[PATCH v2 1/2] NFS: Optimise away the close-to-open getattr if there is no cached data

[PATCH v2 1/2] NFS: Optimise away the close-to-open getattr if there is no cached data

[Trond Myklebust]

If there is no cached data, then there is no need to track the file
change attribute on close.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/inode.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 99a68bd9c178..6307d8de103d 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -761,11 +761,13 @@ EXPORT_SYMBOL_GPL(nfs_put_lock_context);
  * @ctx: pointer to context
  * @is_sync: is this a synchronous close
  *
- * always ensure that the attributes are up to date if we're mounted
- * with close-to-open semantics
+ * Ensure that the attributes are up to date if we're mounted
+ * with close-to-open semantics and we have cached data that will
+ * need to be revalidated on open.
  */
 void nfs_close_context(struct nfs_open_context *ctx, int is_sync)
 {
+	struct nfs_inode *nfsi;
 	struct inode *inode;
 	struct nfs_server *server;
 
@@ -774,7 +776,12 @@ void nfs_close_context(struct nfs_open_context *ctx, int is_sync)
 	if (!is_sync)
 		return;
 	inode = d_inode(ctx->dentry);
-	if (!list_empty(&NFS_I(inode)->open_files))
+	nfsi = NFS_I(inode);
+	if (inode->i_mapping->nrpages == 0)
+		return;
+	if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+		return;
+	if (!list_empty(&nfsi->open_files))
 		return;
 	server = NFS_SERVER(inode);
 	if (server->flags & NFS_MOUNT_NOCTO)
-- 
2.4.3

[PATCH v2 2/2] Revert "NFS: Make close(2) asynchronous when closing NFS O_DIRECT files"

[Trond Myklebust]

This reverts commit f895c53f8ace3c3e49ebf9def90e63fc6d46d2bf.

This commit causes a NFSv4 regression in that close()+unlink() can end
up failing. The reason is that we no longer have a guarantee that the
CLOSE has completed on the server, meaning that the subsequent call to
REMOVE may fail with NFS4ERR_FILE_OPEN if the server implements Windows
unlink() semantics.

Reported-by: <Olga Kornievskaia <aglo@umich.edu>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
---
 fs/nfs/inode.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 6307d8de103d..326d9e10d833 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -853,6 +853,11 @@ void put_nfs_open_context(struct nfs_open_context *ctx)
 }
 EXPORT_SYMBOL_GPL(put_nfs_open_context);
 
+static void put_nfs_open_context_sync(struct nfs_open_context *ctx)
+{
+	__put_nfs_open_context(ctx, 1);
+}
+
 /*
  * Ensure that mmap has a recent RPC credential for use when writing out
  * shared pages
@@ -908,7 +913,7 @@ void nfs_file_clear_open_context(struct file *filp)
 		spin_lock(&inode->i_lock);
 		list_move_tail(&ctx->list, &NFS_I(inode)->open_files);
 		spin_unlock(&inode->i_lock);
-		__put_nfs_open_context(ctx, filp->f_flags & O_DIRECT ? 0 : 1);
+		put_nfs_open_context_sync(ctx);
 	}
 }
 
-- 
2.4.3

Re: [PATCH v2 2/2] Revert "NFS: Make close(2) asynchronous when closing NFS O_DIRECT files"

[Chuck Lever]

On Sep 4, 2015, at 5:01 PM, Trond Myklebust <trond.myklebust@primarydata.com> wrote:

> This reverts commit f895c53f8ace3c3e49ebf9def90e63fc6d46d2bf.
> 
> This commit causes a NFSv4 regression in that close()+unlink() can end
> up failing. The reason is that we no longer have a guarantee that the
> CLOSE has completed on the server, meaning that the subsequent call to
> REMOVE may fail with NFS4ERR_FILE_OPEN if the server implements Windows
> unlink() semantics.
> 
> Reported-by: <Olga Kornievskaia <aglo@umich.edu>
> Cc: Chuck Lever <chuck.lever@oracle.com>

I'm fine with this as long as the current NFSv3 behavior stays
the same. I haven't tested, but I believe 1/2 will guarantee
that NFSv3 close(2) behavior does not change.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>


> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
> ---
> fs/nfs/inode.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index 6307d8de103d..326d9e10d833 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -853,6 +853,11 @@ void put_nfs_open_context(struct nfs_open_context *ctx)
> }
> EXPORT_SYMBOL_GPL(put_nfs_open_context);
> 
> +static void put_nfs_open_context_sync(struct nfs_open_context *ctx)
> +{
> +	__put_nfs_open_context(ctx, 1);
> +}
> +
> /*
>  * Ensure that mmap has a recent RPC credential for use when writing out
>  * shared pages
> @@ -908,7 +913,7 @@ void nfs_file_clear_open_context(struct file *filp)
> 		spin_lock(&inode->i_lock);
> 		list_move_tail(&ctx->list, &NFS_I(inode)->open_files);
> 		spin_unlock(&inode->i_lock);
> -		__put_nfs_open_context(ctx, filp->f_flags & O_DIRECT ? 0 : 1);
> +		put_nfs_open_context_sync(ctx);
> 	}
> }
> 
> -- 
> 2.4.3
> 

--
Chuck Lever