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* Sync reserved Illumos ioctl comment with actual numberTomohiro Kusumi2019-04-141-1/+1
| | | | | | | | | | It's 81 now. Reviewed-by: Olaf Faaland <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Reviewed-by: Igor Kozhukhov <[email protected]> Signed-off-by: Tomohiro Kusumi <[email protected]> Closes #8598
* Restrict kstats and print real pointersSara Hartse2019-04-041-0/+1
| | | | | | | | | | | | | | | There are several places where we use zfs_dbgmsg and %p to print pointers. In the Linux kernel, these values obfuscated to prevent information leaks which means the pointers aren't very useful for debugging crash dumps. We decided to restrict the permissions of dbgmsg (and some other kstats while we were at it) and print pointers with %px in zfs_dbgmsg as well as spl_dumpstack Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: John Gallagher <[email protected]> Signed-off-by: sara hartse <[email protected]> Closes #8467 Closes #8476
* Add TRIM supportBrian Behlendorf2019-03-2917-25/+265
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | UNMAP/TRIM support is a frequently-requested feature to help prevent performance from degrading on SSDs and on various other SAN-like storage back-ends. By issuing UNMAP/TRIM commands for sectors which are no longer allocated the underlying device can often more efficiently manage itself. This TRIM implementation is modeled on the `zpool initialize` feature which writes a pattern to all unallocated space in the pool. The new `zpool trim` command uses the same vdev_xlate() code to calculate what sectors are unallocated, the same per- vdev TRIM thread model and locking, and the same basic CLI for a consistent user experience. The core difference is that instead of writing a pattern it will issue UNMAP/TRIM commands for those extents. The zio pipeline was updated to accommodate this by adding a new ZIO_TYPE_TRIM type and associated spa taskq. This new type makes is straight forward to add the platform specific TRIM/UNMAP calls to vdev_disk.c and vdev_file.c. These new ZIO_TYPE_TRIM zios are handled largely the same way as ZIO_TYPE_READs or ZIO_TYPE_WRITEs. This makes it possible to largely avoid changing the pipieline, one exception is that TRIM zio's may exceed the 16M block size limit since they contain no data. In addition to the manual `zpool trim` command, a background automatic TRIM was added and is controlled by the 'autotrim' property. It relies on the exact same infrastructure as the manual TRIM. However, instead of relying on the extents in a metaslab's ms_allocatable range tree, a ms_trim tree is kept per metaslab. When 'autotrim=on', ranges added back to the ms_allocatable tree are also added to the ms_free tree. The ms_free tree is then periodically consumed by an autotrim thread which systematically walks a top level vdev's metaslabs. Since the automatic TRIM will skip ranges it considers too small there is value in occasionally running a full `zpool trim`. This may occur when the freed blocks are small and not enough time was allowed to aggregate them. An automatic TRIM and a manual `zpool trim` may be run concurrently, in which case the automatic TRIM will yield to the manual TRIM. Reviewed-by: Jorgen Lundman <[email protected]> Reviewed-by: Tim Chase <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: George Wilson <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Contributions-by: Saso Kiselkov <[email protected]> Contributions-by: Tim Chase <[email protected]> Contributions-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #8419 Closes #598
* MMP interval and fail_intervals in uberblockOlaf Faaland2019-03-213-3/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When Multihost is enabled, and a pool is imported, uberblock writes include ub_mmp_delay to allow an importing node to calculate the duration of an activity test. This value, is not enough information. If zfs_multihost_fail_intervals > 0 on the node with the pool imported, the safe minimum duration of the activity test is well defined, but does not depend on ub_mmp_delay: zfs_multihost_fail_intervals * zfs_multihost_interval and if zfs_multihost_fail_intervals == 0 on that node, there is no such well defined safe duration, but the importing host cannot tell whether mmp_delay is high due to I/O delays, or due to a very large zfs_multihost_interval setting on the host which last imported the pool. As a result, it may use a far longer period for the activity test than is necessary. This patch renames ub_mmp_sequence to ub_mmp_config and uses it to record the zfs_multihost_interval and zfs_multihost_fail_intervals values, as well as the mmp sequence. This allows a shorter activity test duration to be calculated by the importing host in most situations. These values are also added to the multihost_history kstat records. It calculates the activity test duration differently depending on whether the new fields are present or not; for importing pools with only ub_mmp_delay, it uses (zfs_multihost_interval + ub_mmp_delay) * zfs_multihost_import_intervals Which results in an activity test duration less sensitive to the leaf count. In addition, it makes a few other improvements: * It updates the "sequence" part of ub_mmp_config when MMP writes in between syncs occur. This allows an importing host to detect MMP on the remote host sooner, when the pool is idle, as it is not limited to the granularity of ub_timestamp (1 second). * It issues writes immediately when zfs_multihost_interval is changed so remote hosts see the updated value as soon as possible. * It fixes a bug where setting zfs_multihost_fail_intervals = 1 results in immediate pool suspension. * Update tests to verify activity check duration is based on recorded tunable values, not tunable values on importing host. * Update tests to verify the expected number of uberblocks have valid MMP fields - fail_intervals, mmp_interval, mmp_seq (sequence number), that sequence number is incrementing, and that uberblock values match tunable settings. Reviewed-by: Andreas Dilger <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7842
* Multiple DVA Scrubbing FixTom Caputi2019-03-151-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | Currently, there is an issue in the sequential scrub code which prevents self healing from working in some cases. The scrub code will split up all DVA copies of a bp and issue each of them separately. The problem is that, since each of the DVAs is no longer associated with the others, the self healing code doesn't have the opportunity to repair problems that show up in one of the DVAs with the data from the others. This patch fixes this issue by ensuring that all IOs issued by the sequential scrub code include all DVAs. Initially, only the first DVA of each is attempted. If an issue arises, the IO is retried with all available copies, giving the self healing code a chance to correct the issue. To test this change, this patch also adds the ability for zinject to specify individual DVAs to inject read errors into. We then add a new test case that utilizes this functionality to ensure scrubs and self-healing reads can handle and transparently fix issues with individual copies of blocks. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #8453
* Detect and prevent mixed raw and non-raw sendsTom Caputi2019-03-134-2/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, there is an issue in the raw receive code where raw receives are allowed to happen on top of previously non-raw received datasets. This is a problem because the source-side dataset doesn't know about how the blocks on the destination were encrypted. As a result, any MAC in the objset's checksum-of-MACs tree that is a parent of both blocks encrypted on the source and blocks encrypted by the destination will be incorrect. This will result in authentication errors when we decrypt the dataset. This patch fixes this issue by adding a new check to the raw receive code. The code now maintains an "IVset guid", which acts as an identifier for the set of IVs used to encrypt a given snapshot. When a snapshot is raw received, the destination snapshot will take this value from the DRR_BEGIN payload. Non-raw receives and normal "zfs snap" operations will cause ZFS to generate a new IVset guid. When a raw incremental stream is received, ZFS will check that the "from" IVset guid in the stream matches that of the "from" destination snapshot. If they do not match, the code will error out the receive, preventing the problem. This patch requires an on-disk format change to add the IVset guids to snapshots and bookmarks. As a result, this patch has errata handling and a tunable to help affected users resolve the issue with as little interruption as possible. Reviewed-by: Paul Dagnelie <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #8308
* Add bookmark v2 on-disk featureTom Caputi2019-03-131-0/+17
| | | | | | | | | | | | | | This patch adds the bookmark v2 feature to the on-disk format. This feature will be needed for the upcoming redacted sends and for an upcoming fix that for raw receives. The feature is not currently used by any code and thus this change is a no-op, aside from the fact that the user can now enable the feature. Reviewed-by: Paul Dagnelie <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Issue #8308
* Fix handling of maxblkid for raw sendsTom Caputi2019-03-132-2/+10
| | | | | | | | | | | | | | | | | | | | | | Currently, the receive code can create an unreadable dataset from a correct raw send stream. This is because it is currently impossible to set maxblkid to a lower value without freeing the associated object. This means truncating files on the send side to a non-0 size could result in corruption. This patch solves this issue by adding a new 'force' flag to dnode_new_blkid() which will allow the raw receive code to force the DMU to accept the provided maxblkid even if it is a lower value than the existing one. For testing purposes the send_encrypted_files.ksh test has been extended to include a variety of truncated files and multiple snapshots. It also now leverages the xattrtest command to help ensure raw receives correctly handle xattrs. Reviewed-by: Paul Dagnelie <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #8168 Closes #8487
* Increase default zfs_multihost_fail_intervals and import_intervalsOlaf Faaland2019-03-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | By default, when multihost is enabled for a pool, the pool is suspended if (zfs_multihost_fail_intervals*zfs_multihost_interval) ms pass without a successful MMP write. This is the recommended configuration. The default value for zfs_multihost_fail_intervals has been 5, and the default value for zfs_multihost_interval has been 1000, so pool suspension occurred at 5 seconds. There have been multiple cases where a single misbehaving device in a pool triggered a SCSI reset, and all I/O paused for 5-6 seconds. This in turn caused MMP to suspend the pool. In the cases observed, the rest of the devices were healthy and the pool was otherwise correctly performing I/O. The reset was handled correctly by ZFS, and by suspending the pool MMP made replacing the device more difficult as well as forcing the host to be rebooted. Increase the default value of zfs_multihost_fail_intervals to 10, so that MMP tolerates up to 10 seconds of failed MMP writes before suspending the pool. Increase the default value of zfs_multihost_import_intervals to 20, to maintain the 2:1 safety factor. This results in a force import taking approximately 20 seconds when MMP is enabled, with default values. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Andreas Dilger <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7709 Closes #8495
* Avoid retrieving unused snapshot propsAlek P2019-03-121-2/+9
| | | | | | | | | | | | | | This patch modifies the zfs_ioc_snapshot_list_next() ioctl to enable it to take input parameters that alter the way looping through the list of snapshots is performed. The idea here is to restrict functions that throw away some of the snapshots returned by the ioctl to a range of snapshots that these functions actually use. This improves efficiency and execution speed for some rollback and send operations. Reviewed-by: Tom Caputi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Signed-off-by: Alek Pinchuk <[email protected]> Closes #8077
* MMP writes rotate over leavesOlaf Faaland2019-03-123-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of choosing a leaf vdev quasi-randomly, by starting at the root vdev and randomly choosing children, rotate over leaves to issue MMP writes. This fixes an issue in a pool whose top-level vdevs have different numbers of leaves. The issue is that the frequency at which individual leaves are chosen for MMP writes is based not on the total number of leaves but based on how many siblings the leaves have. For example, in a pool like this: root-vdev +------+---------------+ vdev1 vdev2 | | | +------+-----+-----+----+ disk1 disk2 disk3 disk4 disk5 disk6 vdev1 and vdev2 will each be chosen 50% of the time. Every time vdev1 is chosen, disk1 will be chosen. However, every time vdev2 is chosen, disk2 is chosen 20% of the time. As a result, disk1 will be sent 5x as many MMP writes as disk2. This may create wear issues in the case of SSDs. It also reduces the effectiveness of MMP as it depends on the writes being evenly distributed for the case where some devices fail or are partitioned. The new code maintains a list of leaf vdevs in the pool. MMP records the last leaf used for an MMP write in mmp->mmp_last_leaf. To choose the next leaf, MMP starts at mmp->mmp_last_leaf and traverses the list, continuing from the head if the tail is reached. It stops when a suitable leaf is found or all leaves have been examined. Added a test to verify MMP write distribution is even. Reviewed-by: Tom Caputi <[email protected]> Reviewed-by: Kash Pande <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: loli10K <[email protected]> Signed-off-by: Olaf Faaland <[email protected]> Closes #7953
* Reorder ZFS ioctls to fix cross-version compatibilityLorenz Brun2019-03-091-3/+3
| | | | | | | | | | | Reorder ZFS ioctls to fix cross-version compatibility. Reviewed-by: Don Brady <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Signed-off-by: Lorenz Brun <[email protected]> Closes #8484
* Stack overflow in recursive bpobj_iterate_implPaul Zuchowski2019-03-061-0/+1
| | | | | | | | | | | | | The function bpobj_iterate_impl overflows the stack when bpobjs are deeply nested. Rewrite the function to eliminate the recursion. Reviewed-by: Serapheim Dimitropoulos <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Paul Zuchowski <[email protected]> Closes #7674 Closes #7675 Closes #7908
* Fix dnode_hold_impl() soft lockuplidongyang2019-02-221-0/+1
| | | | | | | | | | | | | | Soft lockups could happen when multiple threads trying to get zrl on the same dnode handle in order to allocate and initialize the dnode marked as DN_SLOT_ALLOCATED. Don't loop from beginning when we can't get zrl, otherwise we would increase the zrl refcount and nobody can actually lock it. Reviewed by: Tom Caputi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Li Dongyang <[email protected]> Closes #8433
* Introduce auxiliary metaslab histogramsSerapheim Dimitropoulos2019-02-203-0/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduces 3 new histograms per metaslab. These histograms track segments that have made it to the metaslab's space map histogram (and are part of the spacemap) but have not yet reached the ms_allocatable tree on loaded metaslab's because these metaslab's are currently syncing and haven't gone through metaslab_sync_done() yet. The histograms help when we decide whether to load an unloaded metaslab in-order to allocate from it. When calculating the weight of an unloaded metaslab traditionally, we look at the highest bucket of its spacemap's histogram. The problem is that we are not guaranteed to be able to allocated that segment when we load the metaslab because it may still be at the freeing, freed, or defer trees. The new histograms are used when we try to calculate an unloaded metaslab's weight to deal with this issue by removing segments that have would not be in the allocatable tree at runtime. Note, that this method of dealing with this is not completely accurate as adjacent segments are not always consolidated in the space map histogram of a metaslab. In addition and to make things deterministic, we always reset the weight of unloaded metaslabs based on their space map weight (instead of doing that on a need basis). Thus, every time a metaslab is loaded and its weight is reset again (from the weight based on its space map to the one based on its allocatable range tree) we expect (and assert) that this change in weight can only get better if it doesn't stay the same. Reviewed by: Paul Dagnelie <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8358
* zfs should optionally send holdsPaul Zuchowski2019-02-151-1/+2
| | | | | | | | | | | | | Add -h switch to zfs send command to send dataset holds. If holds are present in the stream, zfs receive will create them on the target dataset, unless the zfs receive -h option is used to skip receive of holds. Reviewed-by: Alek Pinchuk <[email protected]> Reviewed-by: loli10K <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Signed-off-by: Paul Zuchowski <[email protected]> Closes #7513
* port async unlinked drain from illumos-nexentaAlek P2019-02-124-0/+22
| | | | | | | | | | | | | | | | | This patch is an async implementation of the existing sync zfs_unlinked_drain() function. This function is called at mount time and is responsible for freeing znodes that we didn't get to freeing before. We don't have to hold mounting of the dataset until the unlinked list is fully drained as is done now. Since we can process the unlinked set asynchronously this results in a better user experience when mounting a dataset with entries in the unlinked set. Reviewed by: Jorgen Lundman <[email protected]> Reviewed by: Tom Caputi <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Signed-off-by: Alek Pinchuk <[email protected]> Closes #8142
* Get rid of space_map_update() for ms_synced_lengthSerapheim Dimitropoulos2019-02-123-13/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Initially, metaslabs and space maps used to be the same thing in ZFS. Later, we started differentiating them by referring to the space map as the on-disk state of the metaslab, making the metaslab a higher-level concept that is metadata that deals with space accounting. Today we've managed to split that code furthermore, with the space map being its own on-disk data structure used in areas of ZFS besides metaslabs (e.g. the vdev-wide space maps used for zpool checkpoint or vdev removal features). This patch refactors the space map code to further split the space map code from the metaslab code. It does so by getting rid of the idea that the space map can have a different in-core and on-disk length (sm_length vs smp_length) which is something that is only used for the metaslab code, and other consumers of space maps just have to deal with. Instead, this patch introduces changes that move the old in-core length of the metaslab's space map to the metaslab structure itself (see ms_synced_length field) while making the space map code only care about the actual space map's length on-disk. The result of this is that space map consumers no longer have to deal with syncing two different lengths for the same structure (e.g. space_map_update() goes away) while metaslab specific behavior stays within the metaslab code. Specifically, the ms_synced_length field keeps track of the amount of data metaslab_load() can read from the metaslab's space map while working concurrently with metaslab_sync() that may be appending to that same space map. As a side note, the patch also adds a few comments around the metaslab code documenting some assumptions and expected behavior. Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8328
* ZVOLs should not be allowed to have childrenloli10K2019-02-081-0/+1
| | | | | | | | | | | | | | | zfs create, receive and rename can bypass this hierarchy rule. Update both userland and kernel module to prevent this issue and use pyzfs unit tests to exercise the ioctls directly. Note: this commit slightly changes zfs_ioc_create() ABI. This allow to differentiate a generic error (EINVAL) from the specific case where we tried to create a dataset below a ZVOL (ZFS_ERR_WRONG_PARENT). Reviewed-by: Paul Dagnelie <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tom Caputi <[email protected]> Signed-off-by: loli10K <[email protected]>
* Rename range_tree_verify to range_tree_verify_not_presentSerapheim Dimitropoulos2019-01-251-1/+2
| | | | | | | | | | | | The range_tree_verify function looks for a segment in a range tree and panics if the segment is present on the tree. This patch gives the function a more descriptive name. Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8327
* Factor metaslab_load_wait() in metaslab_load()Serapheim Dimitropoulos2019-01-182-3/+2
| | | | | | | | | | | | | | Most callers that need to operate on a loaded metaslab, always call metaslab_load_wait() before loading the metaslab just in case someone else is already doing the work. Factoring metaslab_load_wait() within metaslab_load() makes the later more robust, as callers won't have to do the load-wait check explicitly every time they need to load a metaslab. Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8290
* Document guidelines for usage of zfs_dbgmsgSerapheim Dimitropoulos2019-01-181-1/+17
| | | | | | | | | Reviewed-by: Richard Elling <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Igor Kozhukhov <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8299
* Fix error handling incallers of dbuf_hold_level()Tom Caputi2019-01-171-2/+2
| | | | | | | | | | | | Currently, the functions dbuf_prefetch_indirect_done() and dmu_assign_arcbuf_by_dnode() assume that dbuf_hold_level() cannot fail. In the event of an error the former will cause a NULL pointer dereference and the later will trigger a VERIFY. This patch adds error handling to these functions and their callers where necessary. Reviewed by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #8291
* Remove unused vdev_t fieldsSerapheim Dimitropoulos2019-01-171-11/+0
| | | | | | | | | The following fields from the vdev_t struct are not used anywhere. Reviewed-by: George Melikov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8285
* Serialize ZTHR operations to eliminate racesSerapheim Dimitropoulos2019-01-132-20/+4
| | | | | | | | | | | Adds a new lock for serializing operations on zthrs. The commit also includes some code cleanup and refactoring. Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Tom Caputi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8229
* Provide more flexible object allocation interfaceBrian Behlendorf2019-01-102-5/+14
| | | | | | | | | | | | | | | | | | | | | Object allocation performance can be improved for complex operations by providing an interface which returns the newly allocated dnode. This allows the caller to immediately use the dnode without incurring the expense of looking up the dnode by object number. The functions dmu_object_alloc_hold(), zap_create_hold(), and dmu_bonus_hold_by_dnode() were added for this purpose. The zap_create_* functions have been updated to take advantage of this new functionality. The dmu_bonus_hold_impl() function should really have never been included in sys/dmu.h and was removed. It's sole caller was converted to use dmu_bonus_hold_by_dnode(). The new symbols have been exported for use by Lustre. Reviewed-by: Tony Hutter <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #8015
* zfs initialize performance enhancementsGeorge Wilson2019-01-073-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PROBLEM ======== When invoking "zpool initialize" on a pool the command will create a thread to initialize each disk. Unfortunately, it does this serially across many transaction groups which can result in commands taking a long time to return to the user and may appear hung. The same thing is true when trying to suspend/cancel the operation. SOLUTION ========= This change refactors the way we invoke the initialize interface to ensure we can start or stop the intialization in just a few transaction groups. When stopping or cancelling a vdev initialization perform it in two phases. First signal each vdev initialization thread that it should exit, then after all threads have been signaled wait for them to exit. On a pool with 40 leaf vdevs this reduces the vdev initialize stop/cancel time from ~10 minutes to under a second. The reason for this is spa_vdev_initialize() no longer needs to wait on multiple full TXGs per leaf vdev being stopped. This commit additionally adds some missing checks for the passed "initialize_vdevs" input nvlist. The contents of the user provided input "initialize_vdevs" nvlist must be validated to ensure all values are uint64s. This is done in zfs_ioc_pool_initialize() in order to keep all of these checks in a single location. Updated the innvl and outnvl comments to match the formatting used for all other new sytle ioctls. Reviewed by: Matt Ahrens <[email protected]> Reviewed-by: loli10K <[email protected]> Reviewed-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: George Wilson <[email protected]> Closes #8230
* OpenZFS 9102 - zfs should be able to initialize storage devicesGeorge Wilson2019-01-077-3/+128
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PROBLEM ======== The first access to a block incurs a performance penalty on some platforms (e.g. AWS's EBS, VMware VMDKs). Therefore we recommend that volumes are "thick provisioned", where supported by the platform (VMware). This can create a large delay in getting a new virtual machines up and running (or adding storage to an existing Engine). If the thick provision step is omitted, write performance will be suboptimal until all blocks on the LUN have been written. SOLUTION ========= This feature introduces a way to 'initialize' the disks at install or in the background to make sure we don't incur this first read penalty. When an entire LUN is added to ZFS, we make all space available immediately, and allow ZFS to find unallocated space and zero it out. This works with concurrent writes to arbitrary offsets, ensuring that we don't zero out something that has been (or is in the middle of being) written. This scheme can also be applied to existing pools (affecting only free regions on the vdev). Detailed design: - new subcommand:zpool initialize [-cs] <pool> [<vdev> ...] - start, suspend, or cancel initialization - Creates new open-context thread for each vdev - Thread iterates through all metaslabs in this vdev - Each metaslab: - select a metaslab - load the metaslab - mark the metaslab as being zeroed - walk all free ranges within that metaslab and translate them to ranges on the leaf vdev - issue a "zeroing" I/O on the leaf vdev that corresponds to a free range on the metaslab we're working on - continue until all free ranges for this metaslab have been "zeroed" - reset/unmark the metaslab being zeroed - if more metaslabs exist, then repeat above tasks. - if no more metaslabs, then we're done. - progress for the initialization is stored on-disk in the vdev’s leaf zap object. The following information is stored: - the last offset that has been initialized - the state of the initialization process (i.e. active, suspended, or canceled) - the start time for the initialization - progress is reported via the zpool status command and shows information for each of the vdevs that are initializing Porting notes: - Added zfs_initialize_value module parameter to set the pattern written by "zpool initialize". - Added zfs_vdev_{initializing,removal}_{min,max}_active module options. Authored by: George Wilson <[email protected]> Reviewed by: John Wren Kennedy <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Prakash Surya <[email protected]> Reviewed by: loli10K <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Approved by: Richard Lowe <[email protected]> Signed-off-by: Tim Chase <[email protected]> Ported-by: Tim Chase <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/9102 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c3963210eb Closes #8230
* OpenZFS 9284 - arc_reclaim_thread has 2 jobsBrad Lewis2018-12-262-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Following the fix for 9018 (Replace kmem_cache_reap_now() with kmem_cache_reap_soon), the arc_reclaim_thread() no longer blocks while reaping. However, the code is still confusing and error-prone, because this thread has two responsibilities. We should instead separate this into two threads each with their own responsibility: 1. keep `arc_size` under `arc_c`, by calling `arc_adjust()`, which improves `arc_is_overflowing()` 2. keep enough free memory in the system, by calling `arc_kmem_reap_now()` plus `arc_shrink()`, which improves `arc_available_memory()`. Furthermore, we can use the zthr infrastructure to separate the "should we do something" from "do it" parts of the logic, and normalize the start up / shut down of the threads. Authored by: Brad Lewis <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Reviewed by: Dan McDonald <[email protected]> Reviewed by: Tim Kordas <[email protected]> Reviewed by: Tim Chase <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Ported-by: Brad Lewis <[email protected]> Signed-off-by: Brad Lewis <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/9284 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/de753e34f9 Closes #8165
* OpenZFS 9962 - zil_commit should omit cache thrashPrakash Surya2018-12-071-6/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As a result of the changes made in 8585, it's possible for an excessive amount of vdev flush commands to be issued under some workloads. Specifically, when the workload consists of mostly async write activity, interspersed with some sync write and/or fsync activity, we can end up issuing more flush commands to the underlying storage than is actually necessary. As a result of these flush commands, the write latency and overall throughput of the pool can be poorly impacted (latency increases, throughput decreases). Currently, any time an lwb completes, the vdev(s) written to as a result of that lwb will be issued a flush command. The intenion is so the data written to that vdev is on stable storage, prior to communicating to any waiting threads that their data is safe on disk. The problem with this scheme, is that sometimes an lwb will not have any threads waiting for it to complete. This can occur when there's async activity that gets "converted" to sync requests, as a result of calling the zil_async_to_sync() function via zil_commit_impl(). When this occurs, the current code may issue many lwbs that don't have waiters associated with them, resulting in many flush commands, potentially to the same vdev(s). For example, given a pool with a single vdev, and a single fsync() call that results in 10 lwbs being written out (e.g. due to other async writes), that will result in 10 flush commands to that single vdev (a flush issued after each lwb write completes). Ideally, we'd only issue a single flush command to that vdev, after all 10 lwb writes completed. Further, and most important as it pertains to this change, since the flush commands are often very impactful to the performance of the pool's underlying storage, unnecessarily issuing these flush commands can poorly impact the performance of the lwb writes themselves. Thus, we need to avoid issuing flush commands when possible, in order to acheive the best possible performance out of the pool's underlying storage. This change attempts to address this problem by changing the ZIL's logic to only issue a vdev flush command when it detects an lwb that has a thread waiting for it to complete. When an lwb does not have threads waiting for it, the responsibility of issuing the flush command to the vdevs involved with that lwb's write is passed on to the "next" lwb. It's only once a write for an lwb with waiters completes, do we issue the vdev flush command(s). As a result, now when we issue the flush(s), we will issue them to the vdevs involved with that specific lwb's write, but potentially also to vdevs involved with "previous" lwb writes (i.e. if the previous lwbs did not have waiters associated with them). Thus, in our prior example with 10 lwbs, it's only once the last lwb completes (which will be the lwb containing the waiter for the thread that called fsync) will we issue the vdev flush command; all of the other lwbs will find they have no waiters, so they'll pass the responsibility of the flush to the "next" lwb (until reaching the last lwb that has the waiter). Porting Notes: * Reconciled conflicts with the fastwrite feature. Authored by: Prakash Surya <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Brad Lewis <[email protected]> Reviewed by: Patrick Mooney <[email protected]> Reviewed by: Jerry Jelinek <[email protected]> Approved by: Joshua M. Clulow <[email protected]> Ported-by: Signed-off-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/9962 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/545190c6 Closes #8188
* zed: detect and offline physically removed devicesloli10K2018-11-092-0/+2
| | | | | | | | | | | | | | | | This commit adds a new test case to the ZFS Test Suite to verify ZED can detect when a device is physically removed from a running system: the device will be offlined if a spare is not available in the pool. We implement this by using the existing libudev functionality and without relying solely on the FM kernel module capabilities which have been observed to be unreliable with some kernels. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Don Brady <[email protected]> Signed-off-by: loli10K <[email protected]> Closes #1537 Closes #7926
* Add zpool status -s (slow I/Os) and -p (parseable)Tony Hutter2018-11-084-7/+9
| | | | | | | | | | | | | | | | | | This patch adds a new slow I/Os (-s) column to zpool status to show the number of VDEV slow I/Os. This is the number of I/Os that didn't complete in zio_slow_io_ms milliseconds. It also adds a new parsable (-p) flag to display exact values. NAME STATE READ WRITE CKSUM SLOW testpool ONLINE 0 0 0 - mirror-0 ONLINE 0 0 0 - loop0 ONLINE 0 0 0 20 loop1 ONLINE 0 0 0 0 Reviewed-by: Brian Behlendorf <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Signed-off-by: Tony Hutter <[email protected]> Closes #7756 Closes #6885
* Add libzutil for libzfs or libzpool consumersDon Brady2018-11-052-1/+1
| | | | | | | | | | | Adds a libzutil for utility functions that are common to libzfs and libzpool consumers (most of what was in libzfs_import.c). This removes the need for utilities to link against both libzpool and libzfs. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Don Brady <[email protected]> Closes #8050
* Fix dbgmsg printing in ztest and zdbTom Caputi2018-10-241-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch resolves a problem where the -G option in both zdb and ztest would cause the code to call __dprintf() to print zfs_dbgmsg output. This function was not properly wired to add messages to the dbgmsg log as it is in userspace and so the messages were simply dropped. This patch also tries to add some degree of distinction to dprintf() (which now prints directly to stdout) and zfs_dbgmsg() (which adds messages to an internal list that can be dumped with zfs_dbgmsg_print()). In addition, this patch corrects an issue where ztest used a global variable to decide whether to dump the dbgmsg buffer on a crash. This did not work because ztest spins up more instances of itself using execv(), which did not copy the global variable to the new process. The option has been moved to the ztest_shared_opts_t which already exists for interprocess communication. This patch also changes zfs_dbgmsg_print() to use write() calls instead of printf() so that it will not fail when used in a signal handler. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #8010
* OpenZFS 9681 - ztest failure in spa_history_log_internal due to spa_rename()Matthew Ahrens2018-10-191-1/+0
| | | | | | | | | | | | | | Authored by: Matthew Ahrens <[email protected]> Reviewed by: Prakash Surya <[email protected]> Reviewed by: Serapheim Dimitropoulos <[email protected]> Reviewed by: George Melikov <[email protected]> Reviewed by: Tom Caputi <[email protected]> Approved by: Robert Mustacchi <[email protected]> Ported-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/9681 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/6aee0ad7 Closes #8041
* Defer new resilvers until the current one endsTom Caputi2018-10-184-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | Currently, if a resilver is triggered for any reason while an existing one is running, zfs will immediately restart the existing resilver from the beginning to include the new drive. This causes problems for system administrators when a drive fails while another is already resilvering. In this case, the optimal thing to do to reduce risk of data loss is to wait for the current resilver to end before immediately replacing the second failed drive, which allows the system to operate with two incomplete drives for the minimum amount of time. This patch introduces the resilver_defer feature that essentially does this for the admin without forcing them to wait and monitor the resilver manually. The change requires an on-disk feature since we must mark drives that are part of a deferred resilver in the vdev config to ensure that we do not assume they are done resilvering when an existing resilver completes. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: John Kennedy <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: @mmaybee Signed-off-by: Tom Caputi <[email protected]> Closes #7732
* OpenZFS 9862 - fix typo in comment in vdev_impl.hAllan Jude2018-10-181-1/+1
| | | | | | | | | | | | | Authored by: Allan Jude <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Reviewed by: Tony Hutter <[email protected]> Approved by: Robert Mustacchi <[email protected]> Ported-by: George Melikov <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/9862 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/84927f52 Closes #8036
* Linux does not HAVE_SMB_SHAREMatthew Ahrens2018-10-171-1/+0
| | | | | | | | | | Since Linux does not have an in-kernel SMB server, we don't need the code to manage it. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Richard Elling <[email protected]> Signed-off-by: Matthew Ahrens <[email protected]> Closes #8032
* Add types to featureflags in zfsPaul Dagnelie2018-10-161-7/+10
| | | | | | | | | | | | | | | | | | | | The boolean featureflags in use thus far in ZFS are extremely useful, but because they take advantage of the zap layer, more interesting data than just a true/false value can be stored in a featureflag. In redacted send/receive, this is used to store the list of redaction snapshots for a redacted dataset. This change adds the ability for ZFS to store types other than a boolean in a featureflag. The only other implemented type is a uint64_t array. It also modifies the interfaces around dataset features to accomodate the new capabilities, and adds a few new functions to increase encapsulation. This functionality will be used by the Redacted Send/Receive feature. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Closes #7981
* deadlock between mm_sem and tx assign in zfs_write() and page faultilbsmart2018-10-161-1/+1
| | | | | | | | | | | | | | | | | | | The bug time sequence: 1. thread #1, `zfs_write` assign a txg "n". 2. In a same process, thread #2, mmap page fault (which means the `mm_sem` is hold) occurred, `zfs_dirty_inode` open a txg failed, and wait previous txg "n" completed. 3. thread #1 call `uiomove` to write, however page fault is occurred in `uiomove`, which means it need `mm_sem`, but `mm_sem` is hold by thread #2, so it stuck and can't complete, then txg "n" will not complete. So thread #1 and thread #2 are deadlocked. Reviewed-by: Chunwei Chen <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Signed-off-by: Grady Wong <[email protected]> Closes #7939
* Improved error handling for extreme rewindsBrian Behlendorf2018-10-121-3/+3
| | | | | | | | | | | | | | | | | | | | | | | The vdev_checkpoint_sm_object(), vdev_obsolete_sm_object(), and vdev_obsolete_counts_are_precise() functions assume that the only way a zap_lookup() can fail is if the requested entry is missing. While this is the most common cause, it's not the only cause. Attemping to access a damaged ZAP will result in other errors. The most likely scenario for accessing a damaged ZAP is during an extreme rewind pool import. Under these conditions the pool is expected to contain damaged objects and the import code was updated to handle this gracefully. Getting an ECKSUM error from these ZAPs after the pool in import a far less likely, therefore the behavior for call paths was not modified. Reviewed-by: Tim Chase <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #7809 Closes #7921
* OpenZFS 9689 - zfs range lock code should not be zpl-specificMatt Ahrens2018-10-113-70/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ZFS range locking code in zfs_rlock.c/h depends on ZPL-specific data structures, specifically znode_t. However, it's also used by the ZVOL code, which uses a "dummy" znode_t to pass to the range locking code. We should clean this up so that the range locking code is generic and can be used equally by ZPL and ZVOL, and also can be used by future consumers that may need to run in userland (libzpool) as well as the kernel. Porting notes: * Added missing sys/avl.h include to sys/zfs_rlock.h. * Removed 'dbuf is within the locked range' ASSERTs from dmu_sync(). This was needed because ztest does not yet use a locked_range_t. * Removed "Approved by:" tag requirement from OpenZFS commit check to prevent needless warnings when integrating changes which has not been merged to illumos. * Reverted free_list range lock changes which were originally needed to defer the cv_destroy() which was called immediately after cv_broadcast(). With d2733258 this should be safe but if not we may need to reintroduce this logic. * Reverts: The following two commits were reverted and squashed in to this change in order to make it easier to apply OpenZFS 9689. - d88895a0, which removed the dummy znode from zvol_state - e3a07cd0, which updated ztest to use range locks * Preserved optimized rangelock comparison function. Preserved the rangelock free list. The cv_destroy() function will block waiting for all processes in cv_wait() to be scheduled and drop their reference. This is done to ensure it's safe to free the condition variable. However, blocking while holding the rl->rl_lock mutex can result in a deadlock on Linux. A free list is introduced to defer the cv_destroy() and kmem_free() until after the mutex is released. Authored by: Matthew Ahrens <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Reviewed by: Serapheim Dimitropoulos <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Brad Lewis <[email protected]> Ported-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://illumos.org/issues/9689 OpenZFS-commit: https://github.com/openzfs/openzfs/pull/680 External-issue: DLPX-58662 Closes #7980
* Refactor dmu_recv into its own filePaul Dagnelie2018-10-094-31/+70
| | | | | | | | | | This change moves the bottom half of dmu_send.c (where the receive logic is kept) into a new file, dmu_recv.c, and does similarly for receive-related changes in header files. Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Closes #7982
* Add zfs_refcount_transfer_ownership_many()Brian Behlendorf2018-10-091-2/+5
| | | | | | | | | | | | | | | | | | | | | | | When debugging is enabled and a zfs_refcount_t contains multiple holders using the same key, but different ref_counts, the wrong reference_t may be transferred. Add a zfs_refcount_transfer_ownership_many() function, like the existing zfs_refcount_*_many() functions, to match and transfer the correct refcount_t; This issue may occur when using encryption with refcount debugging enabled. An arc_buf_hdr_t can have references for both the hdr->b_l1hdr.b_pabd and hdr->b_crypt_hdr.b_rabd both of which use the hdr as the reference holder. When unsharing the buffer the p_abd should be transferred. This issue does not impact production builds because refcount holders are not tracked. Reviewed-by: Matthew Ahrens <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #7219 Closes #8000
* OpenZFS 9617 - too-frequent TXG sync causes excessive write inflationMatthew Ahrens2018-10-041-1/+1
| | | | | | | | | | | | | | | | | | | | Porting notes: * Renamed zfs_dirty_data_sync_pct to zfs_dirty_data_sync_percent and changed the type to be consistent with the other dirty module params. * Updated zfs-module-parameters.5 accordingly. Authored by: Matthew Ahrens <[email protected]> Reviewed by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Brad Lewis <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Andrew Stormont <[email protected]> Reviewed-by: George Melikov <[email protected]> Approved by: Robert Mustacchi <[email protected]> Ported-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://illumos.org/issues/9617 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7928f4ba Closes #7976
* Add new fnvlist_lookup_* functionsPaul Dagnelie2018-10-031-15/+25
| | | | | | Reviewed by: Serapheim Dimitropoulos <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Closes #7977
* Refcounted DSL Crypto Key MappingsTom Caputi2018-10-032-4/+9
| | | | | | | | | | | | | | | | | | | | | | | | Since native ZFS encryption was merged, we have been fighting against a series of bugs that come down to the same problem: Key mappings (which must be present during all I/O operations) are created and destroyed based on dataset ownership, but I/Os can have traditionally been allowed to "leak" into the next txg after the dataset is disowned. In the past we have attempted to solve this problem by trying to ensure that datasets are disowned ater all I/O is finished by calling txg_wait_synced(), but we have repeatedly found edge cases that need to be squashed and code paths that might incur a high number of txg syncs. This patch attempts to resolve this issue differently, by adding a reference to the key mapping for each txg it is dirtied in. By doing so, we can remove many of the unnecessary calls to txg_wait_synced() we have added in the past and ensure we don't need to deal with this problem in the future. Reviewed-by: Jorgen Lundman <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #7949
* Prefix all refcount functions with zfs_Tim Schumacher2018-10-012-37/+35
| | | | | | | | | | | | Recent changes in the Linux kernel made it necessary to prefix the refcount_add() function with zfs_ due to a name collision. To bring the other functions in line with that and to avoid future collisions, prefix the other refcount functions as well. Reviewed by: Matthew Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Tim Schumacher <[email protected]> Closes #7963
* Remove duplicate macro in dsl_dir.hMatthew Ahrens2018-10-011-1/+0
| | | | | | | | | | | | The DD_FIELD_LAST_REMAP_TXG macro was added twice (with the same value). This change removes one of them. Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed-by: John Kennedy <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Matthew Ahrens <[email protected]> Closes #7968
* Fixes for procfs files backed by linked listsJohn Gallagher2018-09-263-16/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | There are some issues with the way the seq_file interface is implemented for kstats backed by linked lists (zfs_dbgmsgs and certain per-pool debugging info): * We don't account for the fact that seq_file sometimes visits a node multiple times, which results in missing messages when read through procfs. * We don't keep separate state for each reader of a file, so concurrent readers will receive incorrect results. * We don't account for the fact that entries may have been removed from the list between read syscalls, so reading from these files in procfs can cause the system to crash. This change fixes these issues and adds procfs_list, a wrapper around a linked list which abstracts away the details of implementing the seq_file interface for a list and exposing the contents of the list through procfs. Reviewed by: Don Brady <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Brad Lewis <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: John Gallagher <[email protected]> External-issue: LX-1211 Closes #7819
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-17 07:53:52 +0000