Commit graph

7 commits

Author SHA1 Message Date
David Howells fed79fd783 afs: Fix debugging statements with %px to be %p
Fix a couple of %px to be %p in debugging statements.

Fixes: e49c7b2f6d ("afs: Build an abstraction around an "operation" concept")
Fixes: 8a070a9648 ("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>
2020-06-09 18:17:14 +01:00
David Howells 9ca0652596 afs: Fix use of BUG()
Fix afs_compare_addrs() to use WARN_ON(1) instead of BUG() and return 1
(ie. srx_a > srx_b).

There's no point trying to put actual error handling in as this should not
occur unless a new transport address type is allowed by AFS.  And even if
it does, in this particular case, it'll just never match unknown types of
addresses.  This BUG() was more of a 'you need to add a case here'
indicator.

Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
2020-06-09 17:21:03 +01:00
David Howells 20325960f8 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>
2020-06-04 15:37:57 +01:00
David Howells cca37d45d5 afs: Add a tracepoint to track the lifetime of the afs_volume struct
Add a tracepoint to track the lifetime of the afs_volume struct.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-04 15:37:57 +01:00
David Howells 6dfdf5369c afs: Detect cell aliases 3 - YFS Cells with a canonical cell name op
YFS Volume Location servers have an operation by which the cell name may be
queried.  Use this to find out what a YFS server thinks the canonical cell
name should be.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-04 15:37:57 +01:00
David Howells 6ef350b184 afs: Detect cell aliases 2 - Cells with no root volumes
Implement the second phase of cell alias detection.  This part handles
alias detection for cells that don't have root.cell volumes and so we have
to find some other volume or fileserver to query.

We take the first volume from each such cell and attempt to look it up in
the new cell.  If found, we compare the records, if they are the same, we
judge the cell names to be aliases.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-04 15:37:57 +01:00
David Howells 8a070a9648 afs: Detect cell aliases 1 - Cells with root volumes
Put in the first phase of cell alias detection.  This part handles alias
detection for cells that have root.cell volumes (which is expected to be
likely).

When a cell becomes newly active, it is probed for its root.cell volume,
and if it has one, this volume is compared against other root.cell volumes
to find out if the list of fileserver UUIDs have any in common - and if
that's the case, do the address lists of those fileservers have any
addresses in common.  If they do, the new cell is adjudged to be an alias
of the old cell and the old cell is used instead.

Comparing is aided by the server list in struct afs_server_list being
sorted in UUID order and the addresses in the fileserver address lists
being sorted in address order.

The cell then retains the afs_volume object for the root.cell volume, even
if it's not mounted for future alias checking.

This necessary because:

 (1) Whilst fileservers have UUIDs that are meant to be globally unique, in
     practice they are not because cells get cloned without changing the
     UUIDs - so afs_server records need to be per cell.

 (2) Sometimes the DNS is used to make cell aliases - but if we don't know
     they're the same, we may end up with multiple superblocks and multiple
     afs_server records for the same thing, impairing our ability to
     deliver callback notifications of third party changes

 (3) The fileserver RPC API doesn't contain the cell name, so it can't tell
     us which cell it's notifying and can't see that a change made to to
     one cell should notify the same client that's also accessed as the
     other cell.

Reported-by: Jeffrey Altman <jaltman@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2020-06-04 15:37:57 +01:00