[PATCH 8/8] pnfs_post_submit: Revert the pnfs_write_end part of "pnfs: commit and pnfs_write_end"

[Fred Isaman <iisaman@netapp.com>]

From: Fred Isaman <iisaman@citi.umich.edu>

pnfs: commit and pnfs_write_end

Add hooks in the nfs_write_end path, giving a driver the potential for
post-copy manipulation of the page.

[pnfs: pass lseg from write_begin to write_end]
Signed-off-by: Fred Isaman <iisaman@citi.umich.edu>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[pnfs: fix pnfs_commit update_layout range]
    Whole file semantics are different for COMMIT (0,0) and layouts
    (0,NFS4_MAX_UINT64).
Reported-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

Signed-off-by: Fred Isaman <iisaman@netapp.com>
---
 fs/nfs/file.c             |    4 ++++
 fs/nfs/pnfs.c             |   14 ++++++++++++++
 fs/nfs/pnfs.h             |   23 +++++++++++++++++++++++
 include/linux/nfs4_pnfs.h |    3 +++
 4 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 4398953..47eec55 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -487,8 +487,12 @@ static int nfs_write_end(struct file *file, struct address_space *mapping,
 			zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
 	}
 
+	status = pnfs_write_end(file, page, pos, len, copied, fsdata);
+	if (status)
+		goto out;
 	status = nfs_updatepage(file, page, offset, copied, fsdata);
 
+ out:
 	unlock_page(page);
 	page_cache_release(page);
 	pnfs_write_end_cleanup(fsdata);
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 46fe088..c76b791 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1965,6 +1965,20 @@ out:
 	return status;
 }
 
+/* Return 0 on succes, negative on failure */
+/* CAREFUL - what happens if copied < len??? */
+int _pnfs_write_end(struct inode *inode, struct page *page,
+		    loff_t pos, unsigned len,
+		    unsigned copied, struct pnfs_fsdata *fsdata)
+{
+	struct nfs_server *nfss = NFS_SERVER(inode);
+	int status;
+
+	status = nfss->pnfs_curr_ld->ld_io_ops->write_end(inode, page,
+						pos, len, copied, fsdata);
+	return status;
+}
+
 /* Given an nfs request, determine if it should be flushed before proceeding.
  * It should default to returning False, returning True only if there is a
  * specific reason to flush.
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 1c94984..7dc3ecc 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -76,6 +76,9 @@ void pnfs_destroy_layout(struct nfs_inode *);
 int _pnfs_write_begin(struct inode *inode, struct page *page,
 		      loff_t pos, unsigned len,
 		      struct pnfs_fsdata **fsdata);
+int _pnfs_write_end(struct inode *inode, struct page *page,
+		    loff_t pos, unsigned len,
+		    unsigned copied, struct pnfs_fsdata *fsdata);
 int _pnfs_do_flush(struct inode *inode, struct nfs_page *req,
 		   struct pnfs_fsdata *fsdata);
 void _pnfs_modify_new_write_request(struct nfs_page *req,
@@ -197,6 +200,19 @@ static inline int pnfs_do_flush(struct nfs_page *req, void *fsdata)
 		return 0;
 }
 
+static inline int pnfs_write_end(struct file *filp, struct page *page,
+				 loff_t pos, unsigned len, unsigned copied,
+				 void *fsdata)
+{
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct nfs_server *nfss = NFS_SERVER(inode);
+
+	if (PNFS_EXISTS_LDIO_OP(nfss, write_end))
+		return _pnfs_write_end(inode, page, pos, len, copied, fsdata);
+	else
+		return 0;
+}
+
 static inline void pnfs_write_end_cleanup(void *fsdata)
 {
 	pnfs_free_fsdata(fsdata);
@@ -296,6 +312,13 @@ static inline int pnfs_write_begin(struct file *filp, struct page *page,
 	return 0;
 }
 
+static inline int pnfs_write_end(struct file *filp, struct page *page,
+				 loff_t pos, unsigned len, unsigned copied,
+				 void *fsdata)
+{
+	return 0;
+}
+
 static inline void pnfs_write_end_cleanup(void *fsdata)
 {
 }
diff --git a/include/linux/nfs4_pnfs.h b/include/linux/nfs4_pnfs.h
index e01a065..3caac60 100644
--- a/include/linux/nfs4_pnfs.h
+++ b/include/linux/nfs4_pnfs.h
@@ -142,6 +142,9 @@ struct layoutdriver_io_operations {
 	int (*write_begin) (struct pnfs_layout_segment *lseg, struct page *page,
 			    loff_t pos, unsigned count,
 			    struct pnfs_fsdata *fsdata);
+	int (*write_end)(struct inode *inode, struct page *page, loff_t pos,
+			 unsigned count, unsigned copied,
+			 struct pnfs_fsdata *fsdata);
 	void (*new_request)(struct pnfs_layout_segment *lseg,
 			    struct nfs_page *req, loff_t pos, unsigned count,
 			    struct pnfs_fsdata *fsdata);
-- 
1.6.6.1