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* afs: Build an abstraction around an "operation" conceptDavid Howells2020-06-041-173/+127
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Turn the afs_operation struct into the main way that most fileserver operations are managed. Various things are added to the struct, including the following: (1) All the parameters and results of the relevant operations are moved into it, removing corresponding fields from the afs_call struct. afs_call gets a pointer to the op. (2) The target volume is made the main focus of the operation, rather than the target vnode(s), and a bunch of op->vnode->volume are made op->volume instead. (3) Two vnode records are defined (op->file[]) for the vnode(s) involved in most operations. The vnode record (struct afs_vnode_param) contains: - The vnode pointer. - The fid of the vnode to be included in the parameters or that was returned in the reply (eg. FS.MakeDir). - The status and callback information that may be returned in the reply about the vnode. - Callback break and data version tracking for detecting simultaneous third-parth changes. (4) Pointers to dentries to be updated with new inodes. (5) An operations table pointer. The table includes pointers to functions for issuing AFS and YFS-variant RPCs, handling the success and abort of an operation and handling post-I/O-lock local editing of a directory. To make this work, the following function restructuring is made: (A) The rotation loop that issues calls to fileservers that can be found in each function that wants to issue an RPC (such as afs_mkdir()) is extracted out into common code, in a new file called fs_operation.c. (B) The rotation loops, such as the one in afs_mkdir(), are replaced with a much smaller piece of code that allocates an operation, sets the parameters and then calls out to the common code to do the actual work. (C) The code for handling the success and failure of an operation are moved into operation functions (as (5) above) and these are called from the core code at appropriate times. (D) The pseudo inode getting stuff used by the dynamic root code is moved over into dynroot.c. (E) struct afs_iget_data is absorbed into the operation struct and afs_iget() expects to be given an op pointer and a vnode record. (F) Point (E) doesn't work for the root dir of a volume, but we know the FID in advance (it's always vnode 1, unique 1), so a separate inode getter, afs_root_iget(), is provided to special-case that. (G) The inode status init/update functions now also take an op and a vnode record. (H) The RPC marshalling functions now, for the most part, just take an afs_operation struct as their only argument. All the data they need is held there. The result delivery functions write their answers there as well. (I) The call is attached to the operation and then the operation core does the waiting. And then the new operation code is, for the moment, made to just initialise the operation, get the appropriate vnode I/O locks and do the same rotation loop as before. This lays the foundation for the following changes in the future: (*) Overhauling the rotation (again). (*) Support for asynchronous I/O, where the fileserver rotation must be done asynchronously also. Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Rename struct afs_fs_cursor to afs_operationDavid Howells2020-05-311-4/+4
| | | | | | | | | | As a prelude to implementing asynchronous fileserver operations in the afs filesystem, rename struct afs_fs_cursor to afs_operation. This struct is going to form the core of the operation management and is going to acquire more members in later. Signed-off-by: David Howells <dhowells@redhat.com>
* afs: xattr: use scnprintfMark Salyzyn2019-11-211-7/+9
| | | | | | | | | | | | | | sprintf and snprintf are fragile in future maintenance, switch to using scnprintf to ensure no accidental Use After Free conditions are introduced. Signed-off-by: Mark Salyzyn <salyzyn@android.com> Cc: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: David Howells <dhowells@redhat.com> Cc: linux-afs@lists.infradead.org Cc: Jan Kara <jack@suse.cz> Signed-off-by: David Howells <dhowells@redhat.com>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36Thomas Gleixner2019-05-241-5/+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 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 <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* afs: Fix application of status and callback to be under same lockDavid Howells2019-05-161-28/+75
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When applying the status and callback in the response of an operation, apply them in the same critical section so that there's no race between checking the callback state and checking status-dependent state (such as the data version). Fix this by: (1) Allocating a joint {status,callback} record (afs_status_cb) before calling the RPC function for each vnode for which the RPC reply contains a status or a status plus a callback. A flag is set in the record to indicate if a callback was actually received. (2) These records are passed into the RPC functions to be filled in. The afs_decode_status() and yfs_decode_status() functions are removed and the cb_lock is no longer taken. (3) xdr_decode_AFSFetchStatus() and xdr_decode_YFSFetchStatus() no longer update the vnode. (4) xdr_decode_AFSCallBack() and xdr_decode_YFSCallBack() no longer update the vnode. (5) vnodes, expected data-version numbers and callback break counters (cb_break) no longer need to be passed to the reply delivery functions. Note that, for the moment, the file locking functions still need access to both the call and the vnode at the same time. (6) afs_vnode_commit_status() is now given the cb_break value and the expected data_version and the task of applying the status and the callback to the vnode are now done here. This is done under a single taking of vnode->cb_lock. (7) afs_pages_written_back() is now called by afs_store_data() rather than by the reply delivery function. afs_pages_written_back() has been moved to before the call point and is now given the first and last page numbers rather than a pointer to the call. (8) The indicator from YFS.RemoveFile2 as to whether the target file actually got removed (status.abort_code == VNOVNODE) rather than merely dropping a link is now checked in afs_unlink rather than in xdr_decode_YFSFetchStatus(). Supplementary fixes: (*) afs_cache_permit() now gets the caller_access mask from the afs_status_cb object rather than picking it out of the vnode's status record. afs_fetch_status() returns caller_access through its argument list for this purpose also. (*) afs_inode_init_from_status() now uses a write lock on cb_lock rather than a read lock and now sets the callback inside the same critical section. Fixes: c435ee34551e ("afs: Overhaul the callback handling") Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Make some RPC operations non-interruptibleDavid Howells2019-05-161-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <jsbillings@jsbillings.org> Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Fix afs_xattr_get_yfs() to not try freeing an error valueDavid Howells2019-05-151-40/+46
| | | | | | | | | | | | | afs_xattr_get_yfs() tries to free yacl, which may hold an error value (say if yfs_fs_fetch_opaque_acl() failed and returned an error). Fix this by allocating yacl up front (since it's a fixed-length struct, unlike afs_acl) and passing it in to the RPC function. This also allows the flags to be placed in the object rather than passing them through to the RPC function. Fixes: ae46578b963f ("afs: Get YFS ACLs and information through xattrs") Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Fix incorrect error handling in afs_xattr_get_acl()David Howells2019-05-151-5/+4
| | | | | | | | | | | | Fix incorrect error handling in afs_xattr_get_acl() where there appears to be a redundant assignment before return, but in fact the return should be a goto to the error handling at the end of the function. Fixes: 260f082bae6d ("afs: Get an AFS3 ACL as an xattr") Addresses-Coverity: ("Unused Value") Reported-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Joe Perches <joe@perches.com>
* afs: Implement YFS ACL settingDavid Howells2019-05-071-0/+49
| | | | | | | Implement the setting of YFS ACLs in AFS through the interface of setting the afs.yfs.acl extended attribute on the file. Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Get YFS ACLs and information through xattrsDavid Howells2019-05-071-1/+100
| | | | | | | | | | | | | | | | | | | | | | | | | | | The YFS/AuriStor variant of AFS provides more capable ACLs and provides per-volume ACLs and per-file ACLs as well as per-directory ACLs. It also provides some extra information that can be retrieved through four ACLs: (1) afs.yfs.acl The YFS file ACL (not the same format as afs.acl). (2) afs.yfs.vol_acl The YFS volume ACL. (3) afs.yfs.acl_inherited "1" if a file's ACL is inherited from its parent directory, "0" otherwise. (4) afs.yfs.acl_num_cleaned The number of of ACEs removed from the ACL by the server because the PT entries were removed from the PTS database (ie. the subject is no longer known). Signed-off-by: David Howells <dhowells@redhat.com>
* afs: implement acl settingJoe Gorse2019-05-071-2/+50
| | | | | | | | Implements the setting of ACLs in AFS by means of setting the afs.acl extended attribute on the file. Signed-off-by: Joe Gorse <jhgorse@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Get an AFS3 ACL as an xattrDavid Howells2019-05-071-0/+53
| | | | | | | | | | | Implement an xattr on AFS files called "afs.acl" that retrieves a file's ACL. It returns the raw AFS3 ACL from the result of calling FS.FetchACL, leaving any interpretation to userspace. Note that whilst YFS servers will respond to FS.FetchACL, this will render a more-advanced YFS ACL down. Use "afs.yfs.acl" instead for that. Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Fix getting the afs.fid xattrDavid Howells2019-05-071-3/+12
| | | | | | | | | | | | | | | | | | The AFS3 FID is three 32-bit unsigned numbers and is represented as three up-to-8-hex-digit numbers separated by colons to the afs.fid xattr. However, with the advent of support for YFS, the FID is now a 64-bit volume number, a 96-bit vnode/inode number and a 32-bit uniquifier (as before). Whilst the sprintf in afs_xattr_get_fid() has been partially updated (it currently ignores the upper 32 bits of the 96-bit vnode number), the size of the stack-based buffer has not been increased to match, thereby allowing stack corruption to occur. Fix this by increasing the buffer size appropriately and conditionally including the upper part of the vnode number if it is non-zero. The latter requires the lower part to be zero-padded if the upper part is non-zero. Fixes: 3b6492df4153 ("afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFS") Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Fix the afs.cell and afs.volume xattr handlersDavid Howells2019-05-071-2/+2
| | | | | | | | | | Fix the ->get handlers for the afs.cell and afs.volume xattrs to pass the source data size to memcpy() rather than target buffer size. Overcopying the source data occasionally causes the kernel to oops. Fixes: d3e3b7eac886 ("afs: Add metadata xattrs") Signed-off-by: David Howells <dhowells@redhat.com>
* afs: Increase to 64-bit volume ID and 96-bit vnode ID for YFSDavid Howells2018-10-241-1/+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>
* afs: Overhaul volume and server record caching and fileserver rotationDavid Howells2017-11-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* afs: Overhaul cell database managementDavid Howells2017-11-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* afs: Add metadata xattrsDavid Howells2017-07-091-0/+121
Add xattrs to allow the user to get/set metadata in lieu of having pioctl() available. The following xattrs are now available: - "afs.cell" The name of the cell in which the vnode's volume resides. - "afs.fid" The volume ID, vnode ID and vnode uniquifier of the file as three hex numbers separated by colons. - "afs.volume" The name of the volume in which the vnode resides. For example: # getfattr -d -m ".*" /mnt/scratch getfattr: Removing leading '/' from absolute path names # file: mnt/scratch afs.cell="mycell.myorg.org" afs.fid="10000b:1:1" afs.volume="scratch" Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>