Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: David Howells <dhowells@redhat.com>
CC: linux-afs@lists.infradead.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJens Axboe <axboe@fb.com>

Make struct afs_read::remain 64-bit so that it can handle huge transfers if
we ever request them or the server decides to give us a bit extra data (the
other fields there are already 64-bit).
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NMarc Dionne <marc.dionne@auristor.com>

get_seconds() returns real wall-clock seconds. On 32-bit systems
this value will overflow in year 2038 and beyond. This patch changes
afs_vnode record to use ktime_get_real_seconds() instead, for the
fields cb_expires and cb_expires_at.
Signed-off-by: NTina Ruchandani <ruchandani.tina@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

get_seconds() returns real wall-clock seconds. On 32-bit systems
this value will overflow in year 2038 and beyond. This patch changes
afs's vlocation record to use ktime_get_real_seconds() instead, for the
fields time_of_death and update_at.
Signed-off-by: NTina Ruchandani <ruchandani.tina@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In AFS, mountpoints appear as symlinks with mode 0644 and normal symlinks
have mode 0777, so use this to distinguish them rather than reading the
content and parsing it.  In the case of a mountpoint, the symlink body is a
formatted string indicating the location of the target volume.

Note that with this, kAFS no longer 'pre-fetches' the contents of symlinks,
so afs_readpage() may fail with an access-denial because when the VFS calls
d_automount(), it wraps the call in an credentials override that sets the
initial creds - thereby preventing access to the caller's keyrings and the
authentication keys held therein.

To this end, a patch reverting that change to the VFS is required also.
Reported-by: NJeffrey Altman <jaltman@auristor.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Flush outstanding writes in afs when an fd is closed.  This is what NFS and
CIFS do.
Reported-by: NMarc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Handle the situation where afs_write_begin() is told to expect that a
full-page write will be made, but this doesn't happen (EFAULT, CTRL-C,
etc.), and so afs_write_end() sees a partial write took place.  Currently,
no attempt is to deal with the discrepency.

Fix this by loading the gap from the server.
Reported-by: NAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Kill struct afs_read::pg_offset as nothing uses it.  It's unnecessary as pos
can be masked off.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Servers may send a callback array that is the same size as
the FID array, or an empty array.  If the callback count is
0, the code would attempt to read (fid_count * 12) bytes of
data, which would fail and result in an unmarshalling error.
This would lead to stale data for remotely modified files
or directories.

Store the callback array size in the internal afs_call
structure and use that to determine the amount of data to
read.
Signed-off-by: NMarc Dionne <marc.dionne@auristor.com>

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode.  This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included.  The
following have been included:

 (1) Make the fields a consistent size on all arches and make them large.

 (2) Spare space, request flags and information flags are provided for
     future expansion.

 (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
     __s64).

 (4) Creation time: The SMB protocol carries the creation time, which could
     be exported by Samba, which will in turn help CIFS make use of
     FS-Cache as that can be used for coherency data (stx_btime).

     This is also specified in NFSv4 as a recommended attribute and could
     be exported by NFSD [Steve French].

 (5) Lightweight stat: Ask for just those details of interest, and allow a
     netfs (such as NFS) to approximate anything not of interest, possibly
     without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
     Dilger] (AT_STATX_DONT_SYNC).

 (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
     its cached attributes are up to date [Trond Myklebust]
     (AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

 (7) Data version number: Could be used by userspace NFS servers [Aneesh
     Kumar].

     Can also be used to modify fill_post_wcc() in NFSD which retrieves
     i_version directly, but has just called vfs_getattr().  It could get
     it from the kstat struct if it used vfs_xgetattr() instead.

     (There's disagreement on the exact semantics of a single field, since
     not all filesystems do this the same way).

 (8) BSD stat compatibility: Including more fields from the BSD stat such
     as creation time (st_btime) and inode generation number (st_gen)
     [Jeremy Allison, Bernd Schubert].

 (9) Inode generation number: Useful for FUSE and userspace NFS servers
     [Bernd Schubert].

     (This was asked for but later deemed unnecessary with the
     open-by-handle capability available and caused disagreement as to
     whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

     (No particular data were offered, but things like last backup
     timestamp, the data version number and the DOS archive bit would come
     into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
     filesystem can now say it doesn't support a standard stat feature if
     that isn't available, so if, for instance, inode numbers or UIDs don't
     exist or are fabricated locally...

     (This requires a separate system call - I have an fsinfo() call idea
     for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
     struct xstat [Steve French].

     (Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
     granularity of each of the times (NFSv4 time_delta) [Steve French].

     (Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
     Note that the Linux IOC flags are a mess and filesystems such as Ext4
     define flags that aren't in linux/fs.h, so translation in the kernel
     may be a necessity (or, possibly, we provide the filesystem type too).

     (Some attributes are made available in stx_attributes, but the general
     feeling was that the IOC flags were to ext[234]-specific and shouldn't
     be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
     Michael Kerrisk].

     (Deferred, probably to fsinfo.  Finding out if there's an ACL or
     seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

     (A __reserved field has been left in the statx_timestamp struct for
     this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

	int ret = statx(int dfd,
			const char *filename,
			unsigned int flags,
			unsigned int mask,
			struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat().  There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags.  There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

 (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
     respect.

 (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
     its attributes with the server - which might require data writeback to
     occur to get the timestamps correct.

 (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
     network filesystem.  The resulting values should be considered
     approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller.  The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat().  It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data.  This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

	struct statx_timestamp {
		__s64	tv_sec;
		__s32	tv_nsec;
		__s32	__reserved;
	};

	struct statx {
		__u32	stx_mask;
		__u32	stx_blksize;
		__u64	stx_attributes;
		__u32	stx_nlink;
		__u32	stx_uid;
		__u32	stx_gid;
		__u16	stx_mode;
		__u16	__spare0[1];
		__u64	stx_ino;
		__u64	stx_size;
		__u64	stx_blocks;
		__u64	__spare1[1];
		struct statx_timestamp	stx_atime;
		struct statx_timestamp	stx_btime;
		struct statx_timestamp	stx_ctime;
		struct statx_timestamp	stx_mtime;
		__u32	stx_rdev_major;
		__u32	stx_rdev_minor;
		__u32	stx_dev_major;
		__u32	stx_dev_minor;
		__u64	__spare2[14];
	};

The defined bits in request_mask and stx_mask are:

	STATX_TYPE		Want/got stx_mode & S_IFMT
	STATX_MODE		Want/got stx_mode & ~S_IFMT
	STATX_NLINK		Want/got stx_nlink
	STATX_UID		Want/got stx_uid
	STATX_GID		Want/got stx_gid
	STATX_ATIME		Want/got stx_atime{,_ns}
	STATX_MTIME		Want/got stx_mtime{,_ns}
	STATX_CTIME		Want/got stx_ctime{,_ns}
	STATX_INO		Want/got stx_ino
	STATX_SIZE		Want/got stx_size
	STATX_BLOCKS		Want/got stx_blocks
	STATX_BASIC_STATS	[The stuff in the normal stat struct]
	STATX_BTIME		Want/got stx_btime{,_ns}
	STATX_ALL		[All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution.  Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does.  The following
attributes map to FS_*_FL flags and are the same numerical value:

	STATX_ATTR_COMPRESSED		File is compressed by the fs
	STATX_ATTR_IMMUTABLE		File is marked immutable
	STATX_ATTR_APPEND		File is append-only
	STATX_ATTR_NODUMP		File is not to be dumped
	STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

	KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

	STATX_ATTR_AUTOMOUNT		Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

 (0) stx_dev_*, stx_blksize.

     These are local system information and are always available.

 (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
     stx_size, stx_blocks.

     These will be returned whether the caller asks for them or not.  The
     corresponding bits in stx_mask will be set to indicate whether they
     actually have valid values.

     If the caller didn't ask for them, then they may be approximated.  For
     example, NFS won't waste any time updating them from the server,
     unless as a byproduct of updating something requested.

     If the values don't actually exist for the underlying object (such as
     UID or GID on a DOS file), then the bit won't be set in the stx_mask,
     even if the caller asked for the value.  In such a case, the returned
     value will be a fabrication.

     Note that there are instances where the type might not be valid, for
     instance Windows reparse points.

 (2) stx_rdev_*.

     This will be set only if stx_mode indicates we're looking at a
     blockdev or a chardev, otherwise will be 0.

 (3) stx_btime.

     Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

	samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output.  Firstly, an NFS directory that crosses to
another FSID.  Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

	[root@andromeda ~]# /tmp/test-statx -A /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:26           Inode: 1703937     Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000
	Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

	[root@andromeda ~]# /tmp/test-statx /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:27           Inode: 2           Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

AFS uses a time based UUID to identify the host itself.  This requires
getting a timestamp which is currently done through the getnstimeofday()
interface that we want to eventually get rid of.

Instead of replacing it with a ktime-based interface, simply remove the
entire function and use generate_random_uuid() instead, which has a v4
("completely random") UUID instead of the time-based one.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Move the afs_uuid struct to linux/uuid.h, rename it to uuid_v1 and change
the u16/u32 fields to __be16/__be32 instead so that the structure can be
cast to a 16-octet network-order buffer.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de

A static checker warning occurs in the AFS filesystem:

	fs/afs/cmservice.c:155 SRXAFSCB_CallBack()
	error: dereferencing freed memory 'call'

due to the reply being sent before we access the server it points to.  The
act of sending the reply causes the call to be freed if an error occurs
(but not if it doesn't).

On top of this, the lifetime handling of afs_call structs is fragile
because they get passed around through workqueues without any sort of
refcounting.

Deal with the issues by:

 (1) Fix the maybe/maybe not nature of the reply sending functions with
     regards to whether they release the call struct.

 (2) Refcount the afs_call struct and sort out places that need to get/put
     references.

 (3) Pass a ref through the work queue and release (or pass on) that ref in
     the work function.  Care has to be taken because a work queue may
     already own a ref to the call.

 (4) Do the cleaning up in the put function only.

 (5) Simplify module cleanup by always incrementing afs_outstanding_calls
     whenever a call is allocated.

 (6) Set the backlog to 0 with kernel_listen() at the beginning of the
     process of closing the socket to prevent new incoming calls from
     occurring and to remove the contribution of preallocated calls from
     afs_outstanding_calls before we wait on it.

A tracepoint is also added to monitor the afs_call refcount and lifetime.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Fixes: 08e0e7c8: "[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC."

The afs_wait_mode struct isn't really necessary.  Client calls only use one
of a choice of two (synchronous or the asynchronous) and incoming calls
don't use the wait at all.  Replace with a boolean parameter.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add three tracepoints to the AFS filesystem:

 (1) The afs_recv_data tracepoint logs data segments that are extracted
     from the data received from the peer through afs_extract_data().

 (2) The afs_notify_call tracepoint logs notification from AF_RXRPC of data
     coming in to an asynchronous call.

 (3) The afs_cb_call tracepoint logs incoming calls that have had their
     operation ID extracted and mapped into a supported cache manager
     service call.

To make (3) work, the name strings in the afs_call_type struct objects have
to be annotated with __tracepoint_string.  This is done with the CM_NAME()
macro.

Further, the AFS call state enum needs a name so that it can be used to
declare parameter types.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Make afs_fs_fetch_data() take a list of pages for bulk data transfer.  This
will allow afs_readpages() to be made more efficient.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

call->operation_ID is sometimes being used as __be32 sometimes is being
used as u32.  Be consistent and settle on using as u32.

Signed-off-by: David Howells <dhowells@redhat.com.

Don't expose skbs to in-kernel users, such as the AFS filesystem, but
instead provide a notification hook the indicates that a call needs
attention and another that indicates that there's a new call to be
collected.

This makes the following possibilities more achievable:

 (1) Call refcounting can be made simpler if skbs don't hold refs to calls.

 (2) skbs referring to non-data events will be able to be freed much sooner
     rather than being queued for AFS to pick up as rxrpc_kernel_recv_data
     will be able to consult the call state.

 (3) We can shortcut the receive phase when a call is remotely aborted
     because we don't have to go through all the packets to get to the one
     cancelling the operation.

 (4) It makes it easier to do encryption/decryption directly between AFS's
     buffers and sk_buffs.

 (5) Encryption/decryption can more easily be done in the AFS's thread
     contexts - usually that of the userspace process that issued a syscall
     - rather than in one of rxrpc's background threads on a workqueue.

 (6) AFS will be able to wait synchronously on a call inside AF_RXRPC.

To make this work, the following interface function has been added:

     int rxrpc_kernel_recv_data(
		struct socket *sock, struct rxrpc_call *call,
		void *buffer, size_t bufsize, size_t *_offset,
		bool want_more, u32 *_abort_code);

This is the recvmsg equivalent.  It allows the caller to find out about the
state of a specific call and to transfer received data into a buffer
piecemeal.

afs_extract_data() and rxrpc_kernel_recv_data() now do all the extraction
logic between them.  They don't wait synchronously yet because the socket
lock needs to be dealt with.

Five interface functions have been removed:

	rxrpc_kernel_is_data_last()
    	rxrpc_kernel_get_abort_code()
    	rxrpc_kernel_get_error_number()
    	rxrpc_kernel_free_skb()
    	rxrpc_kernel_data_consumed()

As a temporary hack, sk_buffs going to an in-kernel call are queued on the
rxrpc_call struct (->knlrecv_queue) rather than being handed over to the
in-kernel user.  To process the queue internally, a temporary function,
temp_deliver_data() has been added.  This will be replaced with common code
between the rxrpc_recvmsg() path and the kernel_rxrpc_recv_data() path in a
future patch.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Provide a function so that kernel users, such as AFS, can ask for the peer
address of a call:

   void rxrpc_kernel_get_peer(struct rxrpc_call *call,
			      struct sockaddr_rxrpc *_srx);

In the future the kernel service won't get sk_buffs to look inside.
Further, this allows us to hide any canonicalisation inside AF_RXRPC for
when IPv6 support is added.

Also propagate this through to afs_find_server() and issue a warning if we
can't handle the address family yet.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Inside the kafs filesystem it is possible to occasionally have a call
processed and terminated before we've had a chance to check whether we need
to clean up the rx queue for that call because afs_send_simple_reply() ends
the call when it is done, but this is done in a workqueue item that might
happen to run to completion before afs_deliver_to_call() completes.

Further, it is possible for rxrpc_kernel_send_data() to be called to send a
reply before the last request-phase data skb is released.  The rxrpc skb
destructor is where the ACK processing is done and the call state is
advanced upon release of the last skb.  ACK generation is also deferred to
a work item because it's possible that the skb destructor is not called in
a context where kernel_sendmsg() can be invoked.

To this end, the following changes are made:

 (1) kernel_rxrpc_data_consumed() is added.  This should be called whenever
     an skb is emptied so as to crank the ACK and call states.  This does
     not release the skb, however.  kernel_rxrpc_free_skb() must now be
     called to achieve that.  These together replace
     rxrpc_kernel_data_delivered().

 (2) kernel_rxrpc_data_consumed() is wrapped by afs_data_consumed().

     This makes afs_deliver_to_call() easier to work as the skb can simply
     be discarded unconditionally here without trying to work out what the
     return value of the ->deliver() function means.

     The ->deliver() functions can, via afs_data_complete(),
     afs_transfer_reply() and afs_extract_data() mark that an skb has been
     consumed (thereby cranking the state) without the need to
     conditionally free the skb to make sure the state is correct on an
     incoming call for when the call processor tries to send the reply.

 (3) rxrpc_recvmsg() now has to call kernel_rxrpc_data_consumed() when it
     has finished with a packet and MSG_PEEK isn't set.

 (4) rxrpc_packet_destructor() no longer calls rxrpc_hard_ACK_data().

     Because of this, we no longer need to clear the destructor and put the
     call before we free the skb in cases where we don't want the ACK/call
     state to be cranked.

 (5) The ->deliver() call-type callbacks are made to return -EAGAIN rather
     than 0 if they expect more data (afs_extract_data() returns -EAGAIN to
     the delivery function already), and the caller is now responsible for
     producing an abort if that was the last packet.

 (6) There are many bits of unmarshalling code where:

 		ret = afs_extract_data(call, skb, last, ...);
		switch (ret) {
		case 0:		break;
		case -EAGAIN:	return 0;
		default:	return ret;
		}

     is to be found.  As -EAGAIN can now be passed back to the caller, we
     now just return if ret < 0:

 		ret = afs_extract_data(call, skb, last, ...);
		if (ret < 0)
			return ret;

 (7) Checks for trailing data and empty final data packets has been
     consolidated as afs_data_complete().  So:

		if (skb->len > 0)
			return -EBADMSG;
		if (!last)
			return 0;

     becomes:

		ret = afs_data_complete(call, skb, last);
		if (ret < 0)
			return ret;

 (8) afs_transfer_reply() now checks the amount of data it has against the
     amount of data desired and the amount of data in the skb and returns
     an error to induce an abort if we don't get exactly what we want.

Without these changes, the following oops can occasionally be observed,
particularly if some printks are inserted into the delivery path:

general protection fault: 0000 [#1] SMP
Modules linked in: kafs(E) af_rxrpc(E) [last unloaded: af_rxrpc]
CPU: 0 PID: 1305 Comm: kworker/u8:3 Tainted: G            E   4.7.0-fsdevel+ #1303
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Workqueue: kafsd afs_async_workfn [kafs]
task: ffff88040be041c0 ti: ffff88040c070000 task.ti: ffff88040c070000
RIP: 0010:[<ffffffff8108fd3c>]  [<ffffffff8108fd3c>] __lock_acquire+0xcf/0x15a1
RSP: 0018:ffff88040c073bc0  EFLAGS: 00010002
RAX: 6b6b6b6b6b6b6b6b RBX: 0000000000000000 RCX: ffff88040d29a710
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88040d29a710
RBP: ffff88040c073c70 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88040be041c0 R15: ffffffff814c928f
FS:  0000000000000000(0000) GS:ffff88041fa00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa4595f4750 CR3: 0000000001c14000 CR4: 00000000001406f0
Stack:
 0000000000000006 000000000be04930 0000000000000000 ffff880400000000
 ffff880400000000 ffffffff8108f847 ffff88040be041c0 ffffffff81050446
 ffff8803fc08a920 ffff8803fc08a958 ffff88040be041c0 ffff88040c073c38
Call Trace:
 [<ffffffff8108f847>] ? mark_held_locks+0x5e/0x74
 [<ffffffff81050446>] ? __local_bh_enable_ip+0x9b/0xa1
 [<ffffffff8108f9ca>] ? trace_hardirqs_on_caller+0x16d/0x189
 [<ffffffff810915f4>] lock_acquire+0x122/0x1b6
 [<ffffffff810915f4>] ? lock_acquire+0x122/0x1b6
 [<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
 [<ffffffff81609dbf>] _raw_spin_lock_irqsave+0x35/0x49
 [<ffffffff814c928f>] ? skb_dequeue+0x18/0x61
 [<ffffffff814c928f>] skb_dequeue+0x18/0x61
 [<ffffffffa009aa92>] afs_deliver_to_call+0x344/0x39d [kafs]
 [<ffffffffa009ab37>] afs_process_async_call+0x4c/0xd5 [kafs]
 [<ffffffffa0099e9c>] afs_async_workfn+0xe/0x10 [kafs]
 [<ffffffff81063a3a>] process_one_work+0x29d/0x57c
 [<ffffffff81064ac2>] worker_thread+0x24a/0x385
 [<ffffffff81064878>] ? rescuer_thread+0x2d0/0x2d0
 [<ffffffff810696f5>] kthread+0xf3/0xfb
 [<ffffffff8160a6ff>] ret_from_fork+0x1f/0x40
 [<ffffffff81069602>] ? kthread_create_on_node+0x1cf/0x1cf
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

call->async_workfn() can take an afs_call* arg rather than a work_struct* as
the functions assigned there are now called from afs_async_workfn() which has
to call container_of() anyway.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NNathaniel Wesley Filardo <nwf@cs.jhu.edu>
Reviewed-by: NTejun Heo <tj@kernel.org>

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

PREPARE_[DELAYED_]WORK() are being phased out.  They have few users
and a nasty surprise in terms of reentrancy guarantee as workqueue
considers work items to be different if they don't have the same work
function.

afs_call->async_work is multiplexed with multiple work functions.
Introduce afs_async_workfn() which invokes afs_call->async_workfn and
always use it as the work function and update the users to set the
->async_workfn field instead of overriding the work function using
PREPARE_WORK().

It would probably be best to route this with other related updates
through the workqueue tree.

Compile tested.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: David Howells <dhowells@redhat.com>
Cc: linux-afs@lists.infradead.org

kill pointless method instances and don't bother with ->owner - it's
ignored for procfs files anyway, make use of remove_proc_subtree() for
removal, get rid of cell->proc_dir.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

A read of a large file on an afs mount failed:

# cat junk.file > /dev/null
cat: junk.file: Bad message

Looking at the trace, call->offset wrapped since it is only an
unsigned short. In afs_extract_data:

        _enter("{%u},{%zu},%d,,%zu", call->offset, len, last, count);
...

        if (call->offset < count) {
                if (last) {
                        _leave(" = -EBADMSG [%d < %zu]", call->offset, count);
                        return -EBADMSG;
                }

Which matches the trace:

[cat   ] ==> afs_extract_data({65132},{524},1,,65536)
[cat   ] <== afs_extract_data() = -EBADMSG [0 < 65536]

call->offset went from 65132 to 0. Fix this by making call->offset an
unsigned int.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers.  Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2.  For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

not used by the instances anymore.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Make AFS use the new d_automount() dentry operation rather than abusing
follow_link() on directories.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

flush_scheduled_work() is going away.  afs needs to make sure all the
works it has queued have finished before being unloaded and there can
be arbitrary number of pending works.  Add afs_wq and use it as the
flush domain instead of the system workqueue.

Also, convert cancel_delayed_work() + flush_scheduled_work() to
cancel_delayed_work_sync() in afs_mntpt_kill_timer().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Cc: linux-afs@lists.infradead.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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

Signed-off-by: NNick Piggin <npiggin@kernel.dk>

Add a dummy printk function for the maintenance of unused printks through gcc
format checking, and also so that side-effect checking is maintained too.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement the ability for the root directory of a mounted AFS filesystem to
accept lookups of arbitrary directory names, to interpet the names as the names
of cells, to look the cell names up in the DNS for AFSDB records and to mount
the root.cell volume of the nominated cell on the pseudo-directory created by
lookup.

This facility is requested by passing:

	-o autocell

to the mountpoint for which this is desired, usually the /afs mount.

To use this facility, a DNS upcall program is required for AFSDB records.  This
can be obtained from:

	http://people.redhat.com/~dhowells/afs/dns.afsdb.c

It should be compiled with -lresolv and -lkeyutils and installed as, say:

	/usr/sbin/dns.afsdb

Then the following line needs to be added to /sbin/request-key.conf:

	create	dns_resolver afsdb:*	*	/usr/sbin/dns.afsdb %k

This can be tested by mounting AFS, say:

	insmod dns_resolver.ko
	insmod af-rxrpc.ko
	insmod kafs.ko rootcell=grand.central.org
	mount -t afs "#grand.central.org:root.cell." /afs -o autocell

and doing:

	ls /afs/grand.central.org/

which should show:

	archive/  cvs/  doc/  local/  project/  service/  software/  user/  www/

if it works.
Signed-off-by: NWang Lei <wang840925@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

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

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Don't put struct file on the stack as it takes up quite a lot of space
and violates lifetime rules for struct file.

Rather than calling afs_readpage() indirectly from the directory routines by
way of read_mapping_page(), split afs_readpage() to have afs_page_filler()
that's given a key instead of a file and call read_cache_page(), specifying the
new function directly.  Use it in afs_readpages() as well.

Also make use of this in afs_mntpt_check_symlink() too for the same reason.
Reported-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

This ensures that dirty data gets flushed properly.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Similar to the fsync issue fixed a while ago in commit
2daea67e we need to write for data to
actually hit the disk before writing out the metadata to guarantee
data integrity for filesystems that modify the inode in the data I/O
completion path.  Currently XFS and NFS handle this manually, and AFS
has a write_inode method that does nothing but waiting for data, while
others are possibly missing out on this.

Fortunately this change has a lot less impact than the fsync change
as none of the write_inode methods starts data writeout of any form
by itself.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

It's just a wrapper for <linux/fscache.h>, so remove it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The attached patch makes the kAFS filesystem in fs/afs/ use FS-Cache, and
through it any attached caches.  The kAFS filesystem will use caching
automatically if it's available.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NSteve Dickson <steved@redhat.com>
Acked-by: NTrond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Tested-by: NDaire Byrne <Daire.Byrne@framestore.com>