ext4: return ENOMEM if sb_getblk() fails

commit 860d21e2c585f7ee8a4ecc06f474fdc33c9474f4 upstream.

The only reason for sb_getblk() failing is if it can't allocate the
buffer_head.  So ENOMEM is more appropriate than EIO.  In addition,
make sure that the file system is marked as being inconsistent if
sb_getblk() fails.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
[xr: Backported to 3.4:
 - Drop change to inline.c
 - Call to ext4_ext_check() from ext4_ext_find_extent() is conditional]
Signed-off-by: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 830e1b2..6dc6153 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -145,6 +145,7 @@
 	struct super_block *sb = inode->i_sb;
 	Indirect *p = chain;
 	struct buffer_head *bh;
+	int ret = -EIO;
 
 	*err = 0;
 	/* i_data is not going away, no lock needed */
@@ -153,8 +154,10 @@
 		goto no_block;
 	while (--depth) {
 		bh = sb_getblk(sb, le32_to_cpu(p->key));
-		if (unlikely(!bh))
+		if (unlikely(!bh)) {
+			ret = -ENOMEM;
 			goto failure;
+		}
 
 		if (!bh_uptodate_or_lock(bh)) {
 			if (bh_submit_read(bh) < 0) {
@@ -176,7 +179,7 @@
 	return NULL;
 
 failure:
-	*err = -EIO;
+	*err = ret;
 no_block:
 	return p;
 }
@@ -470,7 +473,7 @@
 		 */
 		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
 		if (unlikely(!bh)) {
-			err = -EIO;
+			err = -ENOMEM;
 			goto failed;
 		}