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Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c118
1 files changed, 80 insertions, 38 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 5f4cdf3ad913..43a97ee1d4c8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1275,9 +1275,7 @@ static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir,
*need_lookup = false;
dentry = d_lookup(dir, name);
if (dentry) {
- if (d_need_lookup(dentry)) {
- *need_lookup = true;
- } else if (dentry->d_flags & DCACHE_OP_REVALIDATE) {
+ if (dentry->d_flags & DCACHE_OP_REVALIDATE) {
error = d_revalidate(dentry, flags);
if (unlikely(error <= 0)) {
if (error < 0) {
@@ -1383,8 +1381,6 @@ static int lookup_fast(struct nameidata *nd, struct qstr *name,
return -ECHILD;
nd->seq = seq;
- if (unlikely(d_need_lookup(dentry)))
- goto unlazy;
if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
status = d_revalidate(dentry, nd->flags);
if (unlikely(status <= 0)) {
@@ -1410,11 +1406,6 @@ unlazy:
if (unlikely(!dentry))
goto need_lookup;
- if (unlikely(d_need_lookup(dentry))) {
- dput(dentry);
- goto need_lookup;
- }
-
if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval)
status = d_revalidate(dentry, nd->flags);
if (unlikely(status <= 0)) {
@@ -1859,7 +1850,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
if (flags & LOOKUP_ROOT) {
struct inode *inode = nd->root.dentry->d_inode;
if (*name) {
- if (!inode->i_op->lookup)
+ if (!can_lookup(inode))
return -ENOTDIR;
retval = inode_permission(inode, MAY_EXEC);
if (retval)
@@ -1903,6 +1894,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
get_fs_pwd(current->fs, &nd->path);
}
} else {
+ /* Caller must check execute permissions on the starting path component */
struct fd f = fdget_raw(dfd);
struct dentry *dentry;
@@ -1912,16 +1904,10 @@ static int path_init(int dfd, const char *name, unsigned int flags,
dentry = f.file->f_path.dentry;
if (*name) {
- if (!S_ISDIR(dentry->d_inode->i_mode)) {
+ if (!can_lookup(dentry->d_inode)) {
fdput(f);
return -ENOTDIR;
}
-
- retval = inode_permission(dentry->d_inode, MAY_EXEC);
- if (retval) {
- fdput(f);
- return retval;
- }
}
nd->path = f.file->f_path;
@@ -2189,15 +2175,19 @@ int user_path_at(int dfd, const char __user *name, unsigned flags,
* path-walking is complete.
*/
static struct filename *
-user_path_parent(int dfd, const char __user *path, struct nameidata *nd)
+user_path_parent(int dfd, const char __user *path, struct nameidata *nd,
+ unsigned int flags)
{
struct filename *s = getname(path);
int error;
+ /* only LOOKUP_REVAL is allowed in extra flags */
+ flags &= LOOKUP_REVAL;
+
if (IS_ERR(s))
return s;
- error = filename_lookup(dfd, s, LOOKUP_PARENT, nd);
+ error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd);
if (error) {
putname(s);
return ERR_PTR(error);
@@ -3044,12 +3034,22 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
return file;
}
-struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir)
+struct dentry *kern_path_create(int dfd, const char *pathname,
+ struct path *path, unsigned int lookup_flags)
{
struct dentry *dentry = ERR_PTR(-EEXIST);
struct nameidata nd;
int err2;
- int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd);
+ int error;
+ bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
+
+ /*
+ * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any
+ * other flags passed in are ignored!
+ */
+ lookup_flags &= LOOKUP_REVAL;
+
+ error = do_path_lookup(dfd, pathname, LOOKUP_PARENT|lookup_flags, &nd);
if (error)
return ERR_PTR(error);
@@ -3113,13 +3113,14 @@ void done_path_create(struct path *path, struct dentry *dentry)
}
EXPORT_SYMBOL(done_path_create);
-struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir)
+struct dentry *user_path_create(int dfd, const char __user *pathname,
+ struct path *path, unsigned int lookup_flags)
{
struct filename *tmp = getname(pathname);
struct dentry *res;
if (IS_ERR(tmp))
return ERR_CAST(tmp);
- res = kern_path_create(dfd, tmp->name, path, is_dir);
+ res = kern_path_create(dfd, tmp->name, path, lookup_flags);
putname(tmp);
return res;
}
@@ -3175,12 +3176,13 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
struct dentry *dentry;
struct path path;
int error;
+ unsigned int lookup_flags = 0;
error = may_mknod(mode);
if (error)
return error;
-
- dentry = user_path_create(dfd, filename, &path, 0);
+retry:
+ dentry = user_path_create(dfd, filename, &path, lookup_flags);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
@@ -3203,6 +3205,10 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
}
out:
done_path_create(&path, dentry);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
return error;
}
@@ -3241,8 +3247,10 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
struct dentry *dentry;
struct path path;
int error;
+ unsigned int lookup_flags = LOOKUP_DIRECTORY;
- dentry = user_path_create(dfd, pathname, &path, 1);
+retry:
+ dentry = user_path_create(dfd, pathname, &path, lookup_flags);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
@@ -3252,6 +3260,10 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
if (!error)
error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
done_path_create(&path, dentry);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
return error;
}
@@ -3327,8 +3339,9 @@ static long do_rmdir(int dfd, const char __user *pathname)
struct filename *name;
struct dentry *dentry;
struct nameidata nd;
-
- name = user_path_parent(dfd, pathname, &nd);
+ unsigned int lookup_flags = 0;
+retry:
+ name = user_path_parent(dfd, pathname, &nd, lookup_flags);
if (IS_ERR(name))
return PTR_ERR(name);
@@ -3370,6 +3383,10 @@ exit2:
exit1:
path_put(&nd.path);
putname(name);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
return error;
}
@@ -3423,8 +3440,9 @@ static long do_unlinkat(int dfd, const char __user *pathname)
struct dentry *dentry;
struct nameidata nd;
struct inode *inode = NULL;
-
- name = user_path_parent(dfd, pathname, &nd);
+ unsigned int lookup_flags = 0;
+retry:
+ name = user_path_parent(dfd, pathname, &nd, lookup_flags);
if (IS_ERR(name))
return PTR_ERR(name);
@@ -3462,6 +3480,11 @@ exit2:
exit1:
path_put(&nd.path);
putname(name);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ inode = NULL;
+ goto retry;
+ }
return error;
slashes:
@@ -3513,12 +3536,13 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
struct filename *from;
struct dentry *dentry;
struct path path;
+ unsigned int lookup_flags = 0;
from = getname(oldname);
if (IS_ERR(from))
return PTR_ERR(from);
-
- dentry = user_path_create(newdfd, newname, &path, 0);
+retry:
+ dentry = user_path_create(newdfd, newname, &path, lookup_flags);
error = PTR_ERR(dentry);
if (IS_ERR(dentry))
goto out_putname;
@@ -3527,6 +3551,10 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
if (!error)
error = vfs_symlink(path.dentry->d_inode, dentry, from->name);
done_path_create(&path, dentry);
+ if (retry_estale(error, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
out_putname:
putname(from);
return error;
@@ -3613,12 +3641,13 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
if (flags & AT_SYMLINK_FOLLOW)
how |= LOOKUP_FOLLOW;
-
+retry:
error = user_path_at(olddfd, oldname, how, &old_path);
if (error)
return error;
- new_dentry = user_path_create(newdfd, newname, &new_path, 0);
+ new_dentry = user_path_create(newdfd, newname, &new_path,
+ (how & LOOKUP_REVAL));
error = PTR_ERR(new_dentry);
if (IS_ERR(new_dentry))
goto out;
@@ -3635,6 +3664,10 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);
out_dput:
done_path_create(&new_path, new_dentry);
+ if (retry_estale(error, how)) {
+ how |= LOOKUP_REVAL;
+ goto retry;
+ }
out:
path_put(&old_path);
@@ -3807,15 +3840,17 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
struct nameidata oldnd, newnd;
struct filename *from;
struct filename *to;
+ unsigned int lookup_flags = 0;
+ bool should_retry = false;
int error;
-
- from = user_path_parent(olddfd, oldname, &oldnd);
+retry:
+ from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
if (IS_ERR(from)) {
error = PTR_ERR(from);
goto exit;
}
- to = user_path_parent(newdfd, newname, &newnd);
+ to = user_path_parent(newdfd, newname, &newnd, lookup_flags);
if (IS_ERR(to)) {
error = PTR_ERR(to);
goto exit1;
@@ -3887,11 +3922,18 @@ exit3:
unlock_rename(new_dir, old_dir);
mnt_drop_write(oldnd.path.mnt);
exit2:
+ if (retry_estale(error, lookup_flags))
+ should_retry = true;
path_put(&newnd.path);
putname(to);
exit1:
path_put(&oldnd.path);
putname(from);
+ if (should_retry) {
+ should_retry = false;
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
exit:
return error;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 02:58:08 +0100