Commit Graph

83 Commits

Author SHA1 Message Date
Andreas Gruenbacher e3da6be3d7 gfs2: Fix withdraw race
Function gfs2_withdraw() tries to synchronize concurrent callers by
atomically setting the SDF_WITHDRAWN flag in the first caller, setting
the SDF_WITHDRAW_IN_PROG flag to indicate that a withdraw is in
progress, performing the actual withdraw, and clearing the
SDF_WITHDRAW_IN_PROG flag when done.  All other callers wait for the
SDF_WITHDRAW_IN_PROG flag to be cleared before returning.

This leaves a small window in which callers can find the SDF_WITHDRAWN
flag set before the SDF_WITHDRAW_IN_PROG flag has been set, causing them
to return prematurely, before the withdraw has been completed.

Fix that by setting the SDF_WITHDRAWN and SDF_WITHDRAW_IN_PROG flags
atomically.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-09-05 15:58:17 +02:00
Andreas Gruenbacher fe4f7940d2 gfs2: Fix asynchronous thread destruction
The kernel threads are currently stopped and destroyed synchronously by
gfs2_make_fs_ro() and gfs2_put_super(), and asynchronously by
signal_our_withdraw(), with no synchronization, so the synchronous and
asynchronous contexts can race with each other.

First, when creating the kernel threads, take an extra task struct
reference so that the task struct won't go away immediately when they
terminate.  This allows those kthreads to terminate immediately when
they're done rather than hanging around as zombies until they are reaped
by kthread_stop().  When kthread_stop() is called on a terminated
kthread, it will return immediately.

Second, in signal_our_withdraw(), once the SDF_JOURNAL_LIVE flag has
been cleared, wake up the logd and quotad wait queues instead of
stopping the logd and quotad kthreads.  The kthreads are then expected
to terminate automatically within short time, but if they cannot, they
will not block the withdraw.

For example, if a user process and one of the kthread decide to withdraw
at the same time, only one of them will perform the actual withdraw and
the other will wait for it to be done.  If the kthread ends up being the
one to wait, the withdrawing user process won't be able to stop it.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-09-05 15:58:17 +02:00
Andreas Gruenbacher f66af88e33 gfs2: Stop using gfs2_make_fs_ro for withdraw
[   81.372851][ T5532] CPU: 1 PID: 5532 Comm: syz-executor.0 Not tainted 6.2.0-rc1-syzkaller-dirty #0
[   81.382080][ T5532] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
[   81.392343][ T5532] Call Trace:
[   81.395654][ T5532]  <TASK>
[   81.398603][ T5532]  dump_stack_lvl+0x1b1/0x290
[   81.418421][ T5532]  gfs2_assert_warn_i+0x19a/0x2e0
[   81.423480][ T5532]  gfs2_quota_cleanup+0x4c6/0x6b0
[   81.428611][ T5532]  gfs2_make_fs_ro+0x517/0x610
[   81.457802][ T5532]  gfs2_withdraw+0x609/0x1540
[   81.481452][ T5532]  gfs2_inode_refresh+0xb2d/0xf60
[   81.506658][ T5532]  gfs2_instantiate+0x15e/0x220
[   81.511504][ T5532]  gfs2_glock_wait+0x1d9/0x2a0
[   81.516352][ T5532]  do_sync+0x485/0xc80
[   81.554943][ T5532]  gfs2_quota_sync+0x3da/0x8b0
[   81.559738][ T5532]  gfs2_sync_fs+0x49/0xb0
[   81.564063][ T5532]  sync_filesystem+0xe8/0x220
[   81.568740][ T5532]  generic_shutdown_super+0x6b/0x310
[   81.574112][ T5532]  kill_block_super+0x79/0xd0
[   81.578779][ T5532]  deactivate_locked_super+0xa7/0xf0
[   81.584064][ T5532]  cleanup_mnt+0x494/0x520
[   81.593753][ T5532]  task_work_run+0x243/0x300
[   81.608837][ T5532]  exit_to_user_mode_loop+0x124/0x150
[   81.614232][ T5532]  exit_to_user_mode_prepare+0xb2/0x140
[   81.619820][ T5532]  syscall_exit_to_user_mode+0x26/0x60
[   81.625287][ T5532]  do_syscall_64+0x49/0xb0
[   81.629710][ T5532]  entry_SYSCALL_64_after_hwframe+0x63/0xcd

In this backtrace, gfs2_quota_sync() takes quota data references and
then calls do_sync().  Function do_sync() encounters filesystem
corruption and withdraws the filesystem, which (among other things) calls
gfs2_quota_cleanup().  Function gfs2_quota_cleanup() wrongly assumes
that nobody is holding any quota data references anymore, and destroys
all quota data objects.  When gfs2_quota_sync() then resumes and
dereferences the quota data objects it is holding, those objects are no
longer there.

Function gfs2_quota_cleanup() deals with resource deallocation and can
easily be delayed until gfs2_put_super() in the case of a filesystem
withdraw.  In fact, most of the other work gfs2_make_fs_ro() does is
unnecessary during a withdraw as well, so change signal_our_withdraw()
to skip gfs2_make_fs_ro() and perform the necessary steps directly
instead.

Thanks to Edward Adam Davis <eadavis@sina.com> for the initial patches.

Link: https://lore.kernel.org/all/0000000000002b5e2405f14e860f@google.com
Reported-by: syzbot+3f6a670108ce43356017@syzkaller.appspotmail.com
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-09-05 15:58:17 +02:00
Bob Peterson 432928c937 gfs2: Add quota_change type
Function do_qc has two main uses: (1) to re-sync the local quota changes
(qd) to the master quotas, and (2) normal quota changes. In the case of
normal quota changes, the change can be positive or negative, as the
quota usage goes up and down.

Before this patch function do_qc was distinguishing one from another by
whether the resulting value is or isn't zero: In the case of a re-sync
(called do_sync) the quota value is moved from the temporary value to a
master value, so the amount is added to one and subtracted from the
other. The problem is that since the values can be positive or negative
we can occasionally run into situations where we are not doing a re-sync
but the quota change just happens to cancel out the previous value.

In the case of a re-sync extra references and locks are taken, and so
do_qc needs to release them. In the case of a normal quota change, no
extra references and locks are taken, so it must not try to release
them.

The problem is: if the quota change is not a re-sync but the value just
happens to cancel out the original quota change, the resulting zero
value fools do_qc into thinking this is a re-sync and therefore it must
release the extra references. This results in problems, mainly having to
do with slot reference numbers going smaller than zero.

This patch introduces new constants, QC_SYNC and QC_CHANGE so do_qc can
really tell the difference. For QC_SYNC calls it must release the extra
references acquired by gfs2_quota_unlock's call to qd_check_sync. For
QC_CHANGE calls it does not have extra references to put.

Note that this allows quota changes back to a value of zero, and so I
removed an assert warning related to that.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-07-03 22:30:48 +02:00
Andreas Gruenbacher 6c7410f449 gfs2: gfs2_freeze_lock_shared cleanup
All the remaining users of gfs2_freeze_lock_shared() set freeze_gh to
&sdp->sd_freeze_gh and flags to 0, so remove those two parameters.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-07-03 22:30:26 +02:00
Andreas Gruenbacher b77b4a4815 gfs2: Rework freeze / thaw logic
So far, at mount time, gfs2 would take the freeze glock in shared mode
and then immediately drop it again, turning it into a cached glock that
can be reclaimed at any time.  To freeze the filesystem cluster-wide,
the node initiating the freeze would take the freeze glock in exclusive
mode, which would cause the freeze glock's freeze_go_sync() callback to
run on each node.  There, gfs2 would freeze the filesystem and schedule
gfs2_freeze_func() to run.  gfs2_freeze_func() would re-acquire the
freeze glock in shared mode, thaw the filesystem, and drop the freeze
glock again.  The initiating node would keep the freeze glock held in
exclusive mode.  To thaw the filesystem, the initiating node would drop
the freeze glock again, which would allow gfs2_freeze_func() to resume
on all nodes, leaving the filesystem in the thawed state.

It turns out that in freeze_go_sync(), we cannot reliably and safely
freeze the filesystem.  This is primarily because the final unmount of a
filesystem takes a write lock on the s_umount rw semaphore before
calling into gfs2_put_super(), and freeze_go_sync() needs to call
freeze_super() which also takes a write lock on the same semaphore,
causing a deadlock.  We could work around this by trying to take an
active reference on the super block first, which would prevent unmount
from running at the same time.  But that can fail, and freeze_go_sync()
isn't actually allowed to fail.

To get around this, this patch changes the freeze glock locking scheme
as follows:

At mount time, each node takes the freeze glock in shared mode.  To
freeze a filesystem, the initiating node first freezes the filesystem
locally and then drops and re-acquires the freeze glock in exclusive
mode.  All other nodes notice that there is contention on the freeze
glock in their go_callback callbacks, and they schedule
gfs2_freeze_func() to run.  There, they freeze the filesystem locally
and drop and re-acquire the freeze glock before re-thawing the
filesystem.  This is happening outside of the glock state engine, so
there, we are allowed to fail.

From a cluster point of view, taking and immediately dropping a glock is
indistinguishable from taking the glock and only dropping it upon
contention, so this new scheme is compatible with the old one.

Thanks to Li Dong <lidong@vivo.com> for reporting a locking bug in
gfs2_freeze_func() in a previous version of this commit.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-07-03 22:25:02 +02:00
Andreas Gruenbacher cad1e15804 gfs2: Rename SDF_{FS_FROZEN => FREEZE_INITIATOR}
Rename the SDF_FS_FROZEN flag to SDF_FREEZE_INITIATOR to indicate more
clearly that the node that has this flag set is the initiator of the
freeze.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com
2023-06-15 09:57:38 +02:00
Andreas Gruenbacher e392edd5d5 gfs2: Rename gfs2_freeze_lock{ => _shared }
Rename gfs2_freeze_lock to gfs2_freeze_lock_shared to make it a bit more
obvious that this function establishes the "thawed" state of the freeze
glock.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-06-15 09:57:38 +02:00
Andreas Gruenbacher 097cca525a gfs2: Rename the {freeze,thaw}_super callbacks
Rename gfs2_freeze to gfs2_freeze_super and gfs2_unfreeze to
gfs2_thaw_super to match the names of the corresponding super
operations.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-06-15 09:57:38 +02:00
Andreas Gruenbacher af1abe1146 gfs2: Rename remaining "transaction" glock references
The transaction glock was repurposed to serve as the new freeze glock
years ago.  Don't refer to it as the transaction glock anymore.

Also, to be more precise, call it the "freeze glock" instead of the
"freeze lock".  Ditto for the journal glock.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2023-06-15 09:57:38 +02:00
Andreas Gruenbacher c7d7d2d345 gfs2: Merge branch 'for-next.nopid' into for-next
Resolves a conflict in gfs2_inode_lookup() between the following commits:

    gfs2: Use TRY lock in gfs2_inode_lookup for UNLINKED inodes

    gfs2: Mark the remaining process-independent glock holders as GL_NOPID

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2022-10-09 22:56:28 +02:00
Bob Peterson 053640a738 gfs2: Dequeue waiters when withdrawn
When a withdraw occurs, ordinary (not system) glocks may not be granted
anymore. Later, when the file system is unmounted, gfs2_gl_hash_clear()
tries to clear out all the glocks, but these un-grantable pending
waiters prevent some glocks from being freed. So the unmount hangs, at
least for its ten-minute timeout period.

This patch takes measures to remove any pending waiters from
the glocks that will never be granted. This allows the unmount to
proceed in a reasonable period of time.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2022-08-25 17:11:14 +02:00
Bob Peterson 04133b607a gfs2: Prevent double iput for journal on error
When a gfs2 file system is withdrawn it does iput on its journal to
allow recovery from another cluster node. If it's unable to get a
replacement inode for whatever reason, the journal descriptor would
still be pointing at the evicted inode. So when unmount clears out the
list of journals, it would do a second iput referencing the pointer.
To avoid this, set the inode pointer to NULL.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2022-08-25 17:10:59 +02:00
Andreas Gruenbacher ebdc416c9c gfs2: Mark the remaining process-independent glock holders as GL_NOPID
Add the GL_NOPID flag for the remaining glock holders which are not
associated with the current process.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2022-06-29 13:07:54 +02:00
Bob Peterson a739765cd8 gfs2: dump glocks from gfs2_consist_OBJ_i
Before this patch, failed consistency checks printed out the object
that failed, but not the object's glock. This patch makes it also
print out the object glock so we can see the glock's holders and flags
to aid with debugging.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-10-25 08:42:18 +02:00
Bob Peterson 1b8550b5de gfs2: Mark journal inodes as "don't cache"
Before this patch, journal inodes were considered regular inodes,
which meant that instead of evicting them, function iput_final would
just put them on the lru for later processing. If the file system
withdrew for whatever reason, the withdraw would never be seen until
the inode was evicted, which could be indefinitely.

This patch marks all journal inodes as "don't cache" which means
function iput_final will evict them immediately, allowing us to
properly recover the journal on other cluster nodes.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2021-08-20 09:03:46 -05:00
Bob Peterson 7392fbb0a4 gfs2: Make recovery error more readable
Before this patch, withdraws could cause an error that looked like:
Journal recovery skipped for 0 until next mount.
This patch changes it to a more readable:
Journal recovery skipped for jid 0 until next mount.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2021-08-20 09:03:46 -05:00
Bob Peterson f5456b5d67 gfs2: Clean up revokes on normal withdraws
Before this patch, the system ail lists were cleaned up if the logd
process withdrew, but on other withdraws, they were not cleaned up.
This included the cleaning up of the revokes as well.

This patch reorganizes things a bit so that all withdraws (not just logd)
clean up the ail lists, including any pending revokes.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-05-20 13:31:37 +02:00
Lee Jones c551f66c5d gfs2: Fix a number of kernel-doc warnings
Building the kernel with W=1 results in a number of kernel-doc warnings
like incorrect function names and parameter descriptions.  Fix those,
mostly by adding missing parameter descriptions, removing left-over
descriptions, and demoting some less important kernel-doc comments into
regular comments.

Originally proposed by Lee Jones; improved and combined into a single
patch by Andreas.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-04-09 22:14:13 +02:00
Bob Peterson d5bf630f35 gfs2: bypass signal_our_withdraw if no journal
Before this patch, function signal_our_withdraw referenced the journal
inode immediately. But corrupt file systems may have some invalid
journals, in which case our attempt to read it in will withdraw and the
resulting signal_our_withdraw would dereference the NULL value.

This patch adds a check to signal_our_withdraw so that if the journal
has not yet been initialized, it simply returns and does the old-style
withdraw.

Thanks, Andy Price, for his analysis.

Reported-by: syzbot+50a8a9cf8127f2c6f5df@syzkaller.appspotmail.com
Fixes: 601ef0d52e ("gfs2: Force withdraw to replay journals and wait for it to finish")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-03-12 14:55:23 +01:00
Yang Li eb602521f4 gfs2: make function gfs2_make_fs_ro() to void type
It fixes the following warning detected by coccinelle:
./fs/gfs2/super.c:592:5-10: Unneeded variable: "error". Return "0" on
line 628

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2021-03-07 17:04:55 +01:00
Bob Peterson f5f02fde9f gfs2: fix glock confusion in function signal_our_withdraw
If go_free is defined, function signal_our_withdraw is supposed to
synchronize on the GLF_FREEING flag of the inode glock, but it
accidentally does that on the live glock. Fix that and disambiguate
the glock variables.

Fixes: 601ef0d52e ("gfs2: Force withdraw to replay journals and wait for it to finish")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2021-01-25 08:08:44 -05:00
Bob Peterson 96b1454f2e gfs2: move freeze glock outside the make_fs_rw and _ro functions
Before this patch, sister functions gfs2_make_fs_rw and gfs2_make_fs_ro locked
(held) the freeze glock by calling gfs2_freeze_lock and gfs2_freeze_unlock.
The problem is, not all the callers of gfs2_make_fs_ro should be doing this.
The three callers of gfs2_make_fs_ro are: remount (gfs2_reconfigure),
signal_our_withdraw, and unmount (gfs2_put_super). But when unmounting the
file system we can get into the following circular lock dependency:

deactivate_super
   down_write(&s->s_umount); <-------------------------------------- s_umount
   deactivate_locked_super
      gfs2_kill_sb
         kill_block_super
            generic_shutdown_super
               gfs2_put_super
                  gfs2_make_fs_ro
                     gfs2_glock_nq_init sd_freeze_gl
                        freeze_go_sync
                           if (freeze glock in SH)
                              freeze_super (vfs)
                                 down_write(&sb->s_umount); <------- s_umount

This patch moves the hold of the freeze glock outside the two sister rw/ro
functions to their callers, but it doesn't request the glock from
gfs2_put_super, thus eliminating the circular dependency.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-12-23 00:54:21 +01:00
Bob Peterson c77b52c0a1 gfs2: Add common helper for holding and releasing the freeze glock
Many places in the gfs2 code queued and dequeued the freeze glock.
Almost all of them acquire it in SHARED mode, and need to specify the
same LM_FLAG_NOEXP and GL_EXACT flags.

This patch adds common helper functions gfs2_freeze_lock and gfs2_freeze_unlock
to make the code more readable, and to prepare for the next patch.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-12-23 00:54:13 +01:00
Bob Peterson 6e5c4ea37a gfs2: in signal_our_withdraw wait for unfreeze of _this_ fs only
Function signal_our_withdraw needs to work on file systems that have been
partially frozen. To do this, it called flush_workqueue(gfs2_freeze_wq).
This this wrong because it waits for *ALL* file systems to be unfrozen, not
just the one we're withdrawing from. It should only wait for the targetted
file system to be unfrozen. Otherwise it would wait until ALL file systems
are thawed before signaling the withdraw.

This patch changes signal_our_withdraw so it calls flush_work() for the target
file system's freeze work (only) to be completed.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-12-03 17:04:41 +01:00
Andrew Price 0e539ca1bb gfs2: Fix NULL pointer dereference in gfs2_rgrp_dump
When an rindex entry is found to be corrupt, compute_bitstructs() calls
gfs2_consist_rgrpd() which calls gfs2_rgrp_dump() like this:

    gfs2_rgrp_dump(NULL, rgd->rd_gl, fs_id_buf);

gfs2_rgrp_dump then dereferences the gl without checking it and we get

    BUG: KASAN: null-ptr-deref in gfs2_rgrp_dump+0x28/0x280

because there's no rgrp glock involved while reading the rindex on mount.

Fix this by changing gfs2_rgrp_dump to take an rgrp argument.

Reported-by: syzbot+43fa87986bdd31df9de6@syzkaller.appspotmail.com
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-10-14 23:54:43 +02:00
Bob Peterson b839dadae8 gfs2: new slab for transactions
This patch adds a new slab for gfs2 transactions. That allows us to
reduce kernel memory fragmentation, have better organization of data
for analysis of vmcore dumps. A new centralized function is added to
free the slab objects, and it exposes use-after-free by giving
warnings if a transaction is freed while it still has bd elements
attached to its buffers or ail lists. We make sure to initialize
those transaction ail lists so we can check their integrity when freeing.

At a later time, we should add a slab initialization function to
make it more efficient, but for this initial patch I wanted to
minimize the impact.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-06-05 21:24:25 +02:00
Bob Peterson 53af80ce0e gfs2: Fix BUG during unmount after file system withdraw
Before this patch, when the logd daemon was forced to withdraw, it
would try to request its journal be recovered by another cluster node.
However, in single-user cases with lock_nolock, there are no other
nodes to recover the journal. Function signal_our_withdraw() was
recognizing the lock_nolock situation, but not until after it had
evicted its journal inode. Since the journal descriptor that points
to the inode was never removed from the master list, when the unmount
occurred, it did another iput on the evicted inode, which resulted in
a BUG_ON(inode->i_state & I_CLEAR).

This patch moves the check for this situation earlier in function
signal_our_withdraw(), which avoids the extra iput, so the unmount
may happen normally.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-05-08 15:13:27 +02:00
Bob Peterson ca399c96e9 gfs2: flesh out delayed withdraw for gfs2_log_flush
Function gfs2_log_flush() had a few places where it tried to withdraw
from the file system when errors were encountered. The problem is,
it should delay those withdraws until the log flush lock is no longer
held.

This patch creates a new function just for delayed withdraws for
situations like this. If errors=panic was specified on mount, we
still want to do it the old fashioned way because the panic it does
not help to delay in that situation.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-02-27 07:53:18 -06:00
Bob Peterson 7d9f924958 gfs2: Add verbose option to check_journal_clean
Before this patch, function check_journal_clean would give messages
related to journal recovery. That's fine for mount time, but when a
node withdraws and forces replay that way, we don't want all those
distracting and misleading messages. This patch adds a new parameter
to make those messages optional.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-02-27 07:53:17 -06:00
Bob Peterson 601ef0d52e gfs2: Force withdraw to replay journals and wait for it to finish
When a node withdraws from a file system, it often leaves its journal
in an incomplete state. This is especially true when the withdraw is
caused by io errors writing to the journal. Before this patch, a
withdraw would try to write a "shutdown" record to the journal, tell
dlm it's done with the file system, and none of the other nodes
know about the problem. Later, when the problem is fixed and the
withdrawn node is rebooted, it would then discover that its own
journal was incomplete, and replay it. However, replaying it at this
point is almost guaranteed to introduce corruption because the other
nodes are likely to have used affected resource groups that appeared
in the journal since the time of the withdraw. Replaying the journal
later will overwrite any changes made, and not through any fault of
dlm, which was instructed during the withdraw to release those
resources.

This patch makes file system withdraws seen by the entire cluster.
Withdrawing nodes dequeue their journal glock to allow recovery.

The remaining nodes check all the journals to see if they are
clean or in need of replay. They try to replay dirty journals, but
only the journals of withdrawn nodes will be "not busy" and
therefore available for replay.

Until the journal replay is complete, no i/o related glocks may be
given out, to ensure that the replay does not cause the
aforementioned corruption: We cannot allow any journal replay to
overwrite blocks associated with a glock once it is held.

The "live" glock which is now used to signal when a withdraw
occurs. When a withdraw occurs, the node signals its withdraw by
dequeueing the "live" glock and trying to enqueue it in EX mode,
thus forcing the other nodes to all see a demote request, by way
of a "1CB" (one callback) try lock. The "live" glock is not
granted in EX; the callback is only just used to indicate a
withdraw has occurred.

Note that all nodes in the cluster must wait for the recovering
node to finish replaying the withdrawing node's journal before
continuing. To this end, it checks that the journals are clean
multiple times in a retry loop.

Also note that the withdraw function may be called from a wide
variety of situations, and therefore, we need to take extra
precautions to make sure pointers are valid before using them in
many circumstances.

We also need to take care when glocks decide to withdraw, since
the withdraw code now uses glocks.

Also, before this patch, if a process encountered an error and
decided to withdraw, if another process was already withdrawing,
the second withdraw would be silently ignored, which set it free
to unlock its glocks. That's correct behavior if the original
withdrawer encounters further errors down the road. But if
secondary waiters don't wait for the journal replay, unlocking
glocks will allow other nodes to use them, despite the fact that
the journal containing those blocks is being replayed. The
replay needs to finish before our glocks are released to other
nodes. IOW, secondary withdraws need to wait for the first
withdraw to finish.

For example, if an rgrp glock is unlocked by a process that didn't
wait for the first withdraw, a journal replay could introduce file
system corruption by replaying a rgrp block that has already been
granted to a different cluster node.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-02-27 07:53:12 -06:00
Bob Peterson 0d91061a37 gfs2: move check_journal_clean to util.c for future use
Before this patch function check_journal_clean was in ops_fstype.c.
This patch moves it to util.c so we can make use of it elsewhere
in a future patch.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-02-10 07:39:51 -06:00
Bob Peterson 69511080bd gfs2: Introduce concept of a pending withdraw
File system withdraws can be delayed when inconsistencies are
discovered when we cannot withdraw immediately, for example, when
critical spin_locks are held. But delaying the withdraw can cause
gfs2 to ignore the error and keep running for a short period of time.
For example, an rgrp glock may be dequeued and demoted while there
are still buffers that haven't been properly revoked, due to io
errors writing to the journal.

This patch introduces a new concept of a pending withdraw, which
means an inconsistency has been discovered and we need to withdraw
at the earliest possible opportunity. In these cases, we aren't
quite withdrawn yet, but we still need to not dequeue glocks and
other critical things. If we dequeue the glocks and the withdraw
results in our journal being replayed, the replay could overwrite
data that's been modified by a different node that acquired the
glock in the meantime.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
2020-02-10 07:39:47 -06:00
Andreas Gruenbacher 8e28ef1f2f gfs2: Return bool from gfs2_assert functions
The gfs2_assert functions only print messages when the filesystem hasn't been
withdrawn yet, and they indicate whether or not they've printed something in
their return value.  However, none of the callers use that information, so
simply return whether or not the assert has failed.

(The gfs2_assert functions are still backwards; they return false when an
assertion is true.)

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-02-10 07:39:47 -06:00
Andreas Gruenbacher a5ca2f1cb6 gfs2: Turn gfs2_consist into void functions
Change the various gfs2_consist functions to return void.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-02-10 07:39:46 -06:00
Andreas Gruenbacher d7e7ab3f1e gfs2: Remove usused cluster_wide arguments of gfs2_consist functions
These arguments are always passed as 0, and they are never evaluated.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-02-10 07:39:45 -06:00
Andreas Gruenbacher badb55ec20 gfs2: Split gfs2_lm_withdraw into two functions
Split gfs2_lm_withdraw into a function that prints an error message and a
function that withdraws the filesystem.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2020-02-10 07:39:44 -06:00
Bob Peterson eb43e660c0 gfs2: Introduce function gfs2_withdrawn
Add function gfs2_withdrawn and replace all checks for the SDF_WITHDRAWN
bit to call it. This does not change the logic or function of gfs2, and
it facilitates later improvements to the withdraw sequence.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2019-11-14 19:46:18 +01:00
Bob Peterson 98fb057487 gfs2: Fix possible fs name overflows
This patch fixes three places in which temporary character buffers
could overflow due to the addition of the file system id from patch
3792ce973f. Thanks to Dan Carpenter for pointing it out.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2019-09-03 09:42:41 +02:00
Bob Peterson 3792ce973f gfs2: dump fsid when dumping glock problems
Before this patch, if a glock error was encountered, the glock with
the problem was dumped. But sometimes you may have lots of file systems
mounted, and that doesn't tell you which file system it was for.

This patch adds a new boolean parameter fsid to the dump_glock family
of functions. For non-error cases, such as dumping the glocks debugfs
file, the fsid is not dumped in order to keep lock dumps and glocktop
as clean as possible. For all error cases, such as GLOCK_BUG_ON, the
file system id is now printed. This will make it easier to debug.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2019-06-27 21:27:43 +02:00
Bob Peterson 04aea0ca14 gfs2: Rename SDF_SHUTDOWN to SDF_WITHDRAWN
Before this patch, the superblock flag indicating when a file system
is withdrawn was called SDF_SHUTDOWN. This patch simply renames it to
the more obvious SDF_WITHDRAWN.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2019-06-27 21:26:35 +02:00
Thomas Gleixner 7336d0e654 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 398
Based on 1 normalized pattern(s):

  this copyrighted material is made available to anyone wishing to use
  modify copy or redistribute it subject to the terms and conditions
  of the gnu general public license version 2

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 44 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081038.653000175@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:37:12 +02:00
Bob Peterson b524abcc01 gfs2: slow the deluge of io error messages
When an io error is hit, it calls gfs2_io_error_bh_i for every
journal buffer it can't write. Since we changed gfs2_io_error_bh_i
recently to withdraw later in the cycle, it sends a flood of
errors to the console. This patch checks for the file system already
being withdrawn, and if so, doesn't send more messages. It doesn't
stop the flood of messages, but it slows it down and keeps it more
reasonable.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2018-10-05 10:51:11 -05:00
Bob Peterson 72244b6bc7 gfs2: improve debug information when lvb mismatches are found
Before this patch, gfs2_rgrp_bh_get would check for lvb mismatches,
but it wouldn't tell you what was actually wrong. This patch adds
more information to help us debug it. It also makes rgrp consistency
checks dump any bad rgrps, and the rgrp dump code dump any lvbs
as well as the rgrp itself.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
2018-08-28 12:51:08 -05:00
Andreas Gruenbacher 9e1a9ecd13 gfs2: Don't withdraw under a spin lock
In two places, the gfs2_io_error_bh macro is called while holding the
sd_ail_lock spin lock.  This isn't allowed because gfs2_io_error_bh
withdraws the filesystem, which can sleep because it issues a uevent.
To fix that, add a gfs2_io_error_bh_wd macro that does withdraw the
filesystem and change gfs2_io_error_bh to not withdraw the filesystem.
In those places where the new gfs2_io_error_bh is used, withdraw the
filesystem after releasing sd_ail_lock.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Andrew Price <anprice@redhat.com>
2018-06-21 07:39:44 -05:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Benjamin Marzinski 3e11e53041 GFS2: ignore unlock failures after withdraw
After gfs2 has withdrawn the filesystem, it may still have many locks not
in the unlocked state.  If it is using lock_dlm, it will failed trying
the unlocks since it has already unmounted the lock manager. Instead, it
should set the SDF_SKIP_DLM_UNLOCK flag on withdraw, to signal that
it can skip the lock_manager on unlocks, and failback to lock_nolock
style unlocking.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2016-03-24 08:28:48 -04:00
Bob Peterson a097dc7e24 GFS2: Make rgrp reservations part of the gfs2_inode structure
Before this patch, multi-block reservation structures were allocated
from a special slab. This patch folds the structure into the gfs2_inode
structure. The disadvantage is that the gfs2_inode needs more memory,
even when a file is opened read-only. The advantages are: (a) we don't
need the special slab and the extra time it takes to allocate and
deallocate from it. (b) we no longer need to worry that the structure
exists for things like quota management. (c) This also allows us to
remove the calls to get_write_access and put_write_access since we
know the structure will exist.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-12-14 12:16:38 -06:00
Bob Peterson b54e9a0b92 GFS2: Extract quota data from reservations structure (revert 5407e24)
This patch basically reverts the majority of patch 5407e24.
That patch eliminated the gfs2_qadata structure in favor of just
using the reservations structure. The problem with doing that is that
it increases the size of the reservations structure. That is not an
issue until it comes time to fold the reservations structure into the
inode in memory so we know it's always there. By separating out the
quota structure again, we aren't punishing the non-quota users by
making all the inodes bigger, requiring more slab space. This patch
creates a new slab area to allocate the quota stuff so it's managed
a little more sanely.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2015-11-24 08:38:44 -06:00
Joe Perches cb94eb066e GFS2: Convert gfs2_lm_withdraw to use fs_err
vprintk use is not prefixed by a KERN_<LEVEL>,
so emit these messages at KERN_ERR level.

Using %pV can save some code and allow fs_err to
be used, so do it.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2014-03-07 09:39:18 +00:00