[PATCH v4 03/17] vfs: make fstatat retry on ESTALE errors from getattr call
From: Jeff Layton <hidden>
Date: 2012-07-26 11:55:06
Also in:
linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
Signed-off-by: Jeff Layton <redacted> --- 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 b6fbe3d..1ab4400 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 138d93a..00db714 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -2062,6 +2062,7 @@ 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