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/inode.c b/fs/ext4/inode.c
index f2fd71c..25264c4 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -663,7 +663,7 @@
 
 	bh = sb_getblk(inode->i_sb, map.m_pblk);
 	if (!bh) {
-		*errp = -EIO;
+		*errp = -ENOMEM;
 		return NULL;
 	}
 	if (map.m_flags & EXT4_MAP_NEW) {
@@ -3461,11 +3461,8 @@
 	iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
 
 	bh = sb_getblk(sb, block);
-	if (!bh) {
-		EXT4_ERROR_INODE_BLOCK(inode, block,
-				       "unable to read itable block");
-		return -EIO;
-	}
+	if (!bh)
+		return -ENOMEM;
 	if (!buffer_uptodate(bh)) {
 		lock_buffer(bh);