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: a9e5c87ca7 ("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>
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Merge tag 'afs-netfs-lib-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull AFS updates from David Howells:
"Use the new netfs lib.
Begin the process of overhauling the use of the fscache API by AFS and
the introduction of support for features such as Transparent Huge
Pages (THPs).
- Add some support for THPs, including using core VM helper functions
to find details of pages.
- Use the ITER_XARRAY I/O iterator to mediate access to the pagecache
as this handles THPs and doesn't require allocation of large bvec
arrays.
- Delegate address_space read/pre-write I/O methods for AFS to the
netfs helper library. A method is provided to the library that
allows it to issue a read against the server.
This includes a change in use for PG_fscache (it now indicates a
DIO write in progress from the marked page), so a number of waits
need to be deployed for it.
- Split the core AFS writeback function to make it easier to modify
in future patches to handle writing to the cache. [This might
feasibly make more sense moved out into my fscache-iter branch].
I've tested these with "xfstests -g quick" against an AFS volume
(xfstests needs patching to make it work). With this, AFS without a
cache passes all expected xfstests; with a cache, there's an extra
failure, but that's also there before these patches. Fixing that
probably requires a greater overhaul (as can be found on my
fscache-iter branch, but that's for a later time).
Thanks should go to Marc Dionne and Jeff Altman of AuriStor for
exercising the patches in their test farm also"
Link: https://lore.kernel.org/lkml/3785063.1619482429@warthog.procyon.org.uk/
* tag 'afs-netfs-lib-20210426' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
afs: Use the netfs_write_begin() helper
afs: Use new netfs lib read helper API
afs: Use the fs operation ops to handle FetchData completion
afs: Prepare for use of THPs
afs: Extract writeback extension into its own function
afs: Wait on PG_fscache before modifying/releasing a page
afs: Use ITER_XARRAY for writing
afs: Set up the iov_iter before calling afs_extract_data()
afs: Log remote unmarshalling errors
afs: Don't truncate iter during data fetch
afs: Move key to afs_read struct
afs: Print the operation debug_id when logging an unexpected data version
afs: Pass page into dirty region helpers to provide THP size
afs: Disable use of the fscache I/O routines
Pull vfs inode type handling updates from Al Viro:
"We should never change the type bits of ->i_mode or the method tables
(->i_op and ->i_fop) of a live inode.
Unfortunately, not all filesystems took care to prevent that"
* 'work.inode-type-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
spufs: fix bogosity in S_ISGID handling
9p: missing chunk of "fs/9p: Don't update file type when updating file attributes"
openpromfs: don't do unlock_new_inode() until the new inode is set up
hostfs_mknod(): don't bother with init_special_inode()
cifs: have cifs_fattr_to_inode() refuse to change type on live inode
cifs: have ->mkdir() handle race with another client sanely
do_cifs_create(): don't set ->i_mode of something we had not created
gfs2: be careful with inode refresh
ocfs2_inode_lock_update(): make sure we don't change the type bits of i_mode
orangefs_inode_is_stale(): i_mode type bits do *not* form a bitmap...
vboxsf: don't allow to change the inode type
afs: Fix updating of i_mode due to 3rd party change
ceph: don't allow type or device number to change on non-I_NEW inodes
ceph: fix up error handling with snapdirs
new helper: inode_wrong_type()
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: ae46578b96 ("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
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: 260a980317 ("[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>
Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.
As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.
Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
The generic_fillattr() helper fills in the basic attributes associated
with an inode. Enable it to handle idmapped mounts. If the inode is
accessed through an idmapped mount map it into the mount's user
namespace before we store the uid and gid. If the initial user namespace
is passed nothing changes so non-idmapped mounts will see identical
behavior as before.
Link: https://lore.kernel.org/r/20210121131959.646623-12-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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: 5cf9dd55a0 ("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>
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: d2ddc776a4 ("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>
Fix AFS's silly rename by the following means:
(1) Set the destination directory in afs_do_silly_rename() so as to avoid
misbehaviour and indicate that the directory data version will
increment by 1 so as to avoid warnings about unexpected changes in the
DV. Also indicate that the ctime should be updated to avoid xfstest
grumbling.
(2) Note when the server indicates that a directory changed more than we
expected (AFS_OPERATION_DIR_CONFLICT), indicating a conflict with a
third party change, checking on successful completion of unlink and
rename.
The problem is that the FS.RemoveFile RPC op doesn't report the status
of the unlinked file, though YFS.RemoveFile2 does. This can be
mitigated by the assumption that if the directory DV cranked by
exactly 1, we can be sure we removed one link from the file; further,
ordinarily in AFS, files cannot be hardlinked across directories, so
if we reduce nlink to 0, the file is deleted.
However, if the directory DV jumps by more than 1, we cannot know if a
third party intervened by adding or removing a link on the file we
just removed a link from.
The same also goes for any vnode that is at the destination of the
FS.Rename RPC op.
(3) Make afs_vnode_commit_status() apply the nlink drop inside the cb_lock
section along with the other attribute updates if ->op_unlinked is set
on the descriptor for the appropriate vnode.
(4) Issue a follow up status fetch to the unlinked file in the event of a
third party conflict that makes it impossible for us to know if we
actually deleted the file or not.
(5) Provide a flag, AFS_VNODE_SILLY_DELETED, to make afs_getattr() lie to
the user about the nlink of a silly deleted file so that it appears as
0, not 1.
Found with the generic/035 and generic/084 xfstests.
Fixes: e49c7b2f6d ("afs: Build an abstraction around an "operation" concept")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
afs_vnode_commit_status() is only ever called if op->error is 0, so remove
the op->error checks from the function.
Fixes: e49c7b2f6d ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>
afs_check_for_remote_deletion() checks to see if error ENOENT is returned
by the server in response to an operation and, if so, marks the primary
vnode as having been deleted as the FID is no longer valid.
However, it's being called from the operation success functions, where no
abort has happened - and if an inline abort is recorded, it's handled by
afs_vnode_commit_status().
Fix this by actually calling the operation aborted method if provided and
having that point to afs_check_for_remote_deletion().
Fixes: e49c7b2f6d ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the following issues:
(1) Fix writeback to reduce the size of a store operation to i_size,
effectively discarding the extra data.
The problem comes when afs_page_mkwrite() records that a page is about
to be modified by mmap(). It doesn't know what bits of the page are
going to be modified, so it records the whole page as being dirty
(this is stored in page->private as start and end offsets).
Without this, the marshalling for the store to the server extends the
size of the file to the end of the page (in afs_fs_store_data() and
yfs_fs_store_data()).
(2) Fix setattr to actually truncate the pagecache, thereby clearing
the discarded part of a file.
(3) Fix setattr to check that the new size is okay and to disable
ATTR_SIZE if i_size wouldn't change.
(4) Force i_size to be updated as the result of a truncate.
(5) Don't truncate if ATTR_SIZE is not set.
(6) Call pagecache_isize_extended() if the file was enlarged.
Note that truncate_set_size() isn't used because the setting of i_size is
done inside afs_vnode_commit_status() under the vnode->cb_lock.
Found with the generic/029 and generic/393 xfstests.
Fixes: 31143d5d51 ("AFS: implement basic file write support")
Fixes: 4343d00872 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>
The in-kernel afs filesystem ignores ctime because the AFS fileserver
protocol doesn't support ctimes. This, however, causes various xfstests to
fail.
Work around this by:
(1) Setting ctime to attr->ia_ctime in afs_setattr().
(2) Not ignoring ATTR_MTIME_SET, ATTR_TIMES_SET and ATTR_TOUCH settings.
(3) Setting the ctime from the server mtime when on the target file when
creating a hard link to it.
(4) Setting the ctime on directories from their revised mtimes when
renaming/moving a file.
Found by the generic/221 and generic/309 xfstests.
Signed-off-by: David Howells <dhowells@redhat.com>
When doing a partial writeback, afs_write_back_from_locked_page() may
generate an FS.StoreData RPC request that writes out part of a file when a
file has been constructed from pieces by doing seek, write, seek, write,
... as is done by ld.
The FS.StoreData RPC is given the current i_size as the file length, but
the server basically ignores it unless the data length is 0 (in which case
it's just a truncate operation). The revised file length returned in the
result of the RPC may then not reflect what we suggested - and this leads
to i_size getting moved backwards - which causes issues later.
Fix the client to take account of this by ignoring the returned file size
unless the data version number jumped unexpectedly - in which case we're
going to have to clear the pagecache and reload anyway.
This can be observed when doing a kernel build on an AFS mount. The
following pair of commands produce the issue:
ld -m elf_x86_64 -z max-page-size=0x200000 --emit-relocs \
-T arch/x86/realmode/rm/realmode.lds \
arch/x86/realmode/rm/header.o \
arch/x86/realmode/rm/trampoline_64.o \
arch/x86/realmode/rm/stack.o \
arch/x86/realmode/rm/reboot.o \
-o arch/x86/realmode/rm/realmode.elf
arch/x86/tools/relocs --realmode \
arch/x86/realmode/rm/realmode.elf \
>arch/x86/realmode/rm/realmode.relocs
This results in the latter giving:
Cannot read ELF section headers 0/18: Success
as the realmode.elf file got corrupted.
The sequence of events can also be driven with:
xfs_io -t -f \
-c "pwrite -S 0x58 0 0x58" \
-c "pwrite -S 0x59 10000 1000" \
-c "close" \
/afs/example.com/scratch/a
Fixes: 31143d5d51 ("AFS: implement basic file write support")
Signed-off-by: David Howells <dhowells@redhat.com>
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>
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>
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>
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Merge tag 'printk-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek:
- Allow to print symbolic error names via new %pe modifier.
- Use pr_warn() instead of the remaining pr_warning() calls. Fix
formatting of the related lines.
- Add VSPRINTF entry to MAINTAINERS.
* tag 'printk-for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (32 commits)
checkpatch: don't warn about new vsprintf pointer extension '%pe'
MAINTAINERS: Add VSPRINTF
tools lib api: Renaming pr_warning to pr_warn
ASoC: samsung: Use pr_warn instead of pr_warning
lib: cpu_rmap: Use pr_warn instead of pr_warning
trace: Use pr_warn instead of pr_warning
dma-debug: Use pr_warn instead of pr_warning
vgacon: Use pr_warn instead of pr_warning
fs: afs: Use pr_warn instead of pr_warning
sh/intc: Use pr_warn instead of pr_warning
scsi: Use pr_warn instead of pr_warning
platform/x86: intel_oaktrail: Use pr_warn instead of pr_warning
platform/x86: asus-laptop: Use pr_warn instead of pr_warning
platform/x86: eeepc-laptop: Use pr_warn instead of pr_warning
oprofile: Use pr_warn instead of pr_warning
of: Use pr_warn instead of pr_warning
macintosh: Use pr_warn instead of pr_warning
idsn: Use pr_warn instead of pr_warning
ide: Use pr_warn instead of pr_warning
crypto: n2: Use pr_warn instead of pr_warning
...
Add a couple of tracepoints to track callback management:
(1) afs_cb_miss - Logs when we were unable to apply a callback, either due
to the inode being discarded or due to a competing thread applying a
callback first.
(2) afs_cb_break - Logs when we attempted to clear the noted callback
promise, either due to the server explicitly breaking the callback,
the callback promise lapsing or a local event obsoleting it.
Signed-off-by: David Howells <dhowells@redhat.com>
The setting of i_blocks, which is calculated from i_size, has got
accidentally misordered relative to the setting of i_size when initially
setting up an inode. Further, i_blocks isn't updated by afs_apply_status()
when the size is updated.
To fix this, break the i_size/i_blocks setting out into a helper function
and call it from both places.
Fixes: a58823ac45 ("afs: Fix application of status and callback to be under same lock")
Signed-off-by: David Howells <dhowells@redhat.com>
Occasionally, warnings like this:
vnode modified 2af7 on {10000b:1} [exp 2af2] YFS.FetchStatus(vnode)
are emitted into the kernel log. This indicates that when we were applying
the updated vnode (file) status retrieved from the server to an inode we
saw that the data version number wasn't what we were expecting (in this
case it's 0x2af7 rather than 0x2af2).
We've usually received a callback from the server prior to this point - or
the callback promise has lapsed - so the warning is merely informative and
the state is to be expected.
Fix this by only emitting the warning if the we still think that we have a
valid callback promise and haven't received a callback.
Also change the format slightly so so that the new data version doesn't
look like part of the text, the like is prefixed with "kAFS: " and the
message is ranked as a warning.
Fixes: 31143d5d51 ("AFS: implement basic file write support")
Reported-by: Ian Wienand <iwienand@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Pass the server and volume break counts from before the status fetch
operation that queried the attributes of a file into afs_iget5_set() so
that the new vnode's break counters can be initialised appropriately.
This allows detection of a volume or server break that happened whilst we
were fetching the status or setting up the vnode.
Fixes: c435ee3455 ("afs: Overhaul the callback handling")
Signed-off-by: David Howells <dhowells@redhat.com>
Make use of the status update for the target file that the YFS.RemoveFile2
RPC op returns to correctly update the vnode as to whether the file was
actually deleted or just had nlink reduced.
Fixes: 30062bd13e ("afs: Implement YFS support in the fs client")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix afs_validate() to clear AFS_VNODE_CB_PROMISED on a vnode if we detect
any condition that causes the callback promise to be broken implicitly,
including server break (cb_s_break), volume break (cb_v_break) or callback
expiry.
Fixes: ae3b7361dc ("afs: Fix validation/callback interaction")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Use RCU-based freeing for afs_cb_interest struct objects and use RCU on
vnode->cb_interest. Use that change to allow afs_check_validity() to use
read_seqbegin_or_lock() instead of read_seqlock_excl().
This also requires the caller of afs_check_validity() to hold the RCU read
lock across the call.
Signed-off-by: David Howells <dhowells@redhat.com>
Split afs_validate() so that the part that decides if the vnode is still
valid can be used under LOOKUP_RCU conditions from afs_d_revalidate().
Signed-off-by: David Howells <dhowells@redhat.com>
Don't save callback version and type fields as the version is about the
format of the callback information and the type is relative to the
particular RPC call.
Signed-off-by: David Howells <dhowells@redhat.com>
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: c435ee3455 ("afs: Overhaul the callback handling")
Signed-off-by: David Howells <dhowells@redhat.com>
Don't invalidate the callback promise on a directory if the
AFS_VNODE_DIR_VALID flag is not set (which indicates that the directory
contents are invalid, due to edit failure, callback break, page reclaim).
The directory will be reloaded next time the directory is accessed, so
clearing the callback flag at this point may race with a reload of the
directory and cancel it's recorded callback promise.
Fixes: f3ddee8dc4 ("afs: Fix directory handling")
Signed-off-by: David Howells <dhowells@redhat.com>
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: d2ddc776a4 ("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>
Fix afs_release() to go through the cleanup part of the function if
FMODE_WRITE is set rather than exiting through vfs_fsync() (which skips the
cleanup). The cleanup involves discarding the refs on the key used for
file ops and the writeback key record.
Also fix afs_evict_inode() to clean up any left over wb keys attached to
the inode/vnode when it is removed.
Fixes: 5a81327616 ("afs: Do better accretion of small writes on newly created content")
Signed-off-by: David Howells <dhowells@redhat.com>
While it's not possible to give an accurate number for the blocks
used on the server, populate i_blocks based on the file size so
that 'du' can give a reasonable estimate.
The value is rounded up to 1K granularity, for consistency with
what other AFS clients report, and the servers' 1K usage quota
unit. Note that the value calculated by 'du' at the root of a
volume can still be slightly lower than the quota usage on the
server, as 0-length files are charged 1 quota block, but are
reported as occupying 0 blocks. Again, this is consistent with
other AFS clients.
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Log more information when "kAFS: AFS vnode with undefined type\n" is
displayed due to a vnode record being retrieved from the server that
appears to have a duff file type (usually 0). This prints more information
to try and help pin down the problem.
Signed-off-by: David Howells <dhowells@redhat.com>
Implement sillyrename for AFS unlink and rename, using the NFS variant
implementation as a basis.
Note that the asynchronous file locking extender/releaser has to be
notified with a state change to stop it complaining if there's a race
between that and the actual file deletion.
A tracepoint, afs_silly_rename, is also added to note the silly rename and
the cleanup. The afs_edit_dir tracepoint is given some extra reason
indicators and the afs_flock_ev tracepoint is given a silly-delete file
lock cancellation indicator.
Signed-off-by: David Howells <dhowells@redhat.com>
get_seconds() has a limited range on 32-bit architectures and is
deprecated because of that. While AFS uses the same limits for
its inode timestamps on the wire protocol, let's just use the
simpler current_time() as we do for other file systems.
This will still zero out the 'tv_nsec' field of the timestamps
internally.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the refcounting of the authentication keys in the file locking code.
The vnode->lock_key member points to a key on which it expects to be
holding a ref, but it isn't always given an extra ref, however.
Fixes: 0fafdc9f88 ("afs: Fix file locking")
Signed-off-by: David Howells <dhowells@redhat.com>
A cb_interest record is not necessarily attached to the vnode on entry to
afs_validate(), which can cause an oops when we try to bring the vnode's
cb_s_break up to date in the default case (ie. no current callback promise
and the vnode has not been deleted).
Fix this by simply removing the line, as vnode->cb_s_break will be set when
needed by afs_register_server_cb_interest() when we next get a callback
promise from RPC call.
The oops looks something like:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
...
RIP: 0010:afs_validate+0x66/0x250 [kafs]
...
Call Trace:
afs_d_revalidate+0x8d/0x340 [kafs]
? __d_lookup+0x61/0x150
lookup_dcache+0x44/0x70
? lookup_dcache+0x44/0x70
__lookup_hash+0x24/0xa0
do_unlinkat+0x11d/0x2c0
__x64_sys_unlink+0x23/0x30
do_syscall_64+0x4d/0xf0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: ae3b7361dc ("afs: Fix validation/callback interaction")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
When afs_validate() is called to validate a vnode (inode), there are two
unhandled cases in the fastpath at the top of the function:
(1) If the vnode is promised (AFS_VNODE_CB_PROMISED is set), the break
counters match and the data has expired, then there's an implicit case
in which the vnode needs revalidating.
This has no consequences since the default "valid = false" set at the
top of the function happens to do the right thing.
(2) If the vnode is not promised and it hasn't been deleted
(AFS_VNODE_DELETED is not set) then there's a default case we're not
handling in which the vnode is invalid. If the vnode is invalid, we
need to bring cb_s_break and cb_v_break up to date before we refetch
the status.
As a consequence, once the server loses track of the client
(ie. sufficient time has passed since we last sent it an operation),
it will send us a CB.InitCallBackState* operation when we next try to
talk to it. This calls afs_init_callback_state() which increments
afs_server::cb_s_break, but this then doesn't propagate to the
afs_vnode record.
The result being that every afs_validate() call thereafter sends a
status fetch operation to the server.
Clarify and fix this by:
(A) Setting valid in all the branches rather than initialising it at the
top so that the compiler catches where we've missed.
(B) Restructuring the logic in the 'promised' branch so that we set valid
to false if the callback is due to expire (or has expired) and so that
the final case is that the vnode is still valid.
(C) Adding an else-statement that ups cb_s_break and cb_v_break if the
promised and deleted cases don't match.
Fixes: c435ee3455 ("afs: Overhaul the callback handling")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Calculate the callback expiration time at the point of operation reply
delivery, using the reply time queried from AF_RXRPC on that call as a
base.
Signed-off-by: David Howells <dhowells@redhat.com>
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>
Include the site of detection of AFS protocol errors in trace lines to
better be able to determine what went wrong.
Signed-off-by: David Howells <dhowells@redhat.com>
It's possible for an AFS file server to issue a whole-volume notification
that callbacks on all the vnodes in the file have been broken. This is
done for R/O and backup volumes (which don't have per-file callbacks) and
for things like a volume being taken offline.
Fix callback handling to detect whole-volume notifications, to track it
across operations and to check it during inode validation.
Fixes: c435ee3455 ("afs: Overhaul the callback handling")
Signed-off-by: David Howells <dhowells@redhat.com>
The afs directory loading code (primarily afs_read_dir()) locks all the
pages that hold a directory's content blob to defend against
getdents/getdents races and getdents/lookup races where the competitors
issue conflicting reads on the same data. As the reads will complete
consecutively, they may retrieve different versions of the data and
one may overwrite the data that the other is busy parsing.
Fix this by not locking the pages at all, but rather by turning the
validation lock into an rwsem and getting an exclusive lock on it whilst
reading the data or validating the attributes and a shared lock whilst
parsing the data. Sharing the attribute validation lock should be fine as
the data fetch will retrieve the attributes also.
The individual page locks aren't needed at all as the only place they're
being used is to serialise data loading.
Without this patch, the:
if (!test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {
...
}
part of afs_read_dir() may be skipped, leaving the pages unlocked when we
hit the success: clause - in which case we try to unlock the not-locked
pages, leading to the following oops:
page:ffffe38b405b4300 count:3 mapcount:0 mapping:ffff98156c83a978 index:0x0
flags: 0xfffe000001004(referenced|private)
raw: 000fffe000001004 ffff98156c83a978 0000000000000000 00000003ffffffff
raw: dead000000000100 dead000000000200 0000000000000001 ffff98156b27c000
page dumped because: VM_BUG_ON_PAGE(!PageLocked(page))
page->mem_cgroup:ffff98156b27c000
------------[ cut here ]------------
kernel BUG at mm/filemap.c:1205!
...
RIP: 0010:unlock_page+0x43/0x50
...
Call Trace:
afs_dir_iterate+0x789/0x8f0 [kafs]
? _cond_resched+0x15/0x30
? kmem_cache_alloc_trace+0x166/0x1d0
? afs_do_lookup+0x69/0x490 [kafs]
? afs_do_lookup+0x101/0x490 [kafs]
? key_default_cmp+0x20/0x20
? request_key+0x3c/0x80
? afs_lookup+0xf1/0x340 [kafs]
? __lookup_slow+0x97/0x150
? lookup_slow+0x35/0x50
? walk_component+0x1bf/0x490
? path_lookupat.isra.52+0x75/0x200
? filename_lookup.part.66+0xa0/0x170
? afs_end_vnode_operation+0x41/0x60 [kafs]
? __check_object_size+0x9c/0x171
? strncpy_from_user+0x4a/0x170
? vfs_statx+0x73/0xe0
? __do_sys_newlstat+0x39/0x70
? __x64_sys_getdents+0xc9/0x140
? __x64_sys_getdents+0x140/0x140
? do_syscall_64+0x5b/0x160
? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: f3ddee8dc4 ("afs: Fix directory handling")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
