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    ext4: Make sure all the block allocation paths reserve blocks · a30d542a
    Aneesh Kumar K.V 提交于
    With delayed allocation we need to make sure block are reserved before
    we attempt to allocate them. Otherwise we get block allocation failure
    (ENOSPC) during writepages which cannot be handled. This would mean
    silent data loss (We do a printk stating data will be lost). This patch
    updates the DIO and fallocate code path to do block reservation before
    block allocation. This is needed to make sure parallel DIO and fallocate
    request doesn't take block out of delayed reserve space.
    
    When free blocks count go below a threshold we switch to a slow patch
    which looks at other CPU's accumulated percpu counter values.
    Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
    Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
    a30d542a
ext4.h 44.0 KB