• Mingming's avatar
    ext4: Fix return value of ext4_split_unwritten_extents() to fix direct I/O · ba230c3f
    Mingming authored
    To prepare for a direct I/O write, we need to split the unwritten
    extents before submitting the I/O.  When no extents needed to be
    split, ext4_split_unwritten_extents() was incorrectly returning 0
    instead of the size of uninitialized extents. This bug caused the
    wrong return value sent back to VFS code when it gets called from
    async IO path, leading to an unnecessary fall back to buffered IO.
    
    This bug also hid the fact that the check to see whether or not a
    split would be necessary was incorrect; we can only skip splitting the
    extent if the write completely covers the uninitialized extent.
    Signed-off-by: default avatarMingming Cao <cmm@us.ibm.com>
    Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
    ba230c3f
extents.c 96.6 KB