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| author |   Weston Andros Adamson <dros@primarydata.com> | 2014-07-11 10:20:46 -0400 |
|---|---|---|
| committer |   Trond Myklebust <trond.myklebust@primarydata.com> | 2014-07-12 16:51:41 -0400 |
| commit | 85710a837c2026aae80b7c64187edf1f10027b0b (patch) | |
| tree | 9b8ac697b4bc8aa635a6b97432bc76113703a85a /fs/nfs/pagelist.c | |
| parent | nfs: mark nfs_page reqs with flag for extra ref (diff) | |
| download | linux-dev-85710a837c2026aae80b7c64187edf1f10027b0b.tar.xz linux-dev-85710a837c2026aae80b7c64187edf1f10027b0b.zip | |
nfs: nfs_page should take a ref on the head req
nfs_pages that aren't the the head of a group must take a reference on the
head as long as ->wb_head is set to it. This stops the head from hitting
a refcount of 0 while there is still an active nfs_page for the page group.
This avoids kref warnings in the writeback code when the page group head
is found and referenced.
Signed-off-by: Weston Andros Adamson <dros@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/pagelist.c')
| -rw-r--r-- | fs/nfs/pagelist.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 7368b2130a41..05a63593a61f 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -239,15 +239,21 @@ nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev) WARN_ON_ONCE(prev == req); if (!prev) { + /* a head request */ req->wb_head = req; req->wb_this_page = req; } else { + /* a subrequest */ WARN_ON_ONCE(prev->wb_this_page != prev->wb_head); WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags)); req->wb_head = prev->wb_head; req->wb_this_page = prev->wb_this_page; prev->wb_this_page = req; + /* All subrequests take a ref on the head request until + * nfs_page_group_destroy is called */ + kref_get(&req->wb_head->wb_kref); + /* grab extra ref if head request has extra ref from * the write/commit path to handle handoff between write * and commit lists */ @@ -271,6 +277,10 @@ nfs_page_group_destroy(struct kref *kref) struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref); struct nfs_page *tmp, *next; + /* subrequests must release the ref on the head request */ + if (req->wb_head != req) + nfs_release_request(req->wb_head); + if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN)) return; |