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bcachefs: Fix accidental O(n^2) in fiemap

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Since bch2_seek_pagecache_data() searches for dirty data, we only want
to call it for holes in the extents btree - otherwise we have an
accidental O(n^2), as we repeatedly search the same range.

Reported-by: Marcin Mirosław <marcin@mejor.pl>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet
2025-05-14 13:40:47 -04:00
parent 43b9fece2d
commit a12cb6f758
1 changed files with 3 additions and 1 deletions
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fs/bcachefs/fs.c
+3 -1
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@@ -1429,7 +1429,9 @@ static int bch2_next_fiemap_extent(struct btree_trans *trans,
if (ret)
goto err;
ret = bch2_next_fiemap_pagecache_extent(trans, inode, start, end, cur);
u64 pagecache_end = k.k ? max(start, bkey_start_offset(k.k)) : end;
ret = bch2_next_fiemap_pagecache_extent(trans, inode, start, pagecache_end, cur);
if (ret)
goto err;