Re: [PATCH] Fix queueing work if !bdi_cap_writeback_dirty()

From: OGAWA Hirofumi
Date: Fri Sep 14 2012 - 09:44:24 EST


Jan Kara <jack@xxxxxxx> writes:

>> page reclaim and fsync path have FS handler. So, FS can control those.
>>
>> The modern FS have to control to flush carefully. Many FSes are already
>> ignoring if wbc->sync_mode != WB_SYNC_ALL (e.g. ext3_write_inode,
>> nilfs_writepages), and have own FS task to flush.
> Out of curiosity, what exactly do you need to control in your filesystem
> that makes flusher thread unusable for you? You still have a lot of
> flexibility with ->write_inode() and ->writepages() callbacks...

If flusher is working, it clears dirty flags of inode. But if those
handers can't flush at the time, we have to do redirty or something to
prevent the reclaim.

This job is nothing benefit to just for workaround of flusher, and is
complex and racy.

Thanks.
--
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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