ext4: Check return value of sb_getblk() and friends

Fail block allocation if sb_getblk() returns NULL. In that case,
sb_find_get_block() also likely to fail so that it should skip
calling ext4_forget().

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index d732ef5a835d..611c866ef3fe 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4537,6 +4537,8 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
                         if (!bh)
                                 tbh = sb_find_get_block(inode->i_sb,
                                                         block + i);
+                        if (unlikely(!tbh))
+                                continue;
                         ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
                                     inode, tbh, block + i);
                 }