXT_MAX_BLOCK; +} + +/* + * returns first allocated block from next leaf or EXT_MAX_BLOCK + */ +static unsigned ext4_ext_next_leaf_block(struct inode *inode, + struct ext4_ext_path *path) +{ + int depth; + + BUG_ON(path == NULL); + depth = path->p_depth; + + /* zero-tree has no leaf blocks at all */ + if (depth == 0) + return EXT_MAX_BLOCK; + + /* go to index block */ + depth--; + + while (depth >= 0) { + if (path[depth].p_idx != + EXT_LAST_INDEX(path[depth].p_hdr)) + return le32_to_cpu(path[depth].p_idx[1].ei_block); + depth--; + } + + return EXT_MAX_BLOCK; +} + +/* + * if leaf gets modified and modified extent is first in the leaf + * then we have to correct all indexes above + * TODO: do we need to correct tree in all cases? + */ +int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path) +{ + struct ext4_extent_header *eh; + int depth = ext_depth(inode); + struct ext4_extent *ex; + __le32 border; + int k, err = 0; + + eh = path[depth].p_hdr; + ex = path[depth].p_ext; + BUG_ON(ex == NULL); + BUG_ON(eh == NULL); + + if (depth == 0) { + /* there is no tree at all */ + return 0; + } + + if (ex != EXT_FIRST_EXTENT(eh)) { + /* we correct tree if first leaf got modified only */ + return 0; + } + + /* + * TODO: we need correction if border is smaller then current one + */ + k = depth - 1; + border = path[depth].p_ext->ee_block; + if ((err = ext4_ext_get_access(handle, inode, path + k))) + return err; + path[k].p_idx->ei_block = border; + if ((err = ext4_ext_dirty(handle, inode, path + k))) + return err; + + while (k--) { + /* change all left-side indexes */ + if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) + break; + if ((err = ext4_ext_get_access(handle, inode, path + k))) + break; + path[k].p_idx->ei_block = border; + if ((err = ext4_ext_dirty(handle, inode, path + k))) + break; + } + + return err; +} + +static int inline +ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, + struct ext4_extent *ex2) +{ + /* FIXME: 48bit support */ + if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) + != le32_to_cpu(ex2->ee_block)) + return 0; + +#ifdef AGRESSIVE_TEST + if (le16_to_cpu(ex1->ee_len) >= 4) + return 0; +#endif + + if (le32_to_cpu(ex1->ee_start) + le16_to_cpu(ex1->ee_len) + == le32_to_cpu(ex2->ee_start)) + return 1; + return 0; +} + +/* + * this routine tries to merge requsted extent into the existing + * extent or inserts requested extent as new one into the tree, + * creating new leaf in no-space case + */ +int ext4_ext_insert_extent(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path, + struct ext4_extent *newext) +{ + struct ext4_extent_header * eh; + struct ext4_extent *ex, *fex; + struct ext4_extent *nearex; /* nearest extent */ + struct ext4_ext_path *npath = NULL; + int depth, len, err, next; + + BUG_ON(newext->ee_len == 0); + depth = ext_depth(inode); + ex = path[depth].p_ext; + BUG_ON(path[depth].p_hdr == NULL); + + /* try to insert block into found extent and return */ + if (ex && ext4_can_extents_be_merged(inode, ex, newext)) { + ext_debug("append %d block to %d:%d (from %d)\n", + le16_to_cpu(newext->ee_len), + le32_to_cpu(ex->ee_block), + le16_to_cpu(ex->ee_len), + le32_to_cpu(ex->ee_start)); + if ((err = ext4_ext_get_access(handle, inode, path + depth))) + return err; + ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len) + + le16_to_cpu(newext->ee_len)); + eh = path[depth].p_hdr; + nearex = ex; + goto merge; + } + +repeat: + depth = ext_depth(inode); + eh = path[depth].p_hdr; + if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) + goto has_space; + + /* probably next leaf has space for us? */ + fex = EXT_LAST_EXTENT(eh); + next = ext4_ext_next_leaf_block(inode, path); + if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block) + && next != EXT_MAX_BLOCK) { + ext_debug("next leaf block - %d\n", next); + BUG_ON(npath != NULL); + npath = ext4_ext_find_extent(inode, next, NULL); + if (IS_ERR(npath)) + return PTR_ERR(npath); + BUG_ON(npath->p_depth != path->p_depth); + eh = npath[depth].p_hdr; + if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) { + ext_debug("next leaf isnt full(%d)\n", + le16_to_cpu(eh->eh_entries)); + path = npath; + goto repeat; + } + ext_debug("next leaf has no free space(%d,%d)\n", + le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); + } + + /* + * there is no free space in found leaf + * we're gonna add new leaf in the tree + */ + err = ext4_ext_create_new_leaf(handle, inode, path, newext); + if (err) + goto cleanup; + depth = ext_depth(inode); + eh = path[depth].p_hdr; + +has_space: + nearex = path[depth].p_ext; + + if ((err = ext4_ext_get_access(handle, inode, path + depth))) + goto cleanup; + + if (!nearex) { + /* there is no extent in this leaf, create first one */ + ext_debug("first extent in the leaf: %d:%d:%d\n", + le32_to_cpu(newext->ee_block), + le32_to_cpu(newext->ee_start), + le16_to_cpu(newext->ee_len)); + path[depth].p_ext = EXT_FIRST_EXTENT(eh); + } else if (le32_to_cpu(newext->ee_block) + > le32_to_cpu(nearex->ee_block)) { +/* BUG_ON(newext->ee_block == nearex->ee_block); */ + if (nearex != EXT_LAST_EXTENT(eh)) { + len = EXT_MAX_EXTENT(eh) - nearex; + len = (len - 1) * sizeof(struct ext4_extent); + len = len < 0 ? 0 : len; + ext_debug("insert %d:%d:%d after: nearest 0x%p, " + "move %d from 0x%p to 0x%p\n", + le32_to_cpu(newext->ee_block), + le32_to_cpu(newext->ee_start), + le16_to_cpu(newext->ee_len), + nearex, len, nearex + 1, nearex + 2); + memmove(nearex + 2, nearex + 1, len); + } + path[depth].p_ext = nearex + 1; + } else { + BUG_ON(newext->ee_block == nearex->ee_block); + len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent); + len = len < 0 ? 0 : len; + ext_debug("insert %d:%d:%d before: nearest 0x%p, " + "move %d from 0x%p to 0x%p\n", + le32_to_cpu(newext->ee_block), + le32_to_cpu(newext->ee_start), + le16_to_cpu(newext->ee_len), + nearex, len, nearex + 1, nearex + 2); + memmove(nearex + 1, nearex, len); + path[depth].p_ext = nearex; + } + + eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1); + nearex = path[depth].p_ext; + nearex->ee_block = newext->ee_block; + nearex->ee_start = newext->ee_start; + nearex->ee_len = newext->ee_len; + /* FIXME: support for large fs */ + nearex->ee_start_hi = 0; + +merge: + /* try to merge extents to the right */ + while (nearex < EXT_LAST_EXTENT(eh)) { + if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1)) + break; + /* merge with next extent! */ + nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len) + + le16_to_cpu(nearex[1].ee_len)); + if (nearex + 1 < EXT_LAST_EXTENT(eh)) { + len = (EXT_LAST_EXTENT(eh) - nearex - 1) + * sizeof(struct ext4_extent); + memmove(nearex + 1, nearex + 2, len); + } + eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1); + BUG_ON(eh->eh_entries == 0); + } + + /* try to merge extents to the left */ + + /* time to correct all indexes above */ + err = ext4_ext_correct_indexes(handle, inode, path); + if (err) + goto cleanup; + + err = ext4_ext_dirty(handle, inode, path + depth); + +cleanup: + if (npath) { + ext4_ext_drop_refs(npath); + kfree(npath); + } + ext4_ext_tree_changed(inode); + ext4_ext_invalidate_cache(inode); + return err; +} + +int ext4_ext_walk_space(struct inode *inode, unsigned long block, + unsigned long num, ext_prepare_callback func, + void *cbdata) +{ + struct ext4_ext_path *path = NULL; + struct ext4_ext_cache cbex; + struct ext4_extent *ex; + unsigned long next, start = 0, end = 0; + unsigned long last = block + num; + int depth, exists, err = 0; + + BUG_ON(func == NULL); + BUG_ON(inode == NULL); + + while (block < last && block != EXT_MAX_BLOCK) { + num = last - block; + /* find extent for this block */ + path = ext4_ext_find_extent(inode, block, path); + if (IS_ERR(path)) { + err = PTR_ERR(path); + path = NULL; + break; + } + + depth = ext_depth(inode); + BUG_ON(path[depth].p_hdr == NULL); + ex = path[depth].p_ext; + next = ext4_ext_next_allocated_block(path); + + exists = 0; + if (!ex) { + /* there is no extent yet, so try to allocate + * all requested space */ + start = block; + end = block + num; + } else if (le32_to_cpu(ex->ee_block) > block) { + /* need to allocate space before found extent */ + start = block; + end = le32_to_cpu(ex->ee_block); + if (block + num < end) + end = block + num; + } else if (block >= + le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) { + /* need to allocate space after found extent */ + start = block; + end = block + num; + if (end >= next) + end = next; + } else if (block >= le32_to_cpu(ex->ee_block)) { + /* + * some part of requested space is covered + * by found extent + */ + start = block; + end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len); + if (block + num < end) + end = block + num; + exists = 1; + } else { + BUG(); + } + BUG_ON(end <= start); + + if (!exists) { + cbex.ec_block = start; + cbex.ec_len = end - start; + cbex.ec_start = 0; + cbex.ec_type = EXT4_EXT_CACHE_GAP; + } else { + cbex.ec_block = le32_to_cpu(ex->ee_block); + cbex.ec_len = le16_to_cpu(ex->ee_len); + cbex.ec_start = le32_to_cpu(ex->ee_start); + cbex.ec_type = EXT4_EXT_CACHE_EXTENT; + } + + BUG_ON(cbex.ec_len == 0); + err = func(inode, path, &cbex, cbdata); + ext4_ext_drop_refs(path); + + if (err < 0) + break; + if (err == EXT_REPEAT) + continue; + else if (err == EXT_BREAK) { + err = 0; + break; + } + + if (ext_depth(inode) != depth) { + /* depth was changed. we have to realloc path */ + kfree(path); + path = NULL; + } + + block = cbex.ec_block + cbex.ec_len; + } + + if (path) { + ext4_ext_drop_refs(path); + kfree(path); + } + + return err; +} + +static inline void +ext4_ext_put_in_cache(struct inode *inode, __u32 block, + __u32 len, __u32 start, int type) +{ + struct ext4_ext_cache *cex; + BUG_ON(len == 0); + cex = &EXT4_I(inode)->i_cached_extent; + cex->ec_type = type; + cex->ec_block = block; + cex->ec_len = len; + cex->ec_start = start; +} + +/* + * this routine calculate boundaries of the gap requested block fits into + * and cache this gap + */ +static inline void +ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, + unsigned long block) +{ + int depth = ext_depth(inode); + unsigned long lblock, len; + struct ext4_extent *ex; + + ex = path[depth].p_ext; + if (ex == NULL) { + /* there is no extent yet, so gap is [0;-] */ + lblock = 0; + len = EXT_MAX_BLOCK; + ext_debug("cache gap(whole file):"); + } else if (block < le32_to_cpu(ex->ee_block)) { + lblock = block; + len = le32_to_cpu(ex->ee_block) - block; + ext_debug("cache gap(before): %lu [%lu:%lu]", + (unsigned long) block, + (unsigned long) le32_to_cpu(ex->ee_block), + (unsigned long) le16_to_cpu(ex->ee_len)); + } else if (block >= le32_to_cpu(ex->ee_block) + + le16_to_cpu(ex->ee_len)) { + lblock = le32_to_cpu(ex->ee_block) + + le16_to_cpu(ex->ee_len); + len = ext4_ext_next_allocated_block(path); + ext_debug("cache gap(after): [%lu:%lu] %lu", + (unsigned long) le32_to_cpu(ex->ee_block), + (unsigned long) le16_to_cpu(ex->ee_len), + (unsigned long) block); + BUG_ON(len == lblock); + len = len - lblock; + } else { + lblock = len = 0; + BUG(); + } + + ext_debug(" -> %lu:%lu\n", (unsigned long) lblock, len); + ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP); +} + +static inline int +ext4_ext_in_cache(struct inode *inode, unsigned long block, + struct ext4_extent *ex) +{ + struct ext4_ext_cache *cex; + + cex = &EXT4_I(inode)->i_cached_extent; + + /* has cache valid data? */ + if (cex->ec_type == EXT4_EXT_CACHE_NO) + return EXT4_EXT_CACHE_NO; + + BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP && + cex->ec_type != EXT4_EXT_CACHE_EXTENT); + if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) { + ex->ee_block = cpu_to_le32(cex->ec_block); + ex->ee_start = cpu_to_le32(cex->ec_start); + ex->ee_len = cpu_to_le16(cex->ec_len); + ext_debug("%lu cached by %lu:%lu:%lu\n", + (unsigned long) block, + (unsigned long) cex->ec_block, + (unsigned long) cex->ec_len, + (unsigned long) cex->ec_start); + return cex->ec_type; + } + + /* not in cache */ + return EXT4_EXT_CACHE_NO; +} + +/* + * routine removes index from the index block + * it's used in truncate case only. thus all requests are for + * last index in the block only + */ +int ext4_ext_rm_idx(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path) +{ + struct buffer_head *bh; + int err; + unsigned long leaf; + + /* free index block */ + path--; + leaf = le32_to_cpu(path->p_idx->ei_leaf); + BUG_ON(path->p_hdr->eh_entries == 0); + if ((err = ext4_ext_get_access(handle, inode, path))) + return err; + path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1); + if ((err = ext4_ext_dirty(handle, inode, path))) + return err; + ext_debug("index is empty, remove it, free block %lu\n", leaf); + bh = sb_find_get_block(inode->i_sb, leaf); + ext4_forget(handle, 1, inode, bh, leaf); + ext4_free_blocks(handle, inode, leaf, 1); + return err; +} + +/* + * This routine returns max. credits extent tree can consume. + * It should be OK for low-performance paths like ->writepage() + * To allow many writing process to fit a single transaction, + * caller should calculate credits under truncate_mutex and + * pass actual path. + */ +int inline ext4_ext_calc_credits_for_insert(struct inode *inode, + struct ext4_ext_path *path) +{ + int depth, needed; + + if (path) { + /* probably there is space in leaf? */ + depth = ext_depth(inode); + if (le16_to_cpu(path[depth].p_hdr->eh_entries) + < le16_to_cpu(path[depth].p_hdr->eh_max)) + return 1; + } + + /* + * given 32bit logical block (4294967296 blocks), max. tree + * can be 4 levels in depth -- 4 * 340^4 == 53453440000. + * let's also add one more level for imbalance. + */ + depth = 5; + + /* allocation of new data block(s) */ + needed = 2; + + /* + * tree can be full, so it'd need to grow in depth: + * allocation + old root + new root + */ + needed += 2 + 1 + 1; + + /* + * Index split can happen, we'd need: + * allocate intermediate indexes (bitmap + group) + * + change two blocks at each level, but root (already included) + */ + needed = (depth * 2) + (depth * 2); + + /* any allocation modifies superblock */ + needed += 1; + + return needed; +} + +static int ext4_remove_blocks(handle_t *handle, struct inode *inode, + struct ext4_extent *ex, + unsigned long from, unsigned long to) +{ + struct buffer_head *bh; + int i; + +#ifdef EXTENTS_STATS + { + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + unsigned short ee_len = le16_to_cpu(ex->ee_len); + spin_lock(&sbi->s_ext_stats_lock); + sbi->s_ext_blocks += ee_len; + sbi->s_ext_extents++; + if (ee_len < sbi->s_ext_min) + sbi->s_ext_min = ee_len; + if (ee_len > sbi->s_ext_max) + sbi->s_ext_max = ee_len; + if (ext_depth(inode) > sbi->s_depth_max) + sbi->s_depth_max = ext_depth(inode); + spin_unlock(&sbi->s_ext_stats_lock); + } +#endif + if (from >= le32_to_cpu(ex->ee_block) + && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) { + /* tail removal */ + unsigned long num, start; + num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from; + start = le32_to_cpu(ex->ee_start) + le16_to_cpu(ex->ee_len) - num; + ext_debug("free last %lu blocks starting %lu\n", num, start); + for (i = 0; i < num; i++) { + bh = sb_find_get_block(inode->i_sb, start + i); + ext4_forget(handle, 0, inode, bh, start + i); + } + ext4_free_blocks(handle, inode, start, num); + } else if (from == le32_to_cpu(ex->ee_block) + && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) { + printk("strange request: removal %lu-%lu from %u:%u\n", + from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len)); + } else { + printk("strange request: removal(2) %lu-%lu from %u:%u\n", + from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len)); + } + return 0; +} + +static int +ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, + struct ext4_ext_path *path, unsigned long start) +{ + int err = 0, correct_index = 0; + int depth = ext_depth(inode), credits; + struct ext4_extent_header *eh; + unsigned a, b, block, num; + unsigned long ex_ee_block; + unsigned short ex_ee_len; + struct ext4_extent *ex; + + ext_debug("truncate since %lu in leaf\n", start); + if (!path[depth].p_hdr) + path[depth].p_hdr = ext_block_hdr(path[depth].p_bh); + eh = path[depth].p_hdr; + BUG_ON(eh == NULL); + BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max)); + BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC); + + /* find where to start removing */ + ex = EXT_LAST_EXTENT(eh); + + ex_ee_block = le32_to_cpu(ex->ee_block); + ex_ee_len = le16_to_cpu(ex->ee_len); + + while (ex >= EXT_FIRST_EXTENT(eh) && + ex_ee_block + ex_ee_len > start) { + ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len); + path[depth].p_ext = ex; + + a = ex_ee_block > start ? ex_ee_block : start; + b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ? + ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK; + + ext_debug(" border %u:%u\n", a, b); + + if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) { + block = 0; + num = 0; + BUG(); + } else if (a != ex_ee_block) { + /* remove tail of the extent */ + block = ex_ee_block; + num = a - block; + } else if (b != ex_ee_block + ex_ee_len - 1) { + /* remove head of the extent */ + block = a; + num = b - a; + /* there is no "make a hole" API yet */ + BUG(); + } else { + /* remove whole extent: excellent! */ + block = ex_ee_block; + num = 0; + BUG_ON(a != ex_ee_block); + BUG_ON(b != ex_ee_block + ex_ee_len - 1); + } + + /* at present, extent can't cross block group */ + /* leaf + bitmap + group desc + sb + inode */ + credits = 5; + if (ex == EXT_FIRST_EXTENT(eh)) { + correct_index = 1; + credits += (ext_depth(inode)) + 1; + } +#ifdef CONFIG_QUOTA + credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); +#endif + + handle = ext4_ext_journal_restart(handle, credits); + if (IS_ERR(handle)) { + err = PTR_ERR(handle); + goto out; + } + + err = ext4_ext_get_access(handle, inode, path + depth); + if (err) + goto out; + + err = ext4_remove_blocks(handle, inode, ex, a, b); + if (err) + goto out; + + if (num == 0) { + /* this extent is removed entirely mark slot unused */ + ex->ee_start = 0; + eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1); + } + + ex->ee_block = cpu_to_le32(block); + ex->ee_len = cpu_to_le16(num); + + err = ext4_ext_dirty(handle, inode, path + depth); + if (err) + goto out; + + ext_debug("new extent: %u:%u:%u\n", block, num, + le32_to_cpu(ex->ee_start)); + ex--; + ex_ee_block = le32_to_cpu(ex->ee_block); + ex_ee_len = le16_to_cpu(ex->ee_len); + } + + if (correct_index && eh->eh_entries) + err = ext4_ext_correct_indexes(handle, inode, path); + + /* if this leaf is free, then we should + * remove it from index block above */ + if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) + err = ext4_ext_rm_idx(handle, inode, path + depth); + +out: + return err; +} + +/* + * returns 1 if current index have to be freed (even partial) + */ +static int inline +ext4_ext_more_to_rm(struct ext4_ext_path *path) +{ + BUG_ON(path->p_idx == NULL); + + if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr)) + return 0; + + /* + * if truncate on deeper level happened it it wasn't partial + * so we have to consider current index for truncation + */ + if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block) + return 0; + return 1; +} + +int ext4_ext_remove_space(struct inode *inode, unsigned long start) +{ + struct super_block *sb = inode->i_sb; + int depth = ext_depth(inode); + struct ext4_ext_path *path; + handle_t *handle; + int i = 0, err = 0; + + ext_debug("truncate since %lu\n", start); + + /* probably first extent we're gonna free will be last in block */ + handle = ext4_journal_start(inode, depth + 1); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + ext4_ext_invalidate_cache(inode); + + /* + * we start scanning from right side freeing all the blocks + * after i_size and walking into the deep + */ + path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL); + if (path == NULL) { + ext4_journal_stop(handle); + return -ENOMEM; + } + memset(path, 0, sizeof(struct ext4_ext_path) * (depth + 1)); + path[0].p_hdr = ext_inode_hdr(inode); + if (ext4_ext_check_header(__FUNCTION__, inode, path[0].p_hdr)) { + err = -EIO; + goto out; + } + path[0].p_depth = depth; + + while (i >= 0 && err == 0) { + if (i == depth) { + /* this is leaf block */ + err = ext4_ext_rm_leaf(handle, inode, path, start); + /* root level have p_bh == NULL, brelse() eats this */ + brelse(path[i].p_bh); + path[i].p_bh = NULL; + i--; + continue; + } + + /* this is index block */ + if (!path[i].p_hdr) { + ext_debug("initialize header\n"); + path[i].p_hdr = ext_block_hdr(path[i].p_bh); + if (ext4_ext_check_header(__FUNCTION__, inode, + path[i].p_hdr)) { + err = -EIO; + goto out; + } + } + + BUG_ON(le16_to_cpu(path[i].p_hdr->eh_entries) + > le16_to_cpu(path[i].p_hdr->eh_max)); + BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC); + + if (!path[i].p_idx) { + /* this level hasn't touched yet */ + path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr); + path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1; + ext_debug("init index ptr: hdr 0x%p, num %d\n", + path[i].p_hdr, + le16_to_cpu(path[i].p_hdr->eh_entries)); + } else { + /* we've already was here, see at next index */ + path[i].p_idx--; + } + + ext_debug("level %d - index, first 0x%p, cur 0x%p\n", + i, EXT_FIRST_INDEX(path[i].p_hdr), + path[i].p_idx); + if (ext4_ext_more_to_rm(path + i)) { + /* go to the next level */ + ext_debug("move to level %d (block %d)\n", + i + 1, le32_to_cpu(path[i].p_idx->ei_leaf)); + memset(path + i + 1, 0, sizeof(*path)); + path[i+1].p_bh = + sb_bread(sb, le32_to_cpu(path[i].p_idx->ei_leaf)); + if (!path[i+1].p_bh) { + /* should we reset i_size? */ + err = -EIO; + break; + } + + /* put actual number of indexes to know is this + * number got changed at the next iteration */ + path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); + i++; + } else { + /* we finish processing this index, go up */ + if (path[i].p_hdr->eh_entries == 0 && i > 0) { + /* index is empty, remove it + * handle must be already prepared by the + * truncatei_leaf() */ + err = ext4_ext_rm_idx(handle, inode, path + i); + } + /* root level have p_bh == NULL, brelse() eats this */ + brelse(path[i].p_bh); + path[i].p_bh = NULL; + i--; + ext_debug("return to level %d\n", i); + } + } + + /* TODO: flexible tree reduction should be here */ + if (path->p_hdr->eh_entries == 0) { + /* + * truncate to zero freed all the tree + * so, we need to correct eh_depth + */ + err = ext4_ext_get_access(handle, inode, path); + if (err == 0) { + ext_inode_hdr(inode)->eh_depth = 0; + ext_inode_hdr(inode)->eh_max = + cpu_to_le16(ext4_ext_space_root(inode)); + err = ext4_ext_dirty(handle, inode, path); + } + } +out: + ext4_ext_tree_changed(inode); + ext4_ext_drop_refs(path); + kfree(path); + ext4_journal_stop(handle); + + return err; +} + +/* + * called at mount time + */ +void ext4_ext_init(struct super_block *sb) +{ + /* + * possible initialization would be here + */ + + if (test_opt(sb, EXTENTS)) { + printk("EXT4-fs: file extents enabled"); +#ifdef AGRESSIVE_TEST + printk(", agressive tests"); +#endif +#ifdef CHECK_BINSEARCH + printk(", check binsearch"); +#endif +#ifdef EXTENTS_STATS + printk(", stats"); +#endif + printk("\n"); +#ifdef EXTENTS_STATS + spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock); + EXT4_SB(sb)->s_ext_min = 1 << 30; + EXT4_SB(sb)->s_ext_max = 0; +#endif + } +} + +/* + * called at umount time + */ +void ext4_ext_release(struct super_block *sb) +{ + if (!test_opt(sb, EXTENTS)) + return; + +#ifdef EXTENTS_STATS + if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) { + struct ext4_sb_info *sbi = EXT4_SB(sb); + printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n", + sbi->s_ext_blocks, sbi->s_ext_extents, + sbi->s_ext_blocks / sbi->s_ext_extents); + printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n", + sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max); + } +#endif +} + +int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, sector_t iblock, + unsigned long max_blocks, struct buffer_head *bh_result, + int create, int extend_disksize) +{ + struct ext4_ext_path *path = NULL; + struct ext4_extent newex, *ex; + int goal, newblock, err = 0, depth; + unsigned long allocated = 0; + + __clear_bit(BH_New, &bh_result->b_state); + ext_debug("blocks %d/%lu requested for inode %u\n", (int) iblock, + max_blocks, (unsigned) inode->i_ino); + mutex_lock(&EXT4_I(inode)->truncate_mutex); + + /* check in cache */ + if ((goal = ext4_ext_in_cache(inode, iblock, &newex))) { + if (goal == EXT4_EXT_CACHE_GAP) { + if (!create) { + /* block isn't allocated yet and + * user don't want to allocate it */ + goto out2; + } + /* we should allocate requested block */ + } else if (goal == EXT4_EXT_CACHE_EXTENT) { + /* block is already allocated */ + newblock = iblock + - le32_to_cpu(newex.ee_block) + + le32_to_cpu(newex.ee_start); + /* number of remain blocks in the extent */ + allocated = le16_to_cpu(newex.ee_len) - + (iblock - le32_to_cpu(newex.ee_block)); + goto out; + } else { + BUG(); + } + } + + /* find extent for this block */ + path = ext4_ext_find_extent(inode, iblock, NULL); + if (IS_ERR(path)) { + err = PTR_ERR(path); + path = NULL; + goto out2; + } + + depth = ext_depth(inode); + + /* + * consistent leaf must not be empty + * this situations is possible, though, _during_ tree modification + * this is why assert can't be put in ext4_ext_find_extent() + */ + BUG_ON(path[depth].p_ext == NULL && depth != 0); + + if ((ex = path[depth].p_ext)) { + unsigned long ee_block = le32_to_cpu(ex->ee_block); + unsigned long ee_start = le32_to_cpu(ex->ee_start); + unsigned short ee_len = le16_to_cpu(ex->ee_len); + /* if found exent covers block, simple return it */ + if (iblock >= ee_block && iblock < ee_block + ee_len) { + newblock = iblock - ee_block + ee_start; + /* number of remain blocks in the extent */ + allocated = ee_len - (iblock - ee_block); + ext_debug("%d fit into %lu:%d -> %d\n", (int) iblock, + ee_block, ee_len, newblock); + ext4_ext_put_in_cache(inode, ee_block, ee_len, + ee_start, EXT4_EXT_CACHE_EXTENT); + goto out; + } + } + + /* + * requested block isn't allocated yet + * we couldn't try to create block if create flag is zero + */ + if (!create) { + /* put just found gap into cache to speedup subsequest reqs */ + ext4_ext_put_gap_in_cache(inode, path, iblock); + goto out2; + } + /* + * Okay, we need to do block allocation. Lazily initialize the block + * allocation info here if necessary + */ + if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info)) + ext4_init_block_alloc_info(inode); + + /* allocate new block */ + goal = ext4_ext_find_goal(inode, path, iblock); + allocated = max_blocks; + newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err); + if (!newblock) + goto out2; + ext_debug("allocate new block: goal %d, found %d/%lu\n", + goal, newblock, allocated); + + /* try to insert new extent into found leaf and return */ + newex.ee_block = cpu_to_le32(iblock); + newex.ee_start = cpu_to_le32(newblock); + newex.ee_len = cpu_to_le16(allocated); + err = ext4_ext_insert_extent(handle, inode, path, &newex); + if (err) + goto out2; + + if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize) + EXT4_I(inode)->i_disksize = inode->i_size; + + /* previous routine could use block we allocated */ + newblock = le32_to_cpu(newex.ee_start); + __set_bit(BH_New, &bh_result->b_state); + + ext4_ext_put_in_cache(inode, iblock, allocated, newblock, + EXT4_EXT_CACHE_EXTENT); +out: + if (allocated > max_blocks) + allocated = max_blocks; + ext4_ext_show_leaf(inode, path); + __set_bit(BH_Mapped, &bh_result->b_state); + bh_result->b_bdev = inode->i_sb->s_bdev; + bh_result->b_blocknr = newblock; +out2: + if (path) { + ext4_ext_drop_refs(path); + kfree(path); + } + mutex_unlock(&EXT4_I(inode)->truncate_mutex); + + return err ? err : allocated; +} + +void ext4_ext_truncate(struct inode * inode, struct page *page) +{ + struct address_space *mapping = inode->i_mapping; + struct super_block *sb = inode->i_sb; + unsigned long last_block; + handle_t *handle; + int err = 0; + + /* + * probably first extent we're gonna free will be last in block + */ + err = ext4_writepage_trans_blocks(inode) + 3; + handle = ext4_journal_start(inode, err); + if (IS_ERR(handle)) { + if (page) { + clear_highpage(page); + flush_dcache_page(page); + unlock_page(page); + page_cache_release(page); + } + return; + } + + if (page) + ext4_block_truncate_page(handle, page, mapping, inode->i_size); + + mutex_lock(&EXT4_I(inode)->truncate_mutex); + ext4_ext_invalidate_cache(inode); + + /* + * TODO: optimization is possible here + * probably we need not scaning at all, + * because page truncation is enough + */ + if (ext4_orphan_add(handle, inode)) + goto out_stop; + + /* we have to know where to truncate from in crash case */ + EXT4_I(inode)->i_disksize = inode->i_size; + ext4_mark_inode_dirty(handle, inode); + + last_block = (inode->i_size + sb->s_blocksize - 1) + >> EXT4_BLOCK_SIZE_BITS(sb); + err = ext4_ext_remove_space(inode, last_block); + + /* In a multi-transaction truncate, we only make the final + * transaction synchronous */ + if (IS_SYNC(inode)) + handle->h_sync = 1; + +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); + + mutex_unlock(&EXT4_I(inode)->truncate_mutex); + ext4_journal_stop(handle); +} + +/* + * this routine calculate max number of blocks we could modify + * in order to allocate new block for an inode + */ +int ext4_ext_writepage_trans_blocks(struct inode *inode, int num) +{ + int needed; + + needed = ext4_ext_calc_credits_for_insert(inode, NULL); + + /* caller want to allocate num blocks, but note it includes sb */ + needed = needed * num - (num - 1); + +#ifdef CONFIG_QUOTA + needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); +#endif + + return needed; +} + +EXPORT_SYMBOL(ext4_mark_inode_dirty); +EXPORT_SYMBOL(ext4_ext_invalidate_cache); +EXPORT_SYMBOL(ext4_ext_insert_extent); +EXPORT_SYMBOL(ext4_ext_walk_space); +EXPORT_SYMBOL(ext4_ext_find_goal); +EXPORT_SYMBOL(ext4_ext_calc_credits_for_insert); + |