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>
Commit f50b6f8691 introduced a race in
autofs4 between autofs_lookup_unhashed() and autofs_dentry_release().
autofs_dentry_release() ends up clearing the ->dentry and ->inode members
of autofs_info before removing it from the rehash list. The list is
protected by the rehash lock in both functions, but since
autofs_dentry_release() starts tearing the autofs_info struct down before
removing it from the list, autofs_lookup_unhashed() can get a autofs_info
with a NULL dentry.
This patch moves the clearing of ->dentry and ->inode after the removal
from the rehash list.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
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>
This problem was identified and fixed some time ago by Jeff Moyer but it fell
through the cracks somehow.
It is possible that a user space application could remove and re-create a
directory during a request. To avoid returning a failure from lookup
incorrectly when our current dentry is unhashed we need to check if another
positive, hashed dentry matching this one exists and if so return it instead
of a fail.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
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>
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>
The current header file definitions for autofs version 5 have caused a couple
of problems for application builds downstream.
This fixes the problem by separating the definitions.
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>
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>
Many struct inode_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in the autofs4
filesystem.
Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
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>
Some filesystems, instead of simply decrementing i_nlink, simply zero it
during an unlink operation. We need to catch these in addition to the
decrement operations.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is mostly included for parity with dec_nlink(), where we will have some
more hooks. This one should stay pretty darn straightforward for now.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When a filesystem decrements i_nlink to zero, it means that a write must be
performed in order to drop the inode from the filesystem.
We're shortly going to have keep filesystems from being remounted r/o between
the time that this i_nlink decrement and that write occurs.
So, add a little helper function to do the decrements. We'll tie into it in a
bit to note when i_nlink hits zero.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
During testing I've found that the mount pending flag can be left set at
exit from autofs4_lookup after a failed mount request. This shouldn't be
allowed to happen and causes incorrect error returns.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The check for an empty directory in the autofs4_follow_link method fails
occassionally due to old dentrys. We had the same problem
autofs4_revalidate ages ago. I thought we wouldn't need this in
autofs4_follow_link, silly me.
Signed-off-by: Ian Kent <raven@themaw.net>
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>
For a long time now I have had a problem with not being able to return a
lookup failure on an existsing directory. In autofs this corresponds to a
mount failure on a autofs managed mount entry that is browsable (and so the
mount point directory exists).
While this problem has been present for a long time I've avoided resolving
it because it was not very visible. But now that autofs v5 has "mount and
expire on demand" of nested multiple mounts, such as is found when mounting
an export list from a server, solving the problem cannot be avoided any
longer.
I've tried very hard to find a way to do this entirely within the autofs4
module but have not been able to find a satisfactory way to achieve it.
So, I need to propose a change to the VFS.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If the timeout of an autofs mount is set to zero then umounts are disabled.
This works fine, however the kernel module checks the expire timeout and
goes no further if it is zero. This is not the right thing to do at
shutdown as the module is passed an option to expire mounts regardless of
their timeout setting.
This patch allows autofs to honor the force expire option.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I've found a case where invalid dentrys in a mount tree, waiting to be
cleaned up by d_invalidate, prevent the expected expire.
In this case dentrys created during a lookup for which a mount fails or has
no entry in the mount map contribute to the d_count of the parent dentry.
These dentrys may not be invalidated prior to comparing the interanl usage
count of valid autofs dentrys against the dentry d_count which makes a
mount tree appear busy so it doesn't 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>
Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.
The filesystem is then required to manually set the superblock and root dentry
pointers. For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).
The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.
This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing. In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.
The patch also makes the following changes:
(*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
pointer argument and return an integer, so most filesystems have to change
very little.
(*) If one of the convenience function is not used, then get_sb() should
normally call simple_set_mnt() to instantiate the vfsmount. This will
always return 0, and so can be tail-called from get_sb().
(*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
dcache upon superblock destruction rather than shrink_dcache_anon().
This is required because the superblock may now have multiple trees that
aren't actually bound to s_root, but that still need to be cleaned up. The
currently called functions assume that the whole tree is rooted at s_root,
and that anonymous dentries are not the roots of trees which results in
dentries being left unculled.
However, with the way NFS superblock sharing are currently set to be
implemented, these assumptions are violated: the root of the filesystem is
simply a dummy dentry and inode (the real inode for '/' may well be
inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
with child trees.
[*] Anonymous until discovered from another tree.
(*) The documentation has been adjusted, including the additional bit of
changing ext2_* into foo_* in the documentation.
[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Sukadev Bhattiprolu
Randy Dunlap
Jeff Mahoney
Ian Kent
Josef 'Jeff' Sipek
Arjan van de Ven
Robert P. J. Day
Jiri Kosina
David Howells
Dave Hansen
Theodore Ts'o
Jeff Garzik
Akinobu Mita