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| author | Zheng Liu <wenqing.lz@taobao.com> | 2014-11-25 19:44:37 +0300 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-11-25 19:44:37 +0300 |
| commit | 2f8e0a7c6c89f850ebd5d6c0b9a08317030d1b89 (patch) | |
| tree | 4e03e95c516bab8be44e23861626f0c0f29a3958 /fs/ext4/extents.c | |
| parent | cbd7584e6ead1b79fb0b81573f158b57fa1f0b49 (diff) | |
| download | linux-2f8e0a7c6c89f850ebd5d6c0b9a08317030d1b89.tar.xz | |
ext4: cache extent hole in extent status tree for ext4_da_map_blocks()
Currently extent status tree doesn't cache extent hole when a write
looks up in extent tree to make sure whether a block has been allocated
or not. In this case, we don't put extent hole in extent cache because
later this extent might be removed and a new delayed extent might be
added back. But it will cause a defect when we do a lot of writes. If
we don't put extent hole in extent cache, the following writes also need
to access extent tree to look at whether or not a block has been
allocated. It brings a cache miss. This commit fixes this defect.
Also if the inode doesn't have any extent, this extent hole will be
cached as well.
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/extents.c')
| -rw-r--r-- | fs/ext4/extents.c | 31 |
1 files changed, 16 insertions, 15 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 7ef2f11aca56..1ee24d74270f 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2306,16 +2306,16 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, ext4_lblk_t block) { int depth = ext_depth(inode); - unsigned long len = 0; - ext4_lblk_t lblock = 0; + ext4_lblk_t len; + ext4_lblk_t lblock; struct ext4_extent *ex; + struct extent_status es; ex = path[depth].p_ext; if (ex == NULL) { - /* - * there is no extent yet, so gap is [0;-] and we - * don't cache it - */ + /* there is no extent yet, so gap is [0;-] */ + lblock = 0; + len = EXT_MAX_BLOCKS; ext_debug("cache gap(whole file):"); } else if (block < le32_to_cpu(ex->ee_block)) { lblock = block; @@ -2324,9 +2324,6 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, block, le32_to_cpu(ex->ee_block), ext4_ext_get_actual_len(ex)); - if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1)) - ext4_es_insert_extent(inode, lblock, len, ~0, - EXTENT_STATUS_HOLE); } else if (block >= le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex)) { ext4_lblk_t next; @@ -2340,14 +2337,19 @@ ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path, block); BUG_ON(next == lblock); len = next - lblock; - if (!ext4_find_delalloc_range(inode, lblock, lblock + len - 1)) - ext4_es_insert_extent(inode, lblock, len, ~0, - EXTENT_STATUS_HOLE); } else { BUG(); } - ext_debug(" -> %u:%lu\n", lblock, len); + ext4_es_find_delayed_extent_range(inode, lblock, lblock + len - 1, &es); + if (es.es_len) { + /* There's delayed extent containing lblock? */ + if (es.es_lblk <= lblock) + return; + len = min(es.es_lblk - lblock, len); + } + ext_debug(" -> %u:%u\n", lblock, len); + ext4_es_insert_extent(inode, lblock, len, ~0, EXTENT_STATUS_HOLE); } /* @@ -4368,8 +4370,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, * put just found gap into cache to speed up * subsequent requests */ - if ((flags & EXT4_GET_BLOCKS_NO_PUT_HOLE) == 0) - ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); + ext4_ext_put_gap_in_cache(inode, path, map->m_lblk); goto out2; } |