linux-kernel - [PATCH v1 03/12] vfs: fix readlinkat to retry on ESTALE

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Message-Id: <1335455843-16089-2-git-send-email-jlayton@redhat.com>
Date:	Thu, 26 Apr 2012 11:57:14 -0400
From:	Jeff Layton <jlayton@...hat.com>
To:	viro@...IV.linux.org.uk
Cc:	linux-fsdevel@...r.kernel.org, linux-nfs@...r.kernel.org,
	linux-kernel@...r.kernel.org, miklos@...redi.hu, hch@...radead.org,
	michael.brantley@...haw.com
Subject: [PATCH v1 03/12] vfs: fix readlinkat to retry on ESTALE

Signed-off-by: Jeff Layton <jlayton@...hat.com>
---
 fs/stat.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/fs/stat.c b/fs/stat.c
index f3eef0d..f7904aa 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -299,14 +299,21 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 	struct path path;
 	int error;
 	int empty = 0;
+	unsigned int try = 0;
+	unsigned int lookup_flags = LOOKUP_EMPTY;
 
 	if (bufsiz <= 0)
 		return -EINVAL;
 
-	error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);
-	if (!error) {
-		struct inode *inode = path.dentry->d_inode;
+	do {
+		struct inode *inode;
+
+		error = user_path_at_empty(dfd, pathname, lookup_flags, &path,
+					   &empty);
+		if (error)
+			break;
 
+		inode = path.dentry->d_inode;
 		error = empty ? -ENOENT : -EINVAL;
 		if (inode->i_op->readlink) {
 			error = security_inode_readlink(path.dentry);
@@ -317,7 +324,8 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
 			}
 		}
 		path_put(&path);
-	}
+		lookup_flags |= LOOKUP_REVAL;
+	} while (retry_estale(error, try++));
 	return error;
 }
 
-- 
1.7.7.6

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