pnfs: Do not grab the commit_info lock twice when rescheduling writes

Acked-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Tom Haynes <loghyr@primarydata.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index e5f841cb6227..fd2a2f0e8cbb 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -66,7 +66,7 @@ EXPORT_SYMBOL_GPL(pnfs_generic_commit_release);
 
 /* The generic layer is about to remove the req from the commit list.
  * If this will make the bucket empty, it will need to put the lseg reference.
- * Note this is must be called holding the inode (/cinfo) lock
+ * Note this must be called holding the inode (/cinfo) lock
  */
 void
 pnfs_generic_clear_request_commit(struct nfs_page *req,
@@ -115,7 +115,6 @@ pnfs_generic_transfer_commit_list(struct list_head *src, struct list_head *dst,
         return ret;
 }
 
-/* Note called with cinfo->lock held. */
 static int
 pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
                                  struct nfs_commit_info *cinfo,
@@ -125,6 +124,7 @@ pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
         struct list_head *dst = &bucket->committing;
         int ret;
 
+        lockdep_assert_held(cinfo->lock);
         ret = pnfs_generic_transfer_commit_list(src, dst, cinfo, max);
         if (ret) {
                 cinfo->ds->nwritten -= ret;
@@ -138,14 +138,15 @@ pnfs_generic_scan_ds_commit_list(struct pnfs_commit_bucket *bucket,
         return ret;
 }
 
-/* Move reqs from written to committing lists, returning count of number moved.
- * Note called with cinfo->lock held.
+/* Move reqs from written to committing lists, returning count
+ * of number moved.
  */
 int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo,
                                    int max)
 {
         int i, rv = 0, cnt;
 
+        lockdep_assert_held(cinfo->lock);
         for (i = 0; i < cinfo->ds->nbuckets && max != 0; i++) {
                 cnt = pnfs_generic_scan_ds_commit_list(&cinfo->ds->buckets[i],
                                                        cinfo, max);
@@ -156,7 +157,7 @@ int pnfs_generic_scan_commit_lists(struct nfs_commit_info *cinfo,
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_scan_commit_lists);
 
-/* Pull everything off the committing lists and dump into @dst */
+/* Pull everything off the committing lists and dump into @dst.  */
 void pnfs_generic_recover_commit_reqs(struct list_head *dst,
                                       struct nfs_commit_info *cinfo)
 {
@@ -164,8 +165,8 @@ void pnfs_generic_recover_commit_reqs(struct list_head *dst,
         struct pnfs_layout_segment *freeme;
         int i;
 
+        lockdep_assert_held(cinfo->lock);
 restart:
-        spin_lock(cinfo->lock);
         for (i = 0, b = cinfo->ds->buckets; i < cinfo->ds->nbuckets; i++, b++) {
                 if (pnfs_generic_transfer_commit_list(&b->written, dst,
                                                       cinfo, 0)) {
@@ -173,11 +174,11 @@ restart:
                         b->wlseg = NULL;
                         spin_unlock(cinfo->lock);
                         pnfs_put_lseg(freeme);
+                        spin_lock(cinfo->lock);
                         goto restart;
                 }
         }
         cinfo->ds->nwritten = 0;
-        spin_unlock(cinfo->lock);
 }
 EXPORT_SYMBOL_GPL(pnfs_generic_recover_commit_reqs);