1 files changed, 67 insertions, 32 deletions

diff --git a/fs/open.c b/fs/open.c
index 59071f55bf7f..9b33c0cbfacf 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -61,33 +61,22 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
         return ret;
 }
 
-static long do_sys_truncate(const char __user *pathname, loff_t length)
+long vfs_truncate(struct path *path, loff_t length)
 {
-        struct path path;
         struct inode *inode;
-        int error;
-
-        error = -EINVAL;
-        if (length < 0) /* sorry, but loff_t says... */
-                goto out;
+        long error;
 
-        error = user_path(pathname, &path);
-        if (error)
-                goto out;
-        inode = path.dentry->d_inode;
+        inode = path->dentry->d_inode;
 
         /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
-        error = -EISDIR;
         if (S_ISDIR(inode->i_mode))
-                goto dput_and_out;
-
-        error = -EINVAL;
+                return -EISDIR;
         if (!S_ISREG(inode->i_mode))
-                goto dput_and_out;
+                return -EINVAL;
 
-        error = mnt_want_write(path.mnt);
+        error = mnt_want_write(path->mnt);
         if (error)
-                goto dput_and_out;
+                goto out;
 
         error = inode_permission(inode, MAY_WRITE);
         if (error)
@@ -111,19 +100,40 @@ static long do_sys_truncate(const char __user *pathname, loff_t length)
 
         error = locks_verify_truncate(inode, NULL, length);
         if (!error)
-                error = security_path_truncate(&path);
+                error = security_path_truncate(path);
         if (!error)
-                error = do_truncate(path.dentry, length, 0, NULL);
+                error = do_truncate(path->dentry, length, 0, NULL);
 
 put_write_and_out:
         put_write_access(inode);
 mnt_drop_write_and_out:
-        mnt_drop_write(path.mnt);
-dput_and_out:
-        path_put(&path);
+        mnt_drop_write(path->mnt);
 out:
         return error;
 }
+EXPORT_SYMBOL_GPL(vfs_truncate);
+
+static long do_sys_truncate(const char __user *pathname, loff_t length)
+{
+        unsigned int lookup_flags = LOOKUP_FOLLOW;
+        struct path path;
+        int error;
+
+        if (length < 0) /* sorry, but loff_t says... */
+                return -EINVAL;
+
+retry:
+        error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
+        if (!error) {
+                error = vfs_truncate(&path, length);
+                path_put(&path);
+        }
+        if (retry_estale(error, lookup_flags)) {
+                lookup_flags |= LOOKUP_REVAL;
+                goto retry;
+        }
+        return error;
+}
 
 SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
 {
@@ -306,6 +316,7 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
         struct path path;
         struct inode *inode;
         int res;
+        unsigned int lookup_flags = LOOKUP_FOLLOW;
 
         if (mode & ~S_IRWXO)    /* where's F_OK, X_OK, W_OK, R_OK? */
                 return -EINVAL;
@@ -328,8 +339,8 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
         }
 
         old_cred = override_creds(override_cred);
-
-        res = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
+retry:
+        res = user_path_at(dfd, filename, lookup_flags, &path);
         if (res)
                 goto out;
 
@@ -364,6 +375,10 @@ SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
 
 out_path_release:
         path_put(&path);
+        if (retry_estale(res, lookup_flags)) {
+                lookup_flags |= LOOKUP_REVAL;
+                goto retry;
+        }
 out:
         revert_creds(old_cred);
         put_cred(override_cred);
@@ -379,8 +394,9 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename)
 {
         struct path path;
         int error;
-
-        error = user_path_dir(filename, &path);
+        unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+retry:
+        error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
         if (error)
                 goto out;
 
@@ -392,6 +408,10 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename)
 
 dput_and_out:
         path_put(&path);
+        if (retry_estale(error, lookup_flags)) {
+                lookup_flags |= LOOKUP_REVAL;
+                goto retry;
+        }
 out:
         return error;
 }
@@ -425,8 +445,9 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename)
 {
         struct path path;
         int error;
-
-        error = user_path_dir(filename, &path);
+        unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+retry:
+        error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
         if (error)
                 goto out;
 
@@ -435,7 +456,7 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename)
                 goto dput_and_out;
 
         error = -EPERM;
-        if (!capable(CAP_SYS_CHROOT))
+        if (!nsown_capable(CAP_SYS_CHROOT))
                 goto dput_and_out;
         error = security_path_chroot(&path);
         if (error)
@@ -445,6 +466,10 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename)
         error = 0;
 dput_and_out:
         path_put(&path);
+        if (retry_estale(error, lookup_flags)) {
+                lookup_flags |= LOOKUP_REVAL;
+                goto retry;
+        }
 out:
         return error;
 }
@@ -489,11 +514,16 @@ SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode
 {
         struct path path;
         int error;
-
-        error = user_path_at(dfd, filename, LOOKUP_FOLLOW, &path);
+        unsigned int lookup_flags = LOOKUP_FOLLOW;
+retry:
+        error = user_path_at(dfd, filename, lookup_flags, &path);
         if (!error) {
                 error = chmod_common(&path, mode);
                 path_put(&path);
+                if (retry_estale(error, lookup_flags)) {
+                        lookup_flags |= LOOKUP_REVAL;
+                        goto retry;
+                }
         }
         return error;
 }
@@ -552,6 +582,7 @@ SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
         lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
         if (flag & AT_EMPTY_PATH)
                 lookup_flags |= LOOKUP_EMPTY;
+retry:
         error = user_path_at(dfd, filename, lookup_flags, &path);
         if (error)
                 goto out;
@@ -562,6 +593,10 @@ SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
         mnt_drop_write(path.mnt);
 out_release:
         path_put(&path);
+        if (retry_estale(error, lookup_flags)) {
+                lookup_flags |= LOOKUP_REVAL;
+                goto retry;
+        }
 out:
         return error;
 }