In case when both EEXIST and EROFS would apply we used to
return the former in mkdir(2) and friends. Lest anyone suspects
us of being consistent, in the same situation knfsd gave clients
nfs_erofs...
ro-bind series had switched the syscall side of things to
returning -EROFS and immediately broke an application - namely,
mkdir -p. Patch restores the original behaviour...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Implement a cgroup to track and enforce open and mknod restrictions on device
files. A device cgroup associates a device access whitelist with each cgroup.
A whitelist entry has 4 fields. 'type' is a (all), c (char), or b (block).
'all' means it applies to all types and all major and minor numbers. Major
and minor are either an integer or * for all. Access is a composition of r
(read), w (write), and m (mknod).
The root device cgroup starts with rwm to 'all'. A child devcg gets a copy of
the parent. Admins can then remove devices from the whitelist or add new
entries. A child cgroup can never receive a device access which is denied its
parent. However when a device access is removed from a parent it will not
also be removed from the child(ren).
An entry is added using devices.allow, and removed using
devices.deny. For instance
echo 'c 1:3 mr' > /cgroups/1/devices.allow
allows cgroup 1 to read and mknod the device usually known as
/dev/null. Doing
echo a > /cgroups/1/devices.deny
will remove the default 'a *:* mrw' entry.
CAP_SYS_ADMIN is needed to change permissions or move another task to a new
cgroup. A cgroup may not be granted more permissions than the cgroup's parent
has. Any task can move itself between cgroups. This won't be sufficient, but
we can decide the best way to adequately restrict movement later.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix may-be-used-uninitialized warning]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: James Morris <jmorris@namei.org>
Looks-good-to: Pavel Emelyanov <xemul@openvz.org>
Cc: Daniel Hokka Zakrisson <daniel@hozac.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the first really tricky patch in the series. It elevates the writer
count on a mount each time a non-special file is opened for write.
We used to do this in may_open(), but Miklos pointed out that __dentry_open()
is used as well to create filps. This will cover even those cases, while a
call in may_open() would not have.
There is also an elevated count around the vfs_create() call in open_namei().
See the comments for more details, but we need this to fix a 'create, remount,
fail r/w open()' race.
Some filesystems forego the use of normal vfs calls to create
struct files. Make sure that these users elevate the mnt
writer count because they will get __fput(), and we need
to make sure they're balanced.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This takes care of all of the direct callers of vfs_mknod().
Since a few of these cases also handle normal file creation
as well, this also covers some calls to vfs_create().
So that we don't have to make three mnt_want/drop_write()
calls inside of the switch statement, we move some of its
logic outside of the switch and into a helper function
suggested by Christoph.
This also encapsulates a fix for mknod(S_IFREG) that Miklos
found.
[AV: merged mkdir handling, added missing nfsd pieces]
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
open_namei() will, in the future, need to take mount write counts
over its creation and truncation (via may_open()) operations. It
needs to keep these write counts until any potential filp that is
created gets __fput()'d.
This gets complicated in the error handling and becomes very murky
as to how far open_namei() actually got, and whether or not that
mount write count was taken. That makes it a bad interface.
All that the current do_filp_open() really does is allocate the
nameidata on the stack, then call open_namei().
So, this merges those two functions and moves filp_open() over
to namei.c so it can be close to its buddy: do_filp_open(). It
also gets a kerneldoc comment in the process.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
My end goal here is to make sure all users of may_open()
return filps. This will ensure that we properly release
mount write counts which were taken for the filp in
may_open().
This patch moves the sys_open flags to namei flags
calculation into fs/namei.c. We'll shortly be moving
the nameidata_to_filp() calls into namei.c, and this
gets the sys_open flags to a place where we can get
at them when we need them.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
[PATCH] get stack footprint of pathname resolution back to relative sanity
[PATCH] double iput() on failure exit in hugetlb
[PATCH] double dput() on failure exit in tiny-shmem
[PATCH] fix up new filp allocators
[PATCH] check for null vfsmount in dentry_open()
[PATCH] reiserfs: eliminate private use of struct file in xattr
[PATCH] sanitize hppfs
hppfs pass vfsmount to dentry_open()
[PATCH] restore export of do_kern_mount()
Fix kernel-doc notation warnings in fs/.
Warning(mmotm-2008-0314-1449//fs/super.c:560): missing initial short description on line:
* mark_files_ro
Warning(mmotm-2008-0314-1449//fs/locks.c:1277): missing initial short description on line:
* lease_get_mtime
Warning(mmotm-2008-0314-1449//fs/locks.c:1277): missing initial short description on line:
* lease_get_mtime
Warning(mmotm-2008-0314-1449//fs/namei.c:1368): missing initial short description on line:
* lookup_one_len: filesystem helper to lookup single pathname component
Warning(mmotm-2008-0314-1449//fs/buffer.c:3221): missing initial short description on line:
* bh_uptodate_or_lock: Test whether the buffer is uptodate
Warning(mmotm-2008-0314-1449//fs/buffer.c:3240): missing initial short description on line:
* bh_submit_read: Submit a locked buffer for reading
Warning(mmotm-2008-0314-1449//fs/fs-writeback.c:30): missing initial short description on line:
* writeback_acquire: attempt to get exclusive writeback access to a device
Warning(mmotm-2008-0314-1449//fs/fs-writeback.c:47): missing initial short description on line:
* writeback_in_progress: determine whether there is writeback in progress
Warning(mmotm-2008-0314-1449//fs/fs-writeback.c:58): missing initial short description on line:
* writeback_release: relinquish exclusive writeback access against a device.
Warning(mmotm-2008-0314-1449//include/linux/jbd.h:351): contents before sections
Warning(mmotm-2008-0314-1449//include/linux/jbd.h:561): contents before sections
Warning(mmotm-2008-0314-1449//fs/jbd/transaction.c:1935): missing initial short description on line:
* void journal_invalidatepage()
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>
Somebody had put struct nameidata in stack frame of link_path_walk().
Unfortunately, there are certain realities to deal with:
* It's in the middle of recursion. Depth is equal to the nesting
depth of symlinks, i.e. up to 8.
* struct namiedata is, even if one discards the intent junk,
at least 12 pointers + 5 ints.
* moreover, adding a stack frame is not free in that situation.
* there are fs methods called on top of that, and they also have
stack footprint.
* kernel stack is not infinite.
The thing is, even if one chooses to deal with -ESTALE that way (and it's
one hell of an overkill), the only thing that needs to be preserved is
vfsmount + dentry, not the entire struct nameidata.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This introduces the symmetric function to path_put() for getting a reference
to the dentry and vfsmount of a struct path in the right order.
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add path_put() functions for releasing a reference to the dentry and
vfsmount of a struct path in the right order
* Switch from path_release(nd) to path_put(&nd->path)
* Rename dput_path() to path_put_conditional()
[akpm@linux-foundation.org: fix cifs]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the central patch of a cleanup series. In most cases there is no good
reason why someone would want to use a dentry for itself. This series reflects
that fact and embeds a struct path into nameidata.
Together with the other patches of this series
- it enforced the correct order of getting/releasing the reference count on
<dentry,vfsmount> pairs
- it prepares the VFS for stacking support since it is essential to have a
struct path in every place where the stack can be traversed
- it reduces the overall code size:
without patch series:
text data bss dec hex filename
5321639 858418 715768 6895825 6938d1 vmlinux
with patch series:
text data bss dec hex filename
5320026 858418 715768 6894212 693284 vmlinux
This patch:
Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix cifs]
[akpm@linux-foundation.org: fix smack]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, no notification event has been sent when inode's link count
changed. This is inconvenient for the application in some cases:
Suppose you have the following directory structure
foo/test
bar/
and you watch test. If someone does "mv foo/test bar/", you get event
IN_MOVE_SELF and you know something has happened with the file "test".
However if someone does "ln foo/test bar/test" and "rm foo/test" you get no
inotify event for the file "test" (only directories "foo" and "bar" receive
events).
Furthermore it could be argued that link count belongs to file's metadata and
thus IN_ATTRIB should be sent when it changes.
The following patch implements sending of IN_ATTRIB inotify events when link
count of the inode changes, i.e., when a hardlink to the inode is created or
when it is removed. This event is sent in addition to all the events sent so
far. In particular, when a last link to a file is removed, IN_ATTRIB event is
sent in addition to IN_DELETE_SELF event.
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Morten Welinder <mwelinder@gmail.com>
Cc: Robert Love <rlove@google.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Steven French <sfrench@us.ibm.com>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Way back when (in commit 834f2a4a15, aka
"VFS: Allow the filesystem to return a full file pointer on open intent"
to be exact), Trond changed the open logic to keep track of the original
flags to a file open, in order to pass down the the intent of a dentry
lookup to the low-level filesystem.
However, when doing that reorganization, it changed the meaning of
namei_flags, and thus inadvertently changed the test of access mode for
directories (and RO filesystem) to use the wrong flag. So fix those
test back to use access mode ("acc_mode") rather than the open flag
("flag").
Issue noticed by Bill Roman at Datalight.
Reported-and-tested-by: Bill Roman <bill.roman@datalight.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new attribute flag ATTR_OPEN, with the meaning: "truncation was
initiated by open() due to the O_TRUNC flag".
This way filesystems wanting to implement truncation within their ->open()
method can ignore such truncate requests.
This is a quick & dirty hack, but it comes for free.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
First of all, this makes the structure jumping look a little bit cleaner. So,
this stands alone as a tiny cleanup. But, we also need 'mnt' by itself a few
more times later in this series, so this isn't _just_ a cleanup.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
may_open() calls vfs_permission() before it does checks for IS_RDONLY(inode).
It checks _again_ inside of vfs_permission().
The check inside of vfs_permission() is going away eventually. With the
mnt_want/drop_write() functions, all of the r/o checks (except for this one)
are consistently done before calling permission(). Because of this, I'd like
to use permission() to hold a debugging check to make sure that the
mnt_want/drop_write() calls are actually being made.
So, to do this:
1. remove the IS_RDONLY() check from permission()
2. enforce that you must mnt_want_write() before
even calling permission()
3. actually add the debugging check to permission()
We need to rearrange may_open() to do r/o checks before calling permission().
Here's the patch.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
