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2023-01-14afs: Fix lost servers_outstanding countDavid Howells1-1/+4
[ Upstream commit 36f82c93ee0bd88f1c95a52537906b8178b537f1 ] The afs_fs_probe_dispatcher() work function is passed a count on net->servers_outstanding when it is scheduled (which may come via its timer). This is passed back to the work_item, passed to the timer or dropped at the end of the dispatcher function. But, at the top of the dispatcher function, there are two checks which skip the rest of the function: if the network namespace is being destroyed or if there are no fileservers to probe. These two return paths, however, do not drop the count passed to the dispatcher, and so, sometimes, the destruction of a network namespace, such as induced by rmmod of the kafs module, may get stuck in afs_purge_servers(), waiting for net->servers_outstanding to become zero. Fix this by adding the missing decrements in afs_fs_probe_dispatcher(). Fixes: f6cbb368bcb0 ("afs: Actively poll fileservers to maintain NAT or firewall openings") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/167164544917.2072364.3759519569649459359.stgit@warthog.procyon.org.uk/ Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-08afs: Fix fileserver probe RTT handlingDavid Howells1-2/+2
[ Upstream commit ca57f02295f188d6c65ec02202402979880fa6d8 ] The fileserver probing code attempts to work out the best fileserver to use for a volume by retrieving the RTT calculated by AF_RXRPC for the probe call sent to each server and comparing them. Sometimes, however, no RTT estimate is available and rxrpc_kernel_get_srtt() returns false, leading good fileservers to be given an RTT of UINT_MAX and thus causing the rotation algorithm to ignore them. Fix afs_select_fileserver() to ignore rxrpc_kernel_get_srtt()'s return value and just take the estimated RTT it provides - which will be capped at 1 second. Fixes: 1d4adfaf6574 ("rxrpc: Make rxrpc_kernel_get_srtt() indicate validity") Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Tested-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/166965503999.3392585.13954054113218099395.stgit@warthog.procyon.org.uk/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-23afs: Return -EAGAIN, not -EREMOTEIO, when a file already lockedDavid Howells1-0/+1
[ Upstream commit 0066f1b0e27556381402db3ff31f85d2a2265858 ] When trying to get a file lock on an AFS file, the server may return UAEAGAIN to indicate that the lock is already held. This is currently translated by the default path to -EREMOTEIO. Translate it instead to -EAGAIN so that we know we can retry it. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeffrey E Altman <jaltman@auristor.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/166075761334.3533338.2591992675160918098.stgit@warthog.procyon.org.uk/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-15afs: Use the operation issue time instead of the reply time for callbacksDavid Howells5-12/+5
[ Upstream commit 7903192c4b4a82d792cb0dc5e2779a2efe60d45b ] rxrpc and kafs between them try to use the receive timestamp on the first data packet (ie. the one with sequence number 1) as a base from which to calculate the time at which callback promise and lock expiration occurs. However, we don't know how long it took for the server to send us the reply from it having completed the basic part of the operation - it might then, for instance, have to send a bunch of a callback breaks, depending on the particular operation. Fix this by using the time at which the operation is issued on the client as a base instead. That should never be longer than the server's idea of the expiry time. Fixes: 781070551c26 ("afs: Fix calculation of callback expiry time") Fixes: 2070a3e44962 ("rxrpc: Allow the reply time to be obtained on a client call") Suggested-by: Jeffrey E Altman <jaltman@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-29afs: Fix dynamic root getattrDavid Howells1-1/+2
[ Upstream commit cb78d1b5efffe4cf97e16766329dd7358aed3deb ] The recent patch to make afs_getattr consult the server didn't account for the pseudo-inodes employed by the dynamic root-type afs superblock not having a volume or a server to access, and thus an oops occurs if such a directory is stat'd. Fix this by checking to see if the vnode->volume pointer actually points anywhere before following it in afs_getattr(). This can be tested by stat'ing a directory in /afs. It may be sufficient just to do "ls /afs" and the oops looks something like: BUG: kernel NULL pointer dereference, address: 0000000000000020 ... RIP: 0010:afs_getattr+0x8b/0x14b ... Call Trace: <TASK> vfs_statx+0x79/0xf5 vfs_fstatat+0x49/0x62 Fixes: 2aeb8c86d499 ("afs: Fix afs_getattr() to refetch file status if callback break occurred") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Tested-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/165408450783.1031787.7941404776393751186.stgit@warthog.procyon.org.uk/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-14afs: Fix infinite loop found by xfstest generic/676David Howells1-1/+4
[ Upstream commit 17eabd42560f4636648ad65ba5b20228071e2363 ] In AFS, a directory is handled as a file that the client downloads and parses locally for the purposes of performing lookup and getdents operations. The in-kernel afs filesystem has a number of functions that do this. A directory file is arranged as a series of 2K blocks divided into 32-byte slots, where a directory entry occupies one or more slots, plus each block starts with one or more metadata blocks. When parsing a block, if the last slots are occupied by a dirent that occupies more than a single slot and the file position points at a slot that's not the initial one, the logic in afs_dir_iterate_block() that skips over it won't advance the file pointer to the end of it. This will cause an infinite loop in getdents() as it will keep retrying that block and failing to advance beyond the final entry. Fix this by advancing the file pointer if the next entry will be beyond it when we skip a block. This was found by the generic/676 xfstest but can also be triggered with something like: ~/xfstests-dev/src/t_readdir_3 /xfstest.test/z 4000 1 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Tested-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: http://lore.kernel.org/r/165391973497.110268.2939296942213894166.stgit@warthog.procyon.org.uk/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-09rxrpc, afs: Fix selection of abort codesDavid Howells1-3/+5
[ Upstream commit de696c4784f0706884458893c5a6c39b3a3ff65c ] The RX_USER_ABORT code should really only be used to indicate that the user of the rxrpc service (ie. userspace) implicitly caused a call to be aborted - for instance if the AF_RXRPC socket is closed whilst the call was in progress. (The user may also explicitly abort a call and specify the abort code to use). Change some of the points of generation to use other abort codes instead: (1) Abort the call with RXGEN_SS_UNMARSHAL or RXGEN_CC_UNMARSHAL if we see ENOMEM and EFAULT during received data delivery and abort with RX_CALL_DEAD in the default case. (2) Abort with RXGEN_SS_MARSHAL if we get ENOMEM whilst trying to send a reply. (3) Abort with RX_CALL_DEAD if we stop hearing from the peer if we had heard from the peer and abort with RX_CALL_TIMEOUT if we hadn't. (4) Abort with RX_CALL_DEAD if we try to disconnect a call that's not completed successfully or been aborted. Reported-by: Jeffrey Altman <jaltman@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-05-25afs: Fix afs_getattr() to refetch file status if callback break occurredDavid Howells1-1/+13
[ Upstream commit 2aeb8c86d49967552394d5e723f87454cb53f501 ] If a callback break occurs (change notification), afs_getattr() needs to issue an FS.FetchStatus RPC operation to update the status of the file being examined by the stat-family of system calls. Fix afs_getattr() to do this if AFS_VNODE_CB_PROMISED has been cleared on a vnode by a callback break. Skip this if AT_STATX_DONT_SYNC is set. This can be tested by appending to a file on one AFS client and then using "stat -L" to examine its length on a machine running kafs. This can also be watched through tracing on the kafs machine. The callback break is seen: kworker/1:1-46 [001] ..... 978.910812: afs_cb_call: c=0000005f YFSCB.CallBack kworker/1:1-46 [001] ...1. 978.910829: afs_cb_break: 100058:23b4c:242d2c2 b=2 s=1 break-cb kworker/1:1-46 [001] ..... 978.911062: afs_call_done: c=0000005f ret=0 ab=0 [0000000082994ead] And then the stat command generated no traffic if unpatched, but with this change a call to fetch the status can be observed: stat-4471 [000] ..... 986.744122: afs_make_fs_call: c=000000ab 100058:023b4c:242d2c2 YFS.FetchStatus stat-4471 [000] ..... 986.745578: afs_call_done: c=000000ab ret=0 ab=0 [0000000087fc8c84] Fixes: 08e0e7c82eea ("[AF_RXRPC]: Make the in-kernel AFS filesystem use AF_RXRPC.") Reported-by: Markus Suvanto <markus.suvanto@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Tested-by: Markus Suvanto <markus.suvanto@gmail.com> Tested-by: kafs-testing+fedora34_64checkkafs-build-496@auristor.com Link: https://bugzilla.kernel.org/show_bug.cgi?id=216010 Link: https://lore.kernel.org/r/165308359800.162686.14122417881564420962.stgit@warthog.procyon.org.uk/ # v1 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-30afs: Fix updating of i_blocks on file/dir extensionDavid Howells4-13/+13
[ Upstream commit 9d37e1cab2a9d2cee2737973fa455e6f89eee46a ] When an afs file or directory is modified locally such that the total file size is extended, i_blocks needs to be recalculated too. Fix this by making afs_write_end() and afs_edit_dir_add() call afs_set_i_size() rather than setting inode->i_size directly as that also recalculates inode->i_blocks. This can be tested by creating and writing into directories and files and then examining them with du. Without this change, directories show a 4 blocks (they start out at 2048 bytes) and files show 0 blocks; with this change, they should show a number of blocks proportional to the file size rounded up to 1024. Fixes: 31143d5d515e ("AFS: implement basic file write support") Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...") Reported-by: Markus Suvanto <markus.suvanto@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Tested-by: Markus Suvanto <markus.suvanto@gmail.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/163113612442.352844.11162345591911691150.stgit@warthog.procyon.org.uk/ Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-30afs: Fix incorrect triggering of sillyrename on 3rd-party invalidationDavid Howells1-39/+7
[ Upstream commit 63d49d843ef5fffeea069e0ffdfbd2bf40ba01c6 ] The AFS filesystem is currently triggering the silly-rename cleanup from afs_d_revalidate() when it sees that a dentry has been changed by a third party[1]. It should not be doing this as the cleanup includes deleting the silly-rename target file on iput. Fix this by removing the places in the d_revalidate handling that validate anything other than the directory and the dirent. It probably should not be looking to validate the target inode of the dentry also. This includes removing the point in afs_d_revalidate() where the inode that a dentry used to point to was marked as being deleted (AFS_VNODE_DELETED). We don't know it got deleted. It could have been renamed or it could have hard links remaining. This was reproduced by cloning a git repo onto an afs volume on one machine, switching to another machine and doing "git status", then switching back to the first and doing "git status". The second status would show weird output due to ".git/index" getting deleted by the above mentioned mechanism. A simpler way to do it is to do: machine 1: touch a machine 2: touch b; mv -f b a machine 1: stat a on an afs volume. The bug shows up as the stat failing with ENOENT and the file server log showing that machine 1 deleted "a". Fixes: 79ddbfa500b3 ("afs: Implement sillyrename for unlink and rename") Reported-by: Markus Suvanto <markus.suvanto@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Markus Suvanto <markus.suvanto@gmail.com> cc: linux-afs@lists.infradead.org Link: https://bugzilla.kernel.org/show_bug.cgi?id=214217#c4 [1] Link: https://lore.kernel.org/r/163111668100.283156.3851669884664475428.stgit@warthog.procyon.org.uk/ Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-28afs: Fix tracepoint string placement with built-in AFSDavid Howells1-18/+7
[ Upstream commit 6c881ca0b3040f3e724eae513117ba4ddef86057 ] To quote Alexey[1]: I was adding custom tracepoint to the kernel, grabbed full F34 kernel .config, disabled modules and booted whole shebang as VM kernel. Then did perf record -a -e ... It crashed: general protection fault, probably for non-canonical address 0x435f5346592e4243: 0000 [#1] SMP PTI CPU: 1 PID: 842 Comm: cat Not tainted 5.12.6+ #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 RIP: 0010:t_show+0x22/0xd0 Then reproducer was narrowed to # cat /sys/kernel/tracing/printk_formats Original F34 kernel with modules didn't crash. So I started to disable options and after disabling AFS everything started working again. The root cause is that AFS was placing char arrays content into a section full of _pointers_ to strings with predictable consequences. Non canonical address 435f5346592e4243 is "CB.YFS_" which came from CM_NAME macro. Steps to reproduce: CONFIG_AFS=y CONFIG_TRACING=y # cat /sys/kernel/tracing/printk_formats Fix this by the following means: (1) Add enum->string translation tables in the event header with the AFS and YFS cache/callback manager operations listed by RPC operation ID. (2) Modify the afs_cb_call tracepoint to print the string from the translation table rather than using the string at the afs_call name pointer. (3) Switch translation table depending on the service we're being accessed as (AFS or YFS) in the tracepoint print clause. Will this cause problems to userspace utilities? Note that the symbolic representation of the YFS service ID isn't available to this header, so I've put it in as a number. I'm not sure if this is the best way to do this. (4) Remove the name wrangling (CM_NAME) macro and put the names directly into the afs_call_type structs in cmservice.c. Fixes: 8e8d7f13b6d5a9 ("afs: Add some tracepoints") Reported-by: Alexey Dobriyan (SK hynix) <adobriyan@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: Andrew Morton <akpm@linux-foundation.org> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YLAXfvZ+rObEOdc%2F@localhost.localdomain/ [1] Link: https://lore.kernel.org/r/643721.1623754699@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/162430903582.2896199.6098150063997983353.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/162609463957.3133237.15916579353149746363.stgit@warthog.procyon.org.uk/ # v1 (repost) Link: https://lore.kernel.org/r/162610726860.3408253.445207609466288531.stgit@warthog.procyon.org.uk/ # v2 Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-06-23afs: Fix an IS_ERR() vs NULL checkDan Carpenter1-2/+2
[ Upstream commit a33d62662d275cee22888fa7760fe09d5b9cd1f9 ] The proc_symlink() function returns NULL on error, it doesn't return error pointers. Fixes: 5b86d4ff5dce ("afs: Implement network namespacing") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/YLjMRKX40pTrJvgf@mwanda/ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-06-03afs: Fix the nlink handling of dir-over-dir renameDavid Howells1-1/+3
commit f610a5a29c3cfb7d37bdfa4ef52f72ea51f24a76 upstream. Fix rename of one directory over another such that the nlink on the deleted directory is cleared to 0 rather than being decremented to 1. This was causing the generic/035 xfstest to fail. Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") 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/162194384460.3999479.7605572278074191079.stgit@warthog.procyon.org.uk/ # v1 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14afs: Fix speculative status fetchesDavid Howells6-2/+23
[ Upstream commit 22650f148126571be1098d34160eb4931fc77241 ] The generic/464 xfstest causes kAFS to emit occasional warnings of the form: kAFS: vnode modified {100055:8a} 30->31 YFS.StoreData64 (c=6015) This indicates that the data version received back from the server did not match the expected value (the DV should be incremented monotonically for each individual modification op committed to a vnode). What is happening is that a lookup call is doing a bulk status fetch speculatively on a bunch of vnodes in a directory besides getting the status of the vnode it's actually interested in. This is racing with a StoreData operation (though it could also occur with, say, a MakeDir op). On the client, a modification operation locks the vnode, but the bulk status fetch only locks the parent directory, so no ordering is imposed there (thereby avoiding an avenue to deadlock). On the server, the StoreData op handler doesn't lock the vnode until it's received all the request data, and downgrades the lock after committing the data until it has finished sending change notifications to other clients - which allows the status fetch to occur before it has finished. This means that: - a status fetch can access the target vnode either side of the exclusive section of the modification - the status fetch could start before the modification, yet finish after, and vice-versa. - the status fetch and the modification RPCs can complete in either order. - the status fetch can return either the before or the after DV from the modification. - the status fetch might regress the locally cached DV. Some of these are handled by the previous fix[1], but that's not sufficient because it checks the DV it received against the DV it cached at the start of the op, but the DV might've been updated in the meantime by a locally generated modification op. Fix this by the following means: (1) Keep track of when we're performing a modification operation on a vnode. This is done by marking vnode parameters with a 'modification' note that causes the AFS_VNODE_MODIFYING flag to be set on the vnode for the duration. (2) Alter the speculation race detection to ignore speculative status fetches if either the vnode is marked as being modified or the data version number is not what we expected. Note that whilst the "vnode modified" warning does get recovered from as it causes the client to refetch the status at the next opportunity, it will also invalidate the pagecache, so changes might get lost. Fixes: a9e5c87ca744 ("afs: Fix speculative status fetch going out of order wrt to modifications") Reported-by: Marc Dionne <marc.dionne@auristor.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-and-reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/160605082531.252452.14708077925602709042.stgit@warthog.procyon.org.uk/ [1] Link: https://lore.kernel.org/linux-fsdevel/161961335926.39335.2552653972195467566.stgit@warthog.procyon.org.uk/ # v1 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14afs: Fix updating of i_mode due to 3rd party changeDavid Howells1-3/+3
[ Upstream commit 6e1eb04a87f954eb06a89ee6034c166351dfff6e ] Fix afs_apply_status() to mask off the irrelevant bits from status->mode when OR'ing them into i_mode. This can happen when a 3rd party chmod occurs. Also fix afs_inode_init_from_status() to mask off the mode bits when initialising i_mode. Fixes: 260a980317da ("[AFS]: Add "directory write" support.") Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-25afs: Stop listxattr() from listing "afs.*" attributesDavid Howells6-28/+0
commit a7889c6320b9200e3fe415238f546db677310fa9 upstream. afs_listxattr() lists all the available special afs xattrs (i.e. those in the "afs.*" space), no matter what type of server we're dealing with. But OpenAFS servers, for example, cannot deal with some of the extra-capable attributes that AuriStor (YFS) servers provide. Unfortunately, the presence of the afs.yfs.* attributes causes errors[1] for anything that tries to read them if the server is of the wrong type. Fix the problem by removing afs_listxattr() so that none of the special xattrs are listed (AFS doesn't support xattrs). It does mean, however, that getfattr won't list them, though they can still be accessed with getxattr() and setxattr(). This can be tested with something like: getfattr -d -m ".*" /afs/example.com/path/to/file With this change, none of the afs.* attributes should be visible. Changes: ver #2: - Hide all of the afs.* xattrs, not just the ACL ones. Fixes: ae46578b963f ("afs: Get YFS ACLs and information through xattrs") Reported-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Reviewed-by: Jeffrey Altman <jaltman@auristor.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003502.html [1] Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003567.html # v1 Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003573.html # v2 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-25afs: Fix accessing YFS xattrs on a non-YFS serverDavid Howells2-3/+12
commit 64fcbb6158ecc684d84c64424830a9c37c77c5b9 upstream. If someone attempts to access YFS-related xattrs (e.g. afs.yfs.acl) on a file on a non-YFS AFS server (such as OpenAFS), then the kernel will jump to a NULL function pointer because the afs_fetch_acl_operation descriptor doesn't point to a function for issuing an operation on a non-YFS server[1]. Fix this by making afs_wait_for_operation() check that the issue_afs_rpc method is set before jumping to it and setting -ENOTSUPP if not. This fix also covers other potential operations that also only exist on YFS servers. afs_xattr_get/set_yfs() then need to translate -ENOTSUPP to -ENODATA as the former error is internal to the kernel. The bug shows up as an oops like the following: BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. [...] Call Trace: afs_wait_for_operation+0x83/0x1b0 [kafs] afs_xattr_get_yfs+0xe6/0x270 [kafs] __vfs_getxattr+0x59/0x80 vfs_getxattr+0x11c/0x140 getxattr+0x181/0x250 ? __check_object_size+0x13f/0x150 ? __fput+0x16d/0x250 __x64_sys_fgetxattr+0x64/0xb0 do_syscall_64+0x49/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7fb120a9defe This was triggered with "cp -a" which attempts to copy xattrs, including afs ones, but is easier to reproduce with getfattr, e.g.: getfattr -d -m ".*" /afs/openafs.org/ Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Reported-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Gaja Sophie Peters <gaja.peters@math.uni-hamburg.de> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> Reviewed-by: Jeffrey Altman <jaltman@auristor.com> cc: linux-afs@lists.infradead.org Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003498.html [1] Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003566.html # v1 Link: http://lists.infradead.org/pipermail/linux-afs/2021-March/003572.html # v2 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-10rxrpc: Fix deadlock around release of dst cached on udp tunnelDavid Howells1-3/+3
[ Upstream commit 5399d52233c47905bbf97dcbaa2d7a9cc31670ba ] AF_RXRPC sockets use UDP ports in encap mode. This causes socket and dst from an incoming packet to get stolen and attached to the UDP socket from whence it is leaked when that socket is closed. When a network namespace is removed, the wait for dst records to be cleaned up happens before the cleanup of the rxrpc and UDP socket, meaning that the wait never finishes. Fix this by moving the rxrpc (and, by dependence, the afs) private per-network namespace registrations to the device group rather than subsys group. This allows cached rxrpc local endpoints to be cleared and their UDP sockets closed before we try waiting for the dst records. The symptom is that lines looking like the following: unregister_netdevice: waiting for lo to become free get emitted at regular intervals after running something like the referenced syzbot test. Thanks to Vadim for tracking this down and work out the fix. Reported-by: syzbot+df400f2f24a1677cd7e0@syzkaller.appspotmail.com Reported-by: Vadim Fedorenko <vfedorenko@novek.ru> Fixes: 5271953cad31 ("rxrpc: Use the UDP encap_rcv hook") Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Vadim Fedorenko <vfedorenko@novek.ru> Link: https://lore.kernel.org/r/161196443016.3868642.5577440140646403533.stgit@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-12-09afs: Fix memory leak when mounting with multiple source parametersDavid Howells1-0/+3
There's a memory leak in afs_parse_source() whereby multiple source= parameters overwrite fc->source in the fs_context struct without freeing the previously recorded source. Fix this by only permitting a single source parameter and rejecting with an error all subsequent ones. This was caught by syzbot with the kernel memory leak detector, showing something like the following trace: unreferenced object 0xffff888114375440 (size 32): comm "repro", pid 5168, jiffies 4294923723 (age 569.948s) backtrace: slab_post_alloc_hook+0x42/0x79 __kmalloc_track_caller+0x125/0x16a kmemdup_nul+0x24/0x3c vfs_parse_fs_string+0x5a/0xa1 generic_parse_monolithic+0x9d/0xc5 do_new_mount+0x10d/0x15a do_mount+0x5f/0x8e __do_sys_mount+0xff/0x127 do_syscall_64+0x2d/0x3a entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: 13fcc6837049 ("afs: Add fs_context support") Reported-by: syzbot+86dc6632faaca40133ab@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-22afs: Fix speculative status fetch going out of order wrt to modificationsDavid Howells3-0/+10
When doing a lookup in a directory, the afs filesystem uses a bulk status fetch to speculatively retrieve the statuses of up to 48 other vnodes found in the same directory and it will then either update extant inodes or create new ones - effectively doing 'lookup ahead'. To avoid the possibility of deadlocking itself, however, the filesystem doesn't lock all of those inodes; rather just the directory inode is locked (by the VFS). When the operation completes, afs_inode_init_from_status() or afs_apply_status() is called, depending on whether the inode already exists, to commit the new status. A case exists, however, where the speculative status fetch operation may straddle a modification operation on one of those vnodes. What can then happen is that the speculative bulk status RPC retrieves the old status, and whilst that is happening, the modification happens - which returns an updated status, then the modification status is committed, then we attempt to commit the speculative status. This results in something like the following being seen in dmesg: kAFS: vnode modified {100058:861} 8->9 YFS.InlineBulkStatus showing that for vnode 861 on volume 100058, we saw YFS.InlineBulkStatus say that the vnode had data version 8 when we'd already recorded version 9 due to a local modification. This was causing the cache to be invalidated for that vnode when it shouldn't have been. If it happens on a data file, this might lead to local changes being lost. Fix this by ignoring speculative status updates if the data version doesn't match the expected value. Note that it is possible to get a DV regression if a volume gets restored from a backup - but we should get a callback break in such a case that should trigger a recheck anyway. It might be worth checking the volume creation time in the volsync info and, if a change is observed in that (as would happen on a restore), invalidate all caches associated with the volume. Fixes: 5cf9dd55a0ec ("afs: Prospectively look up extra files when doing a single lookup") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-14afs: Fix afs_write_end() when called with copied == 0 [ver #3]David Howells1-1/+4
When afs_write_end() is called with copied == 0, it tries to set the dirty region, but there's no way to actually encode a 0-length region in the encoding in page->private. "0,0", for example, indicates a 1-byte region at offset 0. The maths miscalculates this and sets it incorrectly. Fix it to just do nothing but unlock and put the page in this case. We don't actually need to mark the page dirty as nothing presumably changed. Fixes: 65dd2d6072d3 ("afs: Alter dirty range encoding in page->private") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-03afs: Fix incorrect freeing of the ACL passed to the YFS ACL store opDavid Howells1-6/+1
The cleanup for the yfs_store_opaque_acl2_operation calls the wrong function to destroy the ACL content buffer. It's an afs_acl struct, not a yfs_acl struct - and the free function for latter may pass invalid pointers to kfree(). Fix this by using the afs_acl_put() function. The yfs_acl_put() function is then no longer used and can be removed. general protection fault, probably for non-canonical address 0x7ebde00000000: 0000 [#1] SMP PTI ... RIP: 0010:compound_head+0x0/0x11 ... Call Trace: virt_to_cache+0x8/0x51 kfree+0x5d/0x79 yfs_free_opaque_acl+0x16/0x29 afs_put_operation+0x60/0x114 __vfs_setxattr+0x67/0x72 __vfs_setxattr_noperm+0x66/0xe9 vfs_setxattr+0x67/0xce setxattr+0x14e/0x184 __do_sys_fsetxattr+0x66/0x8f do_syscall_64+0x2d/0x3a entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-11-03afs: Fix warning due to unadvanced marshalling pointerDavid Howells1-0/+1
When using the afs.yfs.acl xattr to change an AuriStor ACL, a warning can be generated when the request is marshalled because the buffer pointer isn't increased after adding the last element, thereby triggering the check at the end if the ACL wasn't empty. This just causes something like the following warning, but doesn't stop the call from happening successfully: kAFS: YFS.StoreOpaqueACL2: Request buffer underflow (36<108) Fix this simply by increasing the count prior to the check. Fixes: f5e4546347bc ("afs: Implement YFS ACL setting") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-29afs: Fix dirty-region encoding on ppc32 with 64K pagesDavid Howells2-9/+20
The dirty region bounds stored in page->private on an afs page are 15 bits on a 32-bit box and can, at most, represent a range of up to 32K within a 32K page with a resolution of 1 byte. This is a problem for powerpc32 with 64K pages enabled. Further, transparent huge pages may get up to 2M, which will be a problem for the afs filesystem on all 32-bit arches in the future. Fix this by decreasing the resolution. For the moment, a 64K page will have a resolution determined from PAGE_SIZE. In the future, the page will need to be passed in to the helper functions so that the page size can be assessed and the resolution determined dynamically. Note that this might not be the ideal way to handle this, since it may allow some leakage of undirtied zero bytes to the server's copy in the case of a 3rd-party conflict. Fixing that would require a separately allocated record and is a more complicated fix. Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-10-29afs: Fix afs_invalidatepage to adjust the dirty regionDavid Howells3-12/+76
Fix afs_invalidatepage() to adjust the dirty region recorded in page->private when truncating a page. If the dirty region is entirely removed, then the private data is cleared and the page dirty state is cleared. Without this, if the page is truncated and then expanded again by truncate, zeros from the expanded, but no-longer dirty region may get written back to the server if the page gets laundered due to a conflicting 3rd-party write. It mustn't, however, shorten the dirty region of the page if that page is still mmapped and has been marked dirty by afs_page_mkwrite(), so a flag is stored in page->private to record this. Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Alter dirty range encoding in page->privateDavid Howells2-4/+4
Currently, page->private on an afs page is used to store the range of dirtied data within the page, where the range includes the lower bound, but excludes the upper bound (e.g. 0-1 is a range covering a single byte). This, however, requires a superfluous bit for the last-byte bound so that on a 4KiB page, it can say 0-4096 to indicate the whole page, the idea being that having both numbers the same would indicate an empty range. This is unnecessary as the PG_private bit is clear if it's an empty range (as is PG_dirty). Alter the way the dirty range is encoded in page->private such that the upper bound is reduced by 1 (e.g. 0-0 is then specified the same single byte range mentioned above). Applying this to both bounds frees up two bits, one of which can be used in a future commit. This allows the afs filesystem to be compiled on ppc32 with 64K pages; without this, the following warnings are seen: ../fs/afs/internal.h: In function 'afs_page_dirty_to': ../fs/afs/internal.h:881:15: warning: right shift count >= width of type [-Wshift-count-overflow] 881 | return (priv >> __AFS_PAGE_PRIV_SHIFT) & __AFS_PAGE_PRIV_MASK; | ^~ ../fs/afs/internal.h: In function 'afs_page_dirty': ../fs/afs/internal.h:886:28: warning: left shift count >= width of type [-Wshift-count-overflow] 886 | return ((unsigned long)to << __AFS_PAGE_PRIV_SHIFT) | from; | ^~ Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Wrap page->private manipulations in inline functionsDavid Howells2-18/+41
The afs filesystem uses page->private to store the dirty range within a page such that in the event of a conflicting 3rd-party write to the server, we write back just the bits that got changed locally. However, there are a couple of problems with this: (1) I need a bit to note if the page might be mapped so that partial invalidation doesn't shrink the range. (2) There aren't necessarily sufficient bits to store the entire range of data altered (say it's a 32-bit system with 64KiB pages or transparent huge pages are in use). So wrap the accesses in inline functions so that future commits can change how this works. Also move them out of the tracing header into the in-directory header. There's not really any need for them to be in the tracing header. Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Fix where page->private is set during writeDavid Howells1-15/+26
In afs, page->private is set to indicate the dirty region of a page. This is done in afs_write_begin(), but that can't take account of whether the copy into the page actually worked. Fix this by moving the change of page->private into afs_write_end(). Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-29afs: Fix page leak on afs_write_begin() failureDavid Howells1-12/+11
Fix the leak of the target page in afs_write_begin() when it fails. Fixes: 15b4650e55e0 ("afs: convert to new aops") Signed-off-by: David Howells <dhowells@redhat.com> cc: Nick Piggin <npiggin@gmail.com>
2020-10-29afs: Fix to take ref on page when PG_private is setDavid Howells4-26/+18
Fix afs to take a ref on a page when it sets PG_private on it and to drop the ref when removing the flag. Note that in afs_write_begin(), a lot of the time, PG_private is already set on a page to which we're going to add some data. In such a case, we leave the bit set and mustn't increment the page count. As suggested by Matthew Wilcox, use attach/detach_page_private() where possible. Fixes: 31143d5d515e ("AFS: implement basic file write support") Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2020-10-28afs: Fix afs_launder_page to not clear PG_writebackDavid Howells2-4/+7
Fix afs_launder_page() to not clear PG_writeback on the page it is laundering as the flag isn't set in this case. Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-28afs: Fix a use after free in afs_xattr_get_acl()Dan Carpenter1-1/+1
The "op" pointer is freed earlier when we call afs_put_operation(). Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Colin Ian King <colin.king@canonical.com>
2020-10-28afs: Fix tracing deref-before-checkDavid Howells1-1/+2
The patch dca54a7bbb8c: "afs: Add tracing for cell refcount and active user count" from Oct 13, 2020, leads to the following Smatch complaint: fs/afs/cell.c:596 afs_unuse_cell() warn: variable dereferenced before check 'cell' (see line 592) Fix this by moving the retrieval of the cell debug ID to after the check of the validity of the cell pointer. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: dca54a7bbb8c ("afs: Add tracing for cell refcount and active user count") Signed-off-by: David Howells <dhowells@redhat.com> cc: Dan Carpenter <dan.carpenter@oracle.com>
2020-10-28afs: Fix copy_file_range()David Howells1-0/+1
The prevention of splice-write without explicit ops made the copy_file_write() syscall to an afs file (as done by the generic/112 xfstest) fail with EINVAL. Fix by using iter_file_splice_write() for afs. Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-10-17Merge tag 'afs-fixes-20201016' of ↵Linus Torvalds11-172/+269
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull afs updates from David Howells: "A collection of fixes to fix afs_cell struct refcounting, thereby fixing a slew of related syzbot bugs: - Fix the cell tree in the netns to use an rwsem rather than RCU. There seem to be some problems deriving from the use of RCU and a seqlock to walk the rbtree, but it's not entirely clear what since there are several different failures being seen. Changing things to use an rwsem instead makes it more robust. The extra performance derived from using RCU isn't necessary in this case since the only time we're looking up a cell is during mount or when cells are being manually added. - Fix the refcounting by splitting the usage counter into a memory refcount and an active users counter. The usage counter was doing double duty, keeping track of whether a cell is still in use and keeping track of when it needs to be destroyed - but this makes the clean up tricky. Separating these out simplifies the logic. - Fix purging a cell that has an alias. A cell alias pins the cell it's an alias of, but the alias is always later in the list. Trying to purge in a single pass causes rmmod to hang in such a case. - Fix cell removal. If a cell's manager is requeued whilst it's removing itself, the manager will run again and re-remove itself, causing problems in various places. Follow Hillf Danton's suggestion to insert a more terminal state that causes the manager to do nothing post-removal. In additional to the above, two other changes: - Add a tracepoint for the cell refcount and active users count. This helped with debugging the above and may be useful again in future. - Downgrade an assertion to a print when a still-active server is seen during purging. This was happening as a consequence of incomplete cell removal before the servers were cleaned up" * tag 'afs-fixes-20201016' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Don't assert on unpurgeable server records afs: Add tracing for cell refcount and active user count afs: Fix cell removal afs: Fix cell purging with aliases afs: Fix cell refcounting by splitting the usage counter afs: Fix rapid cell addition/removal by not using RCU on cells tree
2020-10-16afs: Don't assert on unpurgeable server recordsDavid Howells1-1/+6
Don't give an assertion failure on unpurgeable afs_server records - which kills the thread - but rather emit a trace line when we are purging a record (which only happens during network namespace removal or rmmod) and print a notice of the problem. Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-16afs: Add tracing for cell refcount and active user countDavid Howells9-55/+101
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 removalDavid Howells2-6/+11
Fix cell removal by inserting a more final state than AFS_CELL_FAILED that indicates that the cell has been unpublished in case the manager is already requeued and will go through again. The new AFS_CELL_REMOVED state will just immediately leave the manager function. Going through a second time in the AFS_CELL_FAILED state will cause it to try to remove the cell again, potentially leading to the proc list being removed. Fixes: 989782dcdc91 ("afs: Overhaul cell database management") Reported-by: syzbot+b994ecf2b023f14832c1@syzkaller.appspotmail.com Reported-by: syzbot+0e0db88e1eb44a91ae8d@syzkaller.appspotmail.com Reported-by: syzbot+2d0585e5efcd43d113c2@syzkaller.appspotmail.com Reported-by: syzbot+1ecc2f9d3387f1d79d42@syzkaller.appspotmail.com Reported-by: syzbot+18d51774588492bf3f69@syzkaller.appspotmail.com Reported-by: syzbot+a5e4946b04d6ca8fa5f3@syzkaller.appspotmail.com Suggested-by: Hillf Danton <hdanton@sina.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: Hillf Danton <hdanton@sina.com>
2020-10-16afs: Fix cell purging with aliasesDavid Howells1-0/+3
When the afs module is removed, one of the things that has to be done is to purge the cell database. afs_cell_purge() cancels the management timer and then starts the cell manager work item to do the purging. This does a single run through and then assumes that all cells are now purged - but this is no longer the case. With the introduction of alias detection, a later cell in the database can now be holding an active count on an earlier cell (cell->alias_of). The purge scan passes by the earlier cell first, but this can't be got rid of until it has discarded the alias. Ordinarily, afs_unuse_cell() would handle this by setting the management timer to trigger another pass - but afs_set_cell_timer() doesn't do anything if the namespace is being removed (net->live == false). rmmod then hangs in the wait on cells_outstanding in afs_cell_purge(). Fix this by making afs_set_cell_timer() directly queue the cell manager if net->live is false. This causes additional management passes. Queueing the cell manager increments cells_outstanding to make sure the wait won't complete until all cells are destroyed. Fixes: 8a070a964877 ("afs: Detect cell aliases 1 - Cells with root volumes") Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-16afs: Fix cell refcounting by splitting the usage counterDavid Howells9-76/+136
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>
2020-10-16afs: Fix rapid cell addition/removal by not using RCU on cells treeDavid Howells5-93/+71
There are a number of problems that are being seen by the rapidly mounting and unmounting an afs dynamic root with an explicit cell and volume specified (which should probably be rejected, but that's a separate issue): What the tests are doing is to look up/create a cell record for the name given and then tear it down again without actually using it to try to talk to a server. This is repeated endlessly, very fast, and the new cell collides with the old one if it's not quick enough to reuse it. It appears (as suggested by Hillf Danton) that the search through the RB tree under a read_seqbegin_or_lock() under RCU conditions isn't safe and that it's not blocking the write_seqlock(), despite taking two passes at it. He suggested that the code should take a ref on the cell it's attempting to look at - but this shouldn't be necessary until we've compared the cell names. It's possible that I'm missing a barrier somewhere. However, using an RCU search for this is overkill, really - we only need to access the cell name in a few places, and they're places where we're may end up sleeping anyway. Fix this by switching to an R/W semaphore instead. Additionally, draw the down_read() call inside the function (renamed to afs_find_cell()) since all the callers were taking the RCU read lock (or should've been[*]). [*] afs_probe_cell_name() should have been, but that doesn't appear to be involved in the bug reports. The symptoms of this look like: general protection fault, probably for non-canonical address 0xf27d208691691fdb: 0000 [#1] PREEMPT SMP KASAN KASAN: maybe wild-memory-access in range [0x93e924348b48fed8-0x93e924348b48fedf] ... RIP: 0010:strncasecmp lib/string.c:52 [inline] RIP: 0010:strncasecmp+0x5f/0x240 lib/string.c:43 afs_lookup_cell_rcu+0x313/0x720 fs/afs/cell.c:88 afs_lookup_cell+0x2ee/0x1440 fs/afs/cell.c:249 afs_parse_source fs/afs/super.c:290 [inline] ... Fixes: 989782dcdc91 ("afs: Overhaul cell database management") Reported-by: syzbot+459a5dce0b4cb70fd076@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> cc: Hillf Danton <hdanton@sina.com> cc: syzkaller-bugs@googlegroups.com
2020-10-13Merge tag 'block-5.10-2020-10-12' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+0
Pull block updates from Jens Axboe: - Series of merge handling cleanups (Baolin, Christoph) - Series of blk-throttle fixes and cleanups (Baolin) - Series cleaning up BDI, seperating the block device from the backing_dev_info (Christoph) - Removal of bdget() as a generic API (Christoph) - Removal of blkdev_get() as a generic API (Christoph) - Cleanup of is-partition checks (Christoph) - Series reworking disk revalidation (Christoph) - Series cleaning up bio flags (Christoph) - bio crypt fixes (Eric) - IO stats inflight tweak (Gabriel) - blk-mq tags fixes (Hannes) - Buffer invalidation fixes (Jan) - Allow soft limits for zone append (Johannes) - Shared tag set improvements (John, Kashyap) - Allow IOPRIO_CLASS_RT for CAP_SYS_NICE (Khazhismel) - DM no-wait support (Mike, Konstantin) - Request allocation improvements (Ming) - Allow md/dm/bcache to use IO stat helpers (Song) - Series improving blk-iocost (Tejun) - Various cleanups (Geert, Damien, Danny, Julia, Tetsuo, Tian, Wang, Xianting, Yang, Yufen, yangerkun) * tag 'block-5.10-2020-10-12' of git://git.kernel.dk/linux-block: (191 commits) block: fix uapi blkzoned.h comments blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue blk-mq: get rid of the dead flush handle code path block: get rid of unnecessary local variable block: fix comment and add lockdep assert blk-mq: use helper function to test hw stopped block: use helper function to test queue register block: remove redundant mq check block: invoke blk_mq_exit_sched no matter whether have .exit_sched percpu_ref: don't refer to ref->data if it isn't allocated block: ratelimit handle_bad_sector() message blk-throttle: Re-use the throtl_set_slice_end() blk-throttle: Open code __throtl_de/enqueue_tg() blk-throttle: Move service tree validation out of the throtl_rb_first() blk-throttle: Move the list operation after list validation blk-throttle: Fix IO hang for a corner case blk-throttle: Avoid tracking latency if low limit is invalid blk-throttle: Avoid getting the current time if tg->last_finish_time is 0 blk-throttle: Remove a meaningless parameter for throtl_downgrade_state() block: Remove redundant 'return' statement ...
2020-10-08afs: Fix deadlock between writeback and truncateDavid Howells3-9/+50
The afs filesystem has a lock[*] that it uses to serialise I/O operations going to the server (vnode->io_lock), as the server will only perform one modification operation at a time on any given file or directory. This prevents the the filesystem from filling up all the call slots to a server with calls that aren't going to be executed in parallel anyway, thereby allowing operations on other files to obtain slots. [*] Note that is probably redundant for directories at least since i_rwsem is used to serialise directory modifications and lookup/reading vs modification. The server does allow parallel non-modification ops, however. When a file truncation op completes, we truncate the in-memory copy of the file to match - but we do it whilst still holding the io_lock, the idea being to prevent races with other operations. However, if writeback starts in a worker thread simultaneously with truncation (whilst notify_change() is called with i_rwsem locked, writeback pays it no heed), it may manage to set PG_writeback bits on the pages that will get truncated before afs_setattr_success() manages to call truncate_pagecache(). Truncate will then wait for those pages - whilst still inside io_lock: # cat /proc/8837/stack [<0>] wait_on_page_bit_common+0x184/0x1e7 [<0>] truncate_inode_pages_range+0x37f/0x3eb [<0>] truncate_pagecache+0x3c/0x53 [<0>] afs_setattr_success+0x4d/0x6e [<0>] afs_wait_for_operation+0xd8/0x169 [<0>] afs_do_sync_operation+0x16/0x1f [<0>] afs_setattr+0x1fb/0x25d [<0>] notify_change+0x2cf/0x3c4 [<0>] do_truncate+0x7f/0xb2 [<0>] do_sys_ftruncate+0xd1/0x104 [<0>] do_syscall_64+0x2d/0x3a [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 The writeback operation, however, stalls indefinitely because it needs to get the io_lock to proceed: # cat /proc/5940/stack [<0>] afs_get_io_locks+0x58/0x1ae [<0>] afs_begin_vnode_operation+0xc7/0xd1 [<0>] afs_store_data+0x1b2/0x2a3 [<0>] afs_write_back_from_locked_page+0x418/0x57c [<0>] afs_writepages_region+0x196/0x224 [<0>] afs_writepages+0x74/0x156 [<0>] do_writepages+0x2d/0x56 [<0>] __writeback_single_inode+0x84/0x207 [<0>] writeback_sb_inodes+0x238/0x3cf [<0>] __writeback_inodes_wb+0x68/0x9f [<0>] wb_writeback+0x145/0x26c [<0>] wb_do_writeback+0x16a/0x194 [<0>] wb_workfn+0x74/0x177 [<0>] process_one_work+0x174/0x264 [<0>] worker_thread+0x117/0x1b9 [<0>] kthread+0xec/0xf1 [<0>] ret_from_fork+0x1f/0x30 and thus deadlock has occurred. Note that whilst afs_setattr() calls filemap_write_and_wait(), the fact that the caller is holding i_rwsem doesn't preclude more pages being dirtied through an mmap'd region. Fix this by: (1) Use the vnode validate_lock to mediate access between afs_setattr() and afs_writepages(): (a) Exclusively lock validate_lock in afs_setattr() around the whole RPC operation. (b) If WB_SYNC_ALL isn't set on entry to afs_writepages(), trying to shared-lock validate_lock and returning immediately if we couldn't get it. (c) If WB_SYNC_ALL is set, wait for the lock. The validate_lock is also used to validate a file and to zap its cache if the file was altered by a third party, so it's probably a good fit for this. (2) Move the truncation outside of the io_lock in setattr, using the same hook as is used for local directory editing. This requires the old i_size to be retained in the operation record as we commit the revised status to the inode members inside the io_lock still, but we still need to know if we reduced the file size. Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-09-24bdi: initialize ->ra_pages and ->io_pages in bdi_initChristoph Hellwig1-1/+0
Set up a readahead size by default, as very few users have a good reason to change it. This means code, ecryptfs, and orangefs now set up the values while they were previously missing it, while ubifs, mtd and vboxsf manually set it to 0 to avoid readahead. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: David Sterba <dsterba@suse.com> [btrfs] Acked-by: Richard Weinberger <richard@nod.at> [ubifs, mtd] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-09-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds6-40/+73
Pull networking fixes from David Miller: 1) Use netif_rx_ni() when necessary in batman-adv stack, from Jussi Kivilinna. 2) Fix loss of RTT samples in rxrpc, from David Howells. 3) Memory leak in hns_nic_dev_probe(), from Dignhao Liu. 4) ravb module cannot be unloaded, fix from Yuusuke Ashizuka. 5) We disable BH for too lokng in sctp_get_port_local(), add a cond_resched() here as well, from Xin Long. 6) Fix memory leak in st95hf_in_send_cmd, from Dinghao Liu. 7) Out of bound access in bpf_raw_tp_link_fill_link_info(), from Yonghong Song. 8) Missing of_node_put() in mt7530 DSA driver, from Sumera Priyadarsini. 9) Fix crash in bnxt_fw_reset_task(), from Michael Chan. 10) Fix geneve tunnel checksumming bug in hns3, from Yi Li. 11) Memory leak in rxkad_verify_response, from Dinghao Liu. 12) In tipc, don't use smp_processor_id() in preemptible context. From Tuong Lien. 13) Fix signedness issue in mlx4 memory allocation, from Shung-Hsi Yu. 14) Missing clk_disable_prepare() in gemini driver, from Dan Carpenter. 15) Fix ABI mismatch between driver and firmware in nfp, from Louis Peens. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (110 commits) net/smc: fix sock refcounting in case of termination net/smc: reset sndbuf_desc if freed net/smc: set rx_off for SMCR explicitly net/smc: fix toleration of fake add_link messages tg3: Fix soft lockup when tg3_reset_task() fails. doc: net: dsa: Fix typo in config code sample net: dp83867: Fix WoL SecureOn password nfp: flower: fix ABI mismatch between driver and firmware tipc: fix shutdown() of connectionless socket ipv6: Fix sysctl max for fib_multipath_hash_policy drivers/net/wan/hdlc: Change the default of hard_header_len to 0 net: gemini: Fix another missing clk_disable_unprepare() in probe net: bcmgenet: fix mask check in bcmgenet_validate_flow() amd-xgbe: Add support for new port mode net: usb: dm9601: Add USB ID of Keenetic Plus DSL vhost: fix typo in error message net: ethernet: mlx4: Fix memory allocation in mlx4_buddy_init() pktgen: fix error message with wrong function name net: ethernet: ti: am65-cpsw: fix rmii 100Mbit link mode cxgb4: fix thermal zone device registration ...
2020-08-27Merge tag 'rxrpc-fixes-20200820' of ↵David S. Miller6-40/+73
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs David Howells says: ==================== rxrpc, afs: Fix probing issues Here are some fixes for rxrpc and afs to fix issues in the RTT measuring in rxrpc and thence the Volume Location server probing in afs: (1) Move the serial number of a received ACK into a local variable to simplify the next patch. (2) Fix the loss of RTT samples due to extra interposed ACKs causing baseline information to be discarded too early. This is a particular problem for afs when it sends a single very short call to probe a server it hasn't talked to recently. (3) Fix rxrpc_kernel_get_srtt() to indicate whether it actually has seen any valid samples or not. (4) Remove a field that's set/woken, but never read/waited on. (5) Expose the RTT and other probe information through procfs to make debugging of this stuff easier. (6) Fix VL rotation in afs to only use summary information from VL probing and not the probe running state (which gets clobbered when next a probe is issued). (7) Fix VL rotation to actually return the error aggregated from the probe errors. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-08-27afs: Remove erroneous fallthough annotationDan Carpenter1-1/+0
The fall through annotation comes after a return statement so it's not reachable. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-24treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva10-82/+82
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-21afs: Fix NULL deref in afs_dynroot_depopulate()David Howells1-9/+11
If an error occurs during the construction of an afs superblock, it's possible that an error occurs after a superblock is created, but before we've created the root dentry. If the superblock has a dynamic root (ie. what's normally mounted on /afs), the afs_kill_super() will call afs_dynroot_depopulate() to unpin any created dentries - but this will oops if the root hasn't been created yet. Fix this by skipping that bit of code if there is no root dentry. This leads to an oops looking like: general protection fault, ... KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] ... RIP: 0010:afs_dynroot_depopulate+0x25f/0x529 fs/afs/dynroot.c:385 ... Call Trace: afs_kill_super+0x13b/0x180 fs/afs/super.c:535 deactivate_locked_super+0x94/0x160 fs/super.c:335 afs_get_tree+0x1124/0x1460 fs/afs/super.c:598 vfs_get_tree+0x89/0x2f0 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x1387/0x2070 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount fs/namespace.c:3390 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3390 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 which is oopsing on this line: inode_lock(root->d_inode); presumably because sb->s_root was NULL. Fixes: 0da0b7fd73e4 ("afs: Display manually added cells in dynamic root mount") Reported-by: syzbot+c1eff8205244ae7e11a6@syzkaller.appspotmail.com Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-20afs: Fix key ref leak in afs_put_operation()David Howells1-0/+1
The afs_put_operation() function needs to put the reference to the key that's authenticating the operation. Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept") Reported-by: Dave Botsch <botsch@cnf.cornell.edu> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>