From: David Howells <dhowells@redhat.com>
To: viro@zeniv.linux.org.uk
Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org,
linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 28/32] vfs: Store the fd_cookie in nameidata, not the dfd int [ver #8]
Date: Fri, 25 May 2018 01:08:25 +0100 [thread overview]
Message-ID: <152720690524.9073.15509053519638438137.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <152720672288.9073.9868393448836301272.stgit@warthog.procyon.org.uk>
Look up dfd in set_nameidata() if not AT_FDCWD and store the resultant
fd_cookie in struct nameidata. LOOKUP_AT_FDCWD is set if AT_FDCWD was
supplied. The fd_cookie is released in restore_nameidata().
This means that where the fd points in a construct like the following:
set_nameidata(&nd, dfd, name);
retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
if (unlikely(retval == -ECHILD))
retval = path_lookupat(&nd, flags, path);
if (unlikely(retval == -ESTALE))
retval = path_lookupat(&nd, flags | LOOKUP_REVAL, path);
doesn't change between the three calls to path_lookupat() or similar.
It also allows us to fish the fd_cookie out for the upcoming move_mount()
syscall which needs to clear a file flag if successful.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/namei.c | 38 +++++++++++++++++++++-----------------
1 file changed, 21 insertions(+), 17 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 6f0dc40f88c5..819d6ee71b46 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -53,8 +53,8 @@
* The new code replaces the old recursive symlink resolution with
* an iterative one (in case of non-nested symlink chains). It does
* this with calls to <fs>_follow_link().
- * As a side effect, dir_namei(), _namei() and follow_link() are now
- * replaced with a single function lookup_dentry() that can handle all
+ * As a side effect, dir_namei(), _namei() and follow_link() are now
+ * replaced with a single function lookup_dentry() that can handle all
* the special cases of the former code.
*
* With the new dcache, the pathname is stored at each inode, at least as
@@ -506,25 +506,34 @@ struct nameidata {
struct filename *name;
struct nameidata *saved;
struct inode *link_inode;
+ struct fd_cookie *dfd;
+ bool have_dfd;
unsigned root_seq;
- int dfd;
} __randomize_layout;
static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
{
struct nameidata *old = current->nameidata;
p->stack = p->internal;
- p->dfd = dfd;
p->name = name;
p->total_link_count = old ? old->total_link_count : 0;
p->saved = old;
current->nameidata = p;
+
+ if (likely(dfd == AT_FDCWD)) {
+ p->dfd = NULL;
+ p->have_dfd = false;
+ } else {
+ p->dfd = __fdget_raw(dfd); /* Error are dealt with later */
+ p->have_dfd = true;
+ }
}
static void restore_nameidata(void)
{
struct nameidata *now = current->nameidata, *old = now->saved;
+ __fdput(now->dfd);
current->nameidata = old;
if (old)
old->total_link_count = now->total_link_count;
@@ -2165,7 +2174,7 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
nd->root.mnt = NULL;
rcu_read_unlock();
return ERR_PTR(-ECHILD);
- } else if (nd->dfd == AT_FDCWD) {
+ } else if (!nd->have_dfd) {
if (flags & LOOKUP_RCU) {
struct fs_struct *fs = current->fs;
unsigned seq;
@@ -2185,22 +2194,18 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
return s;
} else {
/* Caller must check execute permissions on the starting path component */
- struct fd f = fdget_raw(nd->dfd);
struct dentry *dentry;
+ struct file *file = __fdfile(nd->dfd);
- if (!f.file)
+ if (!nd->dfd)
return ERR_PTR(-EBADF);
- dentry = f.file->f_path.dentry;
+ dentry = file->f_path.dentry;
- if (*s) {
- if (!d_can_lookup(dentry)) {
- fdput(f);
- return ERR_PTR(-ENOTDIR);
- }
- }
+ if (*s && !d_can_lookup(dentry))
+ return ERR_PTR(-ENOTDIR);
- nd->path = f.file->f_path;
+ nd->path = file->f_path;
if (flags & LOOKUP_RCU) {
rcu_read_lock();
nd->inode = nd->path.dentry->d_inode;
@@ -2209,7 +2214,6 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
path_get(&nd->path);
nd->inode = nd->path.dentry->d_inode;
}
- fdput(f);
return s;
}
}
@@ -3557,7 +3561,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
if (IS_ERR(filename))
return ERR_CAST(filename);
- set_nameidata(&nd, -1, filename);
+ set_nameidata(&nd, AT_FDCWD, filename);
file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
file = path_openat(&nd, op, flags);
next prev parent reply other threads:[~2018-05-25 0:08 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-25 0:05 [PATCH 00/32] VFS: Introduce filesystem context [ver #8] David Howells
2018-05-25 0:05 ` [PATCH 01/32] VFS: Suppress MS_* flag defs within the kernel unless explicitly enabled " David Howells
2018-05-25 0:05 ` [PATCH 02/32] vfs: Provide documentation for new mount API " David Howells
2018-05-25 0:05 ` [PATCH 03/32] VFS: Introduce the basic header for the new mount API's filesystem context " David Howells
2018-05-31 23:11 ` Al Viro
2018-05-31 23:13 ` Al Viro
2018-05-25 0:05 ` [PATCH 04/32] VFS: Add LSM hooks for the new mount API " David Howells
2018-05-25 0:05 ` [PATCH 05/32] selinux: Implement the new mount API LSM hooks " David Howells
2018-05-25 0:06 ` [PATCH 06/32] smack: Implement filesystem context security " David Howells
2018-05-25 0:06 ` [PATCH 07/32] apparmor: Implement security hooks for the new mount API " David Howells
2018-05-25 0:06 ` [PATCH 08/32] tomoyo: " David Howells
2018-05-25 0:06 ` [PATCH 09/32] VFS: Require specification of size of mount data for internal mounts " David Howells
2018-05-25 0:06 ` [PATCH 10/32] VFS: Implement a filesystem superblock creation/configuration context " David Howells
2018-06-07 19:50 ` Miklos Szeredi
2018-07-03 18:33 ` Eric Biggers
2018-07-03 21:53 ` David Howells
2018-07-03 21:58 ` Al Viro
2018-07-03 22:06 ` David Howells
2018-05-25 0:06 ` [PATCH 11/32] VFS: Remove unused code after filesystem context changes " David Howells
2018-05-25 0:06 ` [PATCH 12/32] procfs: Move proc_fill_super() to fs/proc/root.c " David Howells
2018-05-25 0:06 ` [PATCH 13/32] proc: Add fs_context support to procfs " David Howells
2018-05-25 0:06 ` [PATCH 14/32] ipc: Convert mqueue fs to fs_context " David Howells
2018-05-25 0:07 ` [PATCH 15/32] cpuset: Use " David Howells
2018-05-25 0:07 ` [PATCH 16/32] kernfs, sysfs, cgroup, intel_rdt: Support " David Howells
2018-06-21 18:47 ` [16/32] " Andrei Vagin
2018-06-22 12:52 ` David Howells
2018-06-22 15:30 ` Andrei Vagin
2018-06-22 16:57 ` Andrei Vagin
2018-06-23 23:34 ` David Howells
2018-05-25 0:07 ` [PATCH 17/32] hugetlbfs: Convert to " David Howells
2018-05-25 0:07 ` [PATCH 18/32] VFS: Remove kern_mount_data() " David Howells
2018-05-25 0:07 ` [PATCH 19/32] VFS: Implement fsopen() to prepare for a mount " David Howells
2018-05-31 21:25 ` Al Viro
2018-05-25 0:07 ` [PATCH 20/32] vfs: Make close() unmount the attached mount if so flagged " David Howells
2018-05-31 19:19 ` Al Viro
2018-05-31 19:26 ` Al Viro
2018-06-01 1:52 ` Al Viro
2018-06-01 3:18 ` Al Viro
2018-06-01 5:16 ` Al Viro
2018-05-25 0:07 ` [PATCH 21/32] VFS: Implement fsmount() to effect a pre-configured mount " David Howells
2018-06-04 15:05 ` Arnd Bergmann
2018-06-04 15:24 ` David Howells
2018-05-25 0:07 ` [PATCH 22/32] vfs: Provide an fspick() system call " David Howells
2018-05-25 0:07 ` [PATCH 23/32] VFS: Implement logging through fs_context " David Howells
2018-05-25 1:48 ` Joe Perches
2018-05-25 0:07 ` [PATCH 24/32] vfs: Add some logging to the core users of the fs_context log " David Howells
2018-05-25 0:08 ` [PATCH 25/32] afs: Add fs_context support " David Howells
2018-05-25 0:08 ` [PATCH 26/32] afs: Use fs_context to pass parameters over automount " David Howells
2018-06-07 1:58 ` Goldwyn Rodrigues
2018-06-07 20:45 ` David Howells
2018-05-25 0:08 ` [PATCH 27/32] vfs: Use a 'struct fd_cookie *' type for light fd handling " David Howells
2018-05-25 0:08 ` David Howells [this message]
2018-05-25 0:08 ` [PATCH 29/32] vfs: Don't mix FMODE_* flags with O_* flags " David Howells
2018-05-25 0:08 ` [PATCH 30/32] vfs: Allow cloning of a mount tree with open(O_PATH|O_CLONE_MOUNT) " David Howells
2018-06-01 6:26 ` Christoph Hellwig
2018-06-01 6:39 ` Al Viro
2018-06-01 8:27 ` David Howells
2018-06-02 3:09 ` Al Viro
2018-06-02 3:42 ` Al Viro
2018-06-02 4:04 ` Al Viro
2018-06-02 15:45 ` David Howells
2018-06-02 17:49 ` Al Viro
2018-06-03 0:55 ` [PATCH][RFC] open_tree(2) (was Re: [PATCH 30/32] vfs: Allow cloning of a mount tree with open(O_PATH|O_CLONE_MOUNT) [ver #8]) Al Viro
2018-06-04 10:34 ` Miklos Szeredi
2018-06-04 15:52 ` Al Viro
2018-06-04 15:59 ` Al Viro
2018-06-04 19:27 ` Miklos Szeredi
2018-06-04 15:27 ` David Howells
2018-06-04 17:16 ` Matthew Wilcox
2018-06-04 17:35 ` Al Viro
2018-06-04 19:38 ` Miklos Szeredi
2018-06-01 8:02 ` [PATCH 30/32] vfs: Allow cloning of a mount tree with open(O_PATH|O_CLONE_MOUNT) [ver #8] Amir Goldstein
2018-06-01 8:42 ` David Howells
2018-05-25 0:08 ` [PATCH 31/32] [RFC] fs: Add a move_mount() system call " David Howells
2018-05-31 21:20 ` Al Viro
2018-05-25 0:08 ` [PATCH 32/32] [RFC] fsinfo: Add a system call to allow querying of filesystem information " David Howells
2018-06-04 13:10 ` Arnd Bergmann
2018-06-04 15:01 ` David Howells
2018-06-04 16:00 ` Arnd Bergmann
2018-06-04 19:03 ` David Howells
2018-06-04 20:45 ` Arnd Bergmann
2018-05-31 20:56 ` Test program for move_mount() David Howells
2018-05-31 20:57 ` fsinfo test program David Howells
2018-06-15 4:18 ` [PATCH 00/32] VFS: Introduce filesystem context [ver #8] Eric W. Biederman
2018-06-18 20:30 ` David Howells
2018-06-18 21:33 ` Eric W. Biederman
2018-06-18 23:33 ` Theodore Y. Ts'o
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