| From 0f5d9c66f01a6b20a053822aa7c51b0085286710 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 4 Oct 2021 15:44:16 -0400 |
| Subject: NFS: Fix deadlocks in nfs_scan_commit_list() |
| |
| From: Trond Myklebust <trond.myklebust@hammerspace.com> |
| |
| [ Upstream commit 64a93dbf25d3a1368bb58ddf0f61d0a92d7479e3 ] |
| |
| Partially revert commit 2ce209c42c01 ("NFS: Wait for requests that are |
| locked on the commit list"), since it can lead to deadlocks between |
| commit requests and nfs_join_page_group(). |
| For now we should assume that any locked requests on the commit list are |
| either about to be removed and committed by another task, or the writes |
| they describe are about to be retransmitted. In either case, we should |
| not need to worry. |
| |
| Fixes: 2ce209c42c01 ("NFS: Wait for requests that are locked on the commit list") |
| Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| fs/nfs/write.c | 17 ++--------------- |
| 1 file changed, 2 insertions(+), 15 deletions(-) |
| |
| diff --git a/fs/nfs/write.c b/fs/nfs/write.c |
| index 613c3ef23e07b..30d8e7bc1cef3 100644 |
| --- a/fs/nfs/write.c |
| +++ b/fs/nfs/write.c |
| @@ -1050,25 +1050,11 @@ nfs_scan_commit_list(struct list_head *src, struct list_head *dst, |
| struct nfs_page *req, *tmp; |
| int ret = 0; |
| |
| -restart: |
| list_for_each_entry_safe(req, tmp, src, wb_list) { |
| kref_get(&req->wb_kref); |
| if (!nfs_lock_request(req)) { |
| - int status; |
| - |
| - /* Prevent deadlock with nfs_lock_and_join_requests */ |
| - if (!list_empty(dst)) { |
| - nfs_release_request(req); |
| - continue; |
| - } |
| - /* Ensure we make progress to prevent livelock */ |
| - mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex); |
| - status = nfs_wait_on_request(req); |
| nfs_release_request(req); |
| - mutex_lock(&NFS_I(cinfo->inode)->commit_mutex); |
| - if (status < 0) |
| - break; |
| - goto restart; |
| + continue; |
| } |
| nfs_request_remove_commit_list(req, cinfo); |
| clear_bit(PG_COMMIT_TO_DS, &req->wb_flags); |
| @@ -1935,6 +1921,7 @@ static int __nfs_commit_inode(struct inode *inode, int how, |
| int may_wait = how & FLUSH_SYNC; |
| int ret, nscan; |
| |
| + how &= ~FLUSH_SYNC; |
| nfs_init_cinfo_from_inode(&cinfo, inode); |
| nfs_commit_begin(cinfo.mds); |
| for (;;) { |
| -- |
| 2.33.0 |
| |