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| author | Weston Andros Adamson <dros@primarydata.com> | 2014-11-12 12:08:00 -0500 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2014-11-24 17:00:42 -0500 |
| commit | cb1410c71e0b6b2eba8c1890645a76ff86169d24 (patch) | |
| tree | 22fb6770fed66df7d51676e25e5a525bdd352abe /fs/nfs/write.c | |
| parent | 6a74c0c9402b85647793da70edc9d6b097d54472 (diff) | |
| download | linux-cb1410c71e0b6b2eba8c1890645a76ff86169d24.tar.gz linux-cb1410c71e0b6b2eba8c1890645a76ff86169d24.tar.bz2 linux-cb1410c71e0b6b2eba8c1890645a76ff86169d24.zip | |
NFS: fix subtle change in COMMIT behavior
Recent work in the pgio layer made it possible for there to be more than one
request per page. This caused a subtle change in commit behavior, because
write.c:nfs_commit_unstable_pages compares the number of *pages* waiting for
writeback against the number of requests on a commit list to choose when to
send a COMMIT in a non-blocking flush.
This is probably hard to hit in normal operation - you have to be using
rsize/wsize < PAGE_SIZE, or pnfs with lots of boundaries that are not page
aligned to have a noticeable change in behavior.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/write.c')
| -rw-r--r-- | fs/nfs/write.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c index f83b02dc9166..d489ff3f438f 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -670,7 +670,8 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req) nfs_lock_request(req); spin_lock(&inode->i_lock); - if (!nfsi->npages && NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) + if (!nfsi->nrequests && + NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) inode->i_version++; /* * Swap-space should not get truncated. Hence no need to plug the race @@ -681,9 +682,11 @@ static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req) SetPagePrivate(req->wb_page); set_page_private(req->wb_page, (unsigned long)req); } - nfsi->npages++; + nfsi->nrequests++; /* this a head request for a page group - mark it as having an - * extra reference so sub groups can follow suit */ + * extra reference so sub groups can follow suit. + * This flag also informs pgio layer when to bump nrequests when + * adding subrequests. */ WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags)); kref_get(&req->wb_kref); spin_unlock(&inode->i_lock); @@ -709,7 +712,11 @@ static void nfs_inode_remove_request(struct nfs_page *req) wake_up_page(head->wb_page, PG_private); clear_bit(PG_MAPPED, &head->wb_flags); } - nfsi->npages--; + nfsi->nrequests--; + spin_unlock(&inode->i_lock); + } else { + spin_lock(&inode->i_lock); + nfsi->nrequests--; spin_unlock(&inode->i_lock); } @@ -1735,7 +1742,7 @@ 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 a lot of outstanding writes for this mapping. */ - if (nfsi->commit_info.ncommit <= (nfsi->npages >> 1)) + if (nfsi->commit_info.ncommit <= (nfsi->nrequests >> 1)) goto out_mark_dirty; /* don't wait for the COMMIT response */ |