btrfs: zoned: fix critical section of relocation inode writeback

We use btrfs_zoned_data_reloc_{lock,unlock} to allow only one process to
write out to the relocation inode. That critical section must include all
the IO submission for the inode. However, flush_write_bio() in
extent_writepages() is out of the critical section, causing an IO
submission outside of the lock. This leads to an out of the order IO
submission and fail the relocation process.

Fix it by extending the critical section.

Fixes: 35156d852762 ("btrfs: zoned: only allow one process to add pages to a relocation inode")
CC: stable@vger.kernel.org # 5.16+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 588c7c606a2c6a360539eb074244355f9f06d63a..9c250b8cd548fa0a3fdb1d64bf2b4f0a763cbdd5 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -5240,13 +5240,14 @@ int extent_writepages(struct address_space *mapping,
         */
        btrfs_zoned_data_reloc_lock(BTRFS_I(inode));
        ret = extent_write_cache_pages(mapping, wbc, &epd);
-       btrfs_zoned_data_reloc_unlock(BTRFS_I(inode));
        ASSERT(ret <= 0);
        if (ret < 0) {
+               btrfs_zoned_data_reloc_unlock(BTRFS_I(inode));
                end_write_bio(&epd, ret);
                return ret;
        }
        flush_write_bio(&epd);
+       btrfs_zoned_data_reloc_unlock(BTRFS_I(inode));
        return ret;
 }