NFS: Don't hold the group lock when calling nfs_release_request()

[sfrench/cifs-2.6.git] / fs / nfs / write.c

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index ae26775b5448a7e0885a97072f9b2eb1064c4840..36d34a4c86bd72447f6bfbe0b85a538508e8f0d2 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -532,9 +532,9 @@ try_again:
                } else if (WARN_ON_ONCE(subreq->wb_offset < head->wb_offset ||
                            ((subreq->wb_offset + subreq->wb_bytes) >
                             (head->wb_offset + total_bytes)))) {
+                       nfs_page_group_unlock(head);
                        nfs_unroll_locks(inode, head, subreq);
                        nfs_unlock_and_release_request(subreq);
-                       nfs_page_group_unlock(head);
                        nfs_unlock_and_release_request(head);
                        return ERR_PTR(-EIO);
                }
@@ -1028,23 +1028,31 @@ int
 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
                     struct nfs_commit_info *cinfo, int max)
 {
-       struct nfs_page *req;
+       struct nfs_page *req, *tmp;
        int ret = 0;
 
-       while(!list_empty(src)) {
-               req = list_first_entry(src, struct nfs_page, wb_list);
+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;
-                       continue;
+                       goto restart;
                }
                nfs_request_remove_commit_list(req, cinfo);
+               clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
                nfs_list_add_request(req, dst);
                ret++;
                if ((ret == max) && !cinfo->dreq)
@@ -1053,6 +1061,7 @@ nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
        }
        return ret;
 }
+EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
 
 /*
  * nfs_scan_commit - Scan an inode for commit requests