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 enters the cow path.
In case of free space inode, this ends up with a warning in
cow_file_range().
The same problem applies for 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: <sta...@vger.kernel.org> v2.6.28+
Fixes: 17d217fe970d ("Btrfs: fix nodatasum handling in balancing code")
Signed-off-by: Liu Bo <bo.li....@oracle.com>
---
fs/btrfs/inode.c | 37 ++++++++++++++++++++++++++++++++-----
1 file changed, 32 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index e1a7f3c..ac1a1ac 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1257,6 +1257,8 @@ static noinline int csum_exist_in_range(struct
btrfs_fs_info *fs_info,
list_del(&sums->list);
kfree(sums);
}
+ if (ret < 0)
+ return ret;
return 1;
}
@@ -1386,10 +1388,23 @@ static noinline int run_delalloc_nocow(struct inode
*inode,
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 != -ENOENT) {
+ 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;
@@ -1407,10 +1422,22 @@ static noinline int run_delalloc_nocow(struct inode
*inode,
* 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)) {
--
2.9.4
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