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-rw-r--r--fs/namei.c107
-rw-r--r--include/linux/namei.h2
2 files changed, 46 insertions, 63 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 4521b5ff7c93..450b686e9682 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -613,19 +613,8 @@ do_revalidate_rcu(struct dentry *dentry, struct nameidata *nd)
return dentry;
}
-static inline int need_reval_dot(struct dentry *dentry)
-{
- if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE)))
- return 0;
-
- if (likely(!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)))
- return 0;
-
- return 1;
-}
-
/*
- * force_reval_path - force revalidation of a dentry
+ * handle_reval_path - force revalidation of a dentry
*
* In some situations the path walking code will trust dentries without
* revalidating them. This causes problems for filesystems that depend on
@@ -639,27 +628,28 @@ static inline int need_reval_dot(struct dentry *dentry)
* invalidate the dentry. It's up to the caller to handle putting references
* to the path if necessary.
*/
-static int
-force_reval_path(struct path *path, struct nameidata *nd)
+static inline int handle_reval_path(struct nameidata *nd)
{
+ struct dentry *dentry = nd->path.dentry;
int status;
- struct dentry *dentry = path->dentry;
- /*
- * only check on filesystems where it's possible for the dentry to
- * become stale.
- */
- if (!need_reval_dot(dentry))
+ if (likely(!(nd->flags & LOOKUP_JUMPED)))
+ return 0;
+
+ if (likely(!(dentry->d_flags & DCACHE_OP_REVALIDATE)))
return 0;
+ if (likely(!(dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)))
+ return 0;
+
+ /* Note: we do not d_invalidate() */
status = d_revalidate(dentry, nd);
if (status > 0)
return 0;
- if (!status) {
- d_invalidate(dentry);
+ if (!status)
status = -ESTALE;
- }
+
return status;
}
@@ -728,6 +718,7 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
path_put(&nd->path);
nd->path = nd->root;
path_get(&nd->root);
+ nd->flags |= LOOKUP_JUMPED;
}
nd->inode = nd->path.dentry->d_inode;
@@ -779,11 +770,8 @@ __do_follow_link(const struct path *link, struct nameidata *nd, void **p)
error = 0;
if (s)
error = __vfs_follow_link(nd, s);
- else if (nd->last_type == LAST_BIND) {
- error = force_reval_path(&nd->path, nd);
- if (error)
- path_put(&nd->path);
- }
+ else if (nd->last_type == LAST_BIND)
+ nd->flags |= LOOKUP_JUMPED;
}
return error;
}
@@ -1351,7 +1339,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
while (*name=='/')
name++;
if (!*name)
- goto return_reval;
+ goto return_base;
if (nd->depth)
lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE);
@@ -1385,12 +1373,16 @@ static int link_path_walk(const char *name, struct nameidata *nd)
type = LAST_NORM;
if (this.name[0] == '.') switch (this.len) {
case 2:
- if (this.name[1] == '.')
+ if (this.name[1] == '.') {
type = LAST_DOTDOT;
+ nd->flags |= LOOKUP_JUMPED;
+ }
break;
case 1:
type = LAST_DOT;
}
+ if (likely(type == LAST_NORM))
+ nd->flags &= ~LOOKUP_JUMPED;
/* remove trailing slashes? */
if (!c)
@@ -1456,7 +1448,7 @@ last_component:
} else
follow_dotdot(nd);
}
- goto return_reval;
+ goto return_base;
}
err = do_lookup(nd, &this, &next, &inode);
if (err)
@@ -1483,24 +1475,6 @@ last_component:
lookup_parent:
nd->last = this;
nd->last_type = type;
- if (type == LAST_NORM)
- goto return_base;
-return_reval:
- /*
- * We bypassed the ordinary revalidation routines.
- * We may need to check the cached dentry for staleness.
- */
- if (need_reval_dot(nd->path.dentry)) {
- if (nameidata_drop_rcu_last_maybe(nd))
- return -ECHILD;
- /* Note: we do not d_invalidate() */
- err = d_revalidate(nd->path.dentry, nd);
- if (!err)
- err = -ESTALE;
- if (err < 0)
- break;
- return 0;
- }
return_base:
if (nameidata_drop_rcu_last_maybe(nd))
return -ECHILD;
@@ -1523,7 +1497,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct namei
struct file *file;
nd->last_type = LAST_ROOT; /* if there are only slashes... */
- nd->flags = flags;
+ nd->flags = flags | LOOKUP_JUMPED;
nd->depth = 0;
nd->root.mnt = NULL;
nd->file = NULL;
@@ -1630,6 +1604,9 @@ static int path_lookupat(int dfd, const char *name,
br_read_unlock(vfsmount_lock);
}
+ if (!retval)
+ retval = handle_reval_path(nd);
+
if (nd->file) {
fput(nd->file);
nd->file = NULL;
@@ -1690,7 +1667,7 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
/* same as do_path_lookup */
nd->last_type = LAST_ROOT;
- nd->flags = flags;
+ nd->flags = flags | LOOKUP_JUMPED;
nd->depth = 0;
nd->path.dentry = dentry;
@@ -1703,6 +1680,8 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
current->total_link_count = 0;
result = link_path_walk(name, nd);
+ if (!result)
+ result = handle_reval_path(nd);
if (result == -ESTALE) {
/* nd->path had been dropped */
current->total_link_count = 0;
@@ -1710,8 +1689,11 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
nd->path.mnt = mnt;
nd->inode = dentry->d_inode;
path_get(&nd->path);
- nd->flags |= LOOKUP_REVAL;
+ nd->flags = flags | LOOKUP_JUMPED | LOOKUP_REVAL;
+
result = link_path_walk(name, nd);
+ if (!result)
+ result = handle_reval_path(nd);
}
if (unlikely(!result && !audit_dummy_context() && nd->path.dentry &&
nd->inode))
@@ -2198,30 +2180,29 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
{
struct dentry *dir = nd->path.dentry;
struct file *filp;
- int error = -EISDIR;
+ int error;
switch (nd->last_type) {
case LAST_DOTDOT:
follow_dotdot(nd);
dir = nd->path.dentry;
case LAST_DOT:
- if (need_reval_dot(dir)) {
- int status = d_revalidate(nd->path.dentry, nd);
- if (!status)
- status = -ESTALE;
- if (status < 0) {
- error = status;
- goto exit;
- }
- }
/* fallthrough */
case LAST_ROOT:
+ error = handle_reval_path(nd);
+ if (error)
+ goto exit;
+ error = -EISDIR;
goto exit;
case LAST_BIND:
+ error = handle_reval_path(nd);
+ if (error)
+ goto exit;
audit_inode(pathname, dir);
goto ok;
}
+ error = -EISDIR;
/* trailing slashes? */
if (nd->last.name[nd->last.len])
goto exit;
@@ -2422,7 +2403,7 @@ reval:
/*
* We have the parent and last component.
*/
- nd.flags = flags;
+ nd.flags = (nd.flags & ~LOOKUP_PARENT) | flags;
filp = do_last(&nd, &path, open_flag, acc_mode, mode, pathname);
while (unlikely(!filp)) { /* trailing symlink */
struct path link = path;
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 58ce3433d4ec..265378a707bd 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -63,6 +63,8 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
#define LOOKUP_EXCL 0x0400
#define LOOKUP_RENAME_TARGET 0x0800
+#define LOOKUP_JUMPED 0x1000
+
extern int user_path_at(int, const char __user *, unsigned, struct path *);
#define user_path(name, path) user_path_at(AT_FDCWD, name, LOOKUP_FOLLOW, path)
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-02 21:35:22 +0000