Re: why are WB_SYNC_NONE COMMITs being done with FLUSH_SYNC set ?
From: Wu Fengguang <hidden>
Date: 2010-08-20 00:33:31
Also in:
linux-fsdevel, linux-nfs
Possibly related (same subject, not in this thread)
- 2010-08-30 · Re: why are WB_SYNC_NONE COMMITs being done with FLUSH_SYNC set ? · Wu Fengguang <hidden>
- 2010-08-30 · Re: why are WB_SYNC_NONE COMMITs being done with FLUSH_SYNC set ? · Trond Myklebust <hidden>
- 2010-08-20 · Re: why are WB_SYNC_NONE COMMITs being done with FLUSH_SYNC set ? · Wu Fengguang <hidden>
- 2010-08-20 · Re: why are WB_SYNC_NONE COMMITs being done with FLUSH_SYNC set ? · Wu Fengguang <hidden>
- 2010-08-20 · Re: why are WB_SYNC_NONE COMMITs being done with FLUSH_SYNC set ? · Wu Fengguang <hidden>
Here's a lightly tested patch that turns the check for the two flags into a check for WB_SYNC_NONE. It seems to do the right thing, but I don't have a clear testcase for it. Does this look reasonable?
Yes, I don't see any problems.
quoted hunk ↗ jump to hunk
------------------[snip]------------------------ NFS: don't use FLUSH_SYNC on WB_SYNC_NONE COMMIT calls WB_SYNC_NONE is supposed to mean "don't wait on anything". That should also include not waiting for COMMIT calls to complete. WB_SYNC_NONE is also implied when wbc->nonblocking or wbc->for_background are set, so we can replace those checks in nfs_commit_unstable_pages with a check for WB_SYNC_NONE. Signed-off-by: Jeff Layton <redacted> --- fs/nfs/write.c | 10 +++++----- 1 files changed, 5 insertions(+), 5 deletions(-)diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 874972d..35bd7d0 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c@@ -1436,12 +1436,12 @@ static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_contr /* Don't commit yet if this is a non-blocking flush and there are * lots of outstanding writes for this mapping. */ - if (wbc->sync_mode == WB_SYNC_NONE && - nfsi->ncommit <= (nfsi->npages >> 1)) - goto out_mark_dirty; - - if (wbc->nonblocking || wbc->for_background) + if (wbc->sync_mode == WB_SYNC_NONE) { + if (nfsi->ncommit <= (nfsi->npages >> 1)) + goto out_mark_dirty; flags = 0; + } +
nitpick: I'd slightly prefer an one-line change
- if (wbc->nonblocking || wbc->for_background)
+ if (wbc->sync_mode == WB_SYNC_NONE)
flags = 0;
That way the patch will look more obvious and "git blame" friendly,
and the original "Don't commit.." comment will best match its code.
Reviewed-by: Wu Fengguang <redacted>
Thanks,
Fengguang
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