NFSv4.1: Clean ups and bugfixes for the pNFS read/writeback/commit code

Move more pnfs-isms out of the generic commit code.

Bugfixes:

- filelayout_scan_commit_lists doesn't need to get/put the lseg.
  In fact since it is run under the inode->i_lock, the lseg_put()
  can deadlock.

- Ensure that we distinguish between what needs to be done for
  commit-to-data server and what needs to be done for commit-to-MDS
  using the new flag PG_COMMIT_TO_DS. Otherwise we may end up calling
  put_lseg() on a bucket for a struct nfs_page that got written
  through the MDS.

- Fix a case where we were using list_del() on an nfs_page->wb_list
  instead of list_del_init().

- filelayout_initiate_commit needs to call filelayout_commit_release
  on error instead of the mds_ops->rpc_release(). Otherwise it won't
  clear the commit lock.

Cleanups:

- Let the files layout manage the commit lists for the pNFS case.
  Don't expose stuff like pnfs_choose_commit_list, and the fact
  that the commit buckets hold references to the layout segment
  in common code.

- Cast out the put_lseg() calls for the struct nfs_read/write_data->lseg
  into the pNFS layer from whence they came.

- Let the pNFS layer manage the NFS_INO_PNFS_COMMIT bit.

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

1 files changed, 28 insertions, 27 deletions

diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index ef92f676cf1e..e98ff3027d3a 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -94,9 +94,9 @@ struct pnfs_layoutdriver_type {
         const struct nfs_pageio_ops *pg_read_ops;
         const struct nfs_pageio_ops *pg_write_ops;
 
-        struct list_head * (*choose_commit_list) (struct nfs_page *req,
+        void (*mark_request_commit) (struct nfs_page *req,
                                         struct pnfs_layout_segment *lseg);
-        struct pnfs_layout_segment *(*remove_commit_req) (struct nfs_page *req);
+        void (*clear_request_commit) (struct nfs_page *req);
         int (*scan_commit_lists) (struct inode *inode, int max);
         int (*commit_pagelist)(struct inode *inode, struct list_head *mds_pages, int how);
 
@@ -269,39 +269,42 @@ pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how)
         return NFS_SERVER(inode)->pnfs_curr_ld->commit_pagelist(inode, mds_pages, how);
 }
 
-static inline struct list_head *
-pnfs_choose_commit_list(struct nfs_page *req, struct pnfs_layout_segment *lseg)
+static inline bool
+pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
 {
         struct inode *inode = req->wb_context->dentry->d_inode;
-        struct list_head *rv;
+        struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
 
-        if (lseg && NFS_SERVER(inode)->pnfs_curr_ld->choose_commit_list)
-                rv = NFS_SERVER(inode)->pnfs_curr_ld->choose_commit_list(req, lseg);
-        else
-                rv = &NFS_I(inode)->commit_list;
-        return rv;
+        if (lseg == NULL || ld->mark_request_commit == NULL)
+                return false;
+        ld->mark_request_commit(req, lseg);
+        return true;
 }
 
-static inline struct pnfs_layout_segment *
+static inline bool
 pnfs_clear_request_commit(struct nfs_page *req)
 {
         struct inode *inode = req->wb_context->dentry->d_inode;
+        struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
 
-        if (NFS_SERVER(inode)->pnfs_curr_ld &&
-            NFS_SERVER(inode)->pnfs_curr_ld->remove_commit_req)
-                return NFS_SERVER(inode)->pnfs_curr_ld->remove_commit_req(req);
-        else
-                return NULL;
+        if (ld == NULL || ld->clear_request_commit == NULL)
+                return false;
+        ld->clear_request_commit(req);
+        return true;
 }
 
 static inline int
 pnfs_scan_commit_lists(struct inode *inode, int max)
 {
-        if (NFS_SERVER(inode)->pnfs_curr_ld &&
-            NFS_SERVER(inode)->pnfs_curr_ld->scan_commit_lists)
-                return NFS_SERVER(inode)->pnfs_curr_ld->scan_commit_lists(inode, max);
-        else
+        struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
+        int ret;
+
+        if (ld == NULL || ld->scan_commit_lists == NULL)
                 return 0;
+        ret = ld->scan_commit_lists(inode, max);
+        if (ret != 0)
+                set_bit(NFS_INO_PNFS_COMMIT, &NFS_I(inode)->flags);
+        return ret;
 }
 
 /* Should the pNFS client commit and return the layout upon a setattr */
@@ -403,18 +406,16 @@ pnfs_commit_list(struct inode *inode, struct list_head *mds_pages, int how)
         return PNFS_NOT_ATTEMPTED;
 }
 
-static inline struct list_head *
-pnfs_choose_commit_list(struct nfs_page *req, struct pnfs_layout_segment *lseg)
+static inline bool
+pnfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
 {
-        struct inode *inode = req->wb_context->dentry->d_inode;
-
-        return &NFS_I(inode)->commit_list;
+        return false;
 }
 
-static inline struct pnfs_layout_segment *
+static inline bool
 pnfs_clear_request_commit(struct nfs_page *req)
 {
-        return NULL;
+        return false;
 }
 
 static inline int