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2022-08-02afs: Use refcount_t rather than atomic_tDavid Howells1-3/+3
Use refcount_t rather than atomic_t in afs to make use of the count checking facilities provided. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/165911277768.3745403.423349776836296452.stgit@warthog.procyon.org.uk/ # v1
2022-01-22proc: remove PDE_DATA() completelyMuchun Song1-3/+3
Remove PDE_DATA() completely and replace it with pde_data(). [akpm@linux-foundation.org: fix naming clash in drivers/nubus/proc.c] [akpm@linux-foundation.org: now fix it properly] Link: https://lkml.kernel.org/r/20211124081956.87711-2-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alexey Gladkov <gladkov.alexey@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16afs: Add tracing for cell refcount and active user countDavid Howells1-1/+1
Add a tracepoint to log the cell refcount and active user count and pass in a reason code through various functions that manipulate these counters. Additionally, a helper function, afs_see_cell(), is provided to log interesting places that deal with a cell without actually doing any accounting directly. Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-16afs: Fix cell refcounting by splitting the usage counterDavid Howells1-12/+11
Management of the lifetime of afs_cell struct has some problems due to the usage counter being used to determine whether objects of that type are in use in addition to whether anyone might be interested in the structure. This is made trickier by cell objects being cached for a period of time in case they're quickly reused as they hold the result of a setup process that may be slow (DNS lookups, AFS RPC ops). Problems include the cached root volume from alias resolution pinning its parent cell record, rmmod occasionally hanging and occasionally producing assertion failures. Fix this by splitting the count of active users from the struct reference count. Things then work as follows: (1) The cell cache keeps +1 on the cell's activity count and this has to be dropped before the cell can be removed. afs_manage_cell() tries to exchange the 1 to a 0 with the cells_lock write-locked, and if successful, the record is removed from the net->cells. (2) One struct ref is 'owned' by the activity count. That is put when the active count is reduced to 0 (final_destruction label). (3) A ref can be held on a cell whilst it is queued for management on a work queue without confusing the active count. afs_queue_cell() is added to wrap this. (4) The queue's ref is dropped at the end of the management. This is split out into a separate function, afs_manage_cell_work(). (5) The root volume record is put after a cell is removed (at the final_destruction label) rather then in the RCU destruction routine. (6) Volumes hold struct refs, but aren't active users. (7) Both counts are displayed in /proc/net/afs/cells. There are some management function changes: (*) afs_put_cell() now just decrements the refcount and triggers the RCU destruction if it becomes 0. It no longer sets a timer to have the manager do this. (*) afs_use_cell() and afs_unuse_cell() are added to increase and decrease the active count. afs_unuse_cell() sets the management timer. (*) afs_queue_cell() is added to queue a cell with approprate refs. There are also some other fixes: (*) Don't let /proc/net/afs/cells access a cell's vllist if it's NULL. (*) Make sure that candidate cells in lookups are properly destroyed rather than being simply kfree'd. This ensures the bits it points to are destroyed also. (*) afs_dec_cells_outstanding() is now called in cell destruction rather than at "final_destruction". This ensures that cell->net is still valid to the end of the destructor. (*) As a consequence of the previous two changes, move the increment of net->cells_outstanding that was at the point of insertion into the tree to the allocation routine to correctly balance things. Fixes: 989782dcdc91 ("afs: Overhaul cell database management") Signed-off-by: David Howells <dhowells@redhat.com>
2020-08-20afs: Don't use VL probe running state to make decisions outside probe codeDavid Howells1-1/+1
Don't use the running state for VL server probes to make decisions about which server to use as the state is cleared at the start of a probe and intermediate values might also be misleading. Instead, add a separate 'latest known' rtt in the afs_vlserver struct and a flag to indicate if the server is known to be responding and update these as and when we know what to change them to. Fixes: 3bf0fb6f33dd ("afs: Probe multiple fileservers simultaneously") Signed-off-by: David Howells <dhowells@redhat.com>
2020-08-20afs: Expose information from afs_vlserver through /proc for debuggingDavid Howells1-0/+5
Convert various bitfields in afs_vlserver::probe to a mask and then expose this and some other bits of information through /proc/net/afs/<cell>/vlservers to make it easier to debug VL server communication issues. Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-09afs: Fix memory leak in afs_put_sysnames()Zhihao Cheng1-0/+1
Fix afs_put_sysnames() to actually free the specified afs_sysnames object after its reference count has been decreased to zero and its contents have been released. Fixes: 6f8880d8e681557 ("afs: Implement @sys substitution handling") Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-04afs: Show more a bit more server state in /proc/net/afs/serversDavid Howells1-3/+7
Display more information about the state of a server record, including the flags, rtt and break counter plus the probe state for each server in /proc/net/afs/servers. Rearrange the server flags a bit to make them easier to read at a glance in the proc file. Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-04afs: Reorganise volume and server trees to be rooted on the cellDavid Howells1-9/+6
Reorganise afs_volume objects such that they're in a tree keyed on volume ID, rooted at on an afs_cell object rather than being in multiple trees, each of which is rooted on an afs_server object. afs_server structs become per-cell and acquire a pointer to the cell. The process of breaking a callback then starts with finding the server by its network address, following that to the cell and then looking up each volume ID in the volume tree. This is simpler than the afs_vol_interest/afs_cb_interest N:M mapping web and allows those structs and the code for maintaining them to be simplified or removed. It does make a couple of things a bit more tricky, though: (1) Operations now start with a volume, not a server, so there can be more than one answer as to whether or not the server we'll end up using supports the FS.InlineBulkStatus RPC. (2) CB RPC operations that specify the server UUID. There's still a tree of servers by UUID on the afs_net struct, but the UUIDs in it aren't guaranteed unique. Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-04afs: Detect cell aliases 1 - Cells with root volumesDavid Howells1-2/+3
Put in the first phase of cell alias detection. This part handles alias detection for cells that have root.cell volumes (which is expected to be likely). When a cell becomes newly active, it is probed for its root.cell volume, and if it has one, this volume is compared against other root.cell volumes to find out if the list of fileserver UUIDs have any in common - and if that's the case, do the address lists of those fileservers have any addresses in common. If they do, the new cell is adjudged to be an alias of the old cell and the old cell is used instead. Comparing is aided by the server list in struct afs_server_list being sorted in UUID order and the addresses in the fileserver address lists being sorted in address order. The cell then retains the afs_volume object for the root.cell volume, even if it's not mounted for future alias checking. This necessary because: (1) Whilst fileservers have UUIDs that are meant to be globally unique, in practice they are not because cells get cloned without changing the UUIDs - so afs_server records need to be per cell. (2) Sometimes the DNS is used to make cell aliases - but if we don't know they're the same, we may end up with multiple superblocks and multiple afs_server records for the same thing, impairing our ability to deliver callback notifications of third party changes (3) The fileserver RPC API doesn't contain the cell name, so it can't tell us which cell it's notifying and can't see that a change made to to one cell should notify the same client that's also accessed as the other cell. Reported-by: Jeffrey Altman <jaltman@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-31afs: Show more information in /proc/net/afs/serversDavid Howells1-8/+9
Show more information in /proc/net/afs/servers to make it easier to see what's going on with the server probing. Signed-off-by: David Howells <dhowells@redhat.com>
2020-05-31afs: Split the usage count on struct afs_serverDavid Howells1-4/+5
Split the usage count on the afs_server struct to have an active count that registers who's actually using it separately from the reference count on the object. This allows a future patch to dispatch polling probes without advancing the "unuse" time into the future each time we emit a probe, which would otherwise prevent unused server records from expiring. Included in this: (1) The latter part of afs_destroy_server() in which the RCU destruction of afs_server objects is invoked and the outstanding server count is decremented is split out into __afs_put_server(). (2) afs_put_server() now calls __afs_put_server() rather then setting the management timer. (3) The calls begun by afs_fs_give_up_all_callbacks() and afs_fs_get_capabilities() can now take a ref on the server record, so afs_destroy_server() can just drop its ref and needn't wait for the completion of these calls. They'll put the ref when they're done. (4) Because of (3), afs_fs_probe_done() no longer needs to wake up afs_destroy_server() with server->probe_outstanding. (5) afs_gc_servers can be simplified. It only needs to check if server->active is 0 rather than playing games with the refcount. (6) afs_manage_servers() can propose a server for gc if usage == 0 rather than if ref == 1. The gc is effected by (5). Signed-off-by: David Howells <dhowells@redhat.com>
2019-12-11afs: Show volume name in /proc/net/afs/<cell>/volumesDavid Howells1-3/+4
Show the name of each volume in /proc/net/afs/<cell>/volumes to make it easier to work out the name corresponding to a volume ID. This makes it easier to work out which mounts in /proc/mounts correspond to which volume ID. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner1-5/+1
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 license as published by the free software foundation either version 2 of the license 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 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-15afs: Fix afs_cell records to always have a VL server list recordDavid Howells1-4/+4
Fix it such that afs_cell records always have a VL server list record attached, even if it's a dummy one, so that various checks can be removed. Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-24afs: Probe multiple fileservers simultaneouslyDavid Howells1-3/+3
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 <dhowells@redhat.com>
2018-10-24afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFSDavid Howells1-1/+1
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 <dhowells@redhat.com>
2018-10-24afs: Fix TTL on VL server and address listsDavid Howells1-3/+11
Currently the TTL on VL server and address lists isn't set in all circumstances and may be set to poor choices in others, since the TTL is derived from the SRV/AFSDB DNS record if and when available. Fix the TTL by limiting the range to a minimum and maximum from the current time. At some point these can be made into sysctl knobs. Further, use the TTL we obtained from the upcall to set the expiry on negative results too; in future a mechanism can be added to force reloading of such data. Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-24afs: Implement VL server rotationDavid Howells1-22/+68
Track VL servers as independent entities rather than lumping all their addresses together into one set and implement server-level rotation by: (1) Add the concept of a VL server list, where each server has its own separate address list. This code is similar to the FS server list. (2) Use the DNS resolver to retrieve a set of servers and their associated addresses, ports, preference and weight ratings. (3) In the case of a legacy DNS resolver or an address list given directly through /proc/net/afs/cells, create a list containing just a dummy server record and attach all the addresses to that. (4) Implement a simple rotation policy, for the moment ignoring the priorities and weights assigned to the servers. (5) Show the address list through /proc/net/afs/<cell>/vlservers. This also displays the source and status of the data as indicated by the upcall. Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-12afs: Fix cell proc listDavid Howells1-4/+3
Access to the list of cells by /proc/net/afs/cells has a couple of problems: (1) It should be checking against SEQ_START_TOKEN for the keying the header line. (2) It's only holding the RCU read lock, so it can't just walk over the list without following the proper RCU methods. Fix these by using an hlist instead of an ordinary list and using the appropriate accessor functions to follow it with RCU. Since the code that adds a cell to the list must also necessarily change, sort the list on insertion whilst we're at it. Fixes: 989782dcdc91 ("afs: Overhaul cell database management") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-07afs: Fix cell specification to permit an empty address listDavid Howells1-8/+7
Fix the cell specification mechanism to allow cells to be pre-created without having to specify at least one address (the addresses will be upcalled for). This allows the cell information preload service to avoid the need to issue loads of DNS lookups during boot to get the addresses for each cell (500+ lookups for the 'standard' cell list[*]). The lookups can be done later as each cell is accessed through the filesystem. Also remove the print statement that prints a line every time a new cell is added. [*] There are 144 cells in the list. Each cell is first looked up for an SRV record, and if that fails, for an AFSDB record. These get a list of server names, each of which then has to be looked up to get the addresses for that server. E.g.: dig srv _afs3-vlserver._udp.grand.central.org Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-15afs: Show all of a server's addresses in /proc/fs/afs/serversDavid Howells1-2/+8
Show all of a server's addresses in /proc/fs/afs/servers, placing the second plus addresses on padded lines of their own. The current address is marked with a star. Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-23afs: Implement network namespacingDavid Howells1-255/+103
Implement network namespacing within AFS, but don't yet let mounts occur outside the init namespace. An additional patch will be required propagate the network namespace across automounts. Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-23afs: Mark afs_net::ws_cell as __rcu and set using rcu functionsDavid Howells1-1/+1
The afs_net::ws_cell member is sometimes used under RCU conditions from within an seq-readlock. It isn't, however, marked __rcu and it isn't set using the proper RCU barrier-imposing functions. Fix this by annotating it with __rcu and using appropriate barriers to make sure accesses are correctly ordered. Without this, the code can produce the following warning: >> fs/afs/proc.c:151:24: sparse: incompatible types in comparison expression (different address spaces) Fixes: f044c8847bb6 ("afs: Lay the groundwork for supporting network namespaces") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-18afs: Rearrange fs/afs/proc.c to remove remaining predeclarations.David Howells1-192/+160
Rearrange fs/afs/proc.c to get rid of all the remaining predeclarations. Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-18afs: Rearrange fs/afs/proc.c to move the show routines upDavid Howells1-75/+75
Rearrange fs/afs/proc.c to move the show routines up to the top of each block so the order is show, iteration, ops, file ops, fops. Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-18afs: Rearrange fs/afs/proc.c by moving fops and open functions downDavid Howells1-44/+27
Rearrange fs/afs/proc.c by moving fops and open functions down so as to remove predeclarations. Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-18afs: Move /proc management functions to the end of the fileDavid Howells1-81/+79
In fs/afs/proc.c, move functions that create and remove /proc files to the end of the source file as a first stage in getting rid of all the forward declarations. Signed-off-by: David Howells <dhowells@redhat.com>
2018-05-16afs: simplify procfs codeChristoph Hellwig1-119/+15
Use remove_proc_subtree to remove the whole subtree on cleanup, and unwind the registration loop into individual calls. Switch to use proc_create_seq where applicable. Signed-off-by: Christoph Hellwig <hch@lst.de>
2018-04-09afs: Add stats for data transfer operationsDavid Howells1-0/+7
Add statistics to /proc/fs/afs/stats for data transfer RPC operations. New lines are added that look like: file-rd : n=55794 nb=10252282150 file-wr : n=9789 nb=3247763645 where n= indicates the number of ops completed and nb= indicates the number of bytes successfully transferred. file-rd is the counts for read/fetch operations and file-wr the counts for write/store operations. Note that directory and symlink downloading are included in the file-rd stats at the moment. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09afs: Locally edit directory data for mkdir/create/unlink/...David Howells1-0/+4
Locally edit the contents of an AFS directory upon a successful inode operation that modifies that directory (such as mkdir, create and unlink) so that we can avoid the current practice of re-downloading the directory after each change. This is viable provided that the directory version number we get back from the modifying RPC op is exactly incremented by 1 from what we had previously. The data in the directory contents is in a defined format that we have to parse locally to perform lookups and readdir, so modifying isn't a problem. If the edit fails, we just clear the VALID flag on the directory and it will be reloaded next time it is needed. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09afs: Fix directory handlingDavid Howells1-2/+3
AFS directories are structured blobs that are downloaded just like files and then parsed by the lookup and readdir code and, as such, are currently handled in the pagecache like any other file, with the entire directory content being thrown away each time the directory changes. However, since the blob is a known structure and since the data version counter on a directory increases by exactly one for each change committed to that directory, we can actually edit the directory locally rather than fetching it from the server after each locally-induced change. What we can't do, though, is mix data from the server and data from the client since the server is technically at liberty to rearrange or compress a directory if it sees fit, provided it updates the data version number when it does so and breaks the callback (ie. sends a notification). Further, lookup with lookup-ahead, readdir and, when it arrives, local editing are likely want to scan the whole of a directory. So directory handling needs to be improved to maintain the coherency of the directory blob prior to permitting local directory editing. To this end: (1) If any directory page gets discarded, invalidate and reread the entire directory. (2) If readpage notes that if when it fetches a single page that the version number has changed, the entire directory is flagged for invalidation. (3) Read as much of the directory in one go as we can. Note that this removes local caching of directories in fscache for the moment as we can't pass the pages to fscache_read_or_alloc_pages() since page->lru is in use by the LRU. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09afs: Introduce a statistics proc fileDavid Howells1-0/+37
Introduce a proc file that displays a bunch of statistics for the AFS filesystem in the current network namespace. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09afs: Implement @cell substitution handlingDavid Howells1-1/+34
Implement @cell substitution handling such that if @cell is seen as a name in a dynamic root mount, then the name of the root cell for that network namespace will be substituted for @cell during lookup. The substitution of @cell for the current net namespace is set by writing the cell name to /proc/fs/afs/rootcell. The value can be obtained by reading the file. For example: # mount -t afs none /kafs -o dyn # echo grand.central.org >/proc/fs/afs/rootcell # ls /kafs/@cell archive/ cvs/ doc/ local/ project/ service/ software/ user/ www/ # cat /proc/fs/afs/rootcell grand.central.org Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09afs: Implement @sys substitution handlingDavid Howells1-1/+230
Implement the AFS feature by which @sys at the end of a pathname component may be substituted for one of a list of values, typically naming the operating system. Up to 16 alternatives may be specified and these are tried in turn until one works. Each network namespace has[*] a separate independent list. Upon creation of a new network namespace, the list of values is initialised[*] to a single OpenAFS-compatible string representing arch type plus "_linux26". For example, on x86_64, the sysname is "amd64_linux26". [*] Or will, once network namespace support is finalised in kAFS. The list may be set by: # for i in foo bar linux-x86_64; do echo $i; done >/proc/fs/afs/sysname for which separate writes to the same fd are amalgamated and applied on close. The LF character may be used as a separator to specify multiple items in the same write() call. The list may be cleared by: # echo >/proc/fs/afs/sysname and read by: # cat /proc/fs/afs/sysname foo bar linux-x86_64 Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09afs: Don't over-increment the cell usage count when pinning itDavid Howells1-1/+2
AFS cells that are added or set as the workstation cell through /proc are pinned against removal by setting the AFS_CELL_FL_NO_GC flag on them and taking a ref. The ref should be only taken if the flag wasn't already set. Fix this by making it conditional. Without this an assertion failure will occur during module removal indicating that the refcount is too elevated. Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09afs: Fix checker warningsDavid Howells1-0/+8
Fix warnings raised by checker, including: (*) Warnings raised by unequal comparison for the purposes of sorting, where the endianness doesn't matter: fs/afs/addr_list.c:246:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:246:30: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:248:21: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:248:49: warning: restricted __be32 degrades to integer fs/afs/addr_list.c:283:21: warning: restricted __be16 degrades to integer fs/afs/addr_list.c:283:30: warning: restricted __be16 degrades to integer (*) afs_set_cb_interest() is not actually used and can be removed. (*) afs_cell_gc_delay() should be provided with a sysctl. (*) afs_cell_destroy() needs to use rcu_access_pointer() to read cell->vl_addrs. (*) afs_init_fs_cursor() should be static. (*) struct afs_vnode::permit_cache needs to be marked __rcu. (*) afs_server_rcu() needs to use rcu_access_pointer(). (*) afs_destroy_server() should use rcu_access_pointer() on server->addresses as the server object is no longer accessible. (*) afs_find_server() casts __be16/__be32 values to int in order to directly compare them for the purpose of finding a match in a list, but is should also annotate the cast with __force to avoid checker warnings. (*) afs_check_permit() accesses vnode->permit_cache outside of the RCU readlock, though it doesn't then access the value; the extraneous access is deleted. False positives: (*) Conditional locking around the code in xdr_decode_AFSFetchStatus. This can be dealt with in a separate patch. fs/afs/fsclient.c:148:9: warning: context imbalance in 'xdr_decode_AFSFetchStatus' - different lock contexts for basic block (*) Incorrect handling of seq-retry lock context balance: fs/afs/inode.c:455:38: warning: context imbalance in 'afs_getattr' - different lock contexts for basic block fs/afs/server.c:52:17: warning: context imbalance in 'afs_find_server' - different lock contexts for basic block fs/afs/server.c:128:17: warning: context imbalance in 'afs_find_server_by_uuid' - different lock contexts for basic block Errors: (*) afs_lookup_cell_rcu() needs to break out of the seq-retry loop, not go round again if it successfully found the workstation cell. (*) Fix UUID decode in afs_deliver_cb_probe_uuid(). (*) afs_cache_permit() has a missing rcu_read_unlock() before one of the jumps to the someone_else_changed_it label. Move the unlock to after the label. (*) afs_vl_get_addrs_u() is using ntohl() rather than htonl() when encoding to XDR. (*) afs_deliver_yfsvl_get_endpoints() is using htonl() rather than ntohl() when decoding from XDR. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13afs: Overhaul volume and server record caching and fileserver rotationDavid Howells1-95/+58
The current code assumes that volumes and servers are per-cell and are never shared, but this is not enforced, and, indeed, public cells do exist that are aliases of each other. Further, an organisation can, say, set up a public cell and a private cell with overlapping, but not identical, sets of servers. The difference is purely in the database attached to the VL servers. The current code will malfunction if it sees a server in two cells as it assumes global address -> server record mappings and that each server is in just one cell. Further, each server may have multiple addresses - and may have addresses of different families (IPv4 and IPv6, say). To this end, the following structural changes are made: (1) Server record management is overhauled: (a) Server records are made independent of cell. The namespace keeps track of them, volume records have lists of them and each vnode has a server on which its callback interest currently resides. (b) The cell record no longer keeps a list of servers known to be in that cell. (c) The server records are now kept in a flat list because there's no single address to sort on. (d) Server records are now keyed by their UUID within the namespace. (e) The addresses for a server are obtained with the VL.GetAddrsU rather than with VL.GetEntryByName, using the server's UUID as a parameter. (f) Cached server records are garbage collected after a period of non-use and are counted out of existence before purging is allowed to complete. This protects the work functions against rmmod. (g) The servers list is now in /proc/fs/afs/servers. (2) Volume record management is overhauled: (a) An RCU-replaceable server list is introduced. This tracks both servers and their coresponding callback interests. (b) The superblock is now keyed on cell record and numeric volume ID. (c) The volume record is now tied to the superblock which mounts it, and is activated when mounted and deactivated when unmounted. This makes it easier to handle the cache cookie without causing a double-use in fscache. (d) The volume record is loaded from the VLDB using VL.GetEntryByNameU to get the server UUID list. (e) The volume name is updated if it is seen to have changed when the volume is updated (the update is keyed on the volume ID). (3) The vlocation record is got rid of and VLDB records are no longer cached. Sufficient information is stored in the volume record, though an update to a volume record is now no longer shared between related volumes (volumes come in bundles of three: R/W, R/O and backup). and the following procedural changes are made: (1) The fileserver cursor introduced previously is now fleshed out and used to iterate over fileservers and their addresses. (2) Volume status is checked during iteration, and the server list is replaced if a change is detected. (3) Server status is checked during iteration, and the address list is replaced if a change is detected. (4) The abort code is saved into the address list cursor and -ECONNABORTED returned in afs_make_call() if a remote abort happened rather than translating the abort into an error message. This allows actions to be taken depending on the abort code more easily. (a) If a VMOVED abort is seen then this is handled by rechecking the volume and restarting the iteration. (b) If a VBUSY, VRESTARTING or VSALVAGING abort is seen then this is handled by sleeping for a short period and retrying and/or trying other servers that might serve that volume. A message is also displayed once until the condition has cleared. (c) If a VOFFLINE abort is seen, then this is handled as VBUSY for the moment. (d) If a VNOVOL abort is seen, the volume is rechecked in the VLDB to see if it has been deleted; if not, the fileserver is probably indicating that the volume couldn't be attached and needs salvaging. (e) If statfs() sees one of these aborts, it does not sleep, but rather returns an error, so as not to block the umount program. (5) The fileserver iteration functions in vnode.c are now merged into their callers and more heavily macroised around the cursor. vnode.c is removed. (6) Operations on a particular vnode are serialised on that vnode because the server will lock that vnode whilst it operates on it, so a second op sent will just have to wait. (7) Fileservers are probed with FS.GetCapabilities before being used. This is where service upgrade will be done. (8) A callback interest on a fileserver is set up before an FS operation is performed and passed through to afs_make_call() so that it can be set on the vnode if the operation returns a callback. The callback interest is passed through to afs_iget() also so that it can be set there too. In general, record updating is done on an as-needed basis when we try to access servers, volumes or vnodes rather than offloading it to work items and special threads. Notes: (1) Pre AFS-3.4 servers are no longer supported, though this can be added back if necessary (AFS-3.4 was released in 1998). (2) VBUSY is retried forever for the moment at intervals of 1s. (3) /proc/fs/afs/<cell>/servers no longer exists. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13afs: Add an address list conceptDavid Howells1-12/+11
Add an RCU replaceable address list structure to hold a list of server addresses. The list also holds the To this end: (1) A cell's VL server address list can be loaded directly via insmod or echo to /proc/fs/afs/cells or dynamically from a DNS query for AFSDB or SRV records. (2) Anyone wanting to use a cell's VL server address must wait until the cell record comes online and has tried to obtain some addresses. (3) An FS server's address list, for the moment, has a single entry that is the key to the server list. This will change in the future when a server is instead keyed on its UUID and the VL.GetAddrsU operation is used. (4) An 'address cursor' concept is introduced to handle iteration through the address list. This is passed to the afs_make_call() as, in the future, stuff (such as abort code) that doesn't outlast the call will be returned in it. In the future, we might want to annotate the list with information about how each address fares. We might then want to propagate such annotations over address list replacement. Whilst we're at it, we allow IPv6 addresses to be specified in colon-delimited lists by enclosing them in square brackets. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13afs: Overhaul cell database managementDavid Howells1-9/+6
Overhaul the way that the in-kernel AFS client keeps track of cells in the following manner: (1) Cells are now held in an rbtree to make walking them quicker and RCU managed (though this is probably overkill). (2) Cells now have a manager work item that: (A) Looks after fetching and refreshing the VL server list. (B) Manages cell record lifetime, including initialising and destruction. (B) Manages cell record caching whereby threads are kept around for a certain time after last use and then destroyed. (C) Manages the FS-Cache index cookie for a cell. It is not permitted for a cookie to be in use twice, so we have to be careful to not allow a new cell record to exist at the same time as an old record of the same name. (3) Each AFS network namespace is given a manager work item that manages the cells within it, maintaining a single timer to prod cells into updating their DNS records. This uses the reduce_timer() facility to make the timer expire at the soonest timed event that needs happening. (4) When a module is being unloaded, cells and cell managers are now counted out using dec_after_work() to make sure the module text is pinned until after the data structures have been cleaned up. (5) Each cell's VL server list is now protected by a seqlock rather than a semaphore. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13afs: Allow IPv6 address specification of VL serversDavid Howells1-1/+1
Allow VL server specifications to be given IPv6 addresses as well as IPv4 addresses, for example as: echo add foo.org 1111:2222:3333:0:4444:5555:6666:7777 >/proc/fs/afs/cells Note that ':' is the expected separator for separating IPv4 addresses, but if a ',' is detected or no '.' is detected in the string, the delimiter is switched to ','. This also works with DNS AFSDB or SRV record strings fetched by upcall from userspace. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13afs: Keep and pass sockaddr_rxrpc addresses rather than in_addrDavid Howells1-5/+5
Keep and pass sockaddr_rxrpc addresses around rather than keeping and passing in_addr addresses to allow for the use of IPv6 and non-standard port numbers in future. This also allows the port and service_id fields to be removed from the afs_call struct. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13afs: Push the net ns pointer to more placesDavid Howells1-1/+1
Push the network namespace pointer to more places in AFS, including the afs_server structure (which doesn't hold a ref on the netns). In particular, afs_put_cell() now takes requires a net ns parameter so that it can safely alter the netns after decrementing the cell usage count - the cell will be deallocated by a background thread after being cached for a period, which means that it's not safe to access it after reducing its usage count. Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13afs: Lay the groundwork for supporting network namespacesDavid Howells1-24/+40
Lay the groundwork for supporting network namespaces (netns) to the AFS filesystem by moving various global features to a network-namespace struct (afs_net) and providing an instance of this as a temporary global variable that everything uses via accessor functions for the moment. The following changes have been made: (1) Store the netns in the superblock info. This will be obtained from the mounter's nsproxy on a manual mount and inherited from the parent superblock on an automount. (2) The cell list is made per-netns. It can be viewed through /proc/net/afs/cells and also be modified by writing commands to that file. (3) The local workstation cell is set per-ns in /proc/net/afs/rootcell. This is unset by default. (4) The 'rootcell' module parameter, which sets a cell and VL server list modifies the init net namespace, thereby allowing an AFS root fs to be theoretically used. (5) The volume location lists and the file lock manager are made per-netns. (6) The AF_RXRPC socket and associated I/O bits are made per-ns. The various workqueues remain global for the moment. Changes still to be made: (1) /proc/fs/afs/ should be moved to /proc/net/afs/ and a symlink emplaced from the old name. (2) A per-netns subsys needs to be registered for AFS into which it can store its per-netns data. (3) Rather than the AF_RXRPC socket being opened on module init, it needs to be opened on the creation of a superblock in that netns. (4) The socket needs to be closed when the last superblock using it is destroyed and all outstanding client calls on it have been completed. This prevents a reference loop on the namespace. (5) It is possible that several namespaces will want to use AFS, in which case each one will need its own UDP port. These can either be set through /proc/net/afs/cm_port or the kernel can pick one at random. The init_ns gets 7001 by default. Other issues that need resolving: (1) The DNS keyring needs net-namespacing. (2) Where do upcalls go (eg. DNS request-key upcall)? (3) Need something like open_socket_in_file_ns() syscall so that AFS command line tools attempting to operate on an AFS file/volume have their RPC calls go to the right place. Signed-off-by: David Howells <dhowells@redhat.com>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds1-1/+1
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-04convert a bunch of open-coded instances of memdup_user_nul()Al Viro1-19/+6
A _lot_ of ->write() instances were open-coding it; some are converted to memdup_user_nul(), a lot more remain... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-02-01afs: proc cells and rootcell are writeablePali Rohár1-2/+2
Both proc files are writeable and used for configuring cells. But there is missing correct mode flag for writeable files. Without this patch both proc files are read only. [ It turns out they aren't really read-only, since root can write to them even if the write bit isn't set due to CAP_DAC_OVERRIDE ] Signed-off-by: Pali Rohár <pali.rohar@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-25afs: get rid of junk in fs/afs/proc.cAl Viro1-100/+22
kill pointless method instances and don't bother with ->owner - it's ignored for procfs files anyway, make use of remove_proc_subtree() for removal, get rid of cell->proc_dir. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-04-09procfs: new helper - PDE_DATA(inode)Al Viro1-4/+4
The only part of proc_dir_entry the code outside of fs/proc really cares about is PDE(inode)->data. Provide a helper for that; static inline for now, eventually will be moved to fs/proc, along with the knowledge of struct proc_dir_entry layout. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-11AFS: Implement an autocell mount capability [ver #2]wanglei1-1/+1
Implement the ability for the root directory of a mounted AFS filesystem to accept lookups of arbitrary directory names, to interpet the names as the names of cells, to look the cell names up in the DNS for AFSDB records and to mount the root.cell volume of the nominated cell on the pseudo-directory created by lookup. This facility is requested by passing: -o autocell to the mountpoint for which this is desired, usually the /afs mount. To use this facility, a DNS upcall program is required for AFSDB records. This can be obtained from: http://people.redhat.com/~dhowells/afs/dns.afsdb.c It should be compiled with -lresolv and -lkeyutils and installed as, say: /usr/sbin/dns.afsdb Then the following line needs to be added to /sbin/request-key.conf: create dns_resolver afsdb:* * /usr/sbin/dns.afsdb %k This can be tested by mounting AFS, say: insmod dns_resolver.ko insmod af-rxrpc.ko insmod kafs.ko rootcell=grand.central.org mount -t afs "#grand.central.org:root.cell." /afs -o autocell and doing: ls /afs/grand.central.org/ which should show: archive/ cvs/ doc/ local/ project/ service/ software/ user/ www/ if it works. Signed-off-by: Wang Lei <wang840925@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>