ocfs2: fix disk file size and memory file size mismatch

When doing append direct write in an already allocated cluster, and fast
path in ocfs2_dio_get_block() is triggered, function
ocfs2_dio_end_io_write() will be skipped as there is no context
allocated.

As a result, the disk file size will not be changed as it should be.
The solution is to skip fast path when we are about to change file size.

Fixes: af1310367f41 ("ocfs2: fix sparse file & data ordering issue in direct io.")
Signed-off-by: Ryan Ding <ryan.ding@oracle.com>
Acked-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 10 deletions

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 0f3816325808..328ac7f99d52 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -2167,19 +2167,26 @@ static int ocfs2_dio_get_block(struct inode *inode, sector_t iblock,
         mlog(0, "get block of %lu at %llu:%u req %u\n",
                         inode->i_ino, pos, len, total_len);
 
-        down_read(&oi->ip_alloc_sem);
-        /* This is the fast path for re-write. */
-        ret = ocfs2_get_block(inode, iblock, bh_result, create);
+        /*
+         * Because we need to change file size in ocfs2_dio_end_io_write(), or
+         * we may need to add it to orphan dir. So can not fall to fast path
+         * while file size will be changed.
+         */
+        if (pos + total_len <= i_size_read(inode)) {
+                down_read(&oi->ip_alloc_sem);
+                /* This is the fast path for re-write. */
+                ret = ocfs2_get_block(inode, iblock, bh_result, create);
 
-        up_read(&oi->ip_alloc_sem);
+                up_read(&oi->ip_alloc_sem);
 
-        if (buffer_mapped(bh_result) &&
-            !buffer_new(bh_result) &&
-            ret == 0)
-                goto out;
+                if (buffer_mapped(bh_result) &&
+                    !buffer_new(bh_result) &&
+                    ret == 0)
+                        goto out;
 
-        /* Clear state set by ocfs2_get_block. */
-        bh_result->b_state = 0;
+                /* Clear state set by ocfs2_get_block. */
+                bh_result->b_state = 0;
+        }
 
         dwc = ocfs2_dio_alloc_write_ctx(bh_result, &first_get_block);
         if (unlikely(dwc == NULL)) {