tmpfs: fix SEEK_DATA/SEEK_HOLE regression

Commit 46a1c2c7ae53 ("vfs: export lseek_execute() to modules") broke the
tmpfs SEEK_DATA/SEEK_HOLE implementation, because vfs_setpos() converts
the carefully prepared -ENXIO to -EINVAL.  Other filesystems avoid it in
error cases: do the same in tmpfs.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index a87990cf9f94..8335dbd3fc35 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1798,7 +1798,8 @@ static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence)
                 }
         }
 
-        offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE);
+        if (offset >= 0)
+                offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE);
         mutex_unlock(&inode->i_mutex);
         return offset;
 }