afs: Fix speculative status fetches

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 indic

afs: Fix speculative status fetches

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>

show more ...

afs: Prepare for use of THPs

As a prelude to supporting transparent huge pages, use thp_size() and
similar rather than PAGE_SIZE/SHIFT.

Further, try and frame everything in terms of file positions

afs: Prepare for use of THPs

As a prelude to supporting transparent huge pages, use thp_size() and
similar rather than PAGE_SIZE/SHIFT.

Further, try and frame everything in terms of file positions and lengths
rather than page indices and numbers of pages.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/160588540227.3465195.4752143929716269062.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161118155821.1232039.540445038028845740.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161051439.2537118.15577827510426326534.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340415869.1303470.6040191748634322355.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539559365.286939.18344613540296085269.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653815142.2770958.454490670311230206.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789098713.6155.16394227991842480300.stgit@warthog.procyon.org.uk/ # v6

show more ...

afs: Set up the iov_iter before calling afs_extract_data()

afs_extract_data() sets up a temporary iov_iter and passes it to AF_RXRPC
each time it is called to describe the remaining buffer to be fil

afs: Set up the iov_iter before calling afs_extract_data()

afs_extract_data() sets up a temporary iov_iter and passes it to AF_RXRPC
each time it is called to describe the remaining buffer to be filled.

Instead:

(1) Put an iterator in the afs_call struct.

(2) Set the iterator for each marshalling stage to load data into the
appropriate places. A number of convenience functions are provided to
this end (eg. afs_extract_to_buf()).

This iterator is then passed to afs_extract_data().

(3) Use the new ITER_XARRAY iterator when reading data to load directly
into the inode's pages without needing to create a list of them.

This will allow O_DIRECT calls to be supported in future patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/152898380012.11616.12094591785228251717.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/153685394431.14766.3178466345696987059.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/153999787395.866.11218209749223643998.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/154033911195.12041.3882700371848894587.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/158861250059.340223.1248231474865140653.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/159465827399.1377938.11181327349704960046.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/160588533776.3465195.3612752083351956948.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161118151238.1232039.17015723405750601161.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161047240.2537118.14721975104810564022.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340410333.1303470.16260122230371140878.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539554187.286939.15305559004905459852.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653810525.2770958.4630666029125411789.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789093719.6155.7877160739235087723.stgit@warthog.procyon.org.uk/ # v6

show more ...

afs: Move key to afs_read struct

Stash the key used to authenticate read operations in the afs_read struct.
This will be necessary to reissue the operation against the server if a
read from the cach

afs: Move key to afs_read struct

Stash the key used to authenticate read operations in the afs_read struct.
This will be necessary to reissue the operation against the server if a
read from the cache fails in upcoming cache changes.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/158861248336.340223.1851189950710196001.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/159465823899.1377938.11925978022348532049.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/160588529557.3465195.7303323479305254243.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161118147693.1232039.13780672951838643842.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161043340.2537118.511899217704140722.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340406678.1303470.12676824086429446370.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539550819.286939.1268332875889175195.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653806683.2770958.11300984379283401542.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789089556.6155.14603302893431820997.stgit@warthog.procyon.org.uk/ # v6

show more ...

afs: Stop listxattr() from listing "afs.*" attributes

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.

afs: Stop listxattr() from listing "afs.*" attributes

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

show more ...

fs: make helpers idmap mount aware

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 b

fs: make helpers idmap mount aware

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>

show more ...

afs: Fix directory entry size calculation

The number of dirent records used by an AFS directory entry should be
calculated using the assumption that there is a 16-byte name field in the
first block,

afs: Fix directory entry size calculation

The number of dirent records used by an AFS directory entry should be
calculated using the assumption that there is a 16-byte name field in the
first block, rather than a 20-byte name field (which is actually the case).
This miscalculation is historic and effectively standard, so we have to use
it.

The calculation we need to use is:

1 + (((strlen(name) + 1) + 15) >> 5)

where we are adding one to the strlen() result to account for the NUL
termination.

Fix this by the following means:

(1) Create an inline function to do the calculation for a given name
length.

(2) Use the function to calculate the number of records used for a dirent
in afs_dir_iterate_block().

Use this to move the over-end check out of the loop since it only
needs to be done once.

Further use this to only go through the loop for the 2nd+ records
composing an entry. The only test there now is for if the record is
allocated - and we already checked the first block at the top of the
outer loop.

(3) Add a max name length check in afs_dir_iterate_block().

(4) Make afs_edit_dir_add() and afs_edit_dir_remove() use the function
from (1) to calculate the number of blocks rather than doing it
incorrectly themselves.

Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...")
Fixes: ^1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>

show more ...

afs: Fix the nlink handling of dir-over-dir rename

commit f610a5a29c3cfb7d37bdfa4ef52f72ea51f24a76 upstream.

Fix rename of one directory over another such that the nlink on the deleted
directory is

afs: Fix the nlink handling of dir-over-dir rename

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>

show more ...

afs: Fix speculative status fetches

[ Upstream commit 22650f148126571be1098d34160eb4931fc77241 ]

The generic/464 xfstest causes kAFS to emit occasional warnings of the
form:

kAFS: vnode mo

afs: Fix speculative status fetches

[ 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>

show more ...

afs: Stop listxattr() from listing "afs.*" attributes

commit a7889c6320b9200e3fe415238f546db677310fa9 upstream.

afs_listxattr() lists all the available special afs xattrs (i.e. those in
the "afs.*"

afs: Stop listxattr() from listing "afs.*" attributes

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>

show more ...

afs: Fix speculative status fetch going out of order wrt to modifications

When doing a lookup in a directory, the afs filesystem uses a bulk
status fetch to speculatively retrieve the statuses of up

afs: Fix speculative status fetch going out of order wrt to modifications

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>

show more ...

afs: Fix to take ref on page when PG_private is set

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 o

afs: Fix to take ref on page when PG_private is set

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>

show more ...

treewide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused vari

treewide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
xargs perl -pi -e \
's/\buninitialized_var\(([^\)]+)\)/\1/g;
s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>

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afs: Fix afs_do_lookup() to call correct fetch-status op variant

Fix afs_do_lookup()'s fallback case for when FS.InlineBulkStatus isn't
supported by the server.

In the fallback, it calls FS.FetchSt

afs: Fix afs_do_lookup() to call correct fetch-status op variant

Fix afs_do_lookup()'s fallback case for when FS.InlineBulkStatus isn't
supported by the server.

In the fallback, it calls FS.FetchStatus for the specific vnode it's
meant to be looking up. Commit b6489a49f7b7 broke this by renaming one
of the two identically-named afs_fetch_status_operation descriptors to
something else so that one of them could be made non-static. The site
that used the renamed one, however, wasn't renamed and didn't produce
any warning because the other was declared in a header.

Fix this by making afs_do_lookup() use the renamed variant.

Note that there are two variants of the success method because one is
called from ->lookup() where we may or may not have an inode, but can't
call iget until after we've talked to the server - whereas the other is
called from within iget where we have an inode, but it may or may not be
initialised.

The latter variant expects there to be an inode, but because it's being
called from there former case, there might not be - resulting in an oops
like the following:

BUG: kernel NULL pointer dereference, address: 00000000000000b0
...
RIP: 0010:afs_fetch_status_success+0x27/0x7e
...
Call Trace:
afs_wait_for_operation+0xda/0x234
afs_do_lookup+0x2fe/0x3c1
afs_lookup+0x3c5/0x4bd
__lookup_slow+0xcd/0x10f
walk_component+0xa2/0x10c
path_lookupat.isra.0+0x80/0x110
filename_lookup+0x81/0x104
vfs_statx+0x76/0x109
__do_sys_newlstat+0x39/0x6b
do_syscall_64+0x4c/0x78
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: b6489a49f7b7 ("afs: Fix silly rename")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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afs: Fix silly rename

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 dat

afs: Fix silly rename

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: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>

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afs: Fix use of afs_check_for_remote_deletion()

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
vnod

afs: Fix use of afs_check_for_remote_deletion()

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: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Signed-off-by: David Howells <dhowells@redhat.com>

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afs: Remove afs_operation::abort_code

Remove afs_operation::abort_code as it's read but never set. Use
ac.abort_code instead.

Signed-off-by: David Howells <dhowells@redhat.com>

afs: Concoct ctimes

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

afs: Concoct ctimes

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>

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afs: Fix debugging statements with %px to be %p

Fix a couple of %px to be %p in debugging statements.

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Fixes: 8a070a96

afs: Fix debugging statements with %px to be %p

Fix a couple of %px to be %p in debugging statements.

Fixes: e49c7b2f6de7 ("afs: Build an abstraction around an "operation" concept")
Fixes: 8a070a964877 ("afs: Detect cell aliases 1 - Cells with root volumes")
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

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afs: Reorganise volume and server trees to be rooted on the cell

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 mu

afs: Reorganise volume and server trees to be rooted on the cell

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>

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afs: Build an abstraction around an "operation" concept

Turn the afs_operation struct into the main way that most fileserver
operations are managed. Various things are added to the struct, includin

afs: Build an abstraction around an "operation" concept

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>

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afs: Rename struct afs_fs_cursor to afs_operation

As a prelude to implementing asynchronous fileserver operations in the afs
filesystem, rename struct afs_fs_cursor to afs_operation.

This struct is

afs: Rename struct afs_fs_cursor to afs_operation

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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afs: Always include dir in bulk status fetch from afs_do_lookup()

When a lookup is done in an AFS directory, the filesystem will speculate
and fetch up to 49 other statuses for files in the same dir

afs: Always include dir in bulk status fetch from afs_do_lookup()

When a lookup is done in an AFS directory, the filesystem will speculate
and fetch up to 49 other statuses for files in the same directory and fetch
those as well, turning them into inodes or updating inodes that already
exist.

However, occasionally, a callback break might go missing due to NAT timing
out, but the afs filesystem doesn't then realise that the directory is not
up to date.

Alleviate this by using one of the status slots to check the directory in
which the lookup is being done.

Reported-by: Dave Botsch <botsch@cnf.cornell.edu>
Suggested-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>

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afs: Fix afs_d_validate() to set the right directory version

If a dentry's version is somewhere between invalid_before and the current
directory version, we should be setting it forward to the curre

afs: Fix afs_d_validate() to set the right directory version

If a dentry's version is somewhere between invalid_before and the current
directory version, we should be setting it forward to the current version,
not backwards to the invalid_before version. Note that we're only doing
this at all because dentry::d_fsdata isn't large enough on a 32-bit system.

Fix this by using a separate variable for invalid_before so that we don't
accidentally clobber the current dir version.

Fixes: a4ff7401fbfa ("afs: Keep track of invalid-before version for dentry coherency")
Signed-off-by: David Howells <dhowells@redhat.com>

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afs: Fix race between post-modification dir edit and readdir/d_revalidate

AFS directories are retained locally as a structured file, with lookup
being effected by a local search of the file contents

afs: Fix race between post-modification dir edit and readdir/d_revalidate

AFS directories are retained locally as a structured file, with lookup
being effected by a local search of the file contents. When a modification
(such as mkdir) happens, the dir file content is modified locally rather
than redownloading the directory.

The directory contents are accessed in a number of ways, with a number of
different locks schemes:

(1) Download of contents - dvnode->validate_lock/write in afs_read_dir().

(2) Lookup and readdir - dvnode->validate_lock/read in afs_dir_iterate(),
downgrading from (1) if necessary.

(3) d_revalidate of child dentry - dvnode->validate_lock/read in
afs_do_lookup_one() downgrading from (1) if necessary.

(4) Edit of dir after modification - page locks on individual dir pages.

Unfortunately, because (4) uses different locking scheme to (1) - (3),
nothing protects against the page being scanned whilst the edit is
underway. Even download is not safe as it doesn't lock the pages - relying
instead on the validate_lock to serialise as a whole (the theory being that
directory contents are treated as a block and always downloaded as a
block).

Fix this by write-locking dvnode->validate_lock around the edits. Care
must be taken in the rename case as there may be two different dirs - but
they need not be locked at the same time. In any case, once the lock is
taken, the directory version must be rechecked, and the edit skipped if a
later version has been downloaded by revalidation (there can't have been
any local changes because the VFS holds the inode lock, but there can have
been remote changes).

Fixes: 63a4681ff39c ("afs: Locally edit directory data for mkdir/create/unlink/...")
Signed-off-by: David Howells <dhowells@redhat.com>

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