Commit graph

23 commits

Author SHA1 Message Date
Mikulas Patocka
c241104506 dm snapshot: test chunk size against both origin and snapshot
Validate chunk size against both origin and snapshot sector size

Don't allow chunk size smaller than either origin or snapshot logical
sector size. Reading or writing data not aligned to sector size is not
allowed and causes immediate errors.

This requires us to open the origin before initialising the
exception store and to export dm_snap_origin.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2010-08-12 04:13:51 +01:00
Mikulas Patocka
1e03f97e43 dm snapshot: add merging
Merging is started when origin is resumed and it is stopped when
origin is suspended or when the merging snapshot is destroyed or
errors are detected.

Merging is not yet interlocked with writes: this will be handled in
subsequent patches.

The code relies on callbacks from a private kcopyd thread.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:32 +00:00
Mikulas Patocka
4454a6216f dm exception store: add merge specific methods
Add functions that decide how many consecutive chunks of snapshot to
merge back into the origin next and to update the metadata afterwards.

prepare_merge provides a pointer to the most recent still-to-be-merged
chunk and returns how many previous ones are consecutive and can be
processed together.

commit_merge removes the nr_merged most-recent chunks permanently from
the exception store.  The number must not exceed that returned by
prepare_merge.

Introduce NUM_SNAPSHOT_HDR_CHUNKS to show where the snapshot header
chunk is accounted for.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:29 +00:00
Mike Snitzer
fc56f6fbcc dm snapshot: move cow ref from exception store to snap core
Store the reference to the snapshot cow device in the core snapshot
code instead of each exception store.  It can be accessed through the
new function dm_snap_cow().  Exception stores should each now maintain a
reference to their parent snapshot struct.

This is cleaner and makes part of the forthcoming snapshot merge code simpler.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>
2009-12-10 23:52:12 +00:00
Mike Snitzer
985903bb3a dm snapshot: add allocated metadata to snapshot status
Add number of sectors used by metadata to the end of the snapshot's status
line.

Renamed dm_exception_store_type's 'fraction_full' to 'usage'.  Renamed
arguments to be clearer about what is being returned.  Also added
'metadata_sectors'.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:11 +00:00
Jon Brassow
1d4989c858 dm snapshot: rename dm_snap_exception to dm_exception
The exception structure is not necessarily just a snapshot
element (especially after we pull it out of dm-snap.c).

Renaming appropriately.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:10 +00:00
Mikulas Patocka
102c6ddb1d dm snapshot: simplify sector_to_chunk expression
Removed unnecessary 'and' masking: The right shift discards the lower
bits so there is no need to clear them.

(A later patch needs this change to support a 32-bit chunk_mask.)

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-12-10 23:52:08 +00:00
Mikulas Patocka
df96eee679 dm snapshot: use unsigned integer chunk size
Use unsigned integer chunk size.

Maximum chunk size is 512kB, there won't ever be need to use 4GB chunk size,
so the number can be 32-bit. This fixes compiler failure on 32-bit systems
with large block devices.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-10-16 23:18:17 +01:00
Mikulas Patocka
2defcc3fb4 dm exception store: split set_chunk_size
Break the function set_chunk_size to two functions in preparation for
the fix in the following patch.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-09-04 20:40:41 +01:00
Mikulas Patocka
5657e8fa45 dm: use i_size_read
Use i_size_read() instead of reading i_size.

If someone changes the size of the device simultaneously, i_size_read
is guaranteed to return a valid value (either the old one or the new one).

i_size can return some intermediate invalid value (on 32-bit computers
with 64-bit i_size, the reads to both halves of i_size can be interleaved
with updates to i_size, resulting in garbage being returned).

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-06-22 10:12:14 +01:00
Bartlomiej Zolnierkiewicz
90c699a9ee block: rename CONFIG_LBD to CONFIG_LBDAF
Follow-up to "block: enable by default support for large devices
and files on 32-bit archs".

Rename CONFIG_LBD to CONFIG_LBDAF to:
- allow update of existing [def]configs for "default y" change
- reflect that it is used also for large files support nowadays

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-19 08:08:50 +02:00
Jonathan Brassow
1e302a929e dm snapshot: move status to exception store
Let the exception store types print out their status through
the new API, rather than having the snapshot code do it.

Adjust the buffer position to allow for the preceding DMEMIT in the
arguments to type->status().

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:35 +01:00
Jonathan Brassow
fee1998e9c dm snapshot: move ctr parsing to exception store
First step of having the exception stores parse their own arguments -
generalizing the interface.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:34 +01:00
Jonathan Brassow
71fab00a6b dm snapshot: remove dm_snap header use
Move useful functions out of dm-snap.h and stop using dm-snap.h.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:33 +01:00
Jonathan Brassow
49beb2b87a dm exception store: move cow pointer
Move COW device from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:33 +01:00
Jonathan Brassow
d021684951 dm exception store: move chunk_fields
Move chunk fields from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:32 +01:00
Jonathan Brassow
0cea9c7827 dm exception store: move dm_target pointer
Move target pointer from snapshot to exception store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:32 +01:00
Jonathan Brassow
493df71c64 dm exception store: introduce registry
Move exception stores into a registry.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:31 +01:00
Jonathan Brassow
b2a1146529 dm exception store: separate type from instance
Introduce struct dm_exception_store_type.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-04-02 19:55:30 +01:00
Jonathan Brassow
a159c1ac5f dm snapshot: extend exception store functions
Supply dm_add_exception as a callback to the read_metadata function.
Add a status function ready for a later patch and name the functions
consistently.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:05:19 +00:00
Alasdair G Kergon
4db6bfe02b dm snapshot: split out exception store implementations
Move the existing snapshot exception store implementations out into
separate files.  Later patches will place these behind a new
interface in preparation for alternative implementations.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:05:17 +00:00
Jonathan Brassow
1ae25f9c93 dm snapshot: rename struct exception_store
Rename struct exception_store to dm_exception_store.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:05:16 +00:00
Jonathan Brassow
aea53d92f7 dm snapshot: separate out exception store interface
Pull structures that bridge the gap between snapshot and
exception store out of dm-snap.h and put them in a new
.h file - dm-exception-store.h.  This file will define the
API for new exception stores.

Ultimately, dm-snap.h is unnecessary, since only dm-snap.c
should be using it.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2009-01-06 03:05:15 +00:00