• Vegard Nossum's avatar
    ext4: fix reference counting bug on block allocation error · 459d6b98
    Vegard Nossum authored
    commit 554a5ccc upstream.
    
    If we hit this error when mounted with errors=continue or
    errors=remount-ro:
    
        EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:2940: comm ext4.exe: Allocating blocks 5090-6081 which overlap fs metadata
    
    then ext4_mb_new_blocks() will call ext4_mb_release_context() and try to
    continue. However, ext4_mb_release_context() is the wrong thing to call
    here since we are still actually using the allocation context.
    
    Instead, just error out. We could retry the allocation, but there is a
    possibility of getting stuck in an infinite loop instead, so this seems
    safer.
    
    [ Fixed up so we don't return EAGAIN to userspace. --tytso ]
    
    Fixes: 8556e8f3 ("ext4: Don't allow new groups to be added during block allocation")
    Signed-off-by: default avatarVegard Nossum <vegard.nossum@oracle.com>
    Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
    [bwh: Backported to 3.16: use EIO instead of EFSCORRUPTED]
    Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
    459d6b98
mballoc.c 144 KB