linux-toradex.git/fs/gfs2/glock.c, branch v4.14

gfs2: Fix debugfs glocks dump

2017-09-25T17:32:33+00:00

The switch to rhashtables (commit 88ffbf3e03) broke the debugfs glock
dump (/sys/kernel/debug/gfs2//glocks) for dumps bigger than a
single buffer: the right function for restarting an rhashtable iteration
from the beginning of the hash table is rhashtable_walk_enter;
rhashtable_walk_stop + rhashtable_walk_start will just resume from the
current position.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Bob Peterson 
Cc: stable@vger.kernel.org # v4.3+

gfs2: constify rhashtable_params

2017-08-30T13:14:39+00:00

rhashtable_params are not supposed to change at runtime. All
Functions rhashtable_* working with const rhashtable_params
provided by . So mark the non-const structs
as const.

Signed-off-by: Arvind Yadav 
Signed-off-by: Bob Peterson

GFS2: Fix up some sparse warnings

2017-08-25T23:47:18+00:00

This patch cleans up various pieces of GFS2 to avoid sparse errors.
This doesn't fix them all, but it fixes several. The first error,
in function glock_hash_walk was a genuine bug where the rhashtable
could be started and not stopped.

Signed-off-by: Bob Peterson

gfs2: Clean up waiting on glocks

2017-08-10T15:51:02+00:00

The prepare_to_wait_on_glock and finish_wait_on_glock functions introduced in
commit 56a365be "gfs2: gfs2_glock_get: Wait on freeing glocks" are
better removed, resulting in cleaner code.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Bob Peterson

gfs2: gfs2_evict_inode: Put glocks asynchronously

2017-08-10T15:45:21+00:00

gfs2_evict_inode is called to free inodes under memory pressure.  The
function calls into DLM when an inode's last cluster-wide reference goes
away (remote unlink) and to release the glock and associated DLM lock
before finally destroying the inode.  However, if DLM is blocked on
memory to become available, calling into DLM again will deadlock.

Avoid that by decoupling releasing glocks from destroying inodes in that
case: with gfs2_glock_queue_put, glocks will be dequeued asynchronously
in work queue context, when the associated inodes have likely already
been destroyed.

With this change, inodes can end up being unlinked, remote-unlink can be
triggered, and then the inode can be reallocated before all
remote-unlink callbacks are processed.  To detect that, revalidate the
link count in gfs2_evict_inode to make sure we're not deleting an
allocated, referenced inode.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Bob Peterson

gfs2: gfs2_glock_get: Wait on freeing glocks

2017-08-10T15:39:31+00:00

Keep glocks in their hash table until they are freed instead of removing
them when their last reference is dropped.  This allows to wait for any
previous instances of a glock to go away in gfs2_glock_get before
creating a new glocks.

Special thanks to Andy Price for finding and fixing a problem which also
required us to delete the rcu_read_unlock from the error case in function
gfs2_glock_get.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Bob Peterson

GFS2: Don't waste time locking lru_lock for non-lru glocks

2017-08-09T14:36:39+00:00

Before this patch, glock_dq would call gfs2_glock_remove_from_lru.
For glocks that are never put on the LRU, such as the transaction
glock, this just takes the spin_lock, determines there's nothing to
be done because the list is empty, then unlocks again. This was
causing unnecessary lock contention on the lru_lock spin_lock.
This patch adds a check for GLOF_LRU in the glops before taking
the spin_lock.

Signed-off-by: Bob Peterson

gfs2: Fix glock rhashtable rcu bug

2017-07-07T18:22:05+00:00

Before commit 88ffbf3e03 "GFS2: Use resizable hash table for glocks",
glocks were freed via call_rcu to allow reading the glock hashtable
locklessly using rcu.  This was then changed to free glocks immediately,
which made reading the glock hashtable unsafe.  Bring back the original
code for freeing glocks via call_rcu.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Bob Peterson 
Cc: stable@vger.kernel.org # 4.3+

gfs2: Clean up glock work enqueuing

2017-07-05T12:21:00+00:00

This patch adds a standardized queueing mechanism for glock work
with spin_lock protection to prevent races.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Bob Peterson

GFS2: Allow glocks to be unlocked after withdraw

2017-05-05T19:19:28+00:00

This bug fixes a regression introduced by patch 0d1c7ae9d8.

The intent of the patch was to stop promoting glocks after a
file system is withdrawn due to a variety of errors, because doing
so results in a BUG(). (You should be able to unmount after a
withdraw rather than having the kernel panic.)

Unfortunately, it also stopped demotions, so glocks could not be
unlocked after withdraw, which means the unmount would hang.

This patch allows function do_xmote to demote locks to an
unlocked state after a withdraw, but not promote them.

Signed-off-by: Bob Peterson