• Jan Kara's avatar
    ext4: fix stripe-unaligned allocations · d9b22cf9
    Jan Kara authored
    When a filesystem is created using:
    
    	mkfs.ext4 -b 4096 -E stride=512 <dev>
    
    and we try to allocate 64MB extent, we will end up directly in
    ext4_mb_complex_scan_group(). This is because the request is detected
    as power-of-two allocation (so we start in ext4_mb_regular_allocator()
    with ac_criteria == 0) however the check before
    ext4_mb_simple_scan_group() refuses the direct buddy scan because the
    allocation request is too large. Since cr == 0, the check whether we
    should use ext4_mb_scan_aligned() fails as well and we fall back to
    ext4_mb_complex_scan_group().
    
    Fix the problem by checking for upper limit on power-of-two requests
    directly when detecting them.
    Reported-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
    Signed-off-by: default avatarJan Kara <jack@suse.cz>
    Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    d9b22cf9
mballoc.c 144 KB