From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Neil Brown <neilb@suse.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 16/24] link_path_walk: kill the recursion
Date: Mon, 20 Apr 2015 22:59:23 +0100 [thread overview]
Message-ID: <20150420215923.GQ889@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFw-r-ONxw6FOQy7pdY5bNyJbTQEUsYagbfrjgOnczBLWw@mail.gmail.com>
On Mon, Apr 20, 2015 at 02:42:56PM -0700, Linus Torvalds wrote:
> On Mon, Apr 20, 2015 at 2:41 PM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > And no, we will *never* lift the recursion limit. Not for 1kB, not for
> > 1MB. Never.
>
> Just to clarify: that's for the "remove restrictions completely".
> Upping it to 32 or 40 would be fine. But not with allocations on the
> stack.
Yep. There are two restrictions - one on the total amount of symlinks
encountered (40), and another on the depth of nesting (8). The latter
is due to recursion issues, and with dynamic nd->stack it goes away.
The former, of course, stays, for the reasons you've mentioned - it has
nothing to do with the depth of recursion.
next prev parent reply other threads:[~2015-04-20 21:59 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-20 18:12 [RFC][PATCHSET] non-recursive link_path_walk() and reducing stack footprint Al Viro
2015-04-20 18:12 ` [PATCH 01/24] lustre: rip the private symlink nesting limit out Al Viro
2015-04-20 19:08 ` Andreas Dilger
2015-04-20 19:22 ` Al Viro
2015-04-20 20:35 ` Al Viro
2015-04-20 18:12 ` [PATCH 02/24] VFS: replace {, total_}link_count in task_struct with pointer to nameidata Al Viro
2015-04-20 18:12 ` [PATCH 03/24] ovl: rearrange ovl_follow_link to it doesn't need to call ->put_link Al Viro
2015-04-20 18:12 ` [PATCH 04/24] VFS: replace nameidata arg to ->put_link with a char* Al Viro
2015-04-20 18:12 ` [PATCH 05/24] SECURITY: remove nameidata arg from inode_follow_link Al Viro
2015-04-20 18:12 ` [PATCH 06/24] VFS: remove nameidata args from ->follow_link Al Viro
2015-04-20 18:12 ` [PATCH 07/24] namei: expand nested_symlink() in its only caller Al Viro
2015-04-20 18:12 ` [PATCH 08/24] namei.c: separate the parts of follow_link() that find the link body Al Viro
2015-04-20 18:12 ` [PATCH 09/24] namei: fold follow_link() into link_path_walk() Al Viro
2015-04-20 18:12 ` [PATCH 10/24] link_path_walk: handle get_link() returning ERR_PTR() immediately Al Viro
2015-04-20 18:12 ` [PATCH 11/24] link_path_walk: don't bother with walk_component() after jumping link Al Viro
2015-04-20 18:12 ` [PATCH 12/24] link_path_walk: turn inner loop into explicit goto Al Viro
2015-04-20 18:12 ` [PATCH 13/24] link_path_walk: massage a bit more Al Viro
2015-04-20 18:12 ` [PATCH 14/24] link_path_walk: get rid of duplication Al Viro
2015-04-20 18:12 ` [PATCH 15/24] link_path_walk: final preparations to killing recursion Al Viro
2015-04-20 18:13 ` [PATCH 16/24] link_path_walk: kill the recursion Al Viro
2015-04-20 21:04 ` Linus Torvalds
2015-04-20 21:32 ` Al Viro
2015-04-20 21:39 ` Linus Torvalds
2015-04-20 21:51 ` Al Viro
2015-04-20 21:41 ` Linus Torvalds
2015-04-20 21:42 ` Linus Torvalds
2015-04-20 21:59 ` Al Viro [this message]
2015-04-20 21:52 ` Al Viro
2015-04-20 18:13 ` [PATCH 17/24] link_path_walk: split "return from recursive call" path Al Viro
2015-04-20 18:13 ` [PATCH 18/24] link_path_walk: cleanup - turn goto start; into continue; Al Viro
2015-04-20 18:13 ` [PATCH 19/24] namei: fold may_follow_link() into follow_link() Al Viro
2015-04-20 18:13 ` [PATCH 20/24] namei: introduce nameidata->stack Al Viro
2015-04-20 18:13 ` [PATCH 21/24] namei: regularize use of put_link() and follow_link(), trim arguments Al Viro
2015-04-20 18:13 ` [PATCH 22/24] namei: trim the arguments of get_link() Al Viro
2015-04-20 18:13 ` [PATCH 23/24] new ->follow_link() and ->put_link() calling conventions Al Viro
2015-04-20 18:13 ` [PATCH 24/24] uninline walk_component() Al Viro
2015-04-21 14:49 ` [RFC][PATCHSET] non-recursive link_path_walk() and reducing stack footprint Al Viro
2015-04-21 15:04 ` Christoph Hellwig
2015-04-21 15:12 ` Richard Weinberger
2015-04-21 15:45 ` Al Viro
2015-04-21 16:46 ` Boaz Harrosh
2015-04-21 21:20 ` Al Viro
2015-04-22 18:07 ` Al Viro
2015-04-22 20:12 ` Al Viro
2015-04-22 21:05 ` Al Viro
2015-04-23 7:45 ` NeilBrown
2015-04-23 18:07 ` Al Viro
2015-04-24 6:35 ` NeilBrown
2015-04-24 13:42 ` Al Viro
2015-05-04 5:11 ` Al Viro
2015-05-04 7:30 ` NeilBrown
2015-04-23 5:01 ` Al Viro
2015-04-21 14:51 ` [PATCH] logfs: fix a pagecache leak for symlinks Al Viro
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