• Jan Kara's avatar
    ext4: fix race in transient ENOSPC detection · dbc427ce
    Jan Kara authored
    When there are blocks to free in the running transaction, block
    allocator can return ENOSPC although the filesystem has some blocks to
    free. We use ext4_should_retry_alloc() to force commit of the current
    transaction and return whether anything was committed so that it makes
    sense to retry the allocation. However the transaction may get committed
    after block allocation fails but before we call
    ext4_should_retry_alloc(). So ext4_should_retry_alloc() returns false
    because there is nothing to commit and we wrongly return ENOSPC.
    
    Fix the race by unconditionally returning 1 from ext4_should_retry_alloc()
    when we tried to commit a transaction. This should not add any
    unnecessary retries since we had a transaction running a while ago when
    trying to allocate blocks and we want to retry the allocation once that
    transaction has committed anyway.
    Signed-off-by: default avatarJan Kara <jack@suse.cz>
    Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
    dbc427ce
balloc.c 25.3 KB