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2019-05-24treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 91Thomas Gleixner1-13/+1
Based on 1 normalized pattern(s): is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 or at your option any later version [drbd] is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with [drbd] see the file copying if not write to the free software foundation 675 mass ave cambridge ma 02139 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 16 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075212.050796421@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-20drbd: introduce P_ZEROES (REQ_OP_WRITE_ZEROES on the "wire")Lars Ellenberg1-1/+1
And also re-enable partial-zero-out + discard aligned. With the introduction of REQ_OP_WRITE_ZEROES, we started to use that for both WRITE_ZEROES and DISCARDS, hoping that WRITE_ZEROES would "do what we want", UNMAP if possible, zero-out the rest. The example scenario is some LVM "thin" backend. While an un-allocated block on dm-thin reads as zeroes, on a dm-thin with "skip_block_zeroing=true", after a partial block write allocated that block, that same block may well map "undefined old garbage" from the backends on LBAs that have not yet been written to. If we cannot distinguish between zero-out and discard on the receiving side, to avoid "undefined old garbage" to pop up randomly at later times on supposedly zero-initialized blocks, we'd need to map all discards to zero-out on the receiving side. But that would potentially do a full alloc on thinly provisioned backends, even when the expectation was to unmap/trim/discard/de-allocate. We need to distinguish on the protocol level, whether we need to guarantee zeroes (and thus use zero-out, potentially doing the mentioned full-alloc), or if we want to put the emphasis on discard, and only do a "best effort zeroing" (by "discarding" blocks aligned to discard-granularity, and zeroing only potential unaligned head and tail clippings to at least *try* to avoid "false positives" in an online-verify later), hoping that someone set skip_block_zeroing=false. For some discussion regarding this on dm-devel, see also https://www.mail-archive.com/dm-devel%40redhat.com/msg07965.html https://www.redhat.com/archives/dm-devel/2018-January/msg00271.html For backward compatibility, P_TRIM means zero-out, unless the DRBD_FF_WZEROES feature flag is agreed upon during handshake. To have upper layers even try to submit WRITE ZEROES requests, we need to announce "efficient zeroout" independently. We need to fixup max_write_zeroes_sectors after blk_queue_stack_limits(): if we can handle "zeroes" efficiently on the protocol, we want to do that, even if our backend does not announce max_write_zeroes_sectors itself. Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-29drbd: switch from kmalloc() to kmalloc_array()Roland Kammerer1-1/+1
We had one call to kmalloc that actually allocates an array. Switch that one to the kmalloc_array() function. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2016-06-13drbd: correctly handle failed crypto_alloc_hashLars Ellenberg1-1/+1
crypto_alloc_hash returns an ERR_PTR(), not NULL. Also reset peer_integrity_tfm to NULL, to not call crypto_free_hash() on an errno in the cleanup path. Reported-by: Insu Yun <wuninsu@gmail.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-13drbd: code cleanups without semantic changesFabian Frederick1-0/+8
This contains various cosmetic fixes ranging from simple typos to const-ifying, and using booleans properly. Original commit messages from Fabian's patch set: drbd: debugfs: constify drbd_version_fops drbd: use seq_put instead of seq_print where possible drbd: include linux/uaccess.h instead of asm/uaccess.h drbd: use const char * const for drbd strings drbd: kerneldoc warning fix in w_e_end_data_req() drbd: use unsigned for one bit fields drbd: use bool for peer is_ states drbd: fix typo drbd: use | for bitmask combination drbd: use true/false for bool drbd: fix drbd_bm_init() comments drbd: introduce peer state union drbd: fix maybe_pull_ahead() locking comments drbd: use bool for growing drbd: remove redundant declarations drbd: replace if/BUG by BUG_ON Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Roland Kammerer <roland.kammerer@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-25drbd: make drbd known to lsblk: use bd_link_disk_holderLars Ellenberg1-1/+1
lsblk should be able to pick up stacking device driver relations involving DRBD conveniently. Even though upstream kernel since 2011 says "DON'T USE THIS UNLESS YOU'RE ALREADY USING IT." a new user has been added since (bcache), which sets the precedences for us to use it as well. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-25drbd: drop remnants of connector -- we don't use it anymore in drbd 8.4Lars Ellenberg1-1/+0
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-25drbd: Backport the "events2" commandAndreas Gruenbacher1-0/+16
The events2 command originates from drbd-9 development. It features more information but requires a incompatible change in output format. Therefore the previous events command continues to exist, the new improved events2 command becomes available now. This prepares the user-base for a later switch to the complete drbd9 code base. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-25drbd: Move enum write_ordering_e to drbd.hAndreas Gruenbacher1-0/+7
Also change the enum values to all-capital letters. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-11-10drbd: Minor cleanupsAndreas Gruenbacher1-1/+1
. Update comments . drbd_set_{in,out_of}_sync(): Remove unused parameters . Move common code into adm_del_resource() . Redefine ERR_MINOR_EXISTS -> ERR_MINOR_OR_VOLUME_EXISTS Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-07-10drbd: silence underflow warning in read_in_block()Dan Carpenter1-1/+1
My static checker warns that "data_size" could be negative and underflow the limit check. The code looks suspicious but I don't know if it is a real bug. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-07-10drbd: device->ldev is not guaranteed on an D_ATTACHING diskPhilipp Reisner1-1/+1
Some parts of the code assumed that get_ldev_if_state(device, D_ATTACHING) is sufficient to access the ldev member of the device object. That was wrong. ldev may not be there or might be freed at any time if the device has a disk state of D_ATTACHING. bm_rw() Documented that drbd_bm_read() is only called from drbd_adm_attach. drbd_bm_write() is only called when a reference is held, and it is documented that a caller has to hold a reference before calling drbd_bm_write() drbd_bm_write_page() Use get_ldev() instead of get_ldev_if_state(device, D_ATTACHING) drbd_bmio_set_n_write() No longer use get_ldev_if_state(device, D_ATTACHING). All callers hold a reference to ldev now. drbd_bmio_clear_n_write() All callers where holding a reference of ldev anyways. Remove the misleading get_ldev_if_state(device, D_ATTACHING) drbd_reconsider_max_bio_size() Removed the get_ldev_if_state(device, D_ATTACHING). All callers now pass a struct drbd_backing_dev* when they have a proper reference, or a NULL pointer. Before this fix, the receiver could trigger a NULL pointer deref when in drbd_reconsider_max_bio_size() drbd_bump_write_ordering() Used get_ldev_if_state(device, D_ATTACHING) with the wrong assumption. Remove it, and allow the caller to pass in a struct drbd_backing_dev* when the caller knows that accessing this bdev is safe. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2014-02-17drbd: Move string function prototypes from linux/drbd.h to drbd_string.hAndreas Gruenbacher1-6/+0
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
2014-02-17drbd: Define the size of res_opts->cpu_mask in a single placeAndreas Gruenbacher1-0/+2
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
2013-06-28drbd: Allow online change of al-stripes and al-stripe-sizePhilipp Reisner1-1/+5
Allow to change the AL layout with an resize operation. For that the reisze command gets two new fields: al_stripes and al_stripe_size. In order to make the operation crash save: 1) Lock out all IO and MD-IO 2) Write the super block with MDF_PRIMARY_IND clear 3) write the bitmap to the new location (all zeros, since we allow only while connected) 4) Initialize the new AL-area 5) Write the super block with the restored MDF_PRIMARY_IND. 6) Unfreeze all IO Since the AL-layout has no influence on the protocol, this operation needs to be beforemed on both sides of a resource (if intended). Signed-off-by: Andreas Gruenbacher <agruen@linbit.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-28drbd: use sched_setscheduler()Philipp Reisner1-1/+1
It was unnoticed for some time that assigning to current->policy is no longer sufficient to set a real time priority for a kernel thread. Reported-by: Charlie Suffin <Charlie.Suffin@stratus.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-03-28drbd: Fix disconnect to keep the peer disk state if connection breaks during ↵Philipp Reisner1-1/+2
operation The issue was that if the connection broke while we did the gracefull state change to C_DISCONNECTING (C_TEARDOWN), then we returned a success code from the state engine. (SS_CW_NO_NEED) The result of that is that we missed to call the fence-peer script in such a case. Fixed that by introducing a new error code (SS_OUTDATE_WO_CONN). This one should never reach back into user space. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-11-09drbd: Broadcast sync progress no more often than once per secondPhilipp Reisner1-2/+2
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: disambiguation, s/ERR_DISCARD/ERR_DISCARD_IMPOSSIBLE/Lars Ellenberg1-1/+1
If for some reason (typically "split-brained" cluster manager) drbd replica data has diverged, we can chose a victim, and reconnect using "--discard-my-data", causing the victim to become sync-target, fetching all changed blocks from the peer. If we are Primary, we are potentially in use, and we refuse to "roll back" changes to the data below the page cache and other users. Rename the error symbol for this to ERR_DISCARD_IMPOSSIBLE. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-09drbd: introduce stop-sector to online verifyLars Ellenberg1-1/+1
We now can schedule only a specific range of sectors for online verify, or interrupt a running verify without interrupting the connection. Had to bump the protocol version differently, we are now 101. Added verify_can_do_stop_sector() { protocol >= 97 && protocol != 100; } Also, the return value convention for worker callbacks has changed, we returned "true/false" for "keep the connection up" in 8.3, we return 0 for success and <= for failure in 8.4. Affected: receive_state() Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: New disk option al-updatesPhilipp Reisner1-0/+1
By disabling al-updates one might increase performace. The price for that is that in case a crashed primary (that had al-updates disabled) is reintegraded, it will receive a full-resync instead of a bitmap based resync. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Load balancing method: stripingPhilipp Reisner1-0/+6
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Load balancing of read requestsPhilipp Reisner1-0/+8
New config option for the disk secition "read-balancing", with the values: prefer-local, prefer-remote, round-robin, when-congested-remote. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: on attach, enforce clean meta dataLars Ellenberg1-1/+9
Detection of unclean shutdown has moved into user space. The kernel code will, whenever it updates the meta data, mark it as "unclean", and will refuse to attach to such unclean meta data. "drbdadm up" now schedules "drbdmeta apply-al", which will apply the activity log to the bitmap, and/or reinitialize it, if necessary, as well as set a "clean" indicator flag. This moves a bit code out of kernel space. As a side effect, it also prevents some 8.3 module from accidentally ignoring the 8.4 style activity log, if someone should downgrade, whether on purpose, or accidentally because he changed kernel versions without providing an 8.4 for the new kernel, and the new kernel comes with in-tree 8.3. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Use the terminology suggested by the command names in the source code ↵Andreas Gruenbacher1-2/+2
and messages Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: spelling fix: too smallLars Ellenberg1-2/+2
It is not "to small", but "too small". Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Refuse to change network options online when...Philipp Reisner1-0/+1
* the peer does not speak protocol_version 100 and the user wants to change one of: - wire_protocol - two_primaries - integrity_alg * the user wants to remove the allow_two_primaries flag when there are two primaries Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Fix the upper limit of resync-afterAndreas Gruenbacher1-2/+2
The 32-bit resync_after netlink field takes a device minor number as parameter, which is no longer limited to 255. We cannot statically verify which device numbers are valid, so set the ummer limit to the highest possible signed 32-bit integer. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Allow online change of replication protocol only with agreed_pv >= 100Philipp Reisner1-0/+1
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Introduce protocol version 100 headersAndreas Gruenbacher1-0/+1
The 8 byte header finally becomes too small. With the protocol 100 header we have 16 bit for the volume number, proper 32 bit for the data length, and 32 bit for further extensions in the future. Previous versions of drbd are using version 80 headers for all packets short enough for protocol 80. They support both header versions in worker context, but only version 80 headers in asynchronous context. For backwards compatibility, continue to use version 80 headers for short packets before protocol version 100. From protocol version 100 on, use the same header version for all packets. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-08drbd: Converted drbd_try_outdate_peer() from mdev to tconnPhilipp Reisner1-1/+2
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-04drbd: Allow volumes to become primary only on one sidePhilipp Reisner1-1/+2
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2012-11-04drbd: switch configuration interface from connector to genetlinkLars Ellenberg1-34/+1
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14drbd: Implemented new commands to create/delete connections/minorsPhilipp Reisner1-0/+3
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14drbd: Preparing the connector interface to operator on connectionsPhilipp Reisner1-4/+15
Up to now it only operated on minor numbers. Now it can work also on named connections. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-10-14drbd: new on-disk activity log transaction formatLars Ellenberg1-0/+4
Use a new on-disk transaction format for the activity log, which allows for multiple changes to the active set per transaction. Using 4k transaction blocks, we can now get rid of the work-around code to deal with devices not supporting 512 byte logical block size. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-09-28drbd: Use new header layoutPhilipp Reisner1-1/+1
The new header layout will only be used if the peer supports it of course. For the first packet and the handshake packet the old (h80) layout is used for compatibility reasons. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-08-25drbd: Get rid of BE_DRBD_MAGIC and BE_DRBD_MAGIC_BIGAndreas Gruenbacher1-2/+0
Converting the constants happens at compile time. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-05-24drbd: Fix spellingBart Van Assche1-4/+4
Found these with the help of ispell -l. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
2011-05-24drbd: fix schedule in atomicLars Ellenberg1-1/+1
An administrative detach used to request a state change directly to D_DISKLESS, first suspending IO to avoid the last put_ldev() occuring from an endio handler, potentially in irq context. This is not enough on the receiving side (typically secondary), we may miss some peer_req on the way to local disk, which then may do the last put_ldev() from their drbd_peer_request_endio(). This patch makes the detach always go through the intermediate D_FAILED state. We may consider to rename it D_DETACHING. Alternative approach would be to create yet an other work item to be scheduled on the worker, do the destructor work from there, and get the timing right. manually picked commit 564040f from the drbd 8.4 branch. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-31Fix common misspellingsLucas De Marchi1-2/+2
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-10drbd: Remove unused function atodb_endio()Andreas Gruenbacher1-1/+1
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10drbd: Provide hints with the error message when clearing the sync pause flagPhilipp Reisner1-0/+2
When the user clears the sync-pause flag, and sync stays in pause state, give hints to the user, why it still is in pause state. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10drbd: Rename enum drbd_state_ret_codes to enum drbd_state_rvAndreas Gruenbacher1-2/+2
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10drbd: Rename enum drbd_ret_codes to enum drbd_ret_codeAndreas Gruenbacher1-1/+1
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10drbd: New packet for Ahead/Behind mode: P_OUT_OF_SYNCPhilipp Reisner1-1/+1
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10drbd: Implemented two new connection states Ahead/BehindPhilipp Reisner1-0/+4
In this connection mode, the ahead node no longer replicates application IO. The behind's disk becomes out dated. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2011-03-10drbd: New configuration parameters for dealing with network congestionPhilipp Reisner1-0/+7
net { on_congestion {block|pull-ahead|disconnect}; congestion-fill {sectors}; congestion-extents {al-extents}; } Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2010-10-22drbd: Silenced an assertPhilipp Reisner1-1/+1
That assertion's condition needed adjustment for today's semantics Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
2010-10-15drbd: add race-breaker to drbd_go_disklessLars Ellenberg1-1/+1
This adds a necessary race breaker to these commits: drbd: fix for possible deadlock on IO error during resync drbd: drop wrong debug asserts, fix recently introduced race What we do is get a refcount, check the state, then depending on the state and the requested minimum disk state, either hold it (success), or give it back immediately (failed "try lock"). Some code paths (flushing of drbd metadata) may still grab and hold a refcount even if we are D_FAILED (application IO won't). So even if we hit local_cnt == 0 once after being D_FAILED, we still need to wait for that again after we changed to D_DISKLESS. Once local_cnt reaches 0 while we are D_DISKLESS, we can be sure that no one will look at the protected members anymore, so only then is it safe to free them. We cannot easily convert to standard locking primitives here, as we want to be able to use it in atomic context (we always do a "try lock"), as well as hold references for a "long time" (from IO submission to completion callback). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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