From 8c6e53a79d16b3651ad3abeb415e1c637da75082 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Fri, 11 Nov 2022 11:50:32 +0000 Subject: 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 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 Signed-off-by: David Sterba --- fs/btrfs/extent-io-tree.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/extent-io-tree.h') diff --git a/fs/btrfs/extent-io-tree.h b/fs/btrfs/extent-io-tree.h index 18ab82f62611..e3eeec380844 100644 --- a/fs/btrfs/extent-io-tree.h +++ b/fs/btrfs/extent-io-tree.h @@ -119,7 +119,8 @@ void __cold extent_state_free_cachep(void); u64 count_range_bits(struct extent_io_tree *tree, u64 *start, u64 search_end, - u64 max_bytes, u32 bits, int contig); + u64 max_bytes, u32 bits, int contig, + struct extent_state **cached_state); void free_extent_state(struct extent_state *state); int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end, -- cgit v1.2.3