This is the third commit of the implementation of the CFM protocol
according to 802.1Q section 12.14.

Functionality is extended with CCM frame reception.
The MEP instance now contains CCM based status information.
Most important is the CCM defect status indicating if correct
CCM frames are received with the expected interval.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the second commit of the implementation of the CFM protocol
according to 802.1Q section 12.14.

Functionality is extended with CCM frame transmission.

Interface is extended with these functions:
br_cfm_cc_rdi_set()
br_cfm_cc_ccm_tx()
br_cfm_cc_config_set()

A MEP Continuity Check feature can be configured by
br_cfm_cc_config_set()
    The Continuity Check parameters can be configured to be used when
    transmitting CCM.

A MEP can be configured to start or stop transmission of CCM frames by
br_cfm_cc_ccm_tx()
    The CCM will be transmitted for a selected period in seconds.
    Must call this function before timeout to keep transmission alive.

A MEP transmitting CCM can be configured with inserted RDI in PDU by
br_cfm_cc_rdi_set()
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This is the first commit of the implementation of the CFM protocol
according to 802.1Q section 12.14.

It contains MEP instance create, delete and configuration.

Connectivity Fault Management (CFM) comprises capabilities for
detecting, verifying, and isolating connectivity failures in
Virtual Bridged Networks. These capabilities can be used in
networks operated by multiple independent organizations, each
with restricted management access to each others equipment.

CFM functions are partitioned as follows:
    - Path discovery
    - Fault detection
    - Fault verification and isolation
    - Fault notification
    - Fault recovery

Interface consists of these functions:
br_cfm_mep_create()
br_cfm_mep_delete()
br_cfm_mep_config_set()
br_cfm_cc_config_set()
br_cfm_cc_peer_mep_add()
br_cfm_cc_peer_mep_remove()

A MEP instance is created by br_cfm_mep_create()
    -It is the Maintenance association End Point
     described in 802.1Q section 19.2.
    -It is created on a specific level (1-7) and is assuring
     that no CFM frames are passing through this MEP on lower levels.
    -It initiates and validates CFM frames on its level.
    -It can only exist on a port that is related to a bridge.
    -Attributes given cannot be changed until the instance is
     deleted.

A MEP instance can be deleted by br_cfm_mep_delete().

A created MEP instance has attributes that can be
configured by br_cfm_mep_config_set().

A MEP Continuity Check feature can be configured by
br_cfm_cc_config_set()
    The Continuity Check Receiver state machine can be
    enabled and disabled.
    According to 802.1Q section 19.2.8

A MEP can have Peer MEPs added and removed by
br_cfm_cc_peer_mep_add() and br_cfm_cc_peer_mep_remove()
    The Continuity Check feature can maintain connectivity
    status on each added Peer MEP.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This EtherType is used by all CFM protocal frames transmitted
according to 802.1Q section 12.14.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This makes it possible to include or exclude the CFM
protocol according to 802.1Q section 12.14.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This patch extends the processing of frames in the bridge. Currently MRP
frames needs special processing and the current implementation doesn't
allow a nice way to process different frame types. Therefore try to
improve this by adding a list that contains frame types that need
special processing. This list is iterated for each input frame and if
there is a match based on frame type then these functions will be called
and decide what to do with the frame. It can process the frame then the
bridge doesn't need to do anything or don't process so then the bridge
will do normal forwarding.
Signed-off-by: Henrik Bjoernlund  <henrik.bjoernlund@microchip.com>
Reviewed-by: Horatiu Vultur  <horatiu.vultur@microchip.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Colin Ian King says:

====================
vsock: minor clean up of ioctl error handling

Two minor changes to the ioctl error handling.
====================

Link: https://lore.kernel.org/r/20201027090942.14916-1-colin.king@canonical.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Currently when an invalid ioctl command is used the error return
is -EINVAL.  Fix this by returning the correct error -ENOIOCTLCMD.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

When exercising the kernel with stress-ng with some ioctl tests the
"Unknown ioctl" error message is spamming the kernel log at a high
rate. Remove this message.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Merge tag 'fallthrough-fixes-clang-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull fallthrough fix from Gustavo A. R. Silva:
 "This fixes a ton of fall-through warnings when building with Clang
  12.0.0 and -Wimplicit-fallthrough"

* tag 'fallthrough-fixes-clang-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  include: jhash/signal: Fix fall-through warnings for Clang

Pull networking fixes from Jakub Kicinski:
 "Current release regressions:

   - r8169: fix forced threading conflicting with other shared
     interrupts; we tried to fix the use of raise_softirq_irqoff from an
     IRQ handler on RT by forcing hard irqs, but this driver shares
     legacy PCI IRQs so drop the _irqoff() instead

   - tipc: fix memory leak caused by a recent syzbot report fix to
     tipc_buf_append()

  Current release - bugs in new features:

   - devlink: Unlock on error in dumpit() and fix some error codes

   - net/smc: fix null pointer dereference in smc_listen_decline()

  Previous release - regressions:

   - tcp: Prevent low rmem stalls with SO_RCVLOWAT.

   - net: protect tcf_block_unbind with block lock

   - ibmveth: Fix use of ibmveth in a bridge; the self-imposed filtering
     to only send legal frames to the hypervisor was too strict

   - net: hns3: Clear the CMDQ registers before unmapping BAR region;
     incorrect cleanup order was leading to a crash

   - bnxt_en - handful of fixes to fixes:
      - Send HWRM_FUNC_RESET fw command unconditionally, even if there
        are PCIe errors being reported
      - Check abort error state in bnxt_open_nic().
      - Invoke cancel_delayed_work_sync() for PFs also.
      - Fix regression in workqueue cleanup logic in bnxt_remove_one().

   - mlxsw: Only advertise link modes supported by both driver and
     device, after removal of 56G support from the driver 56G was not
     cleared from advertised modes

   - net/smc: fix suppressed return code

  Previous release - always broken:

   - netem: fix zero division in tabledist, caused by integer overflow

   - bnxt_en: Re-write PCI BARs after PCI fatal error.

   - cxgb4: set up filter action after rewrites

   - net: ipa: command payloads already mapped

  Misc:

   - s390/ism: fix incorrect system EID, it's okay to change since it
     was added in current release

   - vsock: use ns_capable_noaudit() on socket create to suppress false
     positive audit messages"

* tag 'net-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (36 commits)
  r8169: fix issue with forced threading in combination with shared interrupts
  netem: fix zero division in tabledist
  ibmvnic: fix ibmvnic_set_mac
  mptcp: add missing memory scheduling in the rx path
  tipc: fix memory leak caused by tipc_buf_append()
  gtp: fix an use-before-init in gtp_newlink()
  net: protect tcf_block_unbind with block lock
  ibmveth: Fix use of ibmveth in a bridge.
  net/sched: act_mpls: Add softdep on mpls_gso.ko
  ravb: Fix bit fields checking in ravb_hwtstamp_get()
  devlink: Unlock on error in dumpit()
  devlink: Fix some error codes
  chelsio/chtls: fix memory leaks in CPL handlers
  chelsio/chtls: fix deadlock issue
  net: hns3: Clear the CMDQ registers before unmapping BAR region
  bnxt_en: Send HWRM_FUNC_RESET fw command unconditionally.
  bnxt_en: Check abort error state in bnxt_open_nic().
  bnxt_en: Re-write PCI BARs after PCI fatal error.
  bnxt_en: Invoke cancel_delayed_work_sync() for PFs also.
  bnxt_en: Fix regression in workqueue cleanup logic in bnxt_remove_one().
  ...

Pull rdma fixes from Jason Gunthorpe:
 "The good news is people are testing rc1 in the RDMA world - the bad
  news is testing of the for-next area is not as good as I had hoped, as
  we really should have caught at least the rdma_connect_locked() issue
  before now.

  Notable merge window regressions that didn't get caught/fixed in time
  for rc1:

   - Fix in kernel users of rxe, they were broken by the rapid fix to
     undo the uABI breakage in rxe from another patch

   - EFA userspace needs to read the GID table but was broken with the
     new GID table logic

   - Fix user triggerable deadlock in mlx5 using devlink reload

   - Fix deadlock in several ULPs using rdma_connect from the CM handler
     callbacks

   - Memory leak in qedr"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/qedr: Fix memory leak in iWARP CM
  RDMA: Add rdma_connect_locked()
  RDMA/uverbs: Fix false error in query gid IOCTL
  RDMA/mlx5: Fix devlink deadlock on net namespace deletion
  RDMA/rxe: Fix small problem in network_type patch

As reported by Serge flag IRQF_NO_THREAD causes an error if the
interrupt is actually shared and the other driver(s) don't have this
flag set. This situation can occur if a PCI(e) legacy interrupt is
used in combination with forced threading.
There's no good way to deal with this properly, therefore we have to
remove flag IRQF_NO_THREAD. For fixing the original forced threading
issue switch to napi_schedule().

Fixes: 424a646e ("r8169: fix operation under forced interrupt threading")
Link: https://www.spinics.net/lists/netdev/msg694960.htmlReported-by: Serge Belyshev <belyshev@depni.sinp.msu.ru>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Serge Belyshev <belyshev@depni.sinp.msu.ru>
Link: https://lore.kernel.org/r/b5b53bfe-35ac-3768-85bf-74d1290cf394@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Currently it is possible to craft a special netlink RTM_NEWQDISC
command that can result in jitter being equal to 0x80000000. It is
enough to set the 32 bit jitter to 0x02000000 (it will later be
multiplied by 2^6) or just set the 64 bit jitter via
TCA_NETEM_JITTER64. This causes an overflow during the generation of
uniformly distributed numbers in tabledist(), which in turn leads to
division by zero (sigma != 0, but sigma * 2 is 0).

The related fragment of code needs 32-bit division - see commit
9b0ed89 ("netem: remove unnecessary 64 bit modulus"), so switching to
64 bit is not an option.

Fix the issue by keeping the value of jitter within the range that can
be adequately handled by tabledist() - [0;INT_MAX]. As negative std
deviation makes no sense, take the absolute value of the passed value
and cap it at INT_MAX. Inside tabledist(), switch to unsigned 32 bit
arithmetic in order to prevent overflows.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
Reported-by: syzbot+ec762a6342ad0d3c0d8f@syzkaller.appspotmail.com
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Link: https://lore.kernel.org/r/20201028170731.1383332-1-aleksandrnogikh@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Jakub Kicinski brought up a concern in ibmvnic_set_mac().
ibmvnic_set_mac() does this:

	ether_addr_copy(adapter->mac_addr, addr->sa_data);
	if (adapter->state != VNIC_PROBED)
		rc = __ibmvnic_set_mac(netdev, addr->sa_data);

So if state == VNIC_PROBED, the user can assign an invalid address to
adapter->mac_addr, and ibmvnic_set_mac() will still return 0.

The fix is to validate ethernet address at the beginning of
ibmvnic_set_mac(), and move the ether_addr_copy to
the case of "adapter->state != VNIC_PROBED".

Fixes: c26eba03 ("ibmvnic: Update reset infrastructure to support tunable parameters")
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
Link: https://lore.kernel.org/r/20201027220456.71450-1-ljp@linux.ibm.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

When moving the skbs from the subflow into the msk receive
queue, we must schedule there the required amount of memory.

Try to borrow the required memory from the subflow, if needed,
so that we leverage the existing TCP heuristic.

Fixes: 6771bfd9 ("mptcp: update mptcp ack sequence from work queue")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/f6143a6193a083574f11b00dbf7b5ad151bc4ff4.1603810630.git.pabeni@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

In preparation to enable -Wimplicit-fallthrough for Clang, explicitly
add break statements instead of letting the code fall through to the
next case.

This patch adds four break statements that, together, fix almost 40,000
warnings when building Linux 5.10-rc1 with Clang 12.0.0 and this[1] change
reverted. Notice that in order to enable -Wimplicit-fallthrough for Clang,
such change[1] is meant to be reverted at some point. So, this patch helps
to move in that direction.

Something important to mention is that there is currently a discrepancy
between GCC and Clang when dealing with switch fall-through to empty case
statements or to cases that only contain a break/continue/return
statement[2][3][4].

Now that the -Wimplicit-fallthrough option has been globally enabled[5],
any compiler should really warn on missing either a fallthrough annotation
or any of the other case-terminating statements (break/continue/return/
goto) when falling through to the next case statement. Making exceptions
to this introduces variation in case handling which may continue to lead
to bugs, misunderstandings, and a general lack of robustness. The point
of enabling options like -Wimplicit-fallthrough is to prevent human error
and aid developers in spotting bugs before their code is even built/
submitted/committed, therefore eliminating classes of bugs. So, in order
to really accomplish this, we should, and can, move in the direction of
addressing any error-prone scenarios and get rid of the unintentional
fallthrough bug-class in the kernel, entirely, even if there is some minor
redundancy. Better to have explicit case-ending statements than continue to
have exceptions where one must guess as to the right result. The compiler
will eliminate any actual redundancy.

[1] commit e2079e93 ("kbuild: Do not enable -Wimplicit-fallthrough for clang for now")
[2] https://github.com/ClangBuiltLinux/linux/issues/636
[3] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91432
[4] https://godbolt.org/z/xgkvIh
[5] commit a035d552 ("Makefile: Globally enable fall-through warning")
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Pull AFS fixes from David Howells:

 - Fix copy_file_range() to an afs file now returning EINVAL if the
   splice_write file op isn't supplied.

 - Fix a deref-before-check in afs_unuse_cell().

 - Fix a use-after-free in afs_xattr_get_acl().

 - Fix afs to not try to clear PG_writeback when laundering a page.

 - Fix afs to take a ref on a page that it sets PG_private on and to
   drop that ref when clearing PG_private. This is done through recently
   added helpers.

 - Fix a page leak if write_begin() fails.

 - Fix afs_write_begin() to not alter the dirty region info stored in
   page->private, but rather do this in afs_write_end() instead when we
   know what we actually changed.

 - Fix afs_invalidatepage() to alter the dirty region info on a page
   when partial page invalidation occurs so that we don't inadvertantly
   include a span of zeros that will get written back if a page gets
   laundered due to a remote 3rd-party induced invalidation.

   We mustn't, however, reduce the dirty region if the page has been
   seen to be mapped (ie. we got called through the page_mkwrite vector)
   as the page might still be mapped and we might lose data if the file
   is extended again.

 - Fix the dirty region info to have a lower resolution if the size of
   the page is too large for this to be encoded (e.g. powerpc32 with 64K
   pages).

   Note that this might not be the ideal way to handle this, since it
   may allow some leakage of undirtied zero bytes to the server's copy
   in the case of a 3rd-party conflict.

To aid the last two fixes, two additional changes:

 - Wrap the manipulations of the dirty region info stored in
   page->private into helper functions.

 - Alter the encoding of the dirty region so that the region bounds can
   be stored with one fewer bit, making a bit available for the
   indication of mappedness.

* tag 'afs-fixes-20201029' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix dirty-region encoding on ppc32 with 64K pages
  afs: Fix afs_invalidatepage to adjust the dirty region
  afs: Alter dirty range encoding in page->private
  afs: Wrap page->private manipulations in inline functions
  afs: Fix where page->private is set during write
  afs: Fix page leak on afs_write_begin() failure
  afs: Fix to take ref on page when PG_private is set
  afs: Fix afs_launder_page to not clear PG_writeback
  afs: Fix a use after free in afs_xattr_get_acl()
  afs: Fix tracing deref-before-check
  afs: Fix copy_file_range()

Commit ed42989e ("tipc: fix the skb_unshare() in tipc_buf_append()")
replaced skb_unshare() with skb_copy() to not reduce the data reference
counter of the original skb intentionally. This is not the correct
way to handle the cloned skb because it causes memory leak in 2
following cases:
 1/ Sending multicast messages via broadcast link
  The original skb list is cloned to the local skb list for local
  destination. After that, the data reference counter of each skb
  in the original list has the value of 2. This causes each skb not
  to be freed after receiving ACK:
  tipc_link_advance_transmq()
  {
   ...
   /* release skb */
   __skb_unlink(skb, &l->transmq);
   kfree_skb(skb); <-- memory exists after being freed
  }

 2/ Sending multicast messages via replicast link
  Similar to the above case, each skb cannot be freed after purging
  the skb list:
  tipc_mcast_xmit()
  {
   ...
   __skb_queue_purge(pkts); <-- memory exists after being freed
  }

This commit fixes this issue by using skb_unshare() instead. Besides,
to avoid use-after-free error reported by KASAN, the pointer to the
fragment is set to NULL before calling skb_unshare() to make sure that
the original skb is not freed after freeing the fragment 2 times in
case skb_unshare() returns NULL.

Fixes: ed42989e ("tipc: fix the skb_unshare() in tipc_buf_append()")
Acked-by: Jon Maloy <jmaloy@redhat.com>
Reported-by: Thang Hoang Ngo <thang.h.ngo@dektech.com.au>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://lore.kernel.org/r/20201027032403.1823-1-tung.q.nguyen@dektech.com.auSigned-off-by: Jakub Kicinski <kuba@kernel.org>

*_pdp_find() from gtp_encap_recv() would trigger a crash when a peer
sends GTP packets while creating new GTP device.

RIP: 0010:gtp1_pdp_find.isra.0+0x68/0x90 [gtp]
<SNIP>
Call Trace:
 <IRQ>
 gtp_encap_recv+0xc2/0x2e0 [gtp]
 ? gtp1_pdp_find.isra.0+0x90/0x90 [gtp]
 udp_queue_rcv_one_skb+0x1fe/0x530
 udp_queue_rcv_skb+0x40/0x1b0
 udp_unicast_rcv_skb.isra.0+0x78/0x90
 __udp4_lib_rcv+0x5af/0xc70
 udp_rcv+0x1a/0x20
 ip_protocol_deliver_rcu+0xc5/0x1b0
 ip_local_deliver_finish+0x48/0x50
 ip_local_deliver+0xe5/0xf0
 ? ip_protocol_deliver_rcu+0x1b0/0x1b0

gtp_encap_enable() should be called after gtp_hastable_new() otherwise
*_pdp_find() will access the uninitialized hash table.

Fixes: 1e3a3abd ("gtp: make GTP sockets in gtp_newlink optional")
Signed-off-by: Masahiro Fujiwara <fujiwara.masahiro@gmail.com>
Link: https://lore.kernel.org/r/20201027114846.3924-1-fujiwara.masahiro@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Pull ext4 fixes from Ted Ts'o:
 "Bug fixes for the new ext4 fast commit feature, plus a fix for the
  'data=journal' bug fix.

  Also use the generic casefolding support which has now landed in
  fs/libfs.c for 5.10"

* tag 'ext4_for_linus_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: indicate that fast_commit is available via /sys/fs/ext4/feature/...
  ext4: use generic casefolding support
  ext4: do not use extent after put_bh
  ext4: use IS_ERR() for error checking of path
  ext4: fix mmap write protection for data=journal mode
  jbd2: fix a kernel-doc markup
  ext4: use s_mount_flags instead of s_mount_state for fast commit state
  ext4: make num of fast commit blocks configurable
  ext4: properly check for dirty state in ext4_inode_datasync_dirty()
  ext4: fix double locking in ext4_fc_commit_dentry_updates()

The dirty region bounds stored in page->private on an afs page are 15 bits
on a 32-bit box and can, at most, represent a range of up to 32K within a
32K page with a resolution of 1 byte.  This is a problem for powerpc32 with
64K pages enabled.

Further, transparent huge pages may get up to 2M, which will be a problem
for the afs filesystem on all 32-bit arches in the future.

Fix this by decreasing the resolution.  For the moment, a 64K page will
have a resolution determined from PAGE_SIZE.  In the future, the page will
need to be passed in to the helper functions so that the page size can be
assessed and the resolution determined dynamically.

Note that this might not be the ideal way to handle this, since it may
allow some leakage of undirtied zero bytes to the server's copy in the case
of a 3rd-party conflict.  Fixing that would require a separately allocated
record and is a more complicated fix.

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Fix afs_invalidatepage() to adjust the dirty region recorded in
page->private when truncating a page.  If the dirty region is entirely
removed, then the private data is cleared and the page dirty state is
cleared.

Without this, if the page is truncated and then expanded again by truncate,
zeros from the expanded, but no-longer dirty region may get written back to
the server if the page gets laundered due to a conflicting 3rd-party write.

It mustn't, however, shorten the dirty region of the page if that page is
still mmapped and has been marked dirty by afs_page_mkwrite(), so a flag is
stored in page->private to record this.

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>

Currently, page->private on an afs page is used to store the range of
dirtied data within the page, where the range includes the lower bound, but
excludes the upper bound (e.g. 0-1 is a range covering a single byte).

This, however, requires a superfluous bit for the last-byte bound so that
on a 4KiB page, it can say 0-4096 to indicate the whole page, the idea
being that having both numbers the same would indicate an empty range.
This is unnecessary as the PG_private bit is clear if it's an empty range
(as is PG_dirty).

Alter the way the dirty range is encoded in page->private such that the
upper bound is reduced by 1 (e.g. 0-0 is then specified the same single
byte range mentioned above).

Applying this to both bounds frees up two bits, one of which can be used in
a future commit.

This allows the afs filesystem to be compiled on ppc32 with 64K pages;
without this, the following warnings are seen:

../fs/afs/internal.h: In function 'afs_page_dirty_to':
../fs/afs/internal.h:881:15: warning: right shift count >= width of type [-Wshift-count-overflow]
  881 |  return (priv >> __AFS_PAGE_PRIV_SHIFT) & __AFS_PAGE_PRIV_MASK;
      |               ^~
../fs/afs/internal.h: In function 'afs_page_dirty':
../fs/afs/internal.h:886:28: warning: left shift count >= width of type [-Wshift-count-overflow]
  886 |  return ((unsigned long)to << __AFS_PAGE_PRIV_SHIFT) | from;
      |                            ^~

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>

The afs filesystem uses page->private to store the dirty range within a
page such that in the event of a conflicting 3rd-party write to the server,
we write back just the bits that got changed locally.

However, there are a couple of problems with this:

 (1) I need a bit to note if the page might be mapped so that partial
     invalidation doesn't shrink the range.

 (2) There aren't necessarily sufficient bits to store the entire range of
     data altered (say it's a 32-bit system with 64KiB pages or transparent
     huge pages are in use).

So wrap the accesses in inline functions so that future commits can change
how this works.

Also move them out of the tracing header into the in-directory header.
There's not really any need for them to be in the tracing header.
Signed-off-by: David Howells <dhowells@redhat.com>

In afs, page->private is set to indicate the dirty region of a page.  This
is done in afs_write_begin(), but that can't take account of whether the
copy into the page actually worked.

Fix this by moving the change of page->private into afs_write_end().

Fixes: 4343d008 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>

Fix the leak of the target page in afs_write_begin() when it fails.

Fixes: 15b4650e ("afs: convert to new aops")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Nick Piggin <npiggin@gmail.com>

Fix afs to take a ref on a page when it sets PG_private on it and to drop
the ref when removing the flag.

Note that in afs_write_begin(), a lot of the time, PG_private is already
set on a page to which we're going to add some data.  In such a case, we
leave the bit set and mustn't increment the page count.

As suggested by Matthew Wilcox, use attach/detach_page_private() where
possible.

Fixes: 31143d5d ("AFS: implement basic file write support")
Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Pull tracing fix from Steven Rostedt:
 "Fix synthetic event "strcat" overrun

  New synthetic event code used strcat() and miscalculated the ending,
  causing the concatenation to write beyond the allocated memory.

  Instead of using strncat(), the code is switched over to seq_buf which
  has all the mechanisms in place to protect against writing more than
  what is allocated, and cleans up the code a bit"

* tag 'trace-v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing, synthetic events: Replace buggy strcat() with seq_buf operations

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

This switches ext4 over to the generic support provided in libfs.

Since casefolded dentries behave the same in ext4 and f2fs, we decrease
the maintenance burden by unifying them, and any optimizations will
immediately apply to both.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20201028050820.1636571-1-drosen@google.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

ext4_ext_search_right() will read more extent blocks and call put_bh
after we get the information we need.  However, ret_ex will break this
and may cause use-after-free once pagecache has been freed.  Fix it by
copying the extent structure if needed.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Link: https://lore.kernel.org/r/20201028055617.2569255-1-yangerkun@huawei.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

With this fix, fast commit recovery code uses IS_ERR() for path
returned by ext4_find_extent.

Fixes: 8016e29f ("ext4: fast commit recovery path")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027204342.2794949-1-harshadshirwadkar@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

Commit afb585a9 "ext4: data=journal: write-protect pages on
j_submit_inode_data_buffers()") added calls ext4_jbd2_inode_add_write()
to track inode ranges whose mappings need to get write-protected during
transaction commits.  However the added calls use wrong start of a range
(0 instead of page offset) and so write protection is not necessarily
effective.  Use correct range start to fix the problem.

Fixes: afb585a9 ("ext4: data=journal: write-protect pages on j_submit_inode_data_buffers()")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201027132751.29858-1-jack@suse.czSigned-off-by: Theodore Ts'o <tytso@mit.edu>

The kernel-doc markup that documents _fc_replay_callback is
missing an asterisk, causing this warning:

	../include/linux/jbd2.h:1271: warning: Function parameter or member 'j_fc_replay_callback' not described in 'journal_s'

When building the docs.

Fixes: 609f928af48f ("jbd2: fast commit recovery path")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/6055927ada2015b55b413cdd2670533bdc9a8da2.1603791716.git.mchehab+huawei@kernel.orgSigned-off-by: Theodore Ts'o <tytso@mit.edu>

Ext4's fast commit related transient states should use
sb->s_mount_flags instead of persistent sb->s_mount_state.

Fixes: 8016e29f ("ext4: fast commit recovery path")
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-3-harshadshirwadkar@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

This patch reserves a field in the jbd2 superblock for number of fast
commit blocks. When this value is non-zero, Ext4 uses this field to
set the number of fast commit blocks.

Fixes: 6866d7b3 ("ext4/jbd2: add fast commit initialization")
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-2-harshadshirwadkar@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

ext4_inode_datasync_dirty() needs to return 'true' if the inode is
dirty, 'false' otherwise, but the logic seems to be incorrectly changed
by commit aa75f4d3 ("ext4: main fast-commit commit path").

This introduces a problem with swap files that are always failing to be
activated, showing this error in dmesg:

 [   34.406479] swapon: file is not committed

Simple test case to reproduce the problem:

  # fallocate -l 8G swapfile
  # chmod 0600 swapfile
  # mkswap swapfile
  # swapon swapfile

Fix the logic to return the proper state of the inode.

Link: https://lore.kernel.org/lkml/20201024131333.GA32124@xps-13-7390
Fixes: 8016e29f ("ext4: fast commit recovery path")
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201027044915.2553163-1-harshadshirwadkar@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>

Fixed double locking of sbi->s_fc_lock in the above function
as reported by kernel-test-robot.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20201023161339.1449437-1-harshadshirwadkar@gmail.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>