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Subject[PATCH v5 03/19] vfs: make fstatat retry on ESTALE errors from getattr call
Date
Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/namei.c | 2 +-
fs/stat.c | 21 ++++++++++++++++-----
include/linux/fs.h | 1 +
3 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 83a6f46..e66161f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -117,7 +117,7 @@
* POSIX.1 2.4: an empty pathname is invalid (ENOENT).
* PATH_MAX includes the nul terminator --RR.
*/
-static char *getname_flags(const char __user *filename, int flags, int *empty)
+char *getname_flags(const char __user *filename, int flags, int *empty)
{
char *result = __getname(), *err;
int len;
diff --git a/fs/stat.c b/fs/stat.c
index b6ff118..5afeb37 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -72,9 +72,11 @@ EXPORT_SYMBOL(vfs_fstat);
int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
int flag)
{
+ char *name;
struct path path;
int error = -EINVAL;
- int lookup_flags = 0;
+ unsigned int try = 0;
+ unsigned int lookup_flags = 0;

if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
AT_EMPTY_PATH)) != 0)
@@ -85,12 +87,21 @@ int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat,
if (flag & AT_EMPTY_PATH)
lookup_flags |= LOOKUP_EMPTY;

- error = user_path_at(dfd, filename, lookup_flags, &path);
- if (error)
+ name = getname_flags(filename, lookup_flags, NULL);
+ if (IS_ERR(name)) {
+ error = PTR_ERR(name);
goto out;
+ }
+ do {
+ error = kern_path_at(dfd, name, lookup_flags, &path);
+ if (error)
+ break;

- error = vfs_getattr(path.mnt, path.dentry, stat);
- path_put(&path);
+ error = vfs_getattr(path.mnt, path.dentry, stat);
+ path_put(&path);
+ lookup_flags |= LOOKUP_REVAL;
+ } while (retry_estale(error, try++));
+ putname(name);
out:
return error;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index b776a97..f2e7371 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2201,6 +2201,7 @@ extern struct file *file_open_root(struct dentry *, struct vfsmount *,
const char *, int);
extern struct file * dentry_open(const struct path *, int, const struct cred *);
extern int filp_close(struct file *, fl_owner_t id);
+extern char *getname_flags(const char __user *, int, int *);
extern char * getname(const char __user *);
enum {
FILE_CREATED = 1,
--
1.7.11.2


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