v9fs may be used as lower layer of overlayfs and accessing f_path.dentry
can lead to a crash.  In this case it's a NULL pointer dereference in
p9_fid_create().

Fix by replacing direct access of file->f_path.dentry with the
file_dentry() accessor, which will always return a native object.
Reported-by: NAlessio Igor Bogani <alessioigorbogani@gmail.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>
Tested-by: NAlessio Igor Bogani <alessioigorbogani@gmail.com>
Fixes: 4bacc9c9 ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Cc: <stable@vger.kernel.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

preparation for similar switch in ->setxattr() (see the next commit for
rationale).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Including blkdev_direct_IO and dax_do_io.  It has to be ki_pos to actually
work, so eliminate the superflous argument.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and do not assume they are already attached to each other
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and neither can ever be NULL
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When get_acl() is called for an inode whose ACL is not cached yet, the
get_acl inode operation is called to fetch the ACL from the filesystem.
The inode operation is responsible for updating the cached acl with
set_cached_acl().  This is done without locking at the VFS level, so
another task can call set_cached_acl() or forget_cached_acl() before the
get_acl inode operation gets to calling set_cached_acl(), and then
get_acl's call to set_cached_acl() results in caching an outdate ACL.

Prevent this from happening by setting the cached ACL pointer to a
task-specific sentinel value before calling the get_acl inode operation.
Move the responsibility for updating the cached ACL from the get_acl
inode operations to get_acl().  There, only set the cached ACL if the
sentinel value hasn't changed.

The sentinel values are chosen to have odd values.  Likewise, the value
of ACL_NOT_CACHED is odd.  In contrast, ACL object pointers always have
an even value (ACLs are aligned in memory).  This allows to distinguish
uncached ACLs values from ACL objects.

In addition, switch from guarding inode->i_acl and inode->i_default_acl
upates by the inode->i_lock spinlock to using xchg() and cmpxchg().

Filesystems that do not want ACLs returned from their get_acl inode
operations to be cached must call forget_cached_acl() to prevent the VFS
from doing so.

(Patch written by Al Viro and Andreas Gruenbacher.)
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We may sleep inside a the lock, so use a mutex rather than spinlock.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We may sleep inside a the lock, so use a mutex rather than spinlock.
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

new method: ->get_link(); replacement of ->follow_link().  The differences
are:
	* inode and dentry are passed separately
	* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
	* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.

It's a flagday change - the old method is gone, all in-tree instances
converted.  Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode.  That'll change
in the next commits.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

For block devices the pagecache is associated with the inode
on bdevfs, not with the aliasing ones on the mountable filesystems.
The latter have its own ->i_data empty and ->i_mapping pointing
to the (unique per major/minor) bdevfs inode.  That guarantees
cache coherence between all block device inodes with the same
device number.

Eviction of an alias inode has no business trying to evict the
pages belonging to bdevfs one; moreover, ->i_mapping is only
safe to access when the thing is opened.  At the time of
->evict_inode() the victim is definitely *not* opened.  We are
about to kill the address space embedded into struct inode
(inode->i_data) and that's what we need to empty of any pages.

9p instance tries to empty inode->i_mapping instead, which is
both unsafe and bogus - if we have several device nodes with
the same device number in different places, closing one of them
should not try to empty the (shared) page cache.

Fortunately, other instances in the tree are OK; they are
evicting from &inode->i_data instead, as 9p one should.

Cc: stable@vger.kernel.org # v2.6.32+, ones prior to 2.6.36 need only half of that
Reported-by: N"Suzuki K. Poulose" <Suzuki.Poulose@arm.com>
Tested-by: N"Suzuki K. Poulose" <Suzuki.Poulose@arm.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Add an additional "name" field to struct xattr_handler.  When the name
is set, the handler matches attributes with exactly that name.  When the
prefix is set instead, the handler matches attributes with the given
prefix and with a non-empty suffix.

This patch should avoid bugs like the one fixed in commit c361016a in
the future.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: NJames Morris <james.l.morris@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Remove POSIX_ACL_XATTR_{ACCESS,DEFAULT} and GFS2_POSIX_ACL_{ACCESS,DEFAULT}
and replace them with the definitions in <include/uapi/linux/xattr.h>.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: NJames Morris <james.l.morris@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Now that the xattr handler is passed to the xattr handler operations, we
can use the same get and set operations for the user, trusted, and security
xattr namespaces.  In those namespaces, we can access the full attribute
name by "reattaching" the name prefix the vfs has skipped for us.  Add a
xattr_full_name helper to make this obvious in the code.

For the "system.posix_acl_access" and "system.posix_acl_default"
attributes, handler->prefix is the full attribute name; the suffix is the
empty string.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: v9fs-developer@lists.sourceforge.net
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The xattr_handler operations are currently all passed a file system
specific flags value which the operations can use to disambiguate between
different handlers; some file systems use that to distinguish the xattr
namespace, for example.  In some oprations, it would be useful to also have
access to the handler prefix.  To allow that, pass a pointer to the handler
to operations instead of the flags value alone.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The include file was intended to have an include guard, but the #define
part is missing.
Signed-off-by: NTzvetelin Katchov <katchov@gmail.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

new_valid_dev() always returns 1, so the !new_valid_dev() check is not
needed.  Remove it.
Signed-off-by: NYaowei Bai <bywxiaobai@163.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the remote locking fail, we run a local vfs unlock that should work and
return success to userland when we didn't actually lock at all.  We need
to tell the application that tried to lock that it didn't get it, not that
all went well.
Signed-off-by: NDominique Martinet <dominique.martinet@cea.fr>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Instead of having users check for FL_POSIX or FL_FLOCK to call the correct
locks API function, use the check within locks_lock_inode_wait().  This
allows for some later cleanup.
Signed-off-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NJeff Layton <jeff.layton@primarydata.com>

When reading 0 bytes from an empty file on a 9P filesystem, the return
code of read() was not 0 as expected due to an unitialized err variable.

Tested with this simple program:

    #include <assert.h>
    #include <sys/types.h>
    #include <sys/stat.h>
    #include <fcntl.h>
    #include <unistd.h>

    int main(int argc, const char **argv)
    {
        assert(argc == 2);
        char buffer[256];
        int fd = open(argv[1], O_RDONLY|O_NOCTTY);
        assert(fd >= 0);
        assert(read(fd, buffer, 0) == 0);
        return 0;
    }
Signed-off-by: NVincent Bernat <vincent@bernat.im>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Commit 8a0dc95f
("9p: transport API reorganization")
removed Opt_trans in tokens not in enum.
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Cc: stable@vger.kernel.org # all branches
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

On failure, v9fs_session_init() returns with the v9fs_session_info
struct partially initialized and expects the caller to invoke
v9fs_session_close() to clean it up; however, it doesn't track whether
the bdi is initialized or not and curiously invokes bdi_destroy() in
both vfs_session_init() failure path too.

A. If v9fs_session_init() fails before the bdi is initialized, the
   follow-up v9fs_session_close() will invoke bdi_destroy() on an
   uninitialized bdi.

B. If v9fs_session_init() fails after the bdi is initialized,
   bdi_destroy() will be called twice on the same bdi - once in the
   failure path of v9fs_session_init() and then by
   v9fs_session_close().

A is broken no matter what.  B used to be okay because bdi_destroy()
allowed being invoked multiple times on the same bdi, which BTW was
broken in its own way - if bdi_destroy() was invoked on an initialiezd
but !registered bdi, it'd fail to free percpu counters.  Since
f0054bb1 ("writeback: move backing_dev_info->wb_lock and
->worklist into bdi_writeback"), this no longer work - bdi_destroy()
on an initialized but not registered bdi works correctly but multiple
invocations of bdi_destroy() is no longer allowed.

The obvious culprit here is v9fs_session_init()'s odd and broken error
behavior.  It should simply clean up after itself on failures.  This
patch makes the following updates to v9fs_session_init().

* @rc -> @retval error return propagation removed.  It didn't serve
  any purpose.  Just use @rc.

* Move addition to v9fs_sessionlist to the end of the function so that
  incomplete sessions are not put on the list or iterated and error
  path doesn't have to worry about it.

* Update error handling so that it cleans up after itself.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

pointless forward declarations, stale comments
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

its only use is getting passed to nd_jump_link(), which can obtain
it from current->nameidata
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

a) instead of storing the symlink body (via nd_set_link()) and returning
an opaque pointer later passed to ->put_link(), ->follow_link() _stores_
that opaque pointer (into void * passed by address by caller) and returns
the symlink body.  Returning ERR_PTR() on error, NULL on jump (procfs magic
symlinks) and pointer to symlink body for normal symlinks.  Stored pointer
is ignored in all cases except the last one.

Storing NULL for opaque pointer (or not storing it at all) means no call
of ->put_link().

b) the body used to be passed to ->put_link() implicitly (via nameidata).
Now only the opaque pointer is.  In the cases when we used the symlink body
to free stuff, ->follow_link() now should store it as opaque pointer in addition
to returning it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We copy there a kmalloc'ed string and proceed to kfree that string immediately
after that.  Easier to just feed that string to nd_set_link() and _not_
kfree it until ->put_link() (which becomes kfree_put_link() in that case).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Al Viro's IOV changes broke 9p readdir() because the new code
didn't abort the read when it returned nothing. The original
code checked if the combined error/length was <= 0 but in the
new code that accidentally got changed to just an error check.

Add back the return from the function when nothing is read.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Fixes: e1200fe6 ("9p: switch p9_client_read() to passing struct iov_iter *")
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... returning -E... upon error and amount of data left in iter after
(possible) truncation upon success.  Note, that normal case gives
a non-zero (positive) return value, so any tests for != 0 _must_ be
updated.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Conflicts:
	fs/ext4/file.c

all remaining callers are passing 0; some just obscure that fact.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Now that no one is using rw, remove it completely.
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The rw parameter to direct_IO is redundant with iov_iter->type, and
treated slightly differently just about everywhere it's used: some users
do rw & WRITE, and others do rw == WRITE where they should be doing a
bitwise check. Simplify this with the new iov_iter_rw() helper, which
always returns either READ or WRITE.
Signed-off-by: NOmar Sandoval <osandov@osandov.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>