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    ext4: fix reservation release on invalidatepage for delalloc fs · 9705acd6
    Lukas Czerner 提交于
    On delalloc enabled file system on invalidatepage operation
    in ext4_da_page_release_reservation() we want to clear the delayed
    buffer and remove the extent covering the delayed buffer from the extent
    status tree.
    
    However currently there is a bug where on the systems with page size >
    block size we will always remove extents from the start of the page
    regardless where the actual delayed buffers are positioned in the page.
    This leads to the errors like this:
    
    EXT4-fs warning (device loop0): ext4_da_release_space:1225:
    ext4_da_release_space: ino 13, to_free 1 with only 0 reserved data
    blocks
    
    This however can cause data loss on writeback time if the file system is
    in ENOSPC condition because we're releasing reservation for someones
    else delayed buffer.
    
    Fix this by only removing extents that corresponds to the part of the
    page we want to invalidate.
    
    This problem is reproducible by the following fio receipt (however I was
    only able to reproduce it with fio-2.1 or older.
    
    [global]
    bs=8k
    iodepth=1024
    iodepth_batch=60
    randrepeat=1
    size=1m
    directory=/mnt/test
    numjobs=20
    [job1]
    ioengine=sync
    bs=1k
    direct=1
    rw=randread
    filename=file1:file2
    [job2]
    ioengine=libaio
    rw=randwrite
    direct=1
    filename=file1:file2
    [job3]
    bs=1k
    ioengine=posixaio
    rw=randwrite
    direct=1
    filename=file1:file2
    [job5]
    bs=1k
    ioengine=sync
    rw=randread
    filename=file1:file2
    [job7]
    ioengine=libaio
    rw=randwrite
    filename=file1:file2
    [job8]
    ioengine=posixaio
    rw=randwrite
    filename=file1:file2
    [job10]
    ioengine=mmap
    rw=randwrite
    bs=1k
    filename=file1:file2
    [job11]
    ioengine=mmap
    rw=randwrite
    direct=1
    filename=file1:file2
    Signed-off-by: NLukas Czerner <lczerner@redhat.com>
    Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
    Reviewed-by: NJan Kara <jack@suse.cz>
    Cc: stable@vger.kernel.org
    9705acd6
inode.c 153.3 KB