<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/fs/afs, branch v5.7</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net</title>
<updated>2020-05-24T00:16:18+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2020-05-24T00:16:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=caffb99b6929f41a69edbb5aef3a359bf45f3315'/>
<id>caffb99b6929f41a69edbb5aef3a359bf45f3315</id>
<content type='text'>
Pull networking fixes from David Miller:

 1) Fix RCU warnings in ipv6 multicast router code, from Madhuparna
    Bhowmik.

 2) Nexthop attributes aren't being checked properly because of
    mis-initialized iterator, from David Ahern.

 3) Revert iop_idents_reserve() change as it caused performance
    regressions and was just working around what is really a UBSAN bug
    in the compiler. From Yuqi Jin.

 4) Read MAC address properly from ROM in bmac driver (double iteration
    proceeds past end of address array), from Jeremy Kerr.

 5) Add Microsoft Surface device IDs to r8152, from Marc Payne.

 6) Prevent reference to freed SKB in __netif_receive_skb_core(), from
    Boris Sukholitko.

 7) Fix ACK discard behavior in rxrpc, from David Howells.

 8) Preserve flow hash across packet scrubbing in wireguard, from Jason
    A. Donenfeld.

 9) Cap option length properly for SO_BINDTODEVICE in AX25, from Eric
    Dumazet.

10) Fix encryption error checking in kTLS code, from Vadim Fedorenko.

11) Missing BPF prog ref release in flow dissector, from Jakub Sitnicki.

12) dst_cache must be used with BH disabled in tipc, from Eric Dumazet.

13) Fix use after free in mlxsw driver, from Jiri Pirko.

14) Order kTLS key destruction properly in mlx5 driver, from Tariq
    Toukan.

15) Check devm_platform_ioremap_resource() return value properly in
    several drivers, from Tiezhu Yang.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (71 commits)
  net: smsc911x: Fix runtime PM imbalance on error
  net/mlx4_core: fix a memory leak bug.
  net: ethernet: ti: cpsw: fix ASSERT_RTNL() warning during suspend
  net: phy: mscc: fix initialization of the MACsec protocol mode
  net: stmmac: don't attach interface until resume finishes
  net: Fix return value about devm_platform_ioremap_resource()
  net/mlx5: Fix error flow in case of function_setup failure
  net/mlx5e: CT: Correctly get flow rule
  net/mlx5e: Update netdev txq on completions during closure
  net/mlx5: Annotate mutex destroy for root ns
  net/mlx5: Don't maintain a case of del_sw_func being null
  net/mlx5: Fix cleaning unmanaged flow tables
  net/mlx5: Fix memory leak in mlx5_events_init
  net/mlx5e: Fix inner tirs handling
  net/mlx5e: kTLS, Destroy key object after destroying the TIS
  net/mlx5e: Fix allowed tc redirect merged eswitch offload cases
  net/mlx5: Avoid processing commands before cmdif is ready
  net/mlx5: Fix a race when moving command interface to events mode
  net/mlx5: Add command entry handling completion
  rxrpc: Fix a memory leak in rxkad_verify_response()
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull networking fixes from David Miller:

 1) Fix RCU warnings in ipv6 multicast router code, from Madhuparna
    Bhowmik.

 2) Nexthop attributes aren't being checked properly because of
    mis-initialized iterator, from David Ahern.

 3) Revert iop_idents_reserve() change as it caused performance
    regressions and was just working around what is really a UBSAN bug
    in the compiler. From Yuqi Jin.

 4) Read MAC address properly from ROM in bmac driver (double iteration
    proceeds past end of address array), from Jeremy Kerr.

 5) Add Microsoft Surface device IDs to r8152, from Marc Payne.

 6) Prevent reference to freed SKB in __netif_receive_skb_core(), from
    Boris Sukholitko.

 7) Fix ACK discard behavior in rxrpc, from David Howells.

 8) Preserve flow hash across packet scrubbing in wireguard, from Jason
    A. Donenfeld.

 9) Cap option length properly for SO_BINDTODEVICE in AX25, from Eric
    Dumazet.

10) Fix encryption error checking in kTLS code, from Vadim Fedorenko.

11) Missing BPF prog ref release in flow dissector, from Jakub Sitnicki.

12) dst_cache must be used with BH disabled in tipc, from Eric Dumazet.

13) Fix use after free in mlxsw driver, from Jiri Pirko.

14) Order kTLS key destruction properly in mlx5 driver, from Tariq
    Toukan.

15) Check devm_platform_ioremap_resource() return value properly in
    several drivers, from Tiezhu Yang.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (71 commits)
  net: smsc911x: Fix runtime PM imbalance on error
  net/mlx4_core: fix a memory leak bug.
  net: ethernet: ti: cpsw: fix ASSERT_RTNL() warning during suspend
  net: phy: mscc: fix initialization of the MACsec protocol mode
  net: stmmac: don't attach interface until resume finishes
  net: Fix return value about devm_platform_ioremap_resource()
  net/mlx5: Fix error flow in case of function_setup failure
  net/mlx5e: CT: Correctly get flow rule
  net/mlx5e: Update netdev txq on completions during closure
  net/mlx5: Annotate mutex destroy for root ns
  net/mlx5: Don't maintain a case of del_sw_func being null
  net/mlx5: Fix cleaning unmanaged flow tables
  net/mlx5: Fix memory leak in mlx5_events_init
  net/mlx5e: Fix inner tirs handling
  net/mlx5e: kTLS, Destroy key object after destroying the TIS
  net/mlx5e: Fix allowed tc redirect merged eswitch offload cases
  net/mlx5: Avoid processing commands before cmdif is ready
  net/mlx5: Fix a race when moving command interface to events mode
  net/mlx5: Add command entry handling completion
  rxrpc: Fix a memory leak in rxkad_verify_response()
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>rxrpc: Fix a warning</title>
<updated>2020-05-22T23:31:39+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-05-22T22:58:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8a1d24e1cc6d96a17f2dcb1400d370cadbfb7cb6'/>
<id>8a1d24e1cc6d96a17f2dcb1400d370cadbfb7cb6</id>
<content type='text'>
Fix a warning due to an uninitialised variable.

le included from ../fs/afs/fs_probe.c:11:
../fs/afs/fs_probe.c: In function 'afs_fileserver_probe_result':
../fs/afs/internal.h:1453:2: warning: 'rtt_us' may be used uninitialized in this function [-Wmaybe-uninitialized]
 1453 |  printk("[%-6.6s] "FMT"\n", current-&gt;comm ,##__VA_ARGS__)
      |  ^~~~~~
../fs/afs/fs_probe.c:35:15: note: 'rtt_us' was declared here

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix a warning due to an uninitialised variable.

le included from ../fs/afs/fs_probe.c:11:
../fs/afs/fs_probe.c: In function 'afs_fileserver_probe_result':
../fs/afs/internal.h:1453:2: warning: 'rtt_us' may be used uninitialized in this function [-Wmaybe-uninitialized]
 1453 |  printk("[%-6.6s] "FMT"\n", current-&gt;comm ,##__VA_ARGS__)
      |  ^~~~~~
../fs/afs/fs_probe.c:35:15: note: 'rtt_us' was declared here

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Don't unlock fetched data pages until the op completes successfully</title>
<updated>2020-05-18T17:29:17+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-05-17T20:21:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9d1be4f4dc5ff1c66c86acfd2c35765d9e3776b3'/>
<id>9d1be4f4dc5ff1c66c86acfd2c35765d9e3776b3</id>
<content type='text'>
Don't call req-&gt;page_done() on each page as we finish filling it with
the data coming from the network.  Whilst this might speed up the
application a bit, it's a problem if there's a network failure and the
operation has to be reissued.

If this happens, an oops occurs because afs_readpages_page_done() clears
the pointer to each page it unlocks and when a retry happens, the
pointers to the pages it wants to fill are now NULL (and the pages have
been unlocked anyway).

Instead, wait till the operation completes successfully and only then
release all the pages after clearing any terminal gap (the server can
give us less data than we requested as we're allowed to ask for more
than is available).

KASAN produces a bug like the following, and even without KASAN, it can
oops and panic.

    BUG: KASAN: wild-memory-access in _copy_to_iter+0x323/0x5f4
    Write of size 1404 at addr 0005088000000000 by task md5sum/5235

    CPU: 0 PID: 5235 Comm: md5sum Not tainted 5.7.0-rc3-fscache+ #250
    Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
    Call Trace:
     memcpy+0x39/0x58
     _copy_to_iter+0x323/0x5f4
     __skb_datagram_iter+0x89/0x2a6
     skb_copy_datagram_iter+0x129/0x135
     rxrpc_recvmsg_data.isra.0+0x615/0xd42
     rxrpc_kernel_recv_data+0x1e9/0x3ae
     afs_extract_data+0x139/0x33a
     yfs_deliver_fs_fetch_data64+0x47a/0x91b
     afs_deliver_to_call+0x304/0x709
     afs_wait_for_call_to_complete+0x1cc/0x4ad
     yfs_fs_fetch_data+0x279/0x288
     afs_fetch_data+0x1e1/0x38d
     afs_readpages+0x593/0x72e
     read_pages+0xf5/0x21e
     __do_page_cache_readahead+0x128/0x23f
     ondemand_readahead+0x36e/0x37f
     generic_file_buffered_read+0x234/0x680
     new_sync_read+0x109/0x17e
     vfs_read+0xe6/0x138
     ksys_read+0xd8/0x14d
     do_syscall_64+0x6e/0x8a
     entry_SYSCALL_64_after_hwframe+0x49/0xb3

Fixes: 196ee9cd2d04 ("afs: Make afs_fs_fetch_data() take a list of pages")
Fixes: 30062bd13e36 ("afs: Implement YFS support in the fs client")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Reviewed-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Don't call req-&gt;page_done() on each page as we finish filling it with
the data coming from the network.  Whilst this might speed up the
application a bit, it's a problem if there's a network failure and the
operation has to be reissued.

If this happens, an oops occurs because afs_readpages_page_done() clears
the pointer to each page it unlocks and when a retry happens, the
pointers to the pages it wants to fill are now NULL (and the pages have
been unlocked anyway).

Instead, wait till the operation completes successfully and only then
release all the pages after clearing any terminal gap (the server can
give us less data than we requested as we're allowed to ask for more
than is available).

KASAN produces a bug like the following, and even without KASAN, it can
oops and panic.

    BUG: KASAN: wild-memory-access in _copy_to_iter+0x323/0x5f4
    Write of size 1404 at addr 0005088000000000 by task md5sum/5235

    CPU: 0 PID: 5235 Comm: md5sum Not tainted 5.7.0-rc3-fscache+ #250
    Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
    Call Trace:
     memcpy+0x39/0x58
     _copy_to_iter+0x323/0x5f4
     __skb_datagram_iter+0x89/0x2a6
     skb_copy_datagram_iter+0x129/0x135
     rxrpc_recvmsg_data.isra.0+0x615/0xd42
     rxrpc_kernel_recv_data+0x1e9/0x3ae
     afs_extract_data+0x139/0x33a
     yfs_deliver_fs_fetch_data64+0x47a/0x91b
     afs_deliver_to_call+0x304/0x709
     afs_wait_for_call_to_complete+0x1cc/0x4ad
     yfs_fs_fetch_data+0x279/0x288
     afs_fetch_data+0x1e1/0x38d
     afs_readpages+0x593/0x72e
     read_pages+0xf5/0x21e
     __do_page_cache_readahead+0x128/0x23f
     ondemand_readahead+0x36e/0x37f
     generic_file_buffered_read+0x234/0x680
     new_sync_read+0x109/0x17e
     vfs_read+0xe6/0x138
     ksys_read+0xd8/0x14d
     do_syscall_64+0x6e/0x8a
     entry_SYSCALL_64_after_hwframe+0x49/0xb3

Fixes: 196ee9cd2d04 ("afs: Make afs_fs_fetch_data() take a list of pages")
Fixes: 30062bd13e36 ("afs: Implement YFS support in the fs client")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
Reviewed-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>rxrpc: Fix the excessive initial retransmission timeout</title>
<updated>2020-05-11T15:42:28+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-05-11T13:54:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c410bf01933e5e09d142c66c3df9ad470a7eec13'/>
<id>c410bf01933e5e09d142c66c3df9ad470a7eec13</id>
<content type='text'>
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 &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Make record checking use TASK_UNINTERRUPTIBLE when appropriate</title>
<updated>2020-04-24T15:33:32+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-04-16T17:17:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c4bfda16d1b40d1c5941c61b5aa336bdd2d9904a'/>
<id>c4bfda16d1b40d1c5941c61b5aa336bdd2d9904a</id>
<content type='text'>
When an operation is meant to be done uninterruptibly (such as
FS.StoreData), we should not be allowing volume and server record checking
to be interrupted.

Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When an operation is meant to be done uninterruptibly (such as
FS.StoreData), we should not be allowing volume and server record checking
to be interrupted.

Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix to actually set AFS_SERVER_FL_HAVE_EPOCH</title>
<updated>2020-04-24T15:32:49+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-04-24T10:21:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=69cf3978f3ada4e54beae4ad44868b5627864884'/>
<id>69cf3978f3ada4e54beae4ad44868b5627864884</id>
<content type='text'>
AFS keeps track of the epoch value from the rxrpc protocol to note (a) when
a fileserver appears to have restarted and (b) when different endpoints of
a fileserver do not appear to be associated with the same fileserver
(ie. all probes back from a fileserver from all of its interfaces should
carry the same epoch).

However, the AFS_SERVER_FL_HAVE_EPOCH flag that indicates that we've
received the server's epoch is never set, though it is used.

Fix this to set the flag when we first receive an epoch value from a probe
sent to the filesystem client from the fileserver.

Fixes: 3bf0fb6f33dd ("afs: Probe multiple fileservers simultaneously")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
AFS keeps track of the epoch value from the rxrpc protocol to note (a) when
a fileserver appears to have restarted and (b) when different endpoints of
a fileserver do not appear to be associated with the same fileserver
(ie. all probes back from a fileserver from all of its interfaces should
carry the same epoch).

However, the AFS_SERVER_FL_HAVE_EPOCH flag that indicates that we've
received the server's epoch is never set, though it is used.

Fix this to set the flag when we first receive an epoch value from a probe
sent to the filesystem client from the fileserver.

Fixes: 3bf0fb6f33dd ("afs: Probe multiple fileservers simultaneously")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Remove some unused bits</title>
<updated>2020-04-24T15:32:49+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-04-24T10:23:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=be59167c8f27592e79c0044a0bbc515b38d5eace'/>
<id>be59167c8f27592e79c0044a0bbc515b38d5eace</id>
<content type='text'>
Remove three bits:

 (1) afs_server::no_epoch is neither set nor used.

 (2) afs_server::have_result is set and a wakeup is applied to it, but
     nothing looks at it or waits on it.

 (3) afs_vl_dump_edestaddrreq() prints afs_addr_list::probed, but nothing
     sets it for VL servers.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Remove three bits:

 (1) afs_server::no_epoch is neither set nor used.

 (2) afs_server::have_result is set and a wakeup is applied to it, but
     nothing looks at it or waits on it.

 (3) afs_vl_dump_edestaddrreq() prints afs_addr_list::probed, but nothing
     sets it for VL servers.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix afs_d_validate() to set the right directory version</title>
<updated>2020-04-13T14:09:01+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-04-11T07:50:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=40fc81027f892284ce31f8b6de1e497f5b47e71f'/>
<id>40fc81027f892284ce31f8b6de1e497f5b47e71f</id>
<content type='text'>
If a dentry's version is somewhere between invalid_before and the current
directory version, we should be setting it forward to the current version,
not backwards to the invalid_before version.  Note that we're only doing
this at all because dentry::d_fsdata isn't large enough on a 32-bit system.

Fix this by using a separate variable for invalid_before so that we don't
accidentally clobber the current dir version.

Fixes: a4ff7401fbfa ("afs: Keep track of invalid-before version for dentry coherency")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If a dentry's version is somewhere between invalid_before and the current
directory version, we should be setting it forward to the current version,
not backwards to the invalid_before version.  Note that we're only doing
this at all because dentry::d_fsdata isn't large enough on a 32-bit system.

Fix this by using a separate variable for invalid_before so that we don't
accidentally clobber the current dir version.

Fixes: a4ff7401fbfa ("afs: Keep track of invalid-before version for dentry coherency")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix race between post-modification dir edit and readdir/d_revalidate</title>
<updated>2020-04-13T14:09:01+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-04-10T14:23:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2105c2820d366b76f38e6ad61c75771881ecc532'/>
<id>2105c2820d366b76f38e6ad61c75771881ecc532</id>
<content type='text'>
AFS directories are retained locally as a structured file, with lookup
being effected by a local search of the file contents.  When a modification
(such as mkdir) happens, the dir file content is modified locally rather
than redownloading the directory.

The directory contents are accessed in a number of ways, with a number of
different locks schemes:

 (1) Download of contents - dvnode-&gt;validate_lock/write in afs_read_dir().

 (2) Lookup and readdir - dvnode-&gt;validate_lock/read in afs_dir_iterate(),
     downgrading from (1) if necessary.

 (3) d_revalidate of child dentry - dvnode-&gt;validate_lock/read in
     afs_do_lookup_one() downgrading from (1) if necessary.

 (4) Edit of dir after modification - page locks on individual dir pages.

Unfortunately, because (4) uses different locking scheme to (1) - (3),
nothing protects against the page being scanned whilst the edit is
underway.  Even download is not safe as it doesn't lock the pages - relying
instead on the validate_lock to serialise as a whole (the theory being that
directory contents are treated as a block and always downloaded as a
block).

Fix this by write-locking dvnode-&gt;validate_lock around the edits.  Care
must be taken in the rename case as there may be two different dirs - but
they need not be locked at the same time.  In any case, once the lock is
taken, the directory version must be rechecked, and the edit skipped if a
later version has been downloaded by revalidation (there can't have been
any local changes because the VFS holds the inode lock, but there can have
been remote changes).

Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
AFS directories are retained locally as a structured file, with lookup
being effected by a local search of the file contents.  When a modification
(such as mkdir) happens, the dir file content is modified locally rather
than redownloading the directory.

The directory contents are accessed in a number of ways, with a number of
different locks schemes:

 (1) Download of contents - dvnode-&gt;validate_lock/write in afs_read_dir().

 (2) Lookup and readdir - dvnode-&gt;validate_lock/read in afs_dir_iterate(),
     downgrading from (1) if necessary.

 (3) d_revalidate of child dentry - dvnode-&gt;validate_lock/read in
     afs_do_lookup_one() downgrading from (1) if necessary.

 (4) Edit of dir after modification - page locks on individual dir pages.

Unfortunately, because (4) uses different locking scheme to (1) - (3),
nothing protects against the page being scanned whilst the edit is
underway.  Even download is not safe as it doesn't lock the pages - relying
instead on the validate_lock to serialise as a whole (the theory being that
directory contents are treated as a block and always downloaded as a
block).

Fix this by write-locking dvnode-&gt;validate_lock around the edits.  Care
must be taken in the rename case as there may be two different dirs - but
they need not be locked at the same time.  In any case, once the lock is
taken, the directory version must be rechecked, and the edit skipped if a
later version has been downloaded by revalidation (there can't have been
any local changes because the VFS holds the inode lock, but there can have
been remote changes).

Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...")
Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>afs: Fix length of dump of bad YFSFetchStatus record</title>
<updated>2020-04-13T14:09:01+00:00</updated>
<author>
<name>David Howells</name>
<email>dhowells@redhat.com</email>
</author>
<published>2020-04-01T22:32:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=3efe55b09a92a59ed8214db801683cf13c9742c4'/>
<id>3efe55b09a92a59ed8214db801683cf13c9742c4</id>
<content type='text'>
Fix the length of the dump of a bad YFSFetchStatus record.  The function
was copied from the AFS version, but the YFS variant contains bigger fields
and extra information, so expand the dump to match.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Fix the length of the dump of a bad YFSFetchStatus record.  The function
was copied from the AFS version, but the YFS variant contains bigger fields
and extra information, so expand the dump to match.

Signed-off-by: David Howells &lt;dhowells@redhat.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
