- 20 Jul, 2016 2 commits
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Tom Caputi authored
A port of the Illumos Crypto Framework to a Linux kernel module (found in module/icp). This is needed to do the actual encryption work. We cannot use the Linux kernel's built in crypto api because it is only exported to GPL-licensed modules. Having the ICP also means the crypto code can run on any of the other kernels under OpenZFS. I ended up porting over most of the internals of the framework, which means that porting over other API calls (if we need them) should be fairly easy. Specifically, I have ported over the API functions related to encryption, digests, macs, and crypto templates. The ICP is able to use assembly-accelerated encryption on amd64 machines and AES-NI instructions on Intel chips that support it. There are place-holder directories for similar assembly optimizations for other architectures (although they have not been written). Signed-off-by:
Tom Caputi <tcaputi@datto.com> Signed-off-by:
Tony Hutter <hutter2@llnl.gov> Signed-off-by:
Brian Behlendorf <behlendorf1@llnl.gov> Issue #4329
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Chunwei Chen authored
When zfs_domount fails zsb will be freed, and its caller mount_nodev/get_sb_nodev will do deactivate_locked_super and calls into zfs_preumount. In order to make sure we don't touch any nonexistent stuff, we must make sure s_fs_info is NULL in the fail path so zfs_preumount can easily check that. Signed-off-by:
Chunwei Chen <david.chen@osnexus.com> Signed-off-by:
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- 19 Jul, 2016 5 commits
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Gvozden Neskovic authored
Print table with speed of methods for each implementation. Last line describes contents of [fastest] selection. Signed-off-by:
Gvozden Neskovic <neskovic@gmail.com> Signed-off-by:
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Gvozden Neskovic authored
- Implementation lock replaced with atomic variable - Trailing whitespace is removed from user specified parameter, to enhance experience when using commands that add newline, e.g. `echo` - raidz_test: remove dependency on `getrusage()` and RUSAGE_THREAD, Issue #4813 - silence `cppcheck` in vdev_raidz, partial solution of Issue #1392 - Minor fixes and cleanups - Enable use of original parity methods in [fastest] configuration. New opaque original ops structure, representing native methods, is added to supported raidz methods. Original parity methods are executed if selected implementation has NULL fn pointer. Signed-off-by:
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Chunwei Chen authored
Wait for iput_async before entering evict_inodes in generic_shutdown_super. The reason we must finish before evict_inodes is when lazytime is on, or when zfs_purgedir calls zfs_zget, iput would bump i_count from 0 to 1. This would race with the i_count check in evict_inodes. This means it could destroy the inode while we are still using it. Signed-off-by:
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Brian Behlendorf authored
Commit 7f60329a removed several kstats which arc_summary.py read. Remove these kstats from arc_summary.py in the same way this was handled in FreeNAS. FreeNAS-commit: https://github.com/freenas/freenas/commit/3901f73 Signed-off-by:
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Tyler J. Stachecki authored
In some cases, the compiler was not respecting the GNU aligned attribute for stack variables in 35a76a03 . This was resulting in a segfault on CentOS 6.7 hosts using gcc 4.4.7-17. This issue was fixed in gcc 4.6. To prevent this from occurring, use unaligned loads and stores for all stack and global memory references in the SSE optimized Fletcher-4 code. Disable zimport testing against master where this flaw exists: TEST_ZIMPORT_VERSIONS="installed" Signed-off-by:
Tyler J. Stachecki <stachecki.tyler@gmail.com> Signed-off-by:
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- 15 Jul, 2016 2 commits
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Roman Strashkin authored
It is possible that the given DS may have hidden child (%recv) datasets - "leftovers" resulting from the previously interrupted 'zfs receieve'. Try to remove the hidden child (%recv) and after that try to remove the target dataset. If the hidden child (%recv) does not exist the original error (EEXIST) will be returned. Signed-off-by:
Roman Strashkin <roman.strashkin@nexenta.com> Signed-off-by:
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Tyler J. Stachecki authored
Builds off of 1eeb4562 (Implementation of AVX2 optimized Fletcher-4) This commit adds another implementation of the Fletcher-4 algorithm. It is automatically selected at module load if it benchmarks higher than all other available implementations. The module benchmark was also amended to analyze the performance of the byteswap-ed version of Fletcher-4, as well as the non-byteswaped version. The average performance of the two is used to select the the fastest implementation available on the host system. Adds a pair of fields to an existing zcommon module parameter: - zfs_fletcher_4_impl (str) "sse2" - new SSE2 implementation if available "ssse3" - new SSSE3 implementation if available Signed-off-by:
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- 14 Jul, 2016 4 commits
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Chris Dunlop authored
A mostly mechanical change, taking into account i_nlink is 32 bits vs ZFS's 64 bit on-disk link count. We revert "xattr dir doesn't get purged during iput" (ddae16a9 ) as this is a more Linux-integrated fix for the same issue. In addition, setting the initial link count on a new node has been changed from setting one less than required in zfs_mknode() then incrementing to the correct count in zfs_link_create() (which was somewhat bizarre in the first place), to setting the correct count in zfs_mknode() and not incrementing it in zfs_link_create(). This both means we no longer set the link count in sa_bulk_update() twice (once for the initial incorrect count then again for the correct count), as well as adhering to the Linux requirement of not incrementing a zero link count without I_LINKABLE (see linux commit f4e0c30c). Signed-off-by:
Chris Dunlop <chris@onthe.net.au> Signed-off-by:
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Chunwei Chen authored
Dropping DBUF_HASH_MUTEX when walking the hash list is unsafe. The dbuf can be freed at any time. Signed-off-by:
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Tim Chase authored
In arc_buf_info(), the arc_buf_t may have no header. If not, don't try to fetch the arc buffer stats and instead just zero them. The null dereferences were observed while accessing the dbuf kstat with awk on a system in which millions of small files were being created in order to overflow the system's metadata limit. Signed-off-by:
Tim Chase <tim@chase2k.com> Signed-off-by:
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Brian Behlendorf authored
Creating the pool in a striped rather than mirrored configuration provides enough space for all upgrade tests to run. Test case zpool_upgrade_007_pos still fails and must be investigated so it has been left disabled. Signed-off-by:
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- 13 Jul, 2016 2 commits
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Gvozden Neskovic authored
The patch covers low-end and older x86 CPUs. Parity generation is equivalent to SSSE3 implementation, but reconstruction is somewhat slower. Previous 'sse' implementation is renamed to 'ssse3' to indicate highest instruction set used. Benchmark results: scalar_rec_p 4 720476442 scalar_rec_q 4 187462804 scalar_rec_r 4 138996096 scalar_rec_pq 4 140834951 scalar_rec_pr 4 129332035 scalar_rec_qr 4 81619194 scalar_rec_pqr 4 53376668 sse2_rec_p 4 2427757064 sse2_rec_q 4 747120861 sse2_rec_r 4 499871637 sse2_rec_pq 4 522403710 sse2_rec_pr 4 464632780 sse2_rec_qr 4 319124434 sse2_rec_pqr 4 205794190 ssse3_rec_p 4 2519939444 ssse3_rec_q 4 1003019289 ssse3_rec_r 4 616428767 ssse3_rec_pq 4 706326396 ssse3_rec_pr 4 570493618 ssse3_rec_qr 4 400185250 ssse3_rec_pqr 4 377541245 original_rec_p 4 691658568 original_rec_q 4 195510948 original_rec_r 4 26075538 original_rec_pq 4 103087368 original_rec_pr 4 15767058 original_rec_qr 4 15513175 original_rec_pqr 4 10746357 Signed-off-by:
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Gvozden Neskovic authored
zfs_ioc_recv_impl() is changed to always allocate the 'errors' nvlist, its callers are responsible for freeing it. Signed-off-by:
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- 12 Jul, 2016 9 commits
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Peng authored
The following scenario can result in garbage in the dn_spill field. The db->db_blkptr must be set to NULL when DNODE_FLAG_SPILL_BLKPTR is clear to ensure the dn_spill field is cleared. Current txg = A. * A new spill buffer is created. Its dbuf is initialized with db_blkptr = NULL and it's dirtied. Current txg = B. * The spill buffer is modified. It's marked as dirty in this txg. * Additional changes make the spill buffer unnecessary because the xattr fits into the bonus buffer, so it's removed. The dbuf is undirtied in this txg, but it's still referenced and cannot be destroyed. Current txg = C. * Starts syncing of txg A * dbuf_sync_leaf() is called for the spill buffer. Since db_blkptr is NULL, dbuf_check_blkptr() is called. * The dbuf starts being written and it reaches the ready state (not done yet). * A new change makes the spill buffer necessary again. sa_build_layouts() ends up calling dbuf_find() to locate the dbuf. It finds the old dbuf because it has not been destroyed yet (it will be destroyed when the previous write is done and there are no more references). The old dbuf has db_blkptr != NULL. * txg A write is complete and the dbuf released. However it's still referenced, so it's not destroyed. Current txg = D. * Starts syncing of txg B * dbuf_sync_leaf() is called for the bonus buffer. Its contents are directly copied into the dnode, overwriting the blkptr area because, in txg B, the bonus buffer was big enough to hold the entire xattr. * At this point, the db_blkptr of the spill buffer used in txg C gets corrupted. Signed-off-by:
Peng <peng.hse@xtaotech.com> Signed-off-by:
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Brian Behlendorf authored
Remove stray trailing } which prevented the raidz stress tests from running in-tree. Signed-off-by: -
Chunwei Chen authored
zp->z_xattr_parent will pin the parent. This will cause huge issue when unlink a file with xattr. Because the unlinked file is pinned, it will never get purged immediately. And because of that, the xattr stuff will never be marked as unlinked. So the whole unlinked stuff will stay there until shrink cache or umount. This change partially reverts e89260a1 . This is safe because only the zp->z_xattr_parent optimization is removed, zpl_xattr_security_init() is still called from the zpl outside the inode lock. Signed-off-by:
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Chunwei Chen authored
We need to set inode->i_nlink to zero so iput will purge it. Without this, it will get purged during shrink cache or umount, which would likely result in deadlock due to zfs_zget waiting forever on its children which are in the dispose_list of the same thread. Signed-off-by:
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Chunwei Chen authored
When generation mismatch, it usually means the file pointed by the file handle was deleted. We should return ESTALE to indicate this. We return ENOENT in zfs_vget since zpl_fh_to_dentry will convert it to ESTALE. Signed-off-by:
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Chunwei Chen authored
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Chunwei Chen authored
This allocation can go way over 1MB, so we should use vmem_alloc instead of kmem_alloc. Large kmem_alloc(1430784, 0x1000), please file an issue... Call Trace: [<ffffffffa0324aff>] ? spl_kmem_zalloc+0xef/0x160 [spl] [<ffffffffa17d0c8d>] ? vdev_metaslab_init+0x9d/0x1f0 [zfs] [<ffffffffa17d46d0>] ? vdev_load+0xc0/0xd0 [zfs] [<ffffffffa17d4643>] ? vdev_load+0x33/0xd0 [zfs] [<ffffffffa17c0004>] ? spa_load+0xfc4/0x1b60 [zfs] [<ffffffffa17c1838>] ? spa_tryimport+0x98/0x430 [zfs] [<ffffffffa17f28b1>] ? zfs_ioc_pool_tryimport+0x41/0x80 [zfs] [<ffffffffa17f5669>] ? zfsdev_ioctl+0x4a9/0x4e0 [zfs] [<ffffffff811bacdf>] ? do_vfs_ioctl+0x2cf/0x4b0 [<ffffffff811baf41>] ? SyS_ioctl+0x81/0xa0 Signed-off-by:
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Chunwei Chen authored
Allow accessing XATTR through export handle is a very bad idea. It would allow user to write whatever they want in fields where they otherwise could not. Signed-off-by:
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Chunwei Chen authored
Certain ioctl operations will call get_zfs_sb, which will holds an active count on sb without checking whether it's active or not. This will result in use-after-free. We fix this by using atomic_inc_not_zero to make sure we got an active sb. P1 P2 --- --- deactivate_locked_super(): s_active = 0 zfs_sb_hold() ->get_zfs_sb(): s_active = 1 ->zpl_kill_sb() -->zpl_put_super() --->zfs_umount() ---->zfs_sb_free(zsb) zfs_sb_rele(zsb) Signed-off-by:
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- 11 Jul, 2016 1 commit
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Gvozden Neskovic authored
If compiled with -O0, gcc doesn't do any stack frame coalescing and -Wframe-larger-than=1024 is triggered in debug mode. Starting with gcc 4.8, new opt level -Og is introduced for debugging, which does not trigger this warning. Fix bench zio size, using SPA_OLD_MAXBLOCKSHIFT Signed-off-by:
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- 29 Jun, 2016 2 commits
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Brian Behlendorf authored
Adds support for resuming interrupted zfs send streams and include all related send/recv bug fixes from upstream OpenZFS. Unlike the upstream implementation this branch does not change the existing ioctl interface. Instead a new ZFS_IOC_RECV_NEW ioctl was added to support resuming zfs send streams. This was done by applying the original upstream patch and then reverting the ioctl changes in a follow up patch. For this reason there are a handful on commits between the relevant patches on this branch which are not interoperable. This was done to make it easier to extract the new ZFS_IOC_RECV_NEW and submit it upstream. Signed-off-by: -
Brian Behlendorf authored
The fletcher_4_native() and fletcher_4_byteswap() functions may only safely use the vectorized implementations when the buffer is 128-bit aligned. This is because both the AVX2 and SSE implementations process four 32-bit words per iterations. Fallback to the scalar implementation which only processes a single 32-bit word for unaligned buffers. Signed-off-by:
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- 28 Jun, 2016 10 commits
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Paul Dagnelie authored
Reviewed by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Yuri Pankov <yuri.pankov@nexenta.com> Ported-by:
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Igor Kozhukhov authored
Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com> Approved by: Dan McDonald <danmcd@omniti.com> Ported-by:
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Brian Behlendorf authored
Adds ZFS_IOC_RECV_NEW for resumable streams and preserves the legacy ZFS_IOC_RECV user/kernel interface. The new interface supports all stream options but is currently only used for resumable streams. This way updated user space utilities will interoperate with older kernel modules. ZFS_IOC_RECV_NEW is modeled after the existing ZFS_IOC_SEND_NEW handler. Non-Linux OpenZFS platforms have opted to change the legacy interface in an incompatible fashion instead of adding a new ioctl. Signed-off-by: -
Dan McDonald authored
Authored by: Dan McDonald <danmcd@omniti.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Yuri Pankov <yuri.pankov@nexenta.com> Reviewed by: Toomas Soome <tsoome@me.com> Approved by: Gordon Ross <gwr@nexenta.com> Ported-by:
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Dan McDonald authored
Authored by: Dan McDonald <danmcd@omniti.com> Reviewed by: John Kennedy <john.kennedy@delphix.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Approved by: Gordon Ross <gordon.ross@nexenta.com> Ported-by:
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Eli Rosenthal authored
Authored by: Eli Rosenthal <eli.rosenthal@delphix.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed by: Paul Dagnelie <pcd@delphix.com> Reviewed by: Dan McDonald <danmcd@omniti.com> Approved by: Robert Mustacchi <rm@joyent.com> Ported-by:
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Andrew Stormont authored
Authored by: Andrew Stormont <astormont@racktopsystems.com> Reviewed by: Anil Vijarnia <avijarnia@racktopsystems.com> Reviewed by: Kim Shrier <kshrier@racktopsystems.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Approved by: Dan McDonald <danmcd@omniti.com> Ported-by:
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Paul Dagnelie authored
Authored by: Paul Dagnelie <pcd@delphix.com> Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Richard Elling <Richard.Elling@RichardElling.com> Approved by: Dan McDonald <danmcd@omniti.com> Ported-by:
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Brian Behlendorf authored
Reviewed by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Paul Dagnelie <pcd@delphix.com> Approved by: Robert Mustacchi <rm@joyent.com> Ported-by:
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Matthew Ahrens authored
2605 want to resume interrupted zfs send Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Paul Dagnelie <pcd@delphix.com> Reviewed by: Richard Elling <Richard.Elling@RichardElling.com> Reviewed by: Xin Li <delphij@freebsd.org> Reviewed by: Arne Jansen <sensille@gmx.net> Approved by: Dan McDonald <danmcd@omniti.com> Ported-by:
kernelOfTruth <kerneloftruth@gmail.com> Signed-off-by:
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- 24 Jun, 2016 3 commits
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Brian Behlendorf authored
Flag 20 was used in OpenZFS as DMU_BACKUP_FEATURE_RESUMING. The DMU_BACKUP_FEATURE_LARGE_DNODE flag must be shifted to 21 and then reserved in the upstream OpenZFS implementation. Signed-off-by:
Ned Bass <bass6@llnl.gov> Closes #4795
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Ned Bass authored
Justification ------------- This feature adds support for variable length dnodes. Our motivation is to eliminate the overhead associated with using spill blocks. Spill blocks are used to store system attribute data (i.e. file metadata) that does not fit in the dnode's bonus buffer. By allowing a larger bonus buffer area the use of a spill block can be avoided. Spill blocks potentially incur an additional read I/O for every dnode in a dnode block. As a worst case example, reading 32 dnodes from a 16k dnode block and all of the spill blocks could issue 33 separate reads. Now suppose those dnodes have size 1024 and therefore don't need spill blocks. Then the worst case number of blocks read is reduced to from 33 to two--one per dnode block. In practice spill blocks may tend to be co-located on disk with the dnode blocks so the reduction in I/O would not be this drastic. In a badly fragmented pool, however, the improvement could be significant. ZFS-on-Linux systems that make heavy use of extended attributes would benefit from this feature. In particular, ZFS-on-Linux supports the xattr=sa dataset property which allows file extended attribute data to be stored in the dnode bonus buffer as an alternative to the traditional directory-based format. Workloads such as SELinux and the Lustre distributed filesystem often store enough xattr data to force spill bocks when xattr=sa is in effect. Large dnodes may therefore provide a performance benefit to such systems. Other use cases that may benefit from this feature include files with large ACLs and symbolic links with long target names. Furthermore, this feature may be desirable on other platforms in case future applications or features are developed that could make use of a larger bonus buffer area. Implementation -------------- The size of a dnode may be a multiple of 512 bytes up to the size of a dnode block (currently 16384 bytes). A dn_extra_slots field was added to the current on-disk dnode_phys_t structure to describe the size of the physical dnode on disk. The 8 bits for this field were taken from the zero filled dn_pad2 field. The field represents how many "extra" dnode_phys_t slots a dnode consumes in its dnode block. This convention results in a value of 0 for 512 byte dnodes which preserves on-disk format compatibility with older software. Similarly, the in-memory dnode_t structure has a new dn_num_slots field to represent the total number of dnode_phys_t slots consumed on disk. Thus dn->dn_num_slots is 1 greater than the corresponding dnp->dn_extra_slots. This difference in convention was adopted because, unlike on-disk structures, backward compatibility is not a concern for in-memory objects, so we used a more natural way to represent size for a dnode_t. The default size for newly created dnodes is determined by the value of a new "dnodesize" dataset property. By default the property is set to "legacy" which is compatible with older software. Setting the property to "auto" will allow the filesystem to choose the most suitable dnode size. Currently this just sets the default dnode size to 1k, but future code improvements could dynamically choose a size based on observed workload patterns. Dnodes of varying sizes can coexist within the same dataset and even within the same dnode block. For example, to enable automatically-sized dnodes, run # zfs set dnodesize=auto tank/fish The user can also specify literal values for the dnodesize property. These are currently limited to powers of two from 1k to 16k. The power-of-2 limitation is only for simplicity of the user interface. Internally the implementation can handle any multiple of 512 up to 16k, and consumers of the DMU API can specify any legal dnode value. The size of a new dnode is determined at object allocation time and stored as a new field in the znode in-memory structure. New DMU interfaces are added to allow the consumer to specify the dnode size that a newly allocated object should use. Existing interfaces are unchanged to avoid having to update every call site and to preserve compatibility with external consumers such as Lustre. The new interfaces names are given below. The versions of these functions that don't take a dnodesize parameter now just call the _dnsize() versions with a dnodesize of 0, which means use the legacy dnode size. New DMU interfaces: dmu_object_alloc_dnsize() dmu_object_claim_dnsize() dmu_object_reclaim_dnsize() New ZAP interfaces: zap_create_dnsize() zap_create_norm_dnsize() zap_create_flags_dnsize() zap_create_claim_norm_dnsize() zap_create_link_dnsize() The constant DN_MAX_BONUSLEN is renamed to DN_OLD_MAX_BONUSLEN. The spa_maxdnodesize() function should be used to determine the maximum bonus length for a pool. These are a few noteworthy changes to key functions: * The prototype for dnode_hold_impl() now takes a "slots" parameter. When the DNODE_MUST_BE_FREE flag is set, this parameter is used to ensure the hole at the specified object offset is large enough to hold the dnode being created. The slots parameter is also used to ensure a dnode does not span multiple dnode blocks. In both of these cases, if a failure occurs, ENOSPC is returned. Keep in mind, these failure cases are only possible when using DNODE_MUST_BE_FREE. If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. dnode_hold_impl() will check if the requested dnode is already consumed as an extra dnode slot by an large dnode, in which case it returns ENOENT. * The function dmu_object_alloc() advances to the next dnode block if dnode_hold_impl() returns an error for a requested object. This is because the beginning of the next dnode block is the only location it can safely assume to either be a hole or a valid starting point for a dnode. * dnode_next_offset_level() and other functions that iterate through dnode blocks may no longer use a simple array indexing scheme. These now use the current dnode's dn_num_slots field to advance to the next dnode in the block. This is to ensure we properly skip the current dnode's bonus area and don't interpret it as a valid dnode. zdb --- The zdb command was updated to display a dnode's size under the "dnsize" column when the object is dumped. For ZIL create log records, zdb will now display the slot count for the object. ztest ----- Ztest chooses a random dnodesize for every newly created object. The random distribution is more heavily weighted toward small dnodes to better simulate real-world datasets. Unused bonus buffer space is filled with non-zero values computed from the object number, dataset id, offset, and generation number. This helps ensure that the dnode traversal code properly skips the interior regions of large dnodes, and that these interior regions are not overwritten by data belonging to other dnodes. A new test visits each object in a dataset. It verifies that the actual dnode size matches what was stored in the ztest block tag when it was created. It also verifies that the unused bonus buffer space is filled with the expected data patterns. ZFS Test Suite -------------- Added six new large dnode-specific tests, and integrated the dnodesize property into existing tests for zfs allow and send/recv. Send/Receive ------------ ZFS send streams for datasets containing large dnodes cannot be received on pools that don't support the large_dnode feature. A send stream with large dnodes sets a DMU_BACKUP_FEATURE_LARGE_DNODE flag which will be unrecognized by an incompatible receiving pool so that the zfs receive will fail gracefully. While not implemented here, it may be possible to generate a backward-compatible send stream from a dataset containing large dnodes. The implementation may be tricky, however, because the send object record for a large dnode would need to be resized to a 512 byte dnode, possibly kicking in a spill block in the process. This means we would need to construct a new SA layout and possibly register it in the SA layout object. The SA layout is normally just sent as an ordinary object record. But if we are constructing new layouts while generating the send stream we'd have to build the SA layout object dynamically and send it at the end of the stream. For sending and receiving between pools that do support large dnodes, the drr_object send record type is extended with a new field to store the dnode slot count. This field was repurposed from unused padding in the structure. ZIL Replay ---------- The dnode slot count is stored in the uppermost 8 bits of the lr_foid field. The bits were unused as the object id is currently capped at 48 bits. Resizing Dnodes --------------- It should be possible to resize a dnode when it is dirtied if the current dnodesize dataset property differs from the dnode's size, but this functionality is not currently implemented. Clearly a dnode can only grow if there are sufficient contiguous unused slots in the dnode block, but it should always be possible to shrink a dnode. Growing dnodes may be useful to reduce fragmentation in a pool with many spill blocks in use. Shrinking dnodes may be useful to allow sending a dataset to a pool that doesn't support the large_dnode feature. Feature Reference Counting -------------------------- The reference count for the large_dnode pool feature tracks the number of datasets that have ever contained a dnode of size larger than 512 bytes. The first time a large dnode is created in a dataset the dataset is converted to an extensible dataset. This is a one-way operation and the only way to decrement the feature count is to destroy the dataset, even if the dataset no longer contains any large dnodes. The complexity of reference counting on a per-dnode basis was too high, so we chose to track it on a per-dataset basis similarly to the large_block feature. Signed-off-by:
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Ned Bass authored
Only attempt to backfill lower metadnode object numbers if at least 4096 objects have been freed since the last rescan, and at most once per transaction group. This avoids a pathology in dmu_object_alloc() that caused O(N^2) behavior for create-heavy workloads and substantially improves object creation rates. As summarized by @mahrens in #4636: "Normally, the object allocator simply checks to see if the next object is available. The slow calls happened when dmu_object_alloc() checks to see if it can backfill lower object numbers. This happens every time we move on to a new L1 indirect block (i.e. every 32 * 128 = 4096 objects). When re-checking lower object numbers, we use the on-disk fill count (blkptr_t:blk_fill) to quickly skip over indirect blocks that don’t have enough free dnodes (defined as an L2 with at least 393,216 of 524,288 dnodes free). Therefore, we may find that a block of dnodes has a low (or zero) fill count, and yet we can’t allocate any of its dnodes, because they've been allocated in memory but not yet written to disk. In this case we have to hold each of the dnodes and then notice that it has been allocated in memory. The end result is that allocating N objects in the same TXG can require CPU usage proportional to N^2." Add a tunable dmu_rescan_dnode_threshold to define the number of objects that must be freed before a rescan is performed. Don't bother to export this as a module option because testing doesn't show a compelling reason to change it. The vast majority of the performance gain comes from limit the rescan to at most once per TXG. Signed-off-by:
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