kernel/linux.git/fs/dlm/user.c, branch v6.6.131

dlm: fix user space lock decision to copy lvb

2024-06-12T09:11:38+00:00

[ Upstream commit ad191e0eeebf64a60ca2d16ca01a223d2b1dd25e ] This patch fixes the copy lvb decision for user space lock requests. Checking dlm_lvb_operations is done earlier, where granted/requested lock modes are available to use in the matrix. The decision had been moved to the wrong location, where granted mode and requested mode where the same, which causes the dlm_lvb_operations matix to produce the wrong copy decision. For PW or EX requests, the caller could get invalid lvb data. Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Sasha Levin

dlm: fix user space lkb refcounting

2024-04-03T13:28:32+00:00

[ Upstream commit 2ab3d705ca5d4f7ea345a21c3da41a447a549649 ] This patch fixes to check on the right return value if it was the last callback. The rv variable got overwritten by the return of copy_result_to_user(). Fixing it by introducing a second variable for the return value and don't let rv being overwritten. Cc: stable@vger.kernel.org Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") Reported-by: Valentin Vidić Closes: https://lore.kernel.org/gfs2/Ze4qSvzGJDt5yxC3@valentin-vidic.from.hr Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Sasha Levin

fs: dlm: move dlm_purge_lkb_callbacks to user module

2023-06-14T15:17:33+00:00

This patch moves the dlm_purge_lkb_callbacks() function from ast to user dlm module as it is only a function being used by dlm user implementation. I got be hinted to hold specific locks regarding the callback handling for dlm_purge_lkb_callbacks() but it was false positive. It is confusing because ast dlm implementation uses a different locking behaviour as user locks uses as DLM handles kernel and user dlm locks differently. To avoid the confusing we move this function to dlm user implementation. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: move internal flags to atomic ops

2023-03-06T21:49:07+00:00

This patch will move the lkb_flags value to the recently introduced lkb_iflags value. For lkb_iflags we use atomic bit operations because some flags like DLM_IFL_CB_PENDING are used while non rsb lock is held to avoid issues with other flag manipulations which might run at the same time we switch to atomic bit operations. Snapshot the bit values to an uint32_t value is only used for debugging/logging use cases and don't need to be 100% correct. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: change dflags to use atomic bits

2023-03-06T21:49:07+00:00

Currently manipulating lkb_dflags assumes to held the rsb lock assigned to the lkb. This is held by dlm message processing after certain time to lookup the right rsb from the received lkb message id. For user space locks flags, which is currently the only use case for lkb_dflags, flags are also being set during dlm character device handling without holding the rsb lock. To minimize the risk that bit operations are getting corrupted we switch to atomic bit operations. This patch will also introduce helpers to snapshot atomic bit values in an non atomic way. There might be still issues with the flag handling e.g. running in case of manipulating bit ops and snapshot them at the same time, but this patch minimize them and will start to use atomic bit operations. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: store lkb distributed flags into own value

2023-03-06T21:49:07+00:00

This patch stores lkb distributed flags value in an separate value instead of sharing internal and distributed flags in lkb->lkb_flags value. This has the advantage to not mask/write back flag values in receive_flags() functionality. The dlm debug_fs does not provide the distributed flags anymore, those can be added in future. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: remove deprecated code parts

2023-03-06T21:49:07+00:00

This patch removes code parts which was declared deprecated by commit 6b0afc0cc3e9 ("fs: dlm: don't use deprecated timeout features by default"). This contains the following dlm functionality: - start a cancel of a dlm request did not complete after certain timeout: The current way how dlm cancellation works and interfering with other dlm requests triggered by the user can end in an overlapping and returning in -EBUSY. The most user don't handle this case and are unaware that DLM can return such errno in such situation. Due the timeout the user are mostly unaware when this happens. - start a netlink warning messages for user space if dlm requests did not complete after certain timeout: This feature was never being built in the only known dlm user space side. As we are to remove the timeout cancellation feature we can directly remove this feature as well. There might be the possibility to bring the timeout cancellation feature back. However the current way of handling the -EBUSY case which is only a software limitation and not a hardware limitation should be changed. We minimize the current code base in DLM cancellation feature to not have to deal with those existing features while solving the DLM cancellation feature in general. UAPI define DLM_LSFL_TIMEWARN is commented as deprecated and reserved value. We should avoid at first to give it a new meaning but let possible users still compile by keeping this define. In far future we can give this flag a new meaning. The same for the DLM_LKF_TIMEOUT lock request flag. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: fix DLM_IFL_CB_PENDING gets overwritten

2023-03-06T21:49:07+00:00

This patch introduce a new internal flag per lkb value to handle internal flags which are handled not on wire. The current lkb internal flags stored as lkb->lkb_flags are split in upper and lower bits, the lower bits are used to share internal flags over wire for other cluster wide lkb copies on other nodes. In commit 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") we introduced a new internal flag for pending callbacks for the dlm callback queue. This flag is protected by the lkb->lkb_cb_lock lock. This patch overlooked that on dlm receive path and the mentioned upper and lower bits, that dlm will read the flags, mask it and write it back. As example receive_flags() in fs/dlm/lock.c. This flag manipulation is not done atomically and is not protected by lkb->lkb_cb_lock. This has unknown side effects of the current callback handling. In future we should move to set/clear/test bit functionality and avoid read, mask and writing back flag values. In later patches we will move the upper parts to the new introduced internal lkb flags which are not shared between other cluster nodes to the new non shared internal flag field to avoid similar issues. Cc: stable@vger.kernel.org Fixes: 61bed0baa4db ("fs: dlm: use a non-static queue for callbacks") Reported-by: Bob Peterson Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: rename DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDING

2022-11-21T15:45:49+00:00

This patch renames DLM_IFL_NEED_SCHED to DLM_IFL_CB_PENDING because CB_PENDING is a proper name to describe this flag. This flag is set when callback enqueue will return DLM_ENQUEUE_CALLBACK_NEED_SCHED because the callback worker need to be queued. The flag tells that callbacks are currently pending to be called and will be unset if the callback work for the specific lkb is done. The term need schedule is part of this time but a proper name is to say that there are some callbacks pending to being called. Signed-off-by: Alexander Aring Signed-off-by: David Teigland

fs: dlm: ast do WARN_ON_ONCE() on hotpath

2022-11-21T15:45:49+00:00

This patch changes the ast hotpath functionality in very unlikely cases that we do WARN_ON_ONCE() instead of WARN_ON() to not spamming the console output if we run into states that it would occur over and over again. Signed-off-by: Alexander Aring Signed-off-by: David Teigland