talos-op-linux/drivers/md/persistent-data/dm-transaction-manager.c, branch v4.4.4

dm persistent data: eliminate unnecessary return values

2015-10-31T23:06:02+00:00

dm_bm_unlock and dm_tm_unlock return an integer value but the returned value is always 0. The calling code sometimes checks the return value and sometimes doesn't. Eliminate these unnecessary return values and also the checks for them. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer

dm transaction manager: add support for prefetching blocks of metadata

2014-11-10T20:25:26+00:00

Introduce the dm_tm_issue_prefetches interface. If you're using a non-blocking clone the tm will build up a list of requested blocks that weren't in core. dm_tm_issue_prefetches will request those blocks to be prefetched. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer

dm transaction manager: fix corruption due to non-atomic transaction commit

2014-03-27T20:56:23+00:00

The persistent-data library used by dm-thin, dm-cache, etc is transactional. If anything goes wrong, such as an io error when writing new metadata or a power failure, then we roll back to the last transaction. Atomicity when committing a transaction is achieved by: a) Never overwriting data from the previous transaction. b) Writing the superblock last, after all other metadata has hit the disk. This commit and the following commit ("dm: take care to copy the space map roots before locking the superblock") fix a bug associated with (b). When committing it was possible for the superblock to still be written in spite of an io error occurring during the preceeding metadata flush. With these commits we're careful not to take the write lock out on the superblock until after the metadata flush has completed. Change the transaction manager's semantics for dm_tm_commit() to assume all data has been flushed _before_ the single superblock that is passed in. As a prerequisite, split the block manager's block unlocking and flushing by simplifying dm_bm_flush_and_unlock() to dm_bm_flush(). Now the unlocking must be done separately. This issue was discovered by forcing io errors at the crucial time using dm-flakey. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org

hlist: drop the node parameter from iterators

2013-02-28T03:10:24+00:00

I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin Acked-by: Paul E. McKenney Signed-off-by: Sasha Levin Cc: Wu Fengguang Cc: Marcelo Tosatti Cc: Gleb Natapov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

drivers/md/persistent-data/dm-transaction-manager.c: rename HASH_SIZE

2013-02-24T01:50:08+00:00

Fix the warning: drivers/md/persistent-data/dm-transaction-manager.c:28:1: warning: "HASH_SIZE" redefined In file included from include/linux/elevator.h:5, from include/linux/blkdev.h:216, from drivers/md/persistent-data/dm-block-manager.h:11, from drivers/md/persistent-data/dm-transaction-manager.h:10, from drivers/md/persistent-data/dm-transaction-manager.c:6: include/linux/hashtable.h:22:1: warning: this is the location of the previous definition Cc: Alasdair Kergon Cc: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

dm persistent data: stop using dm_bm_unlock_move when shadowing blocks in tm

2012-07-27T14:08:09+00:00

Stop using dm_bm_unlock_move when shadowing blocks in the transaction manager as an optimisation and remove the function as it is then no longer used. Some code, such as the space maps, keeps using on-disk data structures from the previous transaction. It can do this because blocks won't be reallocated until the subsequent transaction. Using dm_bm_unlock_move to copy blocks sounds like a win, but it forces a synchronous read should the old block be accessed. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm persistent data: tidy transaction manager creation fns

2012-07-27T14:08:09+00:00

Tidy the transaction manager creation functions. They no longer lock the superblock. Superblock locking is pulled out to the caller. Also export dm_bm_write_lock_zero. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm persistent data: remove debug space map checker

2012-07-27T14:07:58+00:00

Remove debug space map checker from dm persistent data. The space map checker is a wrapper for other space maps that double checks the reference counts are correct. It holds all these reference counts in memory rather than on disk, so uses a lot of memory and is thus restricted to small pools. As yet, this checker hasn't found any issues, but has caused a few of its own due to people turning it on by default with larger pools. Removing. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon

dm persistent data: handle space map checker creation failure

2012-07-03T11:55:35+00:00

If CONFIG_DM_DEBUG_SPACE_MAPS is enabled and dm_sm_checker_create() fails, dm_tm_create_internal() would still return success even though it cleaned up all resources it was supposed to have created. This will lead to a kernel crash: general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC ... RIP: 0010:[] [] dm_bufio_get_block_size+0x9/0x20 Call Trace: [] dm_bm_block_size+0xe/0x10 [] sm_ll_init+0x78/0xd0 [] sm_ll_new_disk+0x16/0xa0 [] dm_sm_disk_create+0xfe/0x160 [] dm_pool_metadata_open+0x16e/0x6a0 [] pool_ctr+0x3f0/0x900 [] dm_table_add_target+0x195/0x450 [] table_load+0xe4/0x330 [] ctl_ioctl+0x15a/0x2c0 [] dm_ctl_ioctl+0x13/0x20 [] do_vfs_ioctl+0x98/0x560 [] sys_ioctl+0x91/0xa0 [] system_call_fastpath+0x16/0x1b Fix the space map checker code to return an appropriate ERR_PTR and have dm_sm_disk_create() and dm_tm_create_internal() check for it with IS_ERR. Reported-by: Vivek Goyal Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org Signed-off-by: Alasdair G Kergon

dm persistent data: fix shadow_info_leak on dm_tm_destroy

2012-07-03T11:55:33+00:00

Cleanup the shadow table before destroying the transaction manager. Reference: leak was identified with kmemleak when running test_discard_random_sectors in the thinp-test-suite. Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org Signed-off-by: Alasdair G Kergon