commit aadf9dcef9d4cd68c73a4ab934f93319c4becc47 upstream.

The trace symbol printer (__print_symbolic()) ignores symbols that map to
an empty string and prints the hex value instead.

Fix the symbol for rxrpc_cong_no_change to " -" instead of "" to avoid
this.

Fixes: b54a134a7de4 ("rxrpc: Fix handling of enums-to-string translation in tracing")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 7126ead910aa9fcc9e16e9e7a8c9179658261f1d ]

Remove the error argument from afs_protocol_error() as it's always
-EBADMSG.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

commit e289f03ea79bbc6574b78ac25682555423a91cbb upstream.

When we have extents shared amongst different inodes in the same subvolume,
if we fsync them in parallel we can end up with checksum items in the log
tree that represent ranges which overlap.

For example, consider we have inodes A and B, both sharing an extent that
covers the logical range from X to X + 64KiB:

1) Task A starts an fsync on inode A;

2) Task B starts an fsync on inode B;

3) Task A calls btrfs_csum_file_blocks(), and the first search in the
   log tree, through btrfs_lookup_csum(), returns -EFBIG because it
   finds an existing checksum item that covers the range from X - 64KiB
   to X;

4) Task A checks that the checksum item has not reached the maximum
   possible size (MAX_CSUM_ITEMS) and then releases the search path
   before it does another path search for insertion (through a direct
   call to btrfs_search_slot());

5) As soon as task A releases the path and before it does the search
   for insertion, task B calls btrfs_csum_file_blocks() and gets -EFBIG
   too, because there is an existing checksum item that has an end
   offset that matches the start offset (X) of the checksum range we want
   to log;

6) Task B releases the path;

7) Task A does the path search for insertion (through btrfs_search_slot())
   and then verifies that the checksum item that ends at offset X still
   exists and extends its size to insert the checksums for the range from
   X to X + 64KiB;

8) Task A releases the path and returns from btrfs_csum_file_blocks(),
   having inserted the checksums into an existing checksum item that got
   its size extended. At this point we have one checksum item in the log
   tree that covers the logical range from X - 64KiB to X + 64KiB;

9) Task B now does a search for insertion using btrfs_search_slot() too,
   but it finds that the previous checksum item no longer ends at the
   offset X, it now ends at an of offset X + 64KiB, so it leaves that item
   untouched.

   Then it releases the path and calls btrfs_insert_empty_item()
   that inserts a checksum item with a key offset corresponding to X and
   a size for inserting a single checksum (4 bytes in case of crc32c).
   Subsequent iterations end up extending this new checksum item so that
   it contains the checksums for the range from X to X + 64KiB.

   So after task B returns from btrfs_csum_file_blocks() we end up with
   two checksum items in the log tree that have overlapping ranges, one
   for the range from X - 64KiB to X + 64KiB, and another for the range
   from X to X + 64KiB.

Having checksum items that represent ranges which overlap, regardless of
being in the log tree or in the chekcsums tree, can lead to problems where
checksums for a file range end up not being found. This type of problem
has happened a few times in the past and the following commits fixed them
and explain in detail why having checksum items with overlapping ranges is
problematic:

  27b9a8122ff71a "Btrfs: fix csum tree corruption, duplicate and outdated checksums"
  b84b8390d6009c "Btrfs: fix file read corruption after extent cloning and fsync"
  40e046acbd2f36 "Btrfs: fix missing data checksums after replaying a log tree"

Since this specific instance of the problem can only happen when logging
inodes, because it is the only case where concurrent attempts to insert
checksums for the same range can happen, fix the issue by using an extent
io tree as a range lock to serialize checksum insertion during inode
logging.

This issue could often be reproduced by the test case generic/457 from
fstests. When it happens it produces the following trace:

 BTRFS critical (device dm-0): corrupt leaf: root=18446744073709551610 block=30625792 slot=42, csum end range (15020032) goes beyond the start range (15015936) of the next csum item
 BTRFS info (device dm-0): leaf 30625792 gen 7 total ptrs 49 free space 2402 owner 18446744073709551610
 BTRFS info (device dm-0): refs 1 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 15884
      item 0 key (18446744073709551606 128 13979648) itemoff 3991 itemsize 4
      item 1 key (18446744073709551606 128 13983744) itemoff 3987 itemsize 4
      item 2 key (18446744073709551606 128 13987840) itemoff 3983 itemsize 4
      item 3 key (18446744073709551606 128 13991936) itemoff 3979 itemsize 4
      item 4 key (18446744073709551606 128 13996032) itemoff 3975 itemsize 4
      item 5 key (18446744073709551606 128 14000128) itemoff 3971 itemsize 4
 (...)
 BTRFS error (device dm-0): block=30625792 write time tree block corruption detected
 ------------[ cut here ]------------
 WARNING: CPU: 1 PID: 15884 at fs/btrfs/disk-io.c:539 btree_csum_one_bio+0x268/0x2d0 [btrfs]
 Modules linked in: btrfs dm_thin_pool ...
 CPU: 1 PID: 15884 Comm: fsx Tainted: G        W         5.6.0-rc7-btrfs-next-58 #1
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
 RIP: 0010:btree_csum_one_bio+0x268/0x2d0 [btrfs]
 Code: c7 c7 ...
 RSP: 0018:ffffbb0109e6f8e0 EFLAGS: 00010296
 RAX: 0000000000000000 RBX: ffffe1c0847b6080 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffffffffaa963988 RDI: 0000000000000001
 RBP: ffff956a4f4d2000 R08: 0000000000000000 R09: 0000000000000001
 R10: 0000000000000526 R11: 0000000000000000 R12: ffff956a5cd28bb0
 R13: 0000000000000000 R14: ffff956a649c9388 R15: 000000011ed82000
 FS:  00007fb419959e80(0000) GS:ffff956a7aa00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000fe6d54 CR3: 0000000138696005 CR4: 00000000003606e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  btree_submit_bio_hook+0x67/0xc0 [btrfs]
  submit_one_bio+0x31/0x50 [btrfs]
  btree_write_cache_pages+0x2db/0x4b0 [btrfs]
  ? __filemap_fdatawrite_range+0xb1/0x110
  do_writepages+0x23/0x80
  __filemap_fdatawrite_range+0xd2/0x110
  btrfs_write_marked_extents+0x15e/0x180 [btrfs]
  btrfs_sync_log+0x206/0x10a0 [btrfs]
  ? kmem_cache_free+0x315/0x3b0
  ? btrfs_log_inode+0x1e8/0xf90 [btrfs]
  ? __mutex_unlock_slowpath+0x45/0x2a0
  ? lockref_put_or_lock+0x9/0x30
  ? dput+0x2d/0x580
  ? dput+0xb5/0x580
  ? btrfs_sync_file+0x464/0x4d0 [btrfs]
  btrfs_sync_file+0x464/0x4d0 [btrfs]
  do_fsync+0x38/0x60
  __x64_sys_fsync+0x10/0x20
  do_syscall_64+0x5c/0x280
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
 RIP: 0033:0x7fb41953a6d0
 Code: 48 3d ...
 RSP: 002b:00007ffcc86bd218 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
 RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007fb41953a6d0
 RDX: 0000000000000009 RSI: 0000000000040000 RDI: 0000000000000003
 RBP: 0000000000040000 R08: 0000000000000001 R09: 0000000000000009
 R10: 0000000000000064 R11: 0000000000000246 R12: 0000556cf4b2c060
 R13: 0000000000000100 R14: 0000000000000000 R15: 0000556cf322b420
 irq event stamp: 0
 hardirqs last  enabled at (0): [<0000000000000000>] 0x0
 hardirqs last disabled at (0): [<ffffffffa96bdedf>] copy_process+0x74f/0x2020
 softirqs last  enabled at (0): [<ffffffffa96bdedf>] copy_process+0x74f/0x2020
 softirqs last disabled at (0): [<0000000000000000>] 0x0
 ---[ end trace d543fc76f5ad7fd8 ]---

In that trace the tree checker detected the overlapping checksum items at
the time when we triggered writeback for the log tree when syncing the
log.

Another trace that can happen is due to BUG_ON() when deleting checksum
items while logging an inode:

 BTRFS critical (device dm-0): slot 81 key (18446744073709551606 128 13635584) new key (18446744073709551606 128 13635584)
 BTRFS info (device dm-0): leaf 30949376 gen 7 total ptrs 98 free space 8527 owner 18446744073709551610
 BTRFS info (device dm-0): refs 4 lock (w:1 r:0 bw:0 br:0 sw:1 sr:0) lock_owner 13473 current 13473
  item 0 key (257 1 0) itemoff 16123 itemsize 160
          inode generation 7 size 262144 mode 100600
  item 1 key (257 12 256) itemoff 16103 itemsize 20
  item 2 key (257 108 0) itemoff 16050 itemsize 53
          extent data disk bytenr 13631488 nr 4096
          extent data offset 0 nr 131072 ram 131072
 (...)
 ------------[ cut here ]------------
 kernel BUG at fs/btrfs/ctree.c:3153!
 invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC PTI
 CPU: 1 PID: 13473 Comm: fsx Not tainted 5.6.0-rc7-btrfs-next-58 #1
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
 RIP: 0010:btrfs_set_item_key_safe+0x1ea/0x270 [btrfs]
 Code: 0f b6 ...
 RSP: 0018:ffff95e3889179d0 EFLAGS: 00010282
 RAX: 0000000000000000 RBX: 0000000000000051 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffffffffb7763988 RDI: 0000000000000001
 RBP: fffffffffffffff6 R08: 0000000000000000 R09: 0000000000000001
 R10: 00000000000009ef R11: 0000000000000000 R12: ffff8912a8ba5a08
 R13: ffff95e388917a06 R14: ffff89138dcf68c8 R15: ffff95e388917ace
 FS:  00007fe587084e80(0000) GS:ffff8913baa00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007fe587091000 CR3: 0000000126dac005 CR4: 00000000003606e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  btrfs_del_csums+0x2f4/0x540 [btrfs]
  copy_items+0x4b5/0x560 [btrfs]
  btrfs_log_inode+0x910/0xf90 [btrfs]
  btrfs_log_inode_parent+0x2a0/0xe40 [btrfs]
  ? dget_parent+0x5/0x370
  btrfs_log_dentry_safe+0x4a/0x70 [btrfs]
  btrfs_sync_file+0x42b/0x4d0 [btrfs]
  __x64_sys_msync+0x199/0x200
  do_syscall_64+0x5c/0x280
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
 RIP: 0033:0x7fe586c65760
 Code: 00 f7 ...
 RSP: 002b:00007ffe250f98b8 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
 RAX: ffffffffffffffda RBX: 00000000000040e1 RCX: 00007fe586c65760
 RDX: 0000000000000004 RSI: 0000000000006b51 RDI: 00007fe58708b000
 RBP: 0000000000006a70 R08: 0000000000000003 R09: 00007fe58700cb61
 R10: 0000000000000100 R11: 0000000000000246 R12: 00000000000000e1
 R13: 00007fe58708b000 R14: 0000000000006b51 R15: 0000558de021a420
 Modules linked in: dm_log_writes ...
 ---[ end trace c92a7f447a8515f5 ]---

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

David Howells says:

====================
rxrpc: Fix retransmission timeout and ACK discard

Here are a couple of fixes and an extra tracepoint for AF_RXRPC:

 (1) Calculate the RTO pretty much as TCP does, rather than making
     something up, including an initial 4s timeout (which causes return
     probes from the fileserver to fail if a packet goes missing), and add
     backoff.

 (2) Fix the discarding of out-of-order received ACKs.  We mustn't let the
     hard-ACK point regress, nor do we want to do unnecessary
     retransmission because the soft-ACK list regresses.  This is not
     trivial, however, due to some loose wording in various old protocol
     specs, the ACK field that should be used for this sometimes has the
     wrong information in it.

 (3) Add a tracepoint to log a discarded ACK.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Add a tracepoint to track received ACKs that are discarded due to being
outside of the Tx window.

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

rxrpc currently uses a fixed 4s retransmission timeout until the RTT is
sufficiently sampled.  This can cause problems with some fileservers with
calls to the cache manager in the afs filesystem being dropped from the
fileserver because a packet goes missing and the retransmission timeout is
greater than the call expiry timeout.

Fix this by:

 (1) Copying the RTT/RTO calculation code from Linux's TCP implementation
     and altering it to fit rxrpc.

 (2) Altering the various users of the RTT to make use of the new SRTT
     value.

 (3) Replacing the use of rxrpc_resend_timeout to use the calculated RTO
     value instead (which is needed in jiffies), along with a backoff.

Notes:

 (1) rxrpc provides RTT samples by matching the serial numbers on outgoing
     DATA packets that have the RXRPC_REQUEST_ACK set and PING ACK packets
     against the reference serial number in incoming REQUESTED ACK and
     PING-RESPONSE ACK packets.

 (2) Each packet that is transmitted on an rxrpc connection gets a new
     per-connection serial number, even for retransmissions, so an ACK can
     be cross-referenced to a specific trigger packet.  This allows RTT
     information to be drawn from retransmitted DATA packets also.

 (3) rxrpc maintains the RTT/RTO state on the rxrpc_peer record rather than
     on an rxrpc_call because many RPC calls won't live long enough to
     generate more than one sample.

 (4) The calculated SRTT value is in units of 8ths of a microsecond rather
     than nanoseconds.

The (S)RTT and RTO values are displayed in /proc/net/rxrpc/peers.

Fixes: 17926a79320a ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: David Howells <dhowells@redhat.com>

Pull block fixes from Jens Axboe:

 - a small series fixing a use-after-free of bdi name (Christoph,Yufen)

 - NVMe fix for a regression with the smaller CQ update (Alexey)

 - NVMe fix for a hang at namespace scanning error recovery (Sagi)

 - fix race with blk-iocost iocg->abs_vdebt updates (Tejun)

* tag 'block-5.7-2020-05-09' of git://git.kernel.dk/linux-block:
  nvme: fix possible hang when ns scanning fails during error recovery
  nvme-pci: fix "slimmer CQ head update"
  bdi: add a ->dev_name field to struct backing_dev_info
  bdi: use bdi_dev_name() to get device name
  bdi: move bdi_dev_name out of line
  vboxsf: don't use the source name in the bdi name
  iocost: protect iocg->abs_vdebt with iocg->waitq.lock

Use the common interface bdi_dev_name() to get device name.

Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>

Add missing <linux/backing-dev.h> include BFQ

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull tracing fixes from Steven Rostedt:

 - Fix bootconfig causing kernels to fail with CONFIG_BLK_DEV_RAM
   enabled

 - Fix allocation leaks in bootconfig tool

 - Fix a double initialization of a variable

 - Fix API bootconfig usage from kprobe boot time events

 - Reject NULL location for kprobes

 - Fix crash caused by preempt delay module not cleaning up kthread
   correctly

 - Add vmalloc_sync_mappings() to prevent x86_64 page faults from
   recursively faulting from tracing page faults

 - Fix comment in gpu/trace kerneldoc header

 - Fix documentation of how to create a trace event class

 - Make the local tracing_snapshot_instance_cond() function static

* tag 'trace-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tools/bootconfig: Fix resource leak in apply_xbc()
  tracing: Make tracing_snapshot_instance_cond() static
  tracing: Fix doc mistakes in trace sample
  gpu/trace: Minor comment updates for gpu_mem_total tracepoint
  tracing: Add a vmalloc_sync_mappings() for safe measure
  tracing: Wait for preempt irq delay thread to finish
  tracing/kprobes: Reject new event if loc is NULL
  tracing/boottime: Fix kprobe event API usage
  tracing/kprobes: Fix a double initialization typo
  bootconfig: Fix to remove bootconfig data from initrd while boot

This change updates the improper comment for the 'size' attribute in the
tracepoint definition. Most gfx drivers pre-fault in physical pages
instead of making virtual allocations. So we drop the 'Virtual' keyword
here and leave this to the implementations.

Link: http://lkml.kernel.org/r/20200428220825.169606-1-zzyiwei@google.com

Signed-off-by: Yiwei Zhang <zzyiwei@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>