your patch "mm: Remove false WARN_ON from pagecache_isize_extended()"

["Jan Beulich" <JBeulich@xxxxxxxx>]

Jan,

having run into that warning too, I looked into it a little, and now
having found that patch am pretty uncertain: Both truncate_setsize()
and pagecache_isize_extended() document that they want to be
called with i_mutex held, so removing the WARN_ON() alone seems
either incomplete or wrong. What I found to work without violating
this documented requirement is the patch below.

Jan

--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -797,7 +797,7 @@ xfs_file_fallocate(
                     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
                return -EOPNOTSUPP;
 
-       xfs_ilock(ip, XFS_IOLOCK_EXCL);
+       xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
        if (mode & FALLOC_FL_PUNCH_HOLE) {
                error = xfs_free_file_space(ip, offset, len);
                if (error)
@@ -877,7 +877,7 @@ xfs_file_fallocate(
        }
 
 out_unlock:
-       xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+       xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);
        return error;
 }