[PATCH v2 03/10] btrfs: defrag: replace hard coded PAGE_SIZE to sectorsize for defrag_lookup_extent()
From: Qu Wenruo <hidden>
Date: 2021-06-02 02:15:42
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
When testing subpage defrag support, I always find some strange inode nbytes error, after a lot of debugging, it turns out that defrag_lookup_extent() is using PAGE_SIZE as size for lookup_extent_mapping(). Since lookup_extent_mapping() is calling __lookup_extent_mapping() with @strict == 1, this means any extent map smaller than one page will be ignored, prevent subpage defrag to grab a correct extent map. There are quite some PAGE_SIZE usage in ioctl.c, but most of them are correct usages, and can be one of the following cases: - ioctl structure size check We want ioctl structure be contained inside one page. - real page opeartions There is one special case left untouched, check_defrag_in_cache(). This function will later be removed completely, thus there is not much meaning to change it now. Signed-off-by: Qu Wenruo <redacted> --- fs/btrfs/ioctl.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0b5a48274266..24b0dc1325d3 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c@@ -1037,23 +1037,24 @@ static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start) struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; struct extent_map *em; - u64 len = PAGE_SIZE; + const u32 sectorsize = BTRFS_I(inode)->root->fs_info->sectorsize; /* * hopefully we have this extent in the tree already, try without * the full extent lock */ read_lock(&em_tree->lock); - em = lookup_extent_mapping(em_tree, start, len); + em = lookup_extent_mapping(em_tree, start, sectorsize); read_unlock(&em_tree->lock); if (!em) { struct extent_state *cached = NULL; - u64 end = start + len - 1; + u64 end = start + sectorsize - 1; /* get the big lock and read metadata off disk */ lock_extent_bits(io_tree, start, end, &cached); - em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, len); + em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, + sectorsize); unlock_extent_cached(io_tree, start, end, &cached); if (IS_ERR(em))
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2.31.1