linux-stable.git/fs/locks.c, branch v6.9

filelock: fix deadlock detection in POSIX locking

2024-02-20T08:53:33+00:00

The FL_POSIX check in __locks_insert_block was inadvertantly broken
recently and is now inserting only OFD locks instead of only legacy
POSIX locks.

This breaks deadlock detection in POSIX locks, and may also be the root
cause of a performance regression noted by the kernel test robot.
Restore the proper sense of the test.

Fixes: b6be3714005c ("filelock: convert __locks_insert_block, conflict and deadlock checks to use file_lock_core")
Reported-by: kernel test robot 
Closes: https://lore.kernel.org/oe-lkp/202402181229.f8147f40-oliver.sang@intel.com
Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240218-flsplit4-v1-1-26454fc090f2@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: don't do security checks on nfsd setlease calls

2024-02-05T12:53:03+00:00

Zdenek reported seeing some AVC denials due to nfsd trying to set
delegations:

    type=AVC msg=audit(09.11.2023 09:03:46.411:496) : avc:  denied  { lease } for  pid=5127 comm=rpc.nfsd capability=lease  scontext=system_u:system_r:nfsd_t:s0 tcontext=system_u:system_r:nfsd_t:s0 tclass=capability permissive=0

When setting delegations on behalf of nfsd, we don't want to do all of
the normal capabilty and LSM checks. nfsd is a kernel thread and runs
with CAP_LEASE set, so the uid checks end up being a no-op in most cases
anyway.

Some nfsd functions can end up running in normal process context when
tearing down the server. At that point, the CAP_LEASE check can fail and
cause the client to not tear down delegations when expected.

Also, the way the per-fs ->setlease handlers work today is a little
convoluted. The non-trivial ones are wrappers around generic_setlease,
so when they fail due to permission problems they usually they end up
doing a little extra work only to determine that they can't set the
lease anyway. It would be more efficient to do those checks earlier.

Transplant the permission checking from generic_setlease to
vfs_setlease, which will make the permission checking happen earlier on
filesystems that have a ->setlease operation. Add a new kernel_setlease
function that bypasses these checks, and switch nfsd to use that instead
of vfs_setlease.

There is one behavioral change here: prior this patch the
setlease_notifier would fire even if the lease attempt was going to fail
the security checks later. With this change, it doesn't fire until the
caller has passed them. I think this is a desirable change overall. nfsd
is the only user of the setlease_notifier and it doesn't benefit from
being notified about failed attempts.

Cc: Ondrej Mosnáček 
Reported-by: Zdenek Pytela 
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2248830
Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240205-bz2248830-v1-1-d0ec0daecba1@kernel.org
Acked-by: Tom Talpey 
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: split leases out of struct file_lock

2024-02-05T12:11:44+00:00

Add a new struct file_lease and move the lease-specific fields from
struct file_lock to it. Convert the appropriate API calls to take
struct file_lease instead, and convert the callers to use them.

There is zero overlap between the lock manager operations for file
locks and the ones for file leases, so split the lease-related
operations off into a new lease_manager_operations struct.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-47-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: convert seqfile handling to use file_lock_core

2024-02-05T12:11:41+00:00

Reduce some pointer manipulation by just using file_lock_core where we
can and only translate to a file_lock when needed.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-33-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: convert locks_translate_pid to take file_lock_core

2024-02-05T12:11:41+00:00

locks_translate_pid is used on both locks and leases, so have that take
struct file_lock_core.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-32-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: convert locks_insert_lock_ctx and locks_delete_lock_ctx

2024-02-05T12:11:41+00:00

Have these functions take a file_lock_core pointer instead of a
file_lock.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-31-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: convert locks_wake_up_blocks to take a file_lock_core pointer

2024-02-05T12:11:41+00:00

Have locks_wake_up_blocks take a file_lock_core pointer, and fix up the
callers to pass one in.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-30-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: make assign_type helper take a file_lock_core pointer

2024-02-05T12:11:40+00:00

Have assign_type take struct file_lock_core instead of file_lock.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-29-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: reorganize locks_delete_block and __locks_insert_block

2024-02-05T12:11:40+00:00

Rename the old __locks_delete_block to __locks_unlink_lock. Rename
change old locks_delete_block function to __locks_delete_block and
have it take a file_lock_core. Make locks_delete_block a simple wrapper
around __locks_delete_block.

Also, change __locks_insert_block to take struct file_lock_core, and
fix up its callers.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-28-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner

filelock: clean up locks_delete_block internals

2024-02-05T12:11:40+00:00

Rework the internals of locks_delete_block to use struct file_lock_core
(mostly just for clarity's sake). The prototype is not changed.

Signed-off-by: Jeff Layton 
Link: https://lore.kernel.org/r/20240131-flsplit-v3-27-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown 
Signed-off-by: Christian Brauner