From 2ce209c42c01ca976ad680fea52a8e8b9a53643b Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 1 Aug 2017 17:29:29 -0400 Subject: [PATCH] NFS: Wait for requests that are locked on the commit list If a request is on the commit list, but is locked, we will currently skip it, which can lead to livelocking when the commit count doesn't reduce to zero. Signed-off-by: Trond Myklebust --- fs/nfs/pagelist.c | 2 ++ fs/nfs/pnfs_nfs.c | 18 ++++++++++++++---- fs/nfs/write.c | 17 +++++++++++++---- 3 files changed, 29 insertions(+), 8 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index ec97c301899b..548ebc7256ff 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -434,6 +434,7 @@ void nfs_release_request(struct nfs_page *req) { kref_put(&req->wb_kref, nfs_page_group_destroy); } +EXPORT_SYMBOL_GPL(nfs_release_request); /** * nfs_wait_on_request - Wait for a request to complete. @@ -452,6 +453,7 @@ nfs_wait_on_request(struct nfs_page *req) return wait_on_bit_io(&req->wb_flags, PG_BUSY, TASK_UNINTERRUPTIBLE); } +EXPORT_SYMBOL_GPL(nfs_wait_on_request); /* * nfs_generic_pg_test - determine if requests can be coalesced diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c index 4b0a809653d1..303ff171cb5d 100644 --- a/fs/nfs/pnfs_nfs.c +++ b/fs/nfs/pnfs_nfs.c @@ -91,13 +91,23 @@ static int pnfs_generic_transfer_commit_list(struct list_head *src, struct list_head *dst, struct nfs_commit_info *cinfo, int max) { - struct nfs_page *req, *tmp; + struct nfs_page *req; int ret = 0; - list_for_each_entry_safe(req, tmp, src, wb_list) { - if (!nfs_lock_request(req)) - continue; + while(!list_empty(src)) { + req = list_first_entry(src, struct nfs_page, wb_list); + kref_get(&req->wb_kref); + if (!nfs_lock_request(req)) { + int status; + 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; + continue; + } nfs_request_remove_commit_list(req, cinfo); clear_bit(PG_COMMIT_TO_DS, &req->wb_flags); nfs_list_add_request(req, dst); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 866702823869..5dd3b212376e 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -1030,13 +1030,22 @@ int nfs_scan_commit_list(struct list_head *src, struct list_head *dst, struct nfs_commit_info *cinfo, int max) { - struct nfs_page *req, *tmp; + struct nfs_page *req; int ret = 0; - list_for_each_entry_safe(req, tmp, src, wb_list) { - if (!nfs_lock_request(req)) - continue; + while(!list_empty(src)) { + req = list_first_entry(src, struct nfs_page, wb_list); kref_get(&req->wb_kref); + if (!nfs_lock_request(req)) { + int status; + 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; + continue; + } nfs_request_remove_commit_list(req, cinfo); nfs_list_add_request(req, dst); ret++; -- 2.20.1