kernel/linux.git/fs/afs/rotate.c, branch linux-5.3.y

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

2019-05-24T15:27:11+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public licence as published by the free software foundation either version 2 of the licence or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 114 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Kate Stewart Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de Signed-off-by: Greg Kroah-Hartman

afs: Make vnode->cb_interest RCU safe

2019-05-16T21:23:21+00:00

Use RCU-based freeing for afs_cb_interest struct objects and use RCU on vnode->cb_interest. Use that change to allow afs_check_validity() to use read_seqbegin_or_lock() instead of read_seqlock_excl(). This also requires the caller of afs_check_validity() to hold the RCU read lock across the call. Signed-off-by: David Howells

afs: Make some RPC operations non-interruptible

2019-05-16T15:25:20+00:00

Make certain RPC operations non-interruptible, including: (*) Set attributes (*) Store data We don't want to get interrupted during a flush on close, flush on unlock, writeback or an inode update, leaving us in a state where we still need to do the writeback or update. (*) Extend lock (*) Release lock We don't want to get lock extension interrupted as the file locks on the server are time-limited. Interruption during lock release is less of an issue since the lock is time-limited, but it's better to complete the release to avoid a several-minute wait to recover it. *Setting* the lock isn't a problem if it's interrupted since we can just return to the user and tell them they were interrupted - at which point they can elect to retry. (*) Silly unlink We want to remove silly unlink files if we can, rather than leaving them for the salvager to clear up. Note that whilst these calls are no longer interruptible, they do have timeouts on them, so if the server stops responding the call will fail with something like ETIME or ECONNRESET. Without this, the following: kAFS: Unexpected error from FS.StoreData -512 appears in dmesg when a pending store data gets interrupted and some processes may just hang. Additionally, make the code that checks/updates the server record ignore failure due to interruption if the main call is uninterruptible and if the server has an address list. The next op will check it again since the expiration time on the old list has past. Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation") Reported-by: Jonathan Billings Reported-by: Marc Dionne Signed-off-by: David Howells

afs: Fix "kAFS: AFS vnode with undefined type 0"

2019-05-16T14:48:20+00:00

Under some circumstances afs_select_fileserver() can return without setting an error in fc->error. The problem is in the no_more_servers segment where the accumulated errors from attempts to contact various servers are integrated into an afs_error-type variable 'e'. The resultant error code is, however, then abandoned. Fix this by getting the error out of e.error and putting it in 'error' so that the next part will store it into fc->error. Not doing this causes a report like the following: kAFS: AFS vnode with undefined type 0 kAFS: A=0 m=0 s=0 v=0 kAFS: vnode 20000025:1:1 because the code following the server selection loop then sees what it thinks is a successful invocation because fc.error is 0. However, it can't apply the status record because it's all zeros. The report is followed on the first instance with a trace looking something like: dump_stack+0x67/0x8e afs_inode_init_from_status.isra.2+0x21b/0x487 afs_fetch_status+0x119/0x1df afs_iget+0x130/0x295 afs_get_tree+0x31d/0x595 vfs_get_tree+0x1f/0xe8 fc_mount+0xe/0x36 afs_d_automount+0x328/0x3c3 follow_managed+0x109/0x20a lookup_fast+0x3bf/0x3f8 do_last+0xc3/0x6a4 path_openat+0x1af/0x236 do_filp_open+0x51/0xae ? _raw_spin_unlock+0x24/0x2d ? __alloc_fd+0x1a5/0x1b7 do_sys_open+0x13b/0x1e8 do_syscall_64+0x7d/0x1b3 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 4584ae96ae30 ("afs: Fix missing net error handling") Signed-off-by: David Howells

afs: Fix missing net error handling

2018-11-30T02:08:14+00:00

kAFS can be given certain network errors (EADDRNOTAVAIL, EHOSTDOWN and ERFKILL) that it doesn't handle in its server/address rotation algorithms. They cause the probing and rotation to abort immediately rather than rotating. Fix this by: (1) Abstracting out the error prioritisation from the VL and FS rotation algorithms into a common function and expand usage into the server probing code. When multiple errors are available, this code selects the one we'd prefer to return. (2) Add handling for EADDRNOTAVAIL, EHOSTDOWN and ERFKILL. Fixes: 0fafdc9f888b ("afs: Fix file locking") Fixes: 0338747d8454 ("afs: Probe multiple fileservers simultaneously") Signed-off-by: David Howells Signed-off-by: Al Viro

afs: Probe multiple fileservers simultaneously

2018-10-23T23:41:09+00:00

Send probes to all the unprobed fileservers in a fileserver list on all addresses simultaneously in an attempt to find out the fastest route whilst not getting stuck for 20s on any server or address that we don't get a reply from. This alleviates the problem whereby attempting to access a new server can take a long time because the rotation algorithm ends up rotating through all servers and addresses until it finds one that responds. Signed-off-by: David Howells

afs: Allow dumping of server cursor on operation failure

2018-10-23T23:41:09+00:00

Provide an option to allow the file or volume location server cursor to be dumped if the rotation routine falls off the end without managing to contact a server. Signed-off-by: David Howells

afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS

2018-10-23T23:41:08+00:00

Increase the sizes of the volume ID to 64 bits and the vnode ID (inode number equivalent) to 96 bits to allow the support of YFS. This requires the iget comparator to check the vnode->fid rather than i_ino and i_generation as i_ino is not sufficiently capacious. It also requires this data to be placed into the vnode cache key for fscache. For the moment, just discard the top 32 bits of the vnode ID when returning it though stat. Signed-off-by: David Howells

afs: Improve FS server rotation error handling

2018-10-23T23:41:07+00:00

Improve the error handling in FS server rotation by: (1) Cache the latest useful error value for the fs operation as a whole in struct afs_fs_cursor separately from the error cached in the afs_addr_cursor struct. The one in the address cursor gets clobbered occasionally. Copy over the error to the fs operation only when it's something we'd be interested in passing to userspace. (2) Make it so that EDESTADDRREQ is the default that is seen only if no addresses are available to be accessed. (3) When calling utility functions, such as checking a volume status or probing a fileserver, don't let a successful result clobber the cached error in the cursor; instead, stash the result in a temporary variable until it has been assessed. (4) Don't return ETIMEDOUT or ETIME if a better error, such as ENETUNREACH, is already cached. (5) On leaving the rotation loop, turn any remote abort code into a more useful error than ECONNABORTED. Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation") Signed-off-by: David Howells

rxrpc: Fix handling of call quietly cancelled out on server

2018-06-04T20:06:26+00:00

Sometimes an in-progress call will stop responding on the fileserver when the fileserver quietly cancels the call with an internally marked abort (RX_CALL_DEAD), without sending an ABORT to the client. This causes the client's call to eventually expire from lack of incoming packets directed its way, which currently leads to it being cancelled locally with ETIME. Note that it's not currently clear as to why this happens as it's really hard to reproduce. The rotation policy implement by kAFS, however, doesn't differentiate between ETIME meaning we didn't get any response from the server and ETIME meaning the call got cancelled mid-flow. The latter leads to an oops when fetching data as the rotation partially resets the afs_read descriptor, which can result in a cleared page pointer being dereferenced because that page has already been filled. Handle this by the following means: (1) Set a flag on a call when we receive a packet for it. (2) Store the highest packet serial number so far received for a call (bearing in mind this may wrap). (3) If, when the "not received anything recently" timeout expires on a call, we've received at least one packet for a call and the connection as a whole has received packets more recently than that call, then cancel the call locally with ECONNRESET rather than ETIME. This indicates that the call was definitely in progress on the server. (4) In kAFS, if the rotation algorithm sees ECONNRESET rather than ETIME, don't try the next server, but rather abort the call. This avoids the oops as we don't try to reuse the afs_read struct. Rather, as-yet ungotten pages will be reread at a later data. Also: (5) Add an rxrpc tracepoint to log detection of the call being reset. Without this, I occasionally see an oops like the following: general protection fault: 0000 [#1] SMP PTI ... RIP: 0010:_copy_to_iter+0x204/0x310 RSP: 0018:ffff8800cae0f828 EFLAGS: 00010206 RAX: 0000000000000560 RBX: 0000000000000560 RCX: 0000000000000560 RDX: ffff8800cae0f968 RSI: ffff8800d58b3312 RDI: 0005080000000000 RBP: ffff8800cae0f968 R08: 0000000000000560 R09: ffff8800ca00f400 R10: ffff8800c36f28d4 R11: 00000000000008c4 R12: ffff8800cae0f958 R13: 0000000000000560 R14: ffff8800d58b3312 R15: 0000000000000560 FS: 00007fdaef108080(0000) GS:ffff8800ca680000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb28a8fa000 CR3: 00000000d2a76002 CR4: 00000000001606e0 Call Trace: skb_copy_datagram_iter+0x14e/0x289 rxrpc_recvmsg_data.isra.0+0x6f3/0xf68 ? trace_buffer_unlock_commit_regs+0x4f/0x89 rxrpc_kernel_recv_data+0x149/0x421 afs_extract_data+0x1e0/0x798 ? afs_wait_for_call_to_complete+0xc9/0x52e afs_deliver_fs_fetch_data+0x33a/0x5ab afs_deliver_to_call+0x1ee/0x5e0 ? afs_wait_for_call_to_complete+0xc9/0x52e afs_wait_for_call_to_complete+0x12b/0x52e ? wake_up_q+0x54/0x54 afs_make_call+0x287/0x462 ? afs_fs_fetch_data+0x3e6/0x3ed ? rcu_read_lock_sched_held+0x5d/0x63 afs_fs_fetch_data+0x3e6/0x3ed afs_fetch_data+0xbb/0x14a afs_readpages+0x317/0x40d __do_page_cache_readahead+0x203/0x2ba ? ondemand_readahead+0x3a7/0x3c1 ondemand_readahead+0x3a7/0x3c1 generic_file_buffered_read+0x18b/0x62f __vfs_read+0xdb/0xfe vfs_read+0xb2/0x137 ksys_read+0x50/0x8c do_syscall_64+0x7d/0x1a0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Note the weird value in RDI which is a result of trying to kmap() a NULL page pointer. Signed-off-by: David Howells Signed-off-by: David S. Miller