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Date: Fri, 26 Aug 2011 07:35:24 -0400 From: Theodore Tso <tytso@....EDU> To: Christoph Hellwig <hch@...radead.org> Cc: Tao Ma <tm@....ma>, Dave Chinner <david@...morbit.com>, Jiaying Zhang <jiayingz@...gle.com>, linux-ext4@...r.kernel.org Subject: Re: [URGENT PATCH] ext4: fix potential deadlock in ext4_evict_inode() On Aug 26, 2011, at 5:17 AM, Christoph Hellwig wrote: > The thing I have queued up for 3.2 makes it very simple: we do not > track I/O ends any more at all, outside of the workqueue. > > For buffered I/O we only mark the page uptodate when all unwritten > extent conversion and size updates have finished. All data integrity > callers and inode eviction wait for the pages to be update so we are > covered. > > For direct I/O we only call inode_dio_done and aio_complete once all > unwritten extent size updates are done. Inodes can't be evicted until > we drop a reference to the inode, which can't happen until the > sync or async dio is done and we drop the inode reference the VFS > holds for it. Sync and fsync are only guaranteed to pick up I/O > that has returned to userspace, so we are covered for that as well. Long term, I definitely want to make ext4 do something similar. What we have now is just way too fragile⦠-- Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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