Commit Graph

249 Commits

Author SHA1 Message Date
Al Viro
d10e8def07 vfs: take mnt_master to struct mount
make IS_MNT_SLAVE take struct mount * at the same time

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:08 -05:00
Al Viro
14cf1fa8f5 vfs: spread struct mount - remaining argument of mnt_set_mountpoint()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:07 -05:00
Al Viro
a8d56d8e4f vfs: spread struct mount - propagate_mnt()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:07 -05:00
Al Viro
6fc7871fed vfs: spread struct mount - get_dominating_id / do_make_slave
next pile of horrors, similar to mnt_parent one; this time it's
mnt_master.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:06 -05:00
Al Viro
6b41d536f7 vfs: take mnt_child/mnt_mounts to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:06 -05:00
Al Viro
68e8a9feab vfs: all counters taken to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:06 -05:00
Al Viro
83adc75322 vfs: spread struct mount - work with counters
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:05 -05:00
Al Viro
a73324da7a vfs: move mnt_mountpoint to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:05 -05:00
Al Viro
0714a53380 vfs: now it can be done - make mnt_parent point to struct mount
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:05 -05:00
Al Viro
3376f34fff vfs: mnt_parent moved to struct mount
the second victim...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:04 -05:00
Al Viro
643822b41e vfs: spread struct mount - is_path_reachable
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:04 -05:00
Al Viro
676da58df7 vfs: spread struct mount - mnt_has_parent
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:04 -05:00
Al Viro
1ab5973862 vfs: spread struct mount - do_umount/propagate_mount_busy
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:03 -05:00
Al Viro
44d964d609 vfs: spread struct mount mnt_set_mountpoint child argument
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:03 -05:00
Al Viro
87129cc0e3 vfs: spread struct mount - clone_mnt/copy_tree argument
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:03 -05:00
Al Viro
692afc312b vfs: spread struct mount - shrink_submounts/select_submounts
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:02 -05:00
Al Viro
761d5c38eb vfs: spread struct mount - umount_tree argument
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:02 -05:00
Al Viro
1b8e5564b9 vfs: the first spoils - mnt_hash moved
taken out of struct vfsmount into struct mount

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:02 -05:00
Al Viro
d5e50f74dd vfs: spread struct mount to remaining users of ->mnt_hash
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:01 -05:00
Al Viro
cb338d06e9 vfs: spread struct mount - clone_mnt/copy_tree result
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:01 -05:00
Al Viro
0f0afb1dcf vfs: spread struct mount - change_mnt_propagation/set_mnt_shared
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:01 -05:00
Al Viro
b105e270b4 vfs: spread struct mount - alloc_vfsmnt/free_vfsmnt/mnt_alloc_id/mnt_free_id
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:00 -05:00
Al Viro
cbbe362cd6 vfs: spread struct mount - tree_contains_unbindable
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:00 -05:00
Al Viro
0fb54e5056 vfs: spread struct mount - attach_recursive_mnt
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:57:00 -05:00
Al Viro
4b8b21f4fe vfs: spread struct mount - mount group id handling
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:59 -05:00
Al Viro
4b2619a571 vfs: spread struct mount - commit_tree
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:59 -05:00
Al Viro
419148da6e vfs: spread struct mount - attach_mnt/detach_mnt
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:59 -05:00
Al Viro
315fc83e56 vfs: spread struct mount - namespace.c internal iterators
next_mnt() return value, first argument
skip_mnt_tree() return value and argument

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:58 -05:00
Al Viro
c71053659e vfs: spread struct mount - __lookup_mnt() result
switch __lookup_mnt() to returning struct mount *; callers adjusted.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:58 -05:00
Al Viro
7d6fec45a5 vfs: start hiding vfsmount guts series
Almost all fields of struct vfsmount are used only by core VFS (and
a fairly small part of it, at that).  The plan: embed struct vfsmount
into struct mount, making the latter visible only to core parts of VFS.
Then move fields from vfsmount to mount, eventually leaving only
mnt_root/mnt_sb/mnt_flags in struct vfsmount.  Filesystem code still
gets pointers to struct vfsmount and remains unchanged; all such
pointers go to struct vfsmount embedded into the instances of struct
mount allocated by fs/namespace.c.  When fs/namespace.c et.al. get
a pointer to vfsmount, they turn it into pointer to mount (using
container_of) and work with that.

This is the first part of series; struct mount is introduced,
allocation switched to using it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:56:57 -05:00
Al Viro
2a79f17e4a vfs: mnt_drop_write_file()
new helper (wrapper around mnt_drop_write()) to be used in pair with
mnt_want_write_file().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:40 -05:00
Al Viro
79e801a906 vfs: make do_kern_mount() static
the only user outside of fs/namespace.c has died

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:39 -05:00
Al Viro
aa0a4cf0ab vfs: dentry_reset_mounted() doesn't use vfsmount argument
lose it

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:37 -05:00
Al Viro
6c449c8dfe unexport put_mnt_ns(), make create_mnt_ns() static outright
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:37 -05:00
Al Viro
afac7cba7e vfs: more mnt_parent cleanups
a) mount --move is checking that ->mnt_parent is non-NULL before
looking if that parent happens to be shared; ->mnt_parent is never
NULL and it's not even an misspelled !mnt_has_parent()

b) pivot_root open-codes is_path_reachable(), poorly.

c) so does path_is_under(), while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:36 -05:00
Al Viro
b2dba1af3c vfs: new internal helper: mnt_has_parent(mnt)
vfsmounts have ->mnt_parent pointing either to a different vfsmount
or to itself; it's never NULL and termination condition in loops
traversing the tree towards root is mnt == mnt->mnt_parent.  At least
one place (see the next patch) is confused about what's going on;
let's add an explicit helper checking it right way and use it in
all places where we need it.  Not that there had been too many,
but...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:36 -05:00
Al Viro
aa9c0e07bb vfs: kill pointless helpers in namespace.c
mnt_{inc,dec}_count() is not cleaner than doing the corresponding
mnt_add_count() directly and mnt_set_count() is not used at all.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:52:36 -05:00
Al Viro
02125a8264 fix apparmor dereferencing potentially freed dentry, sanitize __d_path() API
__d_path() API is asking for trouble and in case of apparmor d_namespace_path()
getting just that.  The root cause is that when __d_path() misses the root
it had been told to look for, it stores the location of the most remote ancestor
in *root.  Without grabbing references.  Sure, at the moment of call it had
been pinned down by what we have in *path.  And if we raced with umount -l, we
could have very well stopped at vfsmount/dentry that got freed as soon as
prepend_path() dropped vfsmount_lock.

It is safe to compare these pointers with pre-existing (and known to be still
alive) vfsmount and dentry, as long as all we are asking is "is it the same
address?".  Dereferencing is not safe and apparmor ended up stepping into
that.  d_namespace_path() really wants to examine the place where we stopped,
even if it's not connected to our namespace.  As the result, it looked
at ->d_sb->s_magic of a dentry that might've been already freed by that point.
All other callers had been careful enough to avoid that, but it's really
a bad interface - it invites that kind of trouble.

The fix is fairly straightforward, even though it's bigger than I'd like:
	* prepend_path() root argument becomes const.
	* __d_path() is never called with NULL/NULL root.  It was a kludge
to start with.  Instead, we have an explicit function - d_absolute_root().
Same as __d_path(), except that it doesn't get root passed and stops where
it stops.  apparmor and tomoyo are using it.
	* __d_path() returns NULL on path outside of root.  The main
caller is show_mountinfo() and that's precisely what we pass root for - to
skip those outside chroot jail.  Those who don't want that can (and do)
use d_path().
	* __d_path() root argument becomes const.  Everyone agrees, I hope.
	* apparmor does *NOT* try to use __d_path() or any of its variants
when it sees that path->mnt is an internal vfsmount.  In that case it's
definitely not mounted anywhere and dentry_path() is exactly what we want
there.  Handling of sysctl()-triggered weirdness is moved to that place.
	* if apparmor is asked to do pathname relative to chroot jail
and __d_path() tells it we it's not in that jail, the sucker just calls
d_absolute_path() instead.  That's the other remaining caller of __d_path(),
BTW.
        * seq_path_root() does _NOT_ return -ENAMETOOLONG (it's stupid anyway -
the normal seq_file logics will take care of growing the buffer and redoing
the call of ->show() just fine).  However, if it gets path not reachable
from root, it returns SEQ_SKIP.  The only caller adjusted (i.e. stopped
ignoring the return value as it used to do).

Reviewed-by: John Johansen <john.johansen@canonical.com>
ACKed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
2011-12-06 23:57:18 -05:00
Al Viro
d31da0f0ba mount_subtree() pointless use-after-free
d'oh... we'd carefully pinned mnt->mnt_sb down, dropped mnt and attempt
to grab s_umount on mnt->mnt_sb.  The trouble is, *mnt might've been
overwritten by now...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-22 12:31:21 -05:00
Al Viro
ea441d1104 new helper: mount_subtree()
takes vfsmount and relative path, does lookup within that vfsmount
(possibly triggering automounts) and returns the result as root
of subtree suitable for return by ->mount() (i.e. a reference to
dentry and an active reference to its superblock grabbed, superblock
locked exclusive).

btrfs and nfs switched to it instead of open-coding the sucker.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-16 22:00:34 -05:00
Al Viro
c133449587 switch create_mnt_ns() to saner calling conventions, fix double mntput() in nfs
Life is much saner if create_mnt_ns(mnt) drops mnt in case of error...
Switch it to such calling conventions, switch callers, fix double mntput() in
fs/nfs/super.c one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-11-16 16:12:14 -05:00
Bryan Schumaker
a877ee03ac vfs: add "device" tag to /proc/self/mountstats
nfsiostat was failing to find mounted filesystems on kernels after
2.6.38 because of changes to show_vfsstat() by commit
c7f404b40a.  This patch adds back the
"device" tag before the nfs server entry so scripts can parse the
mountstats file correctly.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
CC: stable@kernel.org [>=2.6.39]
Signed-off-by: Christoph Hellwig <hch@lst.de>
2011-10-28 13:55:08 +02:00
Trond Myklebust
815d405cef VFS: Fix the remaining automounter semantics regressions
The concensus seems to be that system calls such as stat() etc should
not trigger an automount.  Neither should the l* versions.

This patch therefore adds a LOOKUP_AUTOMOUNT flag to tag those lookups
that _should_ trigger an automount on the last path element.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ Edited to leave out the cases that are already covered by LOOKUP_OPEN,
  LOOKUP_DIRECTORY and LOOKUP_CREATE - all of which also fundamentally
  force automounting for their own reasons   - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-09-26 19:16:46 -07:00
Tim Chen
423e0ab086 VFS : mount lock scalability for internal mounts
For a number of file systems that don't have a mount point (e.g. sockfs
and pipefs), they are not marked as long term. Therefore in
mntput_no_expire, all locks in vfs_mount lock are taken instead of just
local cpu's lock to aggregate reference counts when we release
reference to file objects.  In fact, only local lock need to have been
taken to update ref counts as these file systems are in no danger of
going away until we are ready to unregister them.

The attached patch marks file systems using kern_mount without
mount point as long term.  The contentions of vfs_mount lock
is now eliminated.  Before un-registering such file system,
kern_unmount should be called to remove the long term flag and
make the mount point ready to be freed.

Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-24 10:08:32 -04:00
Kay Sievers
f15146380d fs: seq_file - add event counter to simplify poll() support
Moving the event counter into the dynamically allocated 'struc seq_file'
allows poll() support without the need to allocate its own tracking
structure.

All current users are switched over to use the new counter.

Requested-by: Andrew Morton akpm@linux-foundation.org
Acked-by: NeilBrown <neilb@suse.de>
Tested-by: Lucas De Marchi lucas.demarchi@profusion.mobi
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 20:47:50 -04:00
Roman Borisov
7c6e984dfc fs/namespace.c: bound mount propagation fix
This issue was discovered by users of busybox.  And the bug is actual for
busybox users, I don't know how it affects others.  Apparently, mount is
called with and without MS_SILENT, and this affects mount() behaviour.
But MS_SILENT is only supposed to affect kernel logging verbosity.

The following script was run in an empty test directory:

mkdir -p mount.dir mount.shared1 mount.shared2
touch mount.dir/a mount.dir/b
mount -vv --bind         mount.shared1 mount.shared1
mount -vv --make-rshared mount.shared1
mount -vv --bind         mount.shared2 mount.shared2
mount -vv --make-rshared mount.shared2
mount -vv --bind mount.shared2 mount.shared1
mount -vv --bind mount.dir     mount.shared2
ls -R mount.dir mount.shared1 mount.shared2
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
rm -f mount.dir/a mount.dir/b mount.dir/c
rmdir mount.dir mount.shared1 mount.shared2

mount -vv was used to show the mount() call arguments and result.
Output shows that flag argument has 0x00008000 = MS_SILENT bit:

mount: mount('mount.shared1','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared1','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared2','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared2','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('mount.dir','mount.shared2','(null)',0x00009000,'(null)'):0
mount.dir:
a
b

mount.shared1:

mount.shared2:
a
b

After adding --loud option to remove MS_SILENT bit from just one mount cmd:

mkdir -p mount.dir mount.shared1 mount.shared2
touch mount.dir/a mount.dir/b
mount -vv --bind         mount.shared1 mount.shared1 2>&1
mount -vv --make-rshared mount.shared1               2>&1
mount -vv --bind         mount.shared2 mount.shared2 2>&1
mount -vv --loud --make-rshared mount.shared2               2>&1  # <-HERE
mount -vv --bind mount.shared2 mount.shared1         2>&1
mount -vv --bind mount.dir     mount.shared2         2>&1
ls -R mount.dir mount.shared1 mount.shared2      2>&1
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
umount mount.dir mount.shared1 mount.shared2 2>/dev/null
rm -f mount.dir/a mount.dir/b mount.dir/c
rmdir mount.dir mount.shared1 mount.shared2

The result is different now - look closely at mount.shared1 directory listing.
Now it does show files 'a' and 'b':

mount: mount('mount.shared1','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared1','',0x0010c000,''):0
mount: mount('mount.shared2','mount.shared2','(null)',0x00009000,'(null)'):0
mount: mount('','mount.shared2','',0x00104000,''):0
mount: mount('mount.shared2','mount.shared1','(null)',0x00009000,'(null)'):0
mount: mount('mount.dir','mount.shared2','(null)',0x00009000,'(null)'):0

mount.dir:
a
b

mount.shared1:
a
b

mount.shared2:
a
b

The analysis shows that MS_SILENT flag which is ON by default in any
busybox-> mount operations cames to flags_to_propagation_type function and
causes the error return while is_power_of_2 checking because the function
expects only one bit set.  This doesn't allow to do busybox->mount with
any --make-[r]shared, --make-[r]private etc options.

Moreover, the recently added flags_to_propagation_type() function doesn't
allow us to do such operations as --make-[r]private --make-[r]shared etc.
when MS_SILENT is on.  The idea or clearing the MS_SILENT flag came from
to Denys Vlasenko.

Signed-off-by: Roman Borisov <ext-roman.borisov@nokia.com>
Reported-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Cc: Alexander Shishkin <virtuoso@slind.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-05-26 07:26:44 -04:00
Linus Torvalds
be85bccaa5 Revert "vfs: Export file system uuid via /proc/<pid>/mountinfo"
This reverts commit 93f1c20bc8.

It turns out that libmount misparses it because it adds a '-' character
in the uuid string, which libmount then incorrectly confuses with the
separator string (" - ") at the end of all the optional arguments.

Upstream libmount (in the util-linux tree) has been fixed, but until
that fix actually percolates up to users, we'd better not expose this
change in the kernel.

Let's revisit this later (possibly by exposing the UUID without any '-'
characters in it, avoiding the user-space bug).

Reported-by: Dave Jones <davej@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Karel Zak <kzak@redhat.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-12 13:35:56 -07:00
Mandeep Singh Baines
80cdc6dae7 fs: use appropriate printk priority levels
printk()s without a priority level default to KERN_WARNING.  To reduce
noise at KERN_WARNING, this patch set the priority level appriopriately
for unleveled printks()s.  This should be useful to folks that look at
dmesg warnings closely.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:10 -07:00
Al Viro
b12cea9198 change the locking order for namespace_sem
Have it nested inside ->i_mutex.  Instead of using follow_down()
under namespace_sem, followed by grabbing i_mutex and checking that
mountpoint to be is not dead, do the following:
	grab i_mutex
	check that it's not dead
	grab namespace_sem
	see if anything is mounted there
	if not, we've won
	otherwise
		drop locks
		put_path on what we had
		replace with what's mounted
		retry everything with new mountpoint to be

New helper (lock_mount()) does that.  do_add_mount(), do_move_mount(),
do_loopback() and pivot_root() switched to it; in case of the last
two that eliminates a race we used to have - original code didn't
do follow_down().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-18 08:55:38 -04:00
Al Viro
27cb1572e3 fix deadlock in pivot_root()
Don't hold vfsmount_lock over the loop traversing ->mnt_parent;
do check_mnt(new.mnt) under namespace_sem instead; combined with
namespace_sem held over all that code it'll guarantee the stability
of ->mnt_parent chain all the way to the root.

Doing check_mnt() outside of namespace_sem in case of pivot_root()
is wrong anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-18 08:54:59 -04:00