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author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-03-30 11:12:16 -0400 |
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committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-04-01 13:37:56 -0400 |
commit | a62f8e3bd836bf1abde1648a45e14afd050dbd23 (patch) | |
tree | 2c93e5b4f2768ac87a4fac37e453997096177d4f /fs/nfs/pagelist.c | |
parent | 377840ee48cde0700678ef14141106bbd13e00b5 (diff) | |
download | linux-a62f8e3bd836bf1abde1648a45e14afd050dbd23.tar.bz2 |
NFS: Clean up nfs_lock_and_join_requests()
Clean up nfs_lock_and_join_requests() to simplify the calculation
of the range covered by the page group, taking into account the
presence of mirrors.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs/nfs/pagelist.c')
-rw-r--r-- | fs/nfs/pagelist.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index f535a92403bf..261236157e33 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -131,6 +131,80 @@ nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx) EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait); /* + * nfs_unroll_locks - unlock all newly locked reqs and wait on @req + * @head: head request of page group, must be holding head lock + * @req: request that couldn't lock and needs to wait on the req bit lock + * + * This is a helper function for nfs_lock_and_join_requests + * returns 0 on success, < 0 on error. + */ +static void +nfs_unroll_locks(struct nfs_page *head, struct nfs_page *req) +{ + struct nfs_page *tmp; + + /* relinquish all the locks successfully grabbed this run */ + for (tmp = head->wb_this_page ; tmp != req; tmp = tmp->wb_this_page) { + if (!kref_read(&tmp->wb_kref)) + continue; + nfs_unlock_and_release_request(tmp); + } +} + +/* + * nfs_page_group_lock_subreq - try to lock a subrequest + * @head: head request of page group + * @subreq: request to lock + * + * This is a helper function for nfs_lock_and_join_requests which + * must be called with the head request and page group both locked. + * On error, it returns with the page group unlocked. + */ +static int +nfs_page_group_lock_subreq(struct nfs_page *head, struct nfs_page *subreq) +{ + int ret; + + if (!kref_get_unless_zero(&subreq->wb_kref)) + return 0; + while (!nfs_lock_request(subreq)) { + nfs_page_group_unlock(head); + ret = nfs_wait_on_request(subreq); + if (!ret) + ret = nfs_page_group_lock(head); + if (ret < 0) { + nfs_unroll_locks(head, subreq); + nfs_release_request(subreq); + return ret; + } + } + return 0; +} + +/* + * nfs_page_group_lock_subrequests - try to lock the subrequests + * @head: head request of page group + * + * This is a helper function for nfs_lock_and_join_requests which + * must be called with the head request and page group both locked. + * On error, it returns with the page group unlocked. + */ +int nfs_page_group_lock_subrequests(struct nfs_page *head) +{ + struct nfs_page *subreq; + int ret; + + /* lock each request in the page group */ + for (subreq = head->wb_this_page; subreq != head; + subreq = subreq->wb_this_page) { + ret = nfs_page_group_lock_subreq(head, subreq); + if (ret < 0) + return ret; + } + return 0; +} + +/* * nfs_page_set_headlock - set the request PG_HEADLOCK * @req: request that is to be locked * |