diff options
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/extents.c | 135 |
1 files changed, 89 insertions, 46 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 2352467..8926623 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3153,29 +3153,28 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, struct ext4_extent_header *eh; struct ext4_map_blocks split_map; struct ext4_extent zero_ex; - struct ext4_extent *ex; + struct ext4_extent *ex, *abut_ex; ext4_lblk_t ee_block, eof_block; - unsigned int ee_len, depth; - int allocated, max_zeroout = 0; + unsigned int ee_len, depth, map_len = map->m_len; + int allocated = 0, max_zeroout = 0; int err = 0; int split_flag = 0; ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical" "block %llu, max_blocks %u\n", inode->i_ino, - (unsigned long long)map->m_lblk, map->m_len); + (unsigned long long)map->m_lblk, map_len); sbi = EXT4_SB(inode->i_sb); eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >> inode->i_sb->s_blocksize_bits; - if (eof_block < map->m_lblk + map->m_len) - eof_block = map->m_lblk + map->m_len; + if (eof_block < map->m_lblk + map_len) + eof_block = map->m_lblk + map_len; depth = ext_depth(inode); eh = path[depth].p_hdr; ex = path[depth].p_ext; ee_block = le32_to_cpu(ex->ee_block); ee_len = ext4_ext_get_actual_len(ex); - allocated = ee_len - (map->m_lblk - ee_block); zero_ex.ee_len = 0; trace_ext4_ext_convert_to_initialized_enter(inode, map, ex); @@ -3186,77 +3185,121 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, /* * Attempt to transfer newly initialized blocks from the currently - * uninitialized extent to its left neighbor. This is much cheaper + * uninitialized extent to its neighbor. This is much cheaper * than an insertion followed by a merge as those involve costly - * memmove() calls. This is the common case in steady state for - * workloads doing fallocate(FALLOC_FL_KEEP_SIZE) followed by append - * writes. + * memmove() calls. Transferring to the left is the common case in + * steady state for workloads doing fallocate(FALLOC_FL_KEEP_SIZE) + * followed by append writes. * * Limitations of the current logic: - * - L1: we only deal with writes at the start of the extent. - * The approach could be extended to writes at the end - * of the extent but this scenario was deemed less common. - * - L2: we do not deal with writes covering the whole extent. + * - L1: we do not deal with writes covering the whole extent. * This would require removing the extent if the transfer * is possible. - * - L3: we only attempt to merge with an extent stored in the + * - L2: we only attempt to merge with an extent stored in the * same extent tree node. */ - if ((map->m_lblk == ee_block) && /*L1*/ - (map->m_len < ee_len) && /*L2*/ - (ex > EXT_FIRST_EXTENT(eh))) { /*L3*/ - struct ext4_extent *prev_ex; + if ((map->m_lblk == ee_block) && + /* See if we can merge left */ + (map_len < ee_len) && /*L1*/ + (ex > EXT_FIRST_EXTENT(eh))) { /*L2*/ ext4_lblk_t prev_lblk; ext4_fsblk_t prev_pblk, ee_pblk; - unsigned int prev_len, write_len; + unsigned int prev_len; - prev_ex = ex - 1; - prev_lblk = le32_to_cpu(prev_ex->ee_block); - prev_len = ext4_ext_get_actual_len(prev_ex); - prev_pblk = ext4_ext_pblock(prev_ex); + abut_ex = ex - 1; + prev_lblk = le32_to_cpu(abut_ex->ee_block); + prev_len = ext4_ext_get_actual_len(abut_ex); + prev_pblk = ext4_ext_pblock(abut_ex); ee_pblk = ext4_ext_pblock(ex); - write_len = map->m_len; /* - * A transfer of blocks from 'ex' to 'prev_ex' is allowed + * A transfer of blocks from 'ex' to 'abut_ex' is allowed * upon those conditions: - * - C1: prev_ex is initialized, - * - C2: prev_ex is logically abutting ex, - * - C3: prev_ex is physically abutting ex, - * - C4: prev_ex can receive the additional blocks without + * - C1: abut_ex is initialized, + * - C2: abut_ex is logically abutting ex, + * - C3: abut_ex is physically abutting ex, + * - C4: abut_ex can receive the additional blocks without * overflowing the (initialized) length limit. */ - if ((!ext4_ext_is_uninitialized(prev_ex)) && /*C1*/ + if ((!ext4_ext_is_uninitialized(abut_ex)) && /*C1*/ ((prev_lblk + prev_len) == ee_block) && /*C2*/ ((prev_pblk + prev_len) == ee_pblk) && /*C3*/ - (prev_len < (EXT_INIT_MAX_LEN - write_len))) { /*C4*/ + (prev_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/ err = ext4_ext_get_access(handle, inode, path + depth); if (err) goto out; trace_ext4_ext_convert_to_initialized_fastpath(inode, - map, ex, prev_ex); + map, ex, abut_ex); - /* Shift the start of ex by 'write_len' blocks */ - ex->ee_block = cpu_to_le32(ee_block + write_len); - ext4_ext_store_pblock(ex, ee_pblk + write_len); - ex->ee_len = cpu_to_le16(ee_len - write_len); + /* Shift the start of ex by 'map_len' blocks */ + ex->ee_block = cpu_to_le32(ee_block + map_len); + ext4_ext_store_pblock(ex, ee_pblk + map_len); + ex->ee_len = cpu_to_le16(ee_len - map_len); ext4_ext_mark_uninitialized(ex); /* Restore the flag */ - /* Extend prev_ex by 'write_len' blocks */ - prev_ex->ee_len = cpu_to_le16(prev_len + write_len); + /* Extend abut_ex by 'map_len' blocks */ + abut_ex->ee_len = cpu_to_le16(prev_len + map_len); - /* Mark the block containing both extents as dirty */ - ext4_ext_dirty(handle, inode, path + depth); + /* Result: number of initialized blocks past m_lblk */ + allocated = map_len; + } + } else if (((map->m_lblk + map_len) == (ee_block + ee_len)) && + (map_len < ee_len) && /*L1*/ + ex < EXT_LAST_EXTENT(eh)) { /*L2*/ + /* See if we can merge right */ + ext4_lblk_t next_lblk; + ext4_fsblk_t next_pblk, ee_pblk; + unsigned int next_len; + + abut_ex = ex + 1; + next_lblk = le32_to_cpu(abut_ex->ee_block); + next_len = ext4_ext_get_actual_len(abut_ex); + next_pblk = ext4_ext_pblock(abut_ex); + ee_pblk = ext4_ext_pblock(ex); - /* Update path to point to the right extent */ - path[depth].p_ext = prev_ex; + /* + * A transfer of blocks from 'ex' to 'abut_ex' is allowed + * upon those conditions: + * - C1: abut_ex is initialized, + * - C2: abut_ex is logically abutting ex, + * - C3: abut_ex is physically abutting ex, + * - C4: abut_ex can receive the additional blocks without + * overflowing the (initialized) length limit. + */ + if ((!ext4_ext_is_uninitialized(abut_ex)) && /*C1*/ + ((map->m_lblk + map_len) == next_lblk) && /*C2*/ + ((ee_pblk + ee_len) == next_pblk) && /*C3*/ + (next_len < (EXT_INIT_MAX_LEN - map_len))) { /*C4*/ + err = ext4_ext_get_access(handle, inode, path + depth); + if (err) + goto out; + + trace_ext4_ext_convert_to_initialized_fastpath(inode, + map, ex, abut_ex); + + /* Shift the start of abut_ex by 'map_len' blocks */ + abut_ex->ee_block = cpu_to_le32(next_lblk - map_len); + ext4_ext_store_pblock(abut_ex, next_pblk - map_len); + ex->ee_len = cpu_to_le16(ee_len - map_len); + ext4_ext_mark_uninitialized(ex); /* Restore the flag */ + + /* Extend abut_ex by 'map_len' blocks */ + abut_ex->ee_len = cpu_to_le16(next_len + map_len); /* Result: number of initialized blocks past m_lblk */ - allocated = write_len; - goto out; + allocated = map_len; } } + if (allocated) { + /* Mark the block containing both extents as dirty */ + ext4_ext_dirty(handle, inode, path + depth); + + /* Update path to point to the right extent */ + path[depth].p_ext = abut_ex; + goto out; + } else + allocated = ee_len - (map->m_lblk - ee_block); WARN_ON(map->m_lblk < ee_block); /* |
