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| author |   Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-04-01 13:04:49 -0400 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-04-01 13:34:28 -0400 |
| commit | 08ca8b21f760c0ed5034a5c122092eec22ccf8f4 (patch) | |
| tree | 353ac3390753c2e92e5238c0499f0cbbb8eae294 /fs/nfs/write.c | |
| parent | NFS: Fix a page leak in nfs_destroy_unlinked_subrequests() (diff) | |
| download | linux-dev-08ca8b21f760c0ed5034a5c122092eec22ccf8f4.tar.xz linux-dev-08ca8b21f760c0ed5034a5c122092eec22ccf8f4.zip | |
NFS: Fix races nfs_page_group_destroy() vs nfs_destroy_unlinked_subrequests()
When a subrequest is being detached from the subgroup, we want to
ensure that it is not holding the group lock, or in the process
of waiting for the group lock.
Fixes: 5b2b5187fa85 ("NFS: Fix nfs_page_group_destroy() and nfs_lock_and_join_requests() race cases")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs/write.c')
| -rw-r--r-- | fs/nfs/write.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 626e99cbb50e..a6d7926b0653 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -428,22 +428,28 @@ nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list, destroy_list = (subreq->wb_this_page == old_head) ? NULL : subreq->wb_this_page; + /* Note: lock subreq in order to change subreq->wb_head */ + nfs_page_set_headlock(subreq); WARN_ON_ONCE(old_head != subreq->wb_head); /* make sure old group is not used */ subreq->wb_this_page = subreq; + subreq->wb_head = subreq; clear_bit(PG_REMOVE, &subreq->wb_flags); /* Note: races with nfs_page_group_destroy() */ if (!kref_read(&subreq->wb_kref)) { /* Check if we raced with nfs_page_group_destroy() */ - if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) + if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) { + nfs_page_clear_headlock(subreq); nfs_free_request(subreq); + } else + nfs_page_clear_headlock(subreq); continue; } + nfs_page_clear_headlock(subreq); - subreq->wb_head = subreq; nfs_release_request(old_head); if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) { |