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authorFilipe Manana <fdmanana@suse.com>2022-11-11 14:50:32 +0300
committerDavid Sterba <dsterba@suse.com>2022-12-05 20:00:56 +0300
commit8c6e53a79d16b3651ad3abeb415e1c637da75082 (patch)
tree6df0797723ec865d0b405449395642cde7fed373 /fs/btrfs/file.c
parentcfd7a17d9b4588dd7a29e1a131257bee3e72b766 (diff)
downloadlinux-8c6e53a79d16b3651ad3abeb415e1c637da75082.tar.xz
btrfs: allow passing a cached state record to count_range_bits()
An inode's io_tree can be quite large and there are cases where due to delalloc it can have thousands of extent state records, which makes the red black tree have a depth of 10 or more, making the operation of count_range_bits() slow if we repeatedly call it for a range that starts where, or after, the previous one we called it for. Such use cases are when searching for delalloc in a file range that corresponds to a hole or a prealloc extent, which is done during lseek SEEK_HOLE/DATA and fiemap. So introduce a cached state parameter to count_range_bits() which we use to store the last extent state record we visited, and then allow the caller to pass it again on its next call to count_range_bits(). The next patches in the series will make fiemap and lseek use the new parameter. 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.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 6bc2397e324c..dc8399610ca3 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3235,7 +3235,8 @@ static bool find_delalloc_subrange(struct btrfs_inode *inode, u64 start, u64 end
*delalloc_start_ret = start;
delalloc_len = count_range_bits(&inode->io_tree,
delalloc_start_ret, end,
- len, EXTENT_DELALLOC, 1);
+ len, EXTENT_DELALLOC, 1,
+ NULL);
} else {
spin_unlock(&inode->lock);
}