• Theodore Ts'o's avatar
    ext4: fix BUG_ON in mb_free_blocks() · 08b9d6b9
    Theodore Ts'o authored
    commit c99d1e6e upstream.
    
    If we suffer a block allocation failure (for example due to a memory
    allocation failure), it's possible that we will call
    ext4_discard_allocated_blocks() before we've actually allocated any
    blocks.  In that case, fe_len and fe_start in ac->ac_f_ex will still
    be zero, and this will result in mb_free_blocks(inode, e4b, 0, 0)
    triggering the BUG_ON on mb_free_blocks():
    
    	BUG_ON(last >= (sb->s_blocksize << 3));
    
    Fix this by bailing out of ext4_discard_allocated_blocks() if fs_len
    is zero.
    
    Also fix a missing ext4_mb_unload_buddy() call in
    ext4_discard_allocated_blocks().
    
    Google-Bug-Id: 16844242
    
    Fixes: 86f0afd4Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    08b9d6b9
mballoc.c 144 KB