This is a note to let you know that I've just added the patch titled
Btrfs: fix unexpected cow in run_delalloc_nocow
to the 4.15-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-unexpected-cow-in-run_delalloc_nocow.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5811375325420052fcadd944792a416a43072b7f Mon Sep 17 00:00:00 2001
From: Liu Bo <bo.li.liu@xxxxxxxxxx>
Date: Wed, 31 Jan 2018 17:09:13 -0700
Subject: Btrfs: fix unexpected cow in run_delalloc_nocow
From: Liu Bo <bo.li.liu@xxxxxxxxxx>
commit 5811375325420052fcadd944792a416a43072b7f upstream.
Fstests generic/475 provides a way to fail metadata reads while
checking if checksum exists for the inode inside run_delalloc_nocow(),
and csum_exist_in_range() interprets error (-EIO) as inode having
checksum and makes its caller enter the cow path.
In case of free space inode, this ends up with a warning in
cow_file_range().
The same problem applies to btrfs_cross_ref_exist() since it may also
read metadata in between.
With this, run_delalloc_nocow() bails out when errors occur at the two
places.
cc: <stable@xxxxxxxxxxxxxxx> v2.6.28+
Fixes: 17d217fe970d ("Btrfs: fix nodatasum handling in balancing code")
Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/inode.c | 37 ++++++++++++++++++++++++++++++++-----
1 file changed, 32 insertions(+), 5 deletions(-)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1257,6 +1257,8 @@ static noinline int csum_exist_in_range(
list_del(&sums->list);
kfree(sums);
}
+ if (ret < 0)
+ return ret;
return 1;
}
@@ -1389,10 +1391,23 @@ next_slot:
goto out_check;
if (btrfs_extent_readonly(fs_info, disk_bytenr))
goto out_check;
- if (btrfs_cross_ref_exist(root, ino,
- found_key.offset -
- extent_offset, disk_bytenr))
+ ret = btrfs_cross_ref_exist(root, ino,
+ found_key.offset -
+ extent_offset, disk_bytenr);
+ if (ret) {
+ /*
+ * ret could be -EIO if the above fails to read
+ * metadata.
+ */
+ if (ret < 0) {
+ if (cow_start != (u64)-1)
+ cur_offset = cow_start;
+ goto error;
+ }
+
+ WARN_ON_ONCE(nolock);
goto out_check;
+ }
disk_bytenr += extent_offset;
disk_bytenr += cur_offset - found_key.offset;
num_bytes = min(end + 1, extent_end) - cur_offset;
@@ -1410,10 +1425,22 @@ next_slot:
* this ensure that csum for a given extent are
* either valid or do not exist.
*/
- if (csum_exist_in_range(fs_info, disk_bytenr,
- num_bytes)) {
+ ret = csum_exist_in_range(fs_info, disk_bytenr,
+ num_bytes);
+ if (ret) {
if (!nolock)
btrfs_end_write_no_snapshotting(root);
+
+ /*
+ * ret could be -EIO if the above fails to read
+ * metadata.
+ */
+ if (ret < 0) {
+ if (cow_start != (u64)-1)
+ cur_offset = cow_start;
+ goto error;
+ }
+ WARN_ON_ONCE(nolock);
goto out_check;
}
if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr)) {
Patches currently in stable-queue which might be from bo.li.liu@xxxxxxxxxx are
queue-4.15/btrfs-fix-unexpected-cow-in-run_delalloc_nocow.patch