The autofs4_catatonic_mode() function accesses the wait queue without any
locking but can be called at any time. This could lead to a possible
double free of the name field of the wait and a double fput of the daemon
communication pipe or an fput of a NULL file pointer.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A while ago a patch to resolve a deadlock during directory creation was
merged. This delayed the hashing of lookup dentrys until the ->mkdir()
(or ->symlink()) operation completed to ensure we always went through
->lookup() instead of also having processes go through ->revalidate() so
our VFS locking remained consistent.
Now we are seeing a couple of side affects of that change in situations
with heavy mount activity.
Two cases have been identified:
1) When a mount request is triggered, due to the delayed hashing, the
directory created by user space for the mount point doesn't have the
DCACHE_AUTOFS_PENDING flag set. In the case of an autofs multi-mount
where a tree of mount point directories are created this can lead to
the path walk continuing rather than the dentry being sent to the wait
queue to wait for request completion. This is because, if the pending
flag isn't set, the criteria for deciding this is a mount in progress
fails to hold, namely that the dentry is not a mount point and has no
subdirectories.
2) A mount request dentry is initially created negative and unhashed.
It remains this way until the ->mkdir() callback completes. Since it
is unhashed a fresh dentry is used when the user space mount request
creates the mount point directory. This leaves the original dentry
negative and unhashed. But revalidate has no way to tell the VFS that
the dentry has changed, other than to force another ->lookup() by
returning false, which is at best wastefull and at worst not possible.
This results in an -ENOENT return from the original path walk when in
fact the mount succeeded.
To resolve this we need to ensure that the same dentry is used in all
calls to ->lookup() during the course of a mount request. This patch
achieves that by adding the initial dentry to a look aside list and
removes it at ->mkdir() or ->symlink() completion (or when the dentry is
released), since these are the only create operations autofs4 supports.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Correct the error of making a positive dentry negative after it has been
instantiated.
The code that makes this error attempts to re-use the dentry from a
concurrent expire and mount to resolve a race and the dentry used for the
lookup must be negative for mounts to trigger in the required cases. The
fact is that the dentry doesn't need to be re-used because all that is
needed is to preserve the flag that indicates an expire is still
incomplete at the time of the mount request.
This change uses the the dentry to check the flag and wait for the expire
to complete then discards it instead of attempting to re-use it.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add uid= and gid= options to /proc/mounts for autofs4 filesystems.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The set of functions process_session, task_session, process_group and
task_pgrp is confusing, as the names can be mixed with each other when looking
at the code for a long time.
The proposals are to
* equip the functions that return the integer with _nr suffix to
represent that fact,
* and to make all functions work with task (not process) by making
the common prefix of the same name.
For monotony the routines signal_session() and set_signal_session() are
replaced with task_session_nr() and set_task_session(), especially since they
are only used with the explicit task->signal dereference.
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix coding style errors (extra spaces, long lines) in autofs and autofs4 files
being modified for container/pidspace issues.
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: <containers@lists.osdl.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove includes of <linux/smp_lock.h> where it is not used/needed.
Suggested by Al Viro.
Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc,
sparc64, and arm (all 59 defconfigs).
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jeff Moyer has identified a race between mount and expire.
What happens is that during an expire the situation can arise that a directory
is removed and another lookup is done before the expire issues a completion
status to the kernel module. In this case, since the the lookup gets a new
dentry, it doesn't know that there is an expire in progress and when it posts
its mount request, matches the existing expire request and waits for its
completion. ENOENT is then returned to user space from lookup (as the dentry
passed in is now unhashed) without having performed the mount request.
The solution used here is to keep track of dentrys in this unhashed state and
reuse them, if possible, in order to preserve the flags. Additionally, this
infrastructure will provide the framework for the reintroduction of caching of
mount fails removed earlier in development.
Signed-off-by: Ian Kent <raven@themaw.net>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is inspired by Arjan's "Patch series to mark struct
file_operations and struct inode_operations const".
Compile tested with gcc & sparse.
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Run this:
#!/bin/sh
for f in $(grep -Erl "\([^\)]*\) *k[cmz]alloc" *) ; do
echo "De-casting $f..."
perl -pi -e "s/ ?= ?\([^\)]*\) *(k[cmz]alloc) *\(/ = \1\(/" $f
done
And then go through and reinstate those cases where code is casting pointers
to non-pointers.
And then drop a few hunks which conflicted with outstanding work.
Cc: Russell King <rmk@arm.linux.org.uk>, Ian Molton <spyro@f2s.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Steven French <sfrench@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Jaroslav Kysela <perex@suse.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When kernel is compiled with old version of autofs (CONFIG_AUTOFS_FS), and
new (observed at least with 5.x.x) automount deamon is started, kernel
correctly reports incompatible version of kernel and userland daemon, but
then screws things up instead of correct handling of the error:
autofs: kernel does not match daemon version
=====================================
[ BUG: bad unlock balance detected! ]
-------------------------------------
automount/4199 is trying to release lock (&type->s_umount_key) at:
[<c0163b9e>] get_sb_nodev+0x76/0xa4
but there are no more locks to release!
other info that might help us debug this:
no locks held by automount/4199.
stack backtrace:
[<c0103b15>] dump_trace+0x68/0x1b2
[<c0103c77>] show_trace_log_lvl+0x18/0x2c
[<c01041db>] show_trace+0xf/0x11
[<c010424d>] dump_stack+0x12/0x14
[<c012e02c>] print_unlock_inbalance_bug+0xe7/0xf3
[<c012fd4f>] lock_release+0x8d/0x164
[<c012b452>] up_write+0x14/0x27
[<c0163b9e>] get_sb_nodev+0x76/0xa4
[<c0163689>] vfs_kern_mount+0x83/0xf6
[<c016373e>] do_kern_mount+0x2d/0x3e
[<c017513f>] do_mount+0x607/0x67a
[<c0175224>] sys_mount+0x72/0xa4
[<c0102b96>] sysenter_past_esp+0x5f/0x99
DWARF2 unwinder stuck at sysenter_past_esp+0x5f/0x99
Leftover inexact backtrace:
=======================
and then deadlock comes.
The problem: autofs_fill_super() returns EINVAL to get_sb_nodev(), but
before that, it calls kill_anon_super() to destroy the superblock which
won't be needed. This is however way too soon to call kill_anon_super(),
because get_sb_nodev() has to perform its own cleanup of the superblock
first (deactivate_super(), etc.). The correct time to call
kill_anon_super() is in the autofs_kill_sb() callback, which is called by
deactivate_super() at proper time, when the superblock is ready to be
killed.
I can see the same faulty codepath also in autofs4. This patch solves
issues in both filesystems in a same way - it postpones the
kill_anon_super() until the proper time is signalized by deactivate_super()
calling the kill_sb() callback.
[raven@themaw.net: update comment]
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Ian Kent <raven@themaw.net>
Cc: <stable@kernel.org>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Resolve the panic on failed mount of an autofs filesystem originally
reported by Mao Bibo.
It addresses two issues that happen after the mount fail. The first a NULL
pointer reference to a field (pipe) in the autofs superblock info structure
and second the lack of super block cleanup by the autofs and autofs4
modules.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make sure all dentries refs are released before calling kill_anon_super() so
that the assumption that generic_shutdown_super() can completely destroy the
dentry tree for there will be no external references holds true.
What was being done in the put_super() superblock op, is now done in the
kill_sb() filesystem op instead, prior to calling kill_anon_super().
This makes the struct autofs_sb_info::root member variable redundant (since
sb->s_root is still available), and so that is removed. The calls to
shrink_dcache_sb() are also removed since they're also redundant as
shrink_dcache_for_umount() will now be called after the cleanup routine.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Ian Kent <raven@themaw.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This eliminates the i_blksize field from struct inode. Filesystems that want
to provide a per-inode st_blksize can do so by providing their own getattr
routine instead of using the generic_fillattr() function.
Note that some filesystems were providing pretty much random (and incorrect)
values for i_blksize.
[bunk@stusta.de: cleanup]
[akpm@osdl.org: generic_fillattr() fix]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a proper prototype for autofs4_dentry_release() to autofs_i.h.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We have to have a valid sbi here, or we'd have oopsed already. (There's a
dereference of sbi->catatonic a few lines above)
Coverity #740
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds a follow_link inode method for the root of an autofs direct
mount trigger. It also adds the corresponding mount options and updates the
show_mount method.
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add show_options method to display autofs4 mount options in the proc
filesystem.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix the case where an expire returns busy on a tree mount when it is in fact
not busy. This case was overlooked when the patch to prevent the expiring
away of "scaffolding" directories for tree mounts was applied.
The problem arises when a tree of mounts is a member of a map with other keys.
The current logic will not expire the tree if any other mount in the map is
busy. The solution is to maintain a "minimum" use count for each autofs
dentry and compare this to the actual dentry usage count during expire.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Semaphore to mutex conversion.
The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some long time ago, dentry struct was carefully tuned so that on 32 bits
UP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a multiple
of memory cache lines.
Then RCU was added and dentry struct enlarged by two pointers, with nice
results for SMP, but not so good on UP, because breaking the above tuning
(128 + 8 = 136 bytes)
This patch reverts this unwanted side effect, by using an union (d_u),
where d_rcu and d_child are placed so that these two fields can share their
memory needs.
At the time d_free() is called (and d_rcu is really used), d_child is known
to be empty and not touched by the dentry freeing.
Lockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so
the previous content of d_child is not needed if said dentry was unhashed
but still accessed by a CPU because of RCU constraints)
As dentry cache easily contains millions of entries, a size reduction is
worth the extra complexity of the ugly C union.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Paul Jackson <pj@sgi.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@epoch.ncsc.mil>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is the fs/ part of the big kfree cleanup patch.
Remove pointless checks for NULL prior to calling kfree() in fs/.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If the automount daemon receives a signal which causes it to sumarily
terminate the autofs4 module leaks dentries. The same problem exists with
detached mount requests without the warning.
This patch cleans these dentries at umount.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For tree mount maps, a call to chdir or chroot, to a directory above the
moint point directories at a certain time during the expire results in the
expire incorrectly thinking the tree is not busy. This patch adds a check
to see if the filesystem above the tree mount points is busy and also locks
the filesystem during the tree mount expire to prevent the race.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Ian Kent