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

[PATCH 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 | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 99a68bd9c178..ebaf991e4b02 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -766,6 +766,7 @@ EXPORT_SYMBOL_GPL(nfs_put_lock_context);
  */
 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 +775,12 @@ 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 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.

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 ebaf991e4b02..54eb47799a41 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -852,6 +852,11 @@ 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
@@ -907,7 +912,7 @@ 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 1/2] NFS: Optimise away the close-to-open getattr if there is no cached data

[Chuck Lever]

On Sep 4, 2015, at 3:24 PM, Trond Myklebust <trond.myklebust@primarydata.com> wrote:

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

This makes sense. nfs_close_context() is only used by NFSv2
and NFSv3.

Should you update the documenting comment?


> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
> ---
> fs/nfs/inode.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
> index 99a68bd9c178..ebaf991e4b02 100644
> --- a/fs/nfs/inode.c
> +++ b/fs/nfs/inode.c
> @@ -766,6 +766,7 @@ EXPORT_SYMBOL_GPL(nfs_put_lock_context);
>  */
> 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 +775,12 @@ 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
> 
> --
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--
Chuck Lever

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

[Trond Myklebust]

On Fri, Sep 4, 2015 at 3:38 PM, Chuck Lever <chuck.lever@oracle.com> wrote:
>
> On Sep 4, 2015, at 3:24 PM, Trond Myklebust <trond.myklebust@primarydata.com> wrote:
>
>> If there is no cached data, then there is no need to track the file
>> change attribute on close.
>
> This makes sense. nfs_close_context() is only used by NFSv2
> and NFSv3.
>
> Should you update the documenting comment?

Good point. I'll do that...