From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jia He <justin.he@arm.com>, Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Jonathan Corbet <corbet@lwn.net>, Al Viro <viro@ftp.linux.org.uk>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ira Weiny <ira.weiny@intel.com>,
Eric Biggers <ebiggers@google.com>,
"Ahmed S. Darwish" <a.darwish@linutronix.de>,
"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH RFC 1/3] fs: introduce helper d_path_fast()
Date: Sat, 8 May 2021 21:05:44 +0000 [thread overview]
Message-ID: <YJb9KFBO7MwJeDHz@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <CAHk-=whZhNXiOGgw8mXG+PTpGvxnRG1v5_GjtjHpoYXd2Fn_Ow@mail.gmail.com>
On Sat, May 08, 2021 at 01:39:45PM -0700, Linus Torvalds wrote:
> +static inline int prepend_entries(struct prepend_buffer *b, const struct path *path, const struct path *root, struct mount *mnt)
If anything, s/path/dentry/, since vfsmnt here will be equal to &mnt->mnt all along.
> +{
> + struct dentry *dentry = path->dentry;
> + struct vfsmount *vfsmnt = path->mnt;
> +
> + while (dentry != root->dentry || vfsmnt != root->mnt) {
> + int error;
> + struct dentry * parent;
> +
> + if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
> + struct mount *parent = READ_ONCE(mnt->mnt_parent);
> + struct mnt_namespace *mnt_ns;
> +
> + /* Escaped? */
> + if (dentry != vfsmnt->mnt_root)
> + return 3;
> +
> + /* Global root? */
> + if (mnt != parent) {
> + dentry = READ_ONCE(mnt->mnt_mountpoint);
> + mnt = parent;
> + vfsmnt = &mnt->mnt;
> + continue;
> + }
> + mnt_ns = READ_ONCE(mnt->mnt_ns);
> + /* open-coded is_mounted() to use local mnt_ns */
> + if (!IS_ERR_OR_NULL(mnt_ns) && !is_anon_ns(mnt_ns))
> + return 1; // absolute root
> +
> + return 2; // detached or not attached yet
> + break;
?
> + }
> + parent = dentry->d_parent;
> + prefetch(parent);
> + error = prepend_name(b, &dentry->d_name);
> + if (error)
> + break;
return error, surely?
> + dentry = parent;
> + }
> + return 0;
> +}
FWIW, if we go that way, I would make that
while (dentry != root->dentry || &mnt->mnt != root->mnt) {
int error;
struct dentry *parent = READ_ONCE(dentry->d_parent);
if (unlikely(dentry == mnt->mnt.mnt_root)) {
struct mount *m = READ_ONCE(mnt->mnt_parent);
/* Global root? */
if (unlikely(mnt == m) {
struct mnt_namespace *mnt_ns;
mnt_ns = READ_ONCE(mnt->mnt_ns);
/* open-coded is_mounted() to use local mnt_ns */
if (!IS_ERR_OR_NULL(mnt_ns) && !is_anon_ns(mnt_ns))
return 1; // absolute root
else
return 2; // detached or not attached yet
}
// cross into whatever it's mounted on
dentry = READ_ONCE(mnt->mnt_mountpoint);
mnt = m;
continue;
}
/* Escaped? */
if (unlikely(dentry == parent))
return 3;
prefetch(parent);
error = prepend_name(b, &dentry->d_name);
if (error)
return error;
dentry = parent;
}
return 0;
next prev parent reply other threads:[~2021-05-08 21:06 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-08 12:25 [PATCH RFC 0/3] make '%pD' print full path for file Jia He
2021-05-08 12:25 ` [PATCH RFC 1/3] fs: introduce helper d_path_fast() Jia He
2021-05-08 15:30 ` Linus Torvalds
2021-05-08 19:13 ` Al Viro
2021-05-08 20:39 ` Linus Torvalds
2021-05-08 21:05 ` Al Viro [this message]
2021-05-08 22:17 ` Linus Torvalds
2021-05-08 22:46 ` Al Viro
2021-05-08 22:48 ` Linus Torvalds
2021-05-08 23:15 ` Al Viro
2021-05-08 23:18 ` Al Viro
2021-05-09 22:58 ` Eric W. Biederman
2021-05-10 12:51 ` Christian Brauner
2021-05-10 7:20 ` Christian Brauner
2021-05-08 22:42 ` Linus Torvalds
2021-05-08 22:47 ` Linus Torvalds
2021-05-09 2:28 ` Al Viro
2021-05-09 2:53 ` Linus Torvalds
2021-05-19 0:43 ` [PATCHSET] d_path cleanups Al Viro
2021-05-19 0:48 ` [PATCH 01/14] d_path: "\0" is {0,0}, not {0} Al Viro
2021-05-19 0:48 ` [PATCH 02/14] d_path: saner calling conventions for __dentry_path() Al Viro
2021-06-25 9:32 ` Justin He
2021-07-07 4:52 ` Justin He
2021-05-19 0:48 ` [PATCH 03/14] d_path: regularize handling of root dentry in __dentry_path() Al Viro
2021-07-07 4:50 ` Justin He
2021-05-19 0:48 ` [PATCH 04/14] d_path: get rid of path_with_deleted() Al Viro
2021-05-19 0:48 ` [PATCH 05/14] getcwd(2): saner logics around prepend_path() call Al Viro
2021-07-07 7:41 ` Justin He
2021-05-19 0:48 ` [PATCH 06/14] d_path: don't bother with return value of prepend() Al Viro
2021-06-24 6:13 ` Justin He
2021-05-19 0:48 ` [PATCH 07/14] d_path: lift -ENAMETOOLONG handling into callers of prepend_path() Al Viro
2021-06-25 9:18 ` Justin He
2021-06-28 5:20 ` Justin He
2021-05-19 0:48 ` [PATCH 08/14] d_path: make prepend_name() boolean Al Viro
2021-05-20 9:12 ` Justin He
2021-05-20 9:19 ` Andy Shevchenko
2021-05-20 14:53 ` Petr Mladek
2021-05-20 19:35 ` Al Viro
2021-07-07 7:43 ` Justin He
2021-05-19 0:48 ` [PATCH 09/14] d_path: introduce struct prepend_buffer Al Viro
2021-06-23 13:28 ` Justin He
2021-06-24 9:29 ` Enrico Weigelt, metux IT consult
2021-06-25 0:43 ` Justin He
2021-06-28 16:42 ` Enrico Weigelt, metux IT consult
2021-06-28 17:10 ` Andy Shevchenko
2021-05-19 0:48 ` [PATCH 10/14] d_path: prepend_path(): get rid of vfsmnt Al Viro
2021-05-19 0:48 ` [PATCH 11/14] d_path: prepend_path(): lift resetting b in case when we'd return 3 out of loop Al Viro
2021-05-19 0:48 ` [PATCH 12/14] d_path: prepend_path(): lift the inner loop into a new helper Al Viro
2021-05-19 8:07 ` Andy Shevchenko
2021-05-19 15:55 ` Al Viro
2021-07-07 7:52 ` Justin He
2021-05-19 0:49 ` [PATCH 13/14] d_path: prepend_path() is unlikely to return non-zero Al Viro
2021-06-25 8:00 ` Justin He
2021-06-25 17:58 ` Al Viro
2021-06-28 3:28 ` Justin He
2021-06-28 4:14 ` Al Viro
2021-06-28 4:36 ` Justin He
2021-06-28 4:37 ` Justin He
2021-05-19 0:49 ` [PATCH 14/14] getcwd(2): clean up error handling Al Viro
2021-07-07 8:03 ` Justin He
2021-06-24 6:05 ` [PATCH 01/14] d_path: "\0" is {0,0}, not {0} Justin He
2021-05-19 2:39 ` [PATCHSET] d_path cleanups Linus Torvalds
2021-06-22 14:00 ` Justin He
2021-05-09 2:20 ` [PATCH RFC 1/3] fs: introduce helper d_path_fast() Al Viro
2021-05-09 4:58 ` Al Viro
2021-05-10 16:16 ` Eric W. Biederman
2021-05-10 15:07 ` Justin He
2021-05-10 17:03 ` Linus Torvalds
2021-05-08 12:25 ` [PATCH RFC 2/3] lib/vsprintf.c: make %pD print full path for file Jia He
2021-05-10 3:46 ` Sergey Senozhatsky
2021-05-10 13:04 ` Petr Mladek
2021-05-10 14:25 ` Justin He
2021-05-27 7:20 ` Justin He
2021-05-27 9:14 ` Petr Mladek
2021-05-08 12:25 ` [PATCH RFC 3/3] s390/hmcdrv: remove the redundant directory path in debug message Jia He
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