linux-toradex.git/drivers/md/persistent-data/dm-space-map-common.c, branch v6.0-rc4

dm space map common: add bounds check to sm_ll_lookup_bitmap()

2022-01-04T18:58:19+00:00

Corrupted metadata could warrant returning error from sm_ll_lookup_bitmap().

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer

dm space map disk: cache a small number of index entries

2021-06-04T16:07:23+00:00

The disk space map stores it's index entries in a btree, these are
accessed very frequently, so having a few cached makes a big difference
to performance.

With this change provisioning a new block takes roughly 20% less cpu.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer

dm space maps: improve performance with inc/dec on ranges of blocks

2021-06-04T16:07:22+00:00

When we break sharing on btree nodes we typically need to increment
the reference counts to every value held in the node.  This can
cause a lot of repeated calls to the space maps.  Fix this by changing
the interface to the space map inc/dec methods to take ranges of
adjacent blocks to be operated on.

For installations that are using a lot of snapshots this will reduce
cpu overhead of fundamental operations such as provisioning a new block,
or deleting a snapshot, by as much as 10 times.

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer

dm space map common: fix division bug in sm_ll_find_free_block()

2021-04-19T16:48:13+00:00

This division bug meant the search for free metadata space could skip
the final allocation bitmap's worth of entries. Fix affects DM thinp,
cache and era targets.

Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber 
Tested-by: Ming-Hung Tsai 
Signed-off-by: Mike Snitzer

dm space map common: fix to ensure new block isn't already in use

2020-01-15T01:15:53+00:00

The space-maps track the reference counts for disk blocks allocated by
both the thin-provisioning and cache targets.  There are variants for
tracking metadata blocks and data blocks.

Transactionality is implemented by never touching blocks from the
previous transaction, so we can rollback in the event of a crash.

When allocating a new block we need to ensure the block is free (has
reference count of 0) in both the current and previous transaction.
Prior to this fix we were doing this by searching for a free block in
the previous transaction, and relying on a 'begin' counter to track
where the last allocation in the current transaction was.  This
'begin' field was not being updated in all code paths (eg, increment
of a data block reference count due to breaking sharing of a neighbour
block in the same btree leaf).

This fix keeps the 'begin' field, but now it's just a hint to speed up
the search.  Instead the current transaction is searched for a free
block, and then the old transaction is double checked to ensure it's
free.  Much simpler.

This fixes reports of sm_disk_new_block()'s BUG_ON() triggering when
DM thin-provisioning's snapshots are heavily used.

Reported-by: Eric Wheeler 
Cc: stable@vger.kernel.org
Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer

dm space map common: remove check for impossible sm_find_free() return value

2019-08-26T19:39:53+00:00

The function sm_find_free() just returns -ENOSPC and 0.
So remove lone caller's check for some other error.

Signed-off-by: ZhangXiaoxu 
Signed-off-by: Mike Snitzer

dm space map common: zero entire ll_disk

2019-04-18T20:18:32+00:00

Otherwise, memory that is allocated (and potentially not previously
zeroed) will get written to disk as part of the space maps.

Signed-off-by: Mike Snitzer

dm: Avoid namespace collision with bitmap API

2018-08-01T22:49:38+00:00

bitmap API (include/linux/bitmap.h) has 'bitmap' prefix for its methods.

On the other hand DM bitmap API is special case.
Adding 'dm' prefix to it to avoid potential name space collision.

No functional changes intended.

Suggested-by: Mike Snitzer 
Signed-off-by: Andy Shevchenko 
Acked-by: Mike Snitzer 
Signed-off-by: Dmitry Torokhov

dm space map common: memcpy the disk root to ensure it's arch aligned

2017-02-16T18:02:54+00:00

The metadata_space_map_root passed to sm_ll_open_metadata() may or may
not be arch aligned, use memcpy to ensure it is.  This is not a fast
path so the extra memcpy doesn't hurt us.

Long-term it'd be better to use the kernel's alignment infrastructure to
remove the memcpy()s that are littered across persistent-data (btree,
array, space-maps, etc).

Signed-off-by: Joe Thornber 
Signed-off-by: Mike Snitzer

dm space map: always set ev if sm_ll_mutate() succeeds

2016-12-08T19:13:15+00:00

If no block was allocated or freed, sm_ll_mutate() wasn't setting
*ev, leaving the variable unitialized. sm_ll_insert(),
sm_disk_inc_block(), and sm_disk_new_block() all check ev to see
if there was an allocation event in sm_ll_mutate(), possibly
reading unitialized data.

If no allocation event occured, sm_ll_mutate() should set *ev
to SM_NONE.

Signed-off-by: Benjamin Marzinski 
Acked-by: Joe Thornber 
Signed-off-by: Mike Snitzer