There are two places where rbd_get_segment() is called.  One, in
rbd_rq_fn(), only needs to know the length within a segment that an
I/O request should be.  The other, in rbd_do_op(), also needs the
name of the object and the offset within it for the I/O request.

Split out rbd_segment_name() into three dedicated functions:
    - rbd_segment_name() allocates and formats the name of the
      object for a segment containing a given rbd image offset
    - rbd_segment_offset() computes the offset within a segment for
      a given rbd image offset
    - rbd_segment_length() computes the length to use for I/O within
      a segment for a request, not to exceed the end of a segment
      object.

In the new functions be a bit more careful, checking for possible
error conditions:
    - watch for errors or overflows returned by snprintf()
    - catch (using BUG_ON()) potential overflow conditions
      when computing segment length
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

It is possible in rbd_get_num_segments() for an overflow to occur
when adding the offset and length.  This is easily avoided.

Since the function returns an int and the one caller is already
prepared to handle errors, have it return -ERANGE if overflow would
occur.

The overflow check would not work if a zero-length request was
being tested, so short-circuit that case, returning 0 for the
number of segments required.  (This condition might be avoided
elsewhere already, I don't know.)

Have the caller end the request if either an error or 0 is returned.
The returned value is passed to __blk_end_request_all(), meaning
a 0 length request is not treated an error.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

There's a test for null rq pointer inside the while loop in
rbd_rq_fn() that's not needed.  That same test already occurred
in the immediatly preceding loop condition test.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

In bio_chain_clone(), at the end of the function the bi_next field
of the tail of the new bio chain is nulled.  This isn't necessary,
because if "tail" is non-null, its value will be the last bio
structure allocated at the top of the while loop in that function.
And before that structure is added to the end of the new chain, its
bi_next pointer is always made null.

While touching that function, clean a few other things:
    - define each local variable on its own line
    - move the definition of "tmp" to an inner scope
    - move the modification of gfpmask closer to where it's used
    - rearrange the logic that sets the chain's tail pointer
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

The "notify_timeout" rbd device option is never used, so get rid of
it.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

Add the ability to map an rbd image read-only, by specifying either
"read_only" or "ro" as an option on the rbd "command line."  Also
allow the inverse to be explicitly specified using "read_write" or
"rw".
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

The rbd options don't really apply to the ceph client.  So don't
store a pointer to it in the ceph_client structure, and put them
(a struct, not a pointer) into the rbd_dev structure proper.

Pass the rbd device structure to rbd_client_create() so it can
assign rbd_dev->rbdc if successful, and have it return an error code
instead of the rbd client pointer.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

This just rearranges things a bit more in rbd_header_from_disk()
so that the snapshot sizes are initialized right after the buffer
to hold them is allocated and doing a little further consolidation
that follows from that.  Also adds a few simple comments.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

The only thing the on-disk snap_names_len field is needed is to
size the buffer allocated to hold a copy of the snapshot names
for an rbd image.

So don't bother saving it in the in-core rbd_image_header structure.
Just use a local variable to hold the required buffer size while
it's needed.

Move the code that actually copies the snapshot names up closer
to where the required length is saved.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

In rbd_header_from_disk() the object prefix buffer is sized based on
the maximum size it's block_name equivalent on disk could be.

Instead, only allocate enough to hold null-terminated string from
the on-disk header--or the maximum size of no NUL is found.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

There is only caller of __rbd_client_find(), and it somewhat
clumsily gets the appropriate lock and gets a reference to the
existing ceph_client structure if it's found.

Instead, have that function handle its own locking, and acquire the
reference if found while it holds the lock.  Drop the underscores
from the name because there's no need to signify anything special
about this function.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

Using list_move_tail() instead of list_del() + list_add_tail().
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Sage Weil <sage@inktank.com>

This fixes a bug that went in with this commit:

    commit f6e0c99092cca7be00fca4080cfc7081739ca544
    Author: Alex Elder <elder@inktank.com>
    Date:   Thu Aug 2 11:29:46 2012 -0500
    rbd: simplify __rbd_init_snaps_header()

The problem is that a new rbd snapshot needs to go either after an
existing snapshot entry, or at the *end* of an rbd device's snapshot
list.  As originally coded, it is placed at the beginning.  This was
based on the assumption the list would be empty (so it wouldn't
matter), but in fact if multiple new snapshots are added to an empty
list in one shot the list will be non-empty after the first one is
added.

This addresses http://tracker.newdream.net/issues/3063Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

In the on-disk image header structure there is a field "block_name"
which represents what we now call the "object prefix" for an rbd
image.  Rename this field "object_prefix" to be consistent with
modern usage.

This appears to be the only remaining vestige of the use of "block"
in symbols that represent objects in the rbd code.

This addresses http://tracker.newdream.net/issues/1761Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>

Make ceph_monc_do_poolop() static to remove the following sparse warning:
 * net/ceph/mon_client.c:616:5: warning: symbol 'ceph_monc_do_poolop' was not
   declared. Should it be static?
Also drops the 'ceph_monc_' prefix, now being a private function.
Signed-off-by: Iulius Curt <icurt@ixiacom.com>
Signed-off-by: Sage Weil <sage@inktank.com>

This is unused; use monc->client->have_fsid.
Signed-off-by: Sage Weil <sage@inktank.com>

A recent change to /sbin/mountall causes any trailing '/' character
in the "device" (or fs_spec) field in /etc/fstab to be stripped.  As
a result, an entry for a ceph mount that intends to mount the root
of the name space ends up with now path portion, and the ceph mount
option processing code rejects this.

That is, an entry in /etc/fstab like:
    cephserver:port:/ /mnt ceph defaults 0 0
provides to the ceph code just "cephserver:port:" as the "device,"
and that gets rejected.

Although this is a bug in /sbin/mountall, we can have the ceph mount
code support an empty/nonexistent path, interpreting it to mean the
root of the name space.

RFC 5952 offers recommendations for how to express IPv6 addresses,
and recommends the usage found in RFC 3986 (which specifies the
format for URI's) for representing both IPv4 and IPv6 addresses that
include port numbers.  (See in particular the definition of
"authority" found in the Appendix of RFC 3986.)

According to those standards, no host specification will ever
contain a '/' character.  As a result, it is sufficient to scan a
provided "device" from an /etc/fstab entry for the first '/'
character, and if it's found, treat that as the beginning of the
path.  If no '/' character is present, we can treat the entire
string as the monitor host specification(s), and assume the path
to be the root of the name space.  We'll still require a ':' to
separate the host portion from the (possibly empty) path portion.

This means that we can more formally define how ceph will interpret
the "device" it's provided when processing a mount request:

    "device" will look like:
        <server_spec>[,<server_spec>...]:[<path>]
    where
        <server_spec> is <ip>[:<port>]
        <path> is optional, but if present must begin with '/'

This addresses http://tracker.newdream.net/issues/2919Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Dan Mick <dan.mick@inktank.com>

Right now rbd_read_header() both reads the header object for an rbd
image and decodes its contents.  It does this repeatedly if needed,
in order to ensure a complete and intact header is obtained.

Separate this process into two steps--reading of the raw header
data (in new function, rbd_dev_v1_header_read()) and separately
decoding its contents (in rbd_header_from_disk()).  As a result,
the latter function no longer requires its allocated_snaps argument.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Add checks on the validity of the snap_count and snap_names_len
field values in rbd_dev_ondisk_valid().  This eliminates the
need to do them in rbd_header_from_disk().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The only caller of rbd_header_from_disk() is rbd_read_header().
It passes as allocated_snaps the number of snapshots it will
have received from the server for the snapshot context that
rbd_header_from_disk() is to interpret.  The first time through
it provides 0--mainly to extract the number of snapshots from
the snapshot context header--so that it can allocate an
appropriately-sized buffer to receive the entire snapshot
context from the server in a second request.

rbd_header_from_disk() will not fill in the array of snapshot ids
unless the number in the snapshot matches the number the caller
had allocated.

This patch adjusts that logic a little further to be more efficient.
rbd_read_header() doesn't even examine the snapshot context unless
the snapshot count (stored in header->total_snaps) matches the
number of snapshots allocated.  So rbd_header_from_disk() doesn't
need to allocate or fill in the snapshot context field at all in
that case.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

This just moves code around for the most part.  It was pulled out as
a separate patch to avoid cluttering up some upcoming patches which
are more substantive.  The point is basically to group everything
related to initializing the snapshot context together.

The only functional change is that rbd_header_from_disk() now
ensures the (in-core) header it is passed is zero-filled.  This
allows a simpler error handling path in rbd_header_from_disk().
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Fix a few spots in rbd_header_from_disk() to use sizeof (object)
rather than sizeof (type).  Use a local variable to record sizes
to shorten some lines and improve readability.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

Fix a number of spots where a pointer value that is known to
have become invalid but was not reset to null.

Also, toss in a change so we use sizeof (object) rather than
sizeof (type).
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The snap_names_len field of an rbd_image_header structure is defined
with type size_t.  That field is used as both the source and target
of 64-bit byte-order swapping operations though, so it's best to
define it with type u64 instead.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

The purpose of __rbd_init_snaps_header() is to compare a new
snapshot context with an rbd device's list of existing snapshots.
It updates the list by adding any new snapshots or removing any
that are not present in the new snapshot context.

The code as written is a little confusing, because it traverses both
the existing snapshot list and the set of snapshots in the snapshot
context in reverse.  This was done based on an assumption about
snapshots that is not true--namely that a duplicate snapshot name
could cause an error in intepreting things if they were not
processed in ascending order.

These precautions are not necessary, because:
    - all snapshots are uniquely identified by their snapshot id
    - a new snapshot cannot be created if the rbd device has another
      snapshot with the same name
(It is furthermore not currently possible to rename a snapshot.)

This patch re-implements __rbd_init_snaps_header() so it passes
through both the existing snapshot list and the entries in the
snapshot context in forward order.  It still does the same thing
as before, but I find the logic considerably easier to understand.

By going forward through the names in the snapshot context, there
is no longer a need for the rbd_prev_snap_name() helper function.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

IBM reported a deadlock in select_parent().  This was found to be caused
by taking rename_lock when already locked when restarting the tree
traversal.

There are two cases when the traversal needs to be restarted:

 1) concurrent d_move(); this can only happen when not already locked,
    since taking rename_lock protects against concurrent d_move().

 2) racing with final d_put() on child just at the moment of ascending
    to parent; rename_lock doesn't protect against this rare race, so it
    can happen when already locked.

Because of case 2, we need to be able to handle restarting the traversal
when rename_lock is already held.  This patch fixes all three callers of
try_to_ascend().

IBM reported that the deadlock is gone with this patch.

[ I rewrote the patch to be smaller and just do the "goto again" if the
  lock was already held, but credit goes to Miklos for the real work.
   - Linus ]
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull IOMMU fixes from Joerg Roedel:
 "Two small patches:

	* One patch to fix the function declarations for
	  !CONFIG_IOMMU_API. This is causing build errors
	  in linux-next and should be fixed for v3.6.

	* Another patch to fix an IOMMU group related NULL pointer
	  dereference."

* tag 'iommu-fixes-v3.6-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/amd: Fix wrong assumption in iommu-group specific code
  iommu: static inline iommu group stub functions

Pull NVMe driver fixes from Matthew Wilcox:
 "Now that actual hardware has been released (don't have any yet
  myself), people are starting to want some of these fixes merged."

Willy doesn't have hardware? Guys...

* git://git.infradead.org/users/willy/linux-nvme:
  NVMe: Cancel outstanding IOs on queue deletion
  NVMe: Free admin queue memory on initialisation failure
  NVMe: Use ida for nvme device instance
  NVMe: Fix whitespace damage in nvme_init
  NVMe: handle allocation failure in nvme_map_user_pages()
  NVMe: Fix uninitialized iod compiler warning
  NVMe: Do not set IO queue depth beyond device max
  NVMe: Set block queue max sectors
  NVMe: use namespace id for nvme_get_features
  NVMe: replace nvme_ns with nvme_dev for user admin
  NVMe: Fix nvme module init when nvme_major is set
  NVMe: Set request queue logical block size

Sasha Levin has been running trinity in a KVM tools guest, and was able
to trigger the BUG_ON() at arch/x86/mm/pat.c:279 (verifying the range of
the memory type).  The call trace showed that it was mtdchar_mmap() that
created an invalid remap_pfn_range().

The problem is that mtdchar_mmap() does various really odd and subtle
things with the vma page offset etc, and uses the wrong types (and the
wrong overflow) detection for it.

For example, the page offset may well be 32-bit on a 32-bit
architecture, but after shifting it up by PAGE_SHIFT, we need to use a
potentially 64-bit resource_size_t to correctly hold the full value.

Also, we need to check that the vma length plus offset doesn't overflow
before we check that it is smaller than the length of the mtdmap region.

This fixes things up and tries to make the code a bit easier to read.
Reported-and-tested-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Artem Bityutskiy <dedekind1@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull networking fixes from David S Miller:

 1) Netfilter xt_limit module can use uninitialized rules, from Jan
    Engelhardt.

 2) Wei Yongjun has found several more spots where error pointers were
    treated as NULL/non-NULL and vice versa.

 3) bnx2x was converted to pci_io{,un}map() but one remaining plain
    iounmap() got missed.  From Neil Horman.

 4) Due to a fence-post type error in initialization of inetpeer entries
    (which is where we store the ICMP rate limiting information), we can
    erroneously drop ICMPs if the inetpeer was created right around when
    jiffies wraps.

    Fix from Nicolas Dichtel.

 5) smsc75xx resume fix from Steve Glendinnig.

 6) LAN87xx smsc chips need an explicit hardware init, from Marek Vasut.

 7) qlcnic uses msleep() with locks held, fix from Narendra K.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  netdev: octeon: fix return value check in octeon_mgmt_init_phy()
  inetpeer: fix token initialization
  qlcnic: Fix scheduling while atomic bug
  bnx2: Clean up remaining iounmap
  net: phy: smsc: Implement PHY config_init for LAN87xx
  smsc75xx: fix resume after device reset
  netdev: pasemi: fix return value check in pasemi_mac_phy_init()
  team: fix return value check
  l2tp: fix return value check
  netfilter: xt_limit: have r->cost != 0 case work

Pull vfs fixes from Al Viro:
 "A couple of fixes; one for automount/lazy umount race, another a
  classic "we don't protect the refcount transition to zero with the
  lock that protects looking for object in hash" kind of crap in lockd."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  close the race in nlmsvc_free_block()
  do_add_mount()/umount -l races

Pull UML fixes from Richard Weinberger.

* 'for-linus-3.6-rc-final' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Preinclude include/linux/kern_levels.h
  um: Fix IPC on um
  um: kill thread->forking
  um: let signal_delivered() do SIGTRAP on singlestepping into handler
  um: don't leak floating point state and segment registers on execve()
  um: take cleaning singlestep to start_thread()

Pull dm fixes from Alasdair G Kergon:
 "A few fixes for problems discovered during the 3.6 cycle.

  Of particular note, are fixes to the thin target's discard support,
  which I hope is finally working correctly; and fixes for multipath
  ioctls and device limits when there are no paths."

* tag 'dm-3.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm:
  dm verity: fix overflow check
  dm thin: fix discard support for data devices
  dm thin: tidy discard support
  dm: retain table limits when swapping to new table with no devices
  dm table: clear add_random unless all devices have it set
  dm: handle requests beyond end of device instead of using BUG_ON
  dm mpath: only retry ioctl when no paths if queue_if_no_path set
  dm thin: do not set discard_zeroes_data

Speculative cache pagecache lookups can elevate the refcount from
under us, so avoid the false positive. If the refcount is < 2 we'll be
notified by a VM_BUG_ON in put_page_testzero as there are two
put_page(src_page) in a row before returning from this function.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The new IOMMU groups code in the AMD IOMMU driver makes the
assumption that there is a pci_dev struct available for all
device-ids listed in the IVRS ACPI table. Unfortunatly this
assumption is not true and so this code causes a NULL
pointer dereference at boot on some systems.

Fix it by making sure the given pointer is never NULL when
passed to the group specific code. The real fix is larger
and will be queued for v3.7.
Reported-by: Florian Dazinger <florian@dazinger.net>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

In case of error, the function of_phy_connect() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value
check should be replaced with NULL test.

dpatch engine is used to auto generate this patch.
(https://github.com/weiyj/dpatch)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull drm fixes from Dave Airlie:
 "The three nouveau fixes quiten unneeded dmesg spam that people are
   seeing and pondering,

  The udl fix stops it from trying to driver monitors that are too big,
  where we get a black screen.

  And a vmware memory alloc problem."

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/nvc0/fifo: ignore bits in PFIFO_INTR that aren't set in PFIFO_INTR_EN
  drm/udl: limit modes to the sku pixel limits.
  vmwgfx: corruption in vmw_event_fence_action_create()
  drm/nvc0/ltcg: mask off intr 0x10
  drm/nouveau: silence a debug message triggered by newer userspace

Pull USB fixes from Greg Kroah-Hartman:
 "Here are two USB bugfixes for your 3.6-rc7 tree.

  The OHCI fix has been reported a number of times and is a regression
  from 3.5, and the patch that causes the regression was on the way to
  the -stable trees before I was reminded (again) that this fix needed
  to get to your tree soon.

  The host controller bugfix was reported in older kernels as being
  pretty easy to trigger, and has been tested by Red Hat and their
  customers.

  Both have been in the usb-next branch in the -next tree for a while
  now, I just cherry-picked them out to get to you in time for the 3.6
  release.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'usb-3.6-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: Fix race condition when removing host controllers
  USB: ohci-at91: fix null pointer in ohci_hcd_at91_overcurrent_irq

Also fix the calls to next_packet_size() for the pause case. This was
missed in 245baf98 ("ALSA: snd-usb: fix calls to next_packet_size").
Signed-off-by: Daniel Mack <zonque@gmail.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reported-and-tested-by: Christian Tefzer <ctrefzer@gmx.de>
Cc: stable@kernel.org
[ Taking directly because Takashi is on vacation  - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>