Messages in this thread | | | Subject | Re: [PATCH] incorrect direct io error handling | From | Dmitriy Monakhov <> | Date | Tue, 19 Dec 2006 09:31:15 +0300 |
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"Chen, Kenneth W" <kenneth.w.chen@intel.com> writes:
> Dmitriy Monakhov wrote on Monday, December 18, 2006 5:23 AM >> This patch is result of discussion started week ago here: >> http://lkml.org/lkml/2006/12/11/66 >> changes from original patch: >> - Update wrong comments about i_mutex locking. >> - Add BUG_ON(!mutex_is_locked(..)) for non blkdev. >> - vmtruncate call only for non blockdev >> LOG: >> If generic_file_direct_write() has fail (ENOSPC condition) inside >> __generic_file_aio_write_nolock() it may have instantiated >> a few blocks outside i_size. And fsck will complain about wrong i_size >> (ext2, ext3 and reiserfs interpret i_size and biggest block difference as error), >> after fsck will fix error i_size will be increased to the biggest block, >> but this blocks contain gurbage from previous write attempt, this is not >> information leak, but its silence file data corruption. This issue affect >> fs regardless the values of blocksize or pagesize. >> We need truncate any block beyond i_size after write have failed , do in simular >> generic_file_buffered_write() error path. If host is !S_ISBLK i_mutex always >> held inside generic_file_aio_write_nolock() and we may safely call vmtruncate(). >> Some fs (XFS at least) may directly call generic_file_direct_write()with >> i_mutex not held. There is no general scenario in this case. This fs have to >> handle generic_file_direct_write() error by its own specific way (place). > > > I'm puzzled that if ext2 is able to instantiate some blocks, then why does it > return no space error? Where is the error coming from? generic_file_aio_write_nolock() ->generic_file_direct_write() ->generic_file_direct_IO() ->ext2_direct_IO(WRITE,...) ->blockdev_direct_IO( ....,ext2_get_block,...)
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