[PATCH v4 04/17] vfs: fix readlinkat to retry on ESTALE

From: Jeff Layton
Date: Thu Jul 26 2012 - 08:00:49 EST


Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/stat.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/fs/stat.c b/fs/stat.c
index 5afeb37..c9d88f7 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -307,14 +307,25 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
struct path path;
int error;
int empty = 0;
+ char *name;
+ 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;
+ name = getname_flags(pathname, lookup_flags, &empty);
+ if (IS_ERR(name))
+ return PTR_ERR(name);
+
+ do {
+ struct inode *inode;
+
+ error = kern_path_at(dfd, name, lookup_flags, &path);
+ if (error)
+ break;

+ inode = path.dentry->d_inode;
error = empty ? -ENOENT : -EINVAL;
if (inode->i_op->readlink) {
error = security_inode_readlink(path.dentry);
@@ -325,7 +336,9 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
}
}
path_put(&path);
- }
+ lookup_flags |= LOOKUP_REVAL;
+ } while (retry_estale(error, try++));
+ putname(name);
return error;
}

--
1.7.11.2

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