From: Filipe Manana Date: Fri, 23 Dec 2022 18:28:53 +0000 (+0000) Subject: btrfs: fix off-by-one in delalloc search during lseek X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2f2e84ca60660402bd81d0859703567c59556e6a;p=linux.git btrfs: fix off-by-one in delalloc search during lseek During lseek, when searching for delalloc in a range that represents a hole and that range has a length of 1 byte, we end up not doing the actual delalloc search in the inode's io tree, resulting in not correctly reporting the offset with data or a hole. This actually only happens when the start offset is 0 because with any other start offset we round it down by sector size. Reproducer: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt/sdc $ xfs_io -f -c "pwrite -q 0 1" /mnt/sdc/foo $ xfs_io -c "seek -d 0" /mnt/sdc/foo Whence Result DATA EOF It should have reported an offset of 0 instead of EOF. Fix this by updating btrfs_find_delalloc_in_range() and count_range_bits() to deal with inclusive ranges properly. These functions are already supposed to work with inclusive end offsets, they just got it wrong in a couple places due to off-by-one mistakes. A test case for fstests will be added later. Reported-by: Joan Bruguera Micó Link: https://lore.kernel.org/linux-btrfs/20221223020509.457113-1-joanbrugueram@gmail.com/ Fixes: b6e833567ea1 ("btrfs: make hole and data seeking a lot more efficient") CC: stable@vger.kernel.org # 6.1 Tested-by: Joan Bruguera Micó Signed-off-by: Filipe Manana Signed-off-by: David Sterba --- diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c index 9ae9cd1e70352..3c7766dfaa694 100644 --- a/fs/btrfs/extent-io-tree.c +++ b/fs/btrfs/extent-io-tree.c @@ -1551,7 +1551,7 @@ u64 count_range_bits(struct extent_io_tree *tree, u64 last = 0; int found = 0; - if (WARN_ON(search_end <= cur_start)) + if (WARN_ON(search_end < cur_start)) return 0; spin_lock(&tree->lock); diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 91b00eb2440e7..834bbcb91102f 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -3354,7 +3354,7 @@ bool btrfs_find_delalloc_in_range(struct btrfs_inode *inode, u64 start, u64 end, bool search_io_tree = true; bool ret = false; - while (cur_offset < end) { + while (cur_offset <= end) { u64 delalloc_start; u64 delalloc_end; bool delalloc;