This is a note to let you know that I've just added the patch titled
btrfs: fix off-by-one in delalloc search during lseek
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-fix-off-by-one-in-delalloc-search-during-lseek.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2f2e84ca60660402bd81d0859703567c59556e6a Mon Sep 17 00:00:00 2001
From: Filipe Manana <fdmanana@xxxxxxxx>
Date: Fri, 23 Dec 2022 18:28:53 +0000
Subject: btrfs: fix off-by-one in delalloc search during lseek
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From: Filipe Manana <fdmanana@xxxxxxxx>
commit 2f2e84ca60660402bd81d0859703567c59556e6a upstream.
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 <joanbrugueram@xxxxxxxxx>
Link: https://lore.kernel.org/linux-btrfs/20221223020509.457113-1-joanbrugueram@xxxxxxxxx/
Fixes: b6e833567ea1 ("btrfs: make hole and data seeking a lot more efficient")
CC: stable@xxxxxxxxxxxxxxx # 6.1
Tested-by: Joan Bruguera Micó <joanbrugueram@xxxxxxxxx>
Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/extent-io-tree.c | 2 +-
fs/btrfs/file.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/fs/btrfs/extent-io-tree.c
+++ b/fs/btrfs/extent-io-tree.c
@@ -1507,7 +1507,7 @@ u64 count_range_bits(struct extent_io_tr
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);
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3671,7 +3671,7 @@ bool btrfs_find_delalloc_in_range(struct
u64 prev_delalloc_end = 0;
bool ret = false;
- while (cur_offset < end) {
+ while (cur_offset <= end) {
u64 delalloc_start;
u64 delalloc_end;
bool delalloc;
Patches currently in stable-queue which might be from fdmanana@xxxxxxxx are
queue-6.1/btrfs-fix-off-by-one-in-delalloc-search-during-lseek.patch
