• Chao Yu's avatar
    f2fs: fix to avoid deadloop in foreground GC · 793ab1c8
    Chao Yu authored
    As Jungyeon reported in bugzilla:
    
    https://bugzilla.kernel.org/show_bug.cgi?id=203211
    
    - Overview
    When mounting the attached crafted image and making a new file, I got this error and the error messages keep repeating.
    
    The image is intentionally fuzzed from a normal f2fs image for testing and I run with option CONFIG_F2FS_CHECK_FS on.
    
    - Reproduces
    mkdir test
    mount -t f2fs tmp.img test
    cd test
    touch t
    
    - Messages
    [   58.820451] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.821485] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.822530] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.823571] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.824616] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.825640] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.826663] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.827698] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.828719] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.829759] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.830783] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.831828] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.832869] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.833888] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.834945] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.835996] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.837028] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.838051] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.839072] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.840100] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.841147] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.842186] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.843214] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.844267] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.845282] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.846305] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    [   58.847341] F2FS-fs (sdb): Inconsistent segment (1) type [1, 0] in SSA and SIT
    ... (repeating)
    
    During GC, if segment type stored in SSA and SIT is inconsistent, we just
    skip migrating current segment directly, since we need to know the exact
    type to decide the migration function we use.
    
    So in foreground GC, we will easily run into a infinite loop as we may
    select the same victim segment which has inconsistent type due to greedy
    policy. In order to end up this, we choose to shutdown filesystem. For
    backgrond GC, we need to do that as well, so that we can avoid latter
    potential infinite looped foreground GC.
    Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
    Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
    793ab1c8
gc.c 32.9 KB