From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Mon, 13 Aug 2012 21:15:50 +0000 (-0400)
Subject: NFS: Convert nfs_get_lock_context to return an ERR_PTR on failure
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=b3c54de6f82d01637796bcc1f667a45f3b32e814;p=openwrt%2Fstaging%2Fblogic.git

NFS: Convert nfs_get_lock_context to return an ERR_PTR on failure

We want to be able to distinguish between allocation failures, and
the case where the lock context is not needed (because there are no
locks).

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index 1ba385b7c90d..22130df16218 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -450,6 +450,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
 	ssize_t result = -ENOMEM;
 	struct inode *inode = iocb->ki_filp->f_mapping->host;
 	struct nfs_direct_req *dreq;
+	struct nfs_lock_context *l_ctx;
 
 	dreq = nfs_direct_req_alloc();
 	if (dreq == NULL)
@@ -457,9 +458,12 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
 
 	dreq->inode = inode;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
-	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
-	if (dreq->l_ctx == NULL)
+	l_ctx = nfs_get_lock_context(dreq->ctx);
+	if (IS_ERR(l_ctx)) {
+		result = PTR_ERR(l_ctx);
 		goto out_release;
+	}
+	dreq->l_ctx = l_ctx;
 	if (!is_sync_kiocb(iocb))
 		dreq->iocb = iocb;
 
@@ -849,6 +853,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
 	ssize_t result = -ENOMEM;
 	struct inode *inode = iocb->ki_filp->f_mapping->host;
 	struct nfs_direct_req *dreq;
+	struct nfs_lock_context *l_ctx;
 
 	dreq = nfs_direct_req_alloc();
 	if (!dreq)
@@ -856,9 +861,12 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
 
 	dreq->inode = inode;
 	dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
-	dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
-	if (dreq->l_ctx == NULL)
+	l_ctx = nfs_get_lock_context(dreq->ctx);
+	if (IS_ERR(l_ctx)) {
+		result = PTR_ERR(l_ctx);
 		goto out_release;
+	}
+	dreq->l_ctx = l_ctx;
 	if (!is_sync_kiocb(iocb))
 		dreq->iocb = iocb;
 
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 9b47610338f5..b5e2913dff2d 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -578,7 +578,7 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
 		spin_unlock(&inode->i_lock);
 		new = kmalloc(sizeof(*new), GFP_KERNEL);
 		if (new == NULL)
-			return NULL;
+			return ERR_PTR(-ENOMEM);
 		nfs_init_lock_context(new);
 		spin_lock(&inode->i_lock);
 		res = __nfs_find_lock_context(ctx);
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 311a79681e2b..dfd764bd943d 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -102,6 +102,7 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
 		   unsigned int offset, unsigned int count)
 {
 	struct nfs_page		*req;
+	struct nfs_lock_context *l_ctx;
 
 	/* try to allocate the request struct */
 	req = nfs_page_alloc();
@@ -109,11 +110,12 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
 		return ERR_PTR(-ENOMEM);
 
 	/* get lock context early so we can deal with alloc failures */
-	req->wb_lock_context = nfs_get_lock_context(ctx);
-	if (req->wb_lock_context == NULL) {
+	l_ctx = nfs_get_lock_context(ctx);
+	if (IS_ERR(l_ctx)) {
 		nfs_page_free(req);
-		return ERR_PTR(-ENOMEM);
+		return ERR_CAST(l_ctx);
 	}
+	req->wb_lock_context = l_ctx;
 
 	/* Initialize the request struct. Initially, we assume a
 	 * long write-back delay. This will be adjusted in