/* * 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> /* * ext_pblock: * combine low and high parts of physical block number into ext4_fsblk_t */ static ext4_fsblk_t ext_pblock(struct ext4_extent *ex) { ext4_fsblk_t block; block = le32_to_cpu(ex->ee_start); block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; return block; } /* * idx_pblock: * combine low and high parts of a leaf physical block number into ext4_fsblk_t */ static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix) { ext4_fsblk_t block; block = le32_to_cpu(ix->ei_leaf); block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; return block; } /* * ext4_ext_store_pblock: * stores a large physical block number into an extent struct, * breaking it into parts */ static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb) { ex->ee_start = cpu_to_le32((unsigned long) (pb & 0xffffffff)); ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); } /* * ext4_idx_store_pblock: * stores a large physical block number into an index struct, * breaking it into parts */ static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb) { ix->ei_leaf = cpu_to_le32((unsigned long) (pb & 0xffffffff)); ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff); } 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 ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, struct ext4_ext_path *path, ext4_fsblk_t block) { struct ext4_inode_info *ei = EXT4_I(inode); ext4_fsblk_t bg_start; ext4_grpblk_t colour; int depth; if (path) { struct ext4_extent *ex; depth = path->p_depth; /* try to predict block placement */ ex = path[depth].p_ext; if (ex) return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block)); /* it looks like index is empty; * try to find starting block 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 ext4_fsblk_t ext4_ext_new_block(handle_t *handle, struct inode *inode, struct ext4_ext_path *path, struct ext4_extent *ex, int *err) { ext4_fsblk_t 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 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 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 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 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->%llu", le32_to_cpu(path->p_idx->ei_block), idx_pblock(path->p_idx)); } else if (path->p_ext) { ext_debug(" %d:%d:%llu ", le32_to_cpu(path->p_ext->ee_block), le16_to_cpu(path->p_ext->ee_len), ext_pblock(path->p_ext)); } 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:%llu ", le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len), ext_pblock(ex)); } 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; } } /* * ext4_ext_binsearch_idx: * binary search for the closest index of the 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->%lld ", le32_to_cpu(path->p_idx->ei_block), idx_block(path->p_idx)); #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 } /* * ext4_ext_binsearch: * binary search for closest extent of the 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: * 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:%llu:%d ", le32_to_cpu(path->p_ext->ee_block), ext_pblock(path->p_ext), 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 = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2), GFP_NOFS); if (!path) return ERR_PTR(-ENOMEM); alloc = 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 = idx_pblock(path[ppos].p_idx); 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); } /* * ext4_ext_insert_index: * insert new index [@logical;@ptr] into the block at @curp; * 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, ext4_fsblk_t ptr) { struct ext4_extent_idx *ix; int len, err; err = ext4_ext_get_access(handle, inode, curp); if (err) 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); ext4_idx_store_pblock(ix, 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; } /* * ext4_ext_split: * 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 extents and index entries (right to the split point) * into the newly allocated blocks * - initializes 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; ext4_fsblk_t newblock, oldblock; __le32 border; ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */ int err = 0; /* make decision: where to split? */ /* FIXME: now decision is simplest: at current extent */ /* if current leaf will be split, 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 split." " 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 mark filesystem read-only. 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 = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS); if (!ablocks) return -ENOMEM; /* 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); err = ext4_journal_get_create_access(handle, bh); if (err) 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 remainder 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:%llu:%d in new leaf %llu\n", le32_to_cpu(path[depth].p_ext->ee_block), ext_pblock(path[depth].p_ext), 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); err = ext4_journal_dirty_metadata(handle, bh); if (err) goto cleanup; brelse(bh); bh = NULL; /* correct old leaf */ if (m) { err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto cleanup; path[depth].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m); err = ext4_ext_dirty(handle, inode, path + depth); if (err) 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, (ext4_fsblk_t)newblock); if (!bh) { err = -EIO; goto cleanup; } lock_buffer(bh); err = ext4_journal_get_create_access(handle, bh); if (err) 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; ext4_idx_store_pblock(fidx, oldblock); ext_debug("int.index at %d (block %llu): %lu -> %llu\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 %llu\n", i, le32_to_cpu(path[i].p_idx->ei_block), idx_pblock(path[i].p_idx), 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); err = ext4_journal_dirty_metadata(handle, bh); if (err) 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 */ 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; } /* * ext4_ext_grow_indepth: * implements tree growing procedure: * - allocates new block * - moves top-level data (index block or leaf) into the new block * - initializes 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; ext4_fsblk_t 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); err = ext4_journal_get_create_access(handle, bh); if (err) { 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); err = ext4_journal_dirty_metadata(handle, bh); if (err) goto out; /* create index in new top-level index: num,max,pointer */ err = ext4_ext_get_access(handle, inode, curp); if (err) 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; ext4_idx_store_pblock(curp->p_idx, newblock); neh = ext_inode_hdr(inode); fidx = EXT_FIRST_INDEX(neh); ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n", le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max), le32_to_cpu(fidx->ei_block), idx_pblock(fidx)); neh->eh_depth = cpu_to_le16(path->p_depth + 1); err = ext4_ext_dirty(handle, inode, curp); out: brelse(bh); return err; } /* * ext4_ext_create_new_leaf: * finds empty index and adds new leaf. * if no free index is 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 contiguous */ 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 the grown tree */ depth = ext_depth(inode); if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) { /* now we need to split */ goto repeat; } } out: return err; } /* * ext4_ext_next_allocated_block: * returns allocated block in subsequent extent or EXT_MAX_BLOCK. * NOTE: it considers block number from index entry as * allocated block. Thus, index entries have to be consistent * with leaves. */ 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; } /* * ext4_ext_next_leaf_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; } /* * ext4_ext_correct_indexes: * 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 than current one */ k = depth - 1; border = path[depth].p_ext->ee_block; err = ext4_ext_get_access(handle, inode, path + k); if (err) return err; path[k].p_idx->ei_block = border; err = ext4_ext_dirty(handle, inode, path + k); if (err) return err; while (k--) { /* change all left-side indexes */ if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr)) break; err = ext4_ext_get_access(handle, inode, path + k); if (err) break; path[k].p_idx->ei_block = border; err = ext4_ext_dirty(handle, inode, path + k); if (err) break; } return err; } static int ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, struct ext4_extent *ex2) { if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) != le32_to_cpu(ex2->ee_block)) return 0; /* * To allow future support for preallocated extents to be added * as an RO_COMPAT feature, refuse to merge to extents if * this can result in the top bit of ee_len being set. */ if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN) return 0; #ifdef AGRESSIVE_TEST if (le16_to_cpu(ex1->ee_len) >= 4) return 0; #endif if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2)) return 1; return 0; } /* * ext4_ext_insert_extent: * tries to merge requsted extent into the existing extent or * inserts requested extent as new one into the tree, * creating new leaf in the 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 %llu)\n", le16_to_cpu(newext->ee_len), le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len), ext_pblock(ex)); err = ext4_ext_get_access(handle, inode, path + depth); if (err) 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 the found leaf. * We're gonna add a 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; err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto cleanup; if (!nearex) { /* there is no extent in this leaf, create first one */ ext_debug("first extent in the leaf: %d:%llu:%d\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), 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:%llu:%d after: nearest 0x%p, " "move %d from 0x%p to 0x%p\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), 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:%llu:%d before: nearest 0x%p, " "move %d from 0x%p to 0x%p\n", le32_to_cpu(newext->ee_block), ext_pblock(newext), 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_start_hi = newext->ee_start_hi; nearex->ee_len = newext->ee_len; 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 = ext_pblock(ex); 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 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; } /* * ext4_ext_put_gap_in_cache: * calculate boundaries of the gap that the requested block fits into * and cache this gap */ static 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 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); ext4_ext_store_pblock(ex, cex->ec_start); ex->ee_len = cpu_to_le16(cex->ec_len); ext_debug("%lu cached by %lu:%lu:%llu\n", (unsigned long) block, (unsigned long) cex->ec_block, (unsigned long) cex->ec_len, cex->ec_start); return cex->ec_type; } /* not in cache */ return EXT4_EXT_CACHE_NO; } /* * ext4_ext_rm_idx: * 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; ext4_fsblk_t leaf; /* free index block */ path--; leaf = idx_pblock(path->p_idx); BUG_ON(path->p_hdr->eh_entries == 0); err = ext4_ext_get_access(handle, inode, path); if (err) return err; path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1); err = ext4_ext_dirty(handle, inode, path); if (err) return err; ext_debug("index is empty, remove it, free block %llu\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; } /* * ext4_ext_calc_credits_for_insert: * This routine returns max. credits that the extent tree can consume. * It should be OK for low-performance paths like ->writepage() * To allow many writing processes to fit into a single transaction, * the caller should calculate credits under truncate_mutex and * pass the actual path. */ int 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 32-bit 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 would need to grow in depth: * we need one credit to modify old root, credits for * new root will be added in split accounting */ needed += 1; /* * Index split can happen, we would 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; ext4_fsblk_t start; num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from; start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num; ext_debug("free last %lu blocks starting %llu\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; mark slot entirely unused */ ext4_ext_store_pblock(ex, 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:%llu\n", block, num, ext_pblock(ex)); 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; } /* * ext4_ext_more_to_rm: * returns 1 if current index has to be freed (even partial) */ static int 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 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 tree depth-wise. */ path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL); if (path == NULL) { ext4_journal_stop(handle); return -ENOMEM; } 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 has 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 been 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 were already 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 %llu)\n", i + 1, idx_pblock(path[i].p_idx)); memset(path + i + 1, 0, sizeof(*path)); path[i+1].p_bh = sb_bread(sb, idx_pblock(path[i].p_idx)); if (!path[i+1].p_bh) { /* should we reset i_size? */ err = -EIO; break; } /* save actual number of indexes since this * number is changed at the next iteration */ path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries); i++; } else { /* we finished 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 has 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, ext4_fsblk_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; ext4_fsblk_t goal, newblock; int 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 */ goal = ext4_ext_in_cache(inode, iblock, &newex); if (goal) { if (goal == EXT4_EXT_CACHE_GAP) { if (!create) { /* block isn't allocated yet and * user doesn'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) + ext_pblock(&newex); /* number of remaining 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 situation 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); ex = path[depth].p_ext; if (ex) { unsigned long ee_block = le32_to_cpu(ex->ee_block); ext4_fsblk_t ee_start = ext_pblock(ex); unsigned short ee_len = le16_to_cpu(ex->ee_len); /* * Allow future support for preallocated extents to be added * as an RO_COMPAT feature: * Uninitialized extents are treated as holes, except that * we avoid (fail) allocating new blocks during a write. */ if (ee_len > EXT_MAX_LEN) goto out2; /* if found extent covers block, simply return it */ if (iblock >= ee_block && iblock < ee_block + ee_len) { newblock = iblock - ee_block + ee_start; /* number of remaining blocks in the extent */ allocated = ee_len - (iblock - ee_block); ext_debug("%d fit into %lu:%d -> %llu\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 speed up * subsequent requests */ 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 %llu, found %llu/%lu\n", goal, newblock, allocated); /* try to insert new extent into found leaf and return */ newex.ee_block = cpu_to_le32(iblock); ext4_ext_store_pblock(&newex, 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 = ext_pblock(&newex); __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 scan 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); } /* * ext4_ext_writepage_trans_blocks: * 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 wants 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);