diff options
| author | Filipe Manana <fdmanana@suse.com> | 2022-11-11 11:50:29 +0000 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2022-12-05 18:00:56 +0100 |
| commit | af979fd618a40009c5cae03de21403848b13a931 (patch) | |
| tree | 1eccf29473490c339d1859da7175217805c542ce /fs/btrfs/file.c | |
| parent | 40daf3e095dbd1059d7e600d27e5bb987f563561 (diff) | |
btrfs: skip unnecessary delalloc searches during lseek/fiemap
During lseek (SEEK_HOLE/DATA) and fiemap, when processing a file range
that corresponds to a hole or a prealloc extent, if we find that there is
no delalloc marked in the inode's io_tree but there is delalloc due to
an extent map in the io tree, then on the next iteration that calls
find_delalloc_subrange() we can skip searching the io tree again, since
on the first call we had no delalloc in the io tree for the whole range.
This change is part of a patchset that has the goal to make performance
better for applications that use lseek's SEEK_HOLE and SEEK_DATA modes to
iterate over the extents of a file. Two examples are the cp program from
coreutils 9.0+ and the tar program (when using its --sparse / -S option).
A sample test and results are listed in the changelog of the last patch
in the series:
1/9 btrfs: remove leftover setting of EXTENT_UPTODATE state in an inode's io_tree
2/9 btrfs: add an early exit when searching for delalloc range for lseek/fiemap
3/9 btrfs: skip unnecessary delalloc searches during lseek/fiemap
4/9 btrfs: search for delalloc more efficiently during lseek/fiemap
5/9 btrfs: remove no longer used btrfs_next_extent_map()
6/9 btrfs: allow passing a cached state record to count_range_bits()
7/9 btrfs: update stale comment for count_range_bits()
8/9 btrfs: use cached state when looking for delalloc ranges with fiemap
9/9 btrfs: use cached state when looking for delalloc ranges with lseek
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
Link: https://lore.kernel.org/linux-btrfs/20221106073028.71F9.409509F4@e16-tech.com/
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5NSVicm7nYBJ7x8fFkDpno8z3PYt5aPU43Bajc1H0h1Q@mail.gmail.com/
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/file.c')
| -rw-r--r-- | fs/btrfs/file.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 9b1f76109682..99cc95487d42 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -3214,6 +3214,7 @@ out: * looping while it gets adjacent subranges, and merging them together. */ static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end, + bool *search_io_tree, u64 *delalloc_start_ret, u64 *delalloc_end_ret) { u64 len = end + 1 - start; @@ -3231,7 +3232,7 @@ static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end spin_lock(&inode->lock); outstanding_extents = inode->outstanding_extents; - if (inode->delalloc_bytes > 0) { + if (*search_io_tree && inode->delalloc_bytes > 0) { spin_unlock(&inode->lock); *delalloc_start_ret = start; delalloc_len = count_range_bits(&inode->io_tree, @@ -3257,6 +3258,9 @@ static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end start = *delalloc_end_ret + 1; len = end + 1 - start; } + } else { + /* No delalloc, future calls don't need to search again. */ + *search_io_tree = false; } /* @@ -3390,6 +3394,7 @@ bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end, { u64 cur_offset = round_down(start, inode->root->fs_info->sectorsize); u64 prev_delalloc_end = 0; + bool search_io_tree = true; bool ret = false; while (cur_offset < end) { @@ -3398,6 +3403,7 @@ bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end, bool delalloc; delalloc = find_delalloc_subrange(inode, cur_offset, end, + &search_io_tree, &delalloc_start, &delalloc_end); if (!delalloc) |