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>

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index c24e077..e0bdbf4 100644 (file)
--- 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