NFSv4.1: Fix a few issues in filelayout_commit_pagelist

- Fix a race in which NFS_I(inode)->commits_outstanding could potentially
  go to zero (triggering a call to nfs_commit_clear_lock()) before we're
  done sending out all the commit RPC calls.

- If nfs_commitdata_alloc fails, there is no reason why we shouldn't
  try to send off all the commits-to-ds.

- Simplify the error handling.

- Change pnfs_commit_list() to always return either
  PNFS_ATTEMPTED or PNFS_NOT_ATTEMPTED.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Fred Isaman <iisaman@netapp.com>

1 files changed, 24 insertions, 23 deletions

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index c24e077c2820..e0bdbf4fe454 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -980,12 +980,14 @@ out_done:
         return rv;
 }
 
-static int alloc_ds_commits(struct inode *inode, struct list_head *list)
+static unsigned int
+alloc_ds_commits(struct inode *inode, struct list_head *list)
 {
         struct pnfs_layout_segment *lseg;
         struct nfs4_filelayout_segment *fl;
         struct nfs_write_data *data;
         int i, j;
+        unsigned int nreq = 0;
 
         /* Won't need this when non-whole file layout segments are supported
          * instead we will use a pnfs_layout_hdr structure */
@@ -998,15 +1000,14 @@ static int alloc_ds_commits(struct inode *inode, struct list_head *list)
                         continue;
                 data = nfs_commitdata_alloc();
                 if (!data)
-                        goto out_bad;
+                        break;
                 data->ds_commit_index = i;
                 data->lseg = lseg;
                 list_add(&data->pages, list);
+                nreq++;
         }
-        put_lseg(lseg);
-        return 0;
 
-out_bad:
+        /* Clean up on error */
         for (j = i; j < fl->number_of_buckets; j++) {
                 if (list_empty(&fl->commit_buckets[i].committing))
                         continue;
@@ -1015,7 +1016,7 @@ out_bad:
         }
         put_lseg(lseg);
         /* Caller will clean up entries put on list */
-        return -ENOMEM;
+        return nreq;
 }
 
 /* This follows nfs_commit_list pretty closely */
@@ -1025,21 +1026,29 @@ filelayout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
 {
         struct nfs_write_data   *data, *tmp;
         LIST_HEAD(list);
+        unsigned int nreq = 0;
 
         if (!list_empty(mds_pages)) {
                 data = nfs_commitdata_alloc();
-                if (!data)
-                        goto out_bad;
-                data->lseg = NULL;
-                list_add(&data->pages, &list);
+                if (data != NULL) {
+                        data->lseg = NULL;
+                        list_add(&data->pages, &list);
+                        nreq++;
+                } else
+                        nfs_retry_commit(mds_pages, NULL);
         }
 
-        if (alloc_ds_commits(inode, &list))
-                goto out_bad;
+        nreq += alloc_ds_commits(inode, &list);
+
+        if (nreq == 0) {
+                nfs_commit_clear_lock(NFS_I(inode));
+                goto out;
+        }
+
+        atomic_add(nreq, &NFS_I(inode)->commits_outstanding);
 
         list_for_each_entry_safe(data, tmp, &list, pages) {
                 list_del_init(&data->pages);
-                atomic_inc(&NFS_I(inode)->commits_outstanding);
                 if (!data->lseg) {
                         nfs_init_commit(data, mds_pages, NULL);
                         nfs_initiate_commit(data, NFS_CLIENT(inode),
@@ -1049,16 +1058,8 @@ filelayout_commit_pagelist(struct inode *inode, struct list_head *mds_pages,
                         filelayout_initiate_commit(data, how);
                 }
         }
-        return 0;
- out_bad:
-        list_for_each_entry_safe(data, tmp, &list, pages) {
-                nfs_retry_commit(&data->pages, data->lseg);
-                list_del_init(&data->pages);
-                nfs_commit_free(data);
-        }
-        nfs_retry_commit(mds_pages, NULL);
-        nfs_commit_clear_lock(NFS_I(inode));
-        return -ENOMEM;
+out:
+        return PNFS_ATTEMPTED;
 }
 
 static void