ext4: silence warning in ext4_writepages()

The loop in mpage_map_and_submit_extent() is guaranteed to always run
at least once since the caller of mpage_map_and_submit_extent() makes
sure map->m_len > 0. So make that explicit using do-while instead of
pure while which also silences the compiler warning about
uninitialized 'err' variable.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0188e65e1f58..19a1643cbdfa 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2163,7 +2163,7 @@ static int mpage_map_and_submit_extent(handle_t *handle,
 
         mpd->io_submit.io_end->offset =
                                 ((loff_t)map->m_lblk) << inode->i_blkbits;
-        while (map->m_len) {
+        do {
                 err = mpage_map_one_extent(handle, mpd);
                 if (err < 0) {
                         struct super_block *sb = inode->i_sb;
@@ -2201,7 +2201,7 @@ static int mpage_map_and_submit_extent(handle_t *handle,
                 err = mpage_map_and_submit_buffers(mpd);
                 if (err < 0)
                         return err;
-        }
+        } while (map->m_len);
 
         /* Update on-disk size after IO is submitted */
         disksize = ((loff_t)mpd->first_page) << PAGE_CACHE_SHIFT;