Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (34 commits)
  dm table: set flush capability based on underlying devices
  dm crypt: optionally support discard requests
  dm raid: add md raid1 support
  dm raid: support metadata devices
  dm raid: add write_mostly parameter
  dm raid: add region_size parameter
  dm raid: improve table parameters documentation
  dm ioctl: forbid multiple device specifiers
  dm ioctl: introduce __get_dev_cell
  dm ioctl: fill in device parameters in more ioctls
  dm flakey: add corrupt_bio_byte feature
  dm flakey: add drop_writes
  dm flakey: support feature args
  dm flakey: use dm_target_offset and support discards
  dm table: share target argument parsing functions
  dm snapshot: skip reading origin when overwriting complete chunk
  dm: ignore merge_bvec for snapshots when safe
  dm table: clean dm_get_device and move exports
  dm raid: tidy includes
  dm ioctl: prevent empty message
  ...

3 files changed, 150 insertions, 57 deletions

diff --git a/Documentation/device-mapper/dm-crypt.txt b/Documentation/device-mapper/dm-crypt.txt
index 6b5c42dbbe84..2c656ae43ba7 100644
--- a/Documentation/device-mapper/dm-crypt.txt
+++ b/Documentation/device-mapper/dm-crypt.txt
@@ -4,7 +4,8 @@ dm-crypt
 Device-Mapper's "crypt" target provides transparent encryption of block devices
 using the kernel crypto API.
 
-Parameters: <cipher> <key> <iv_offset> <device path> <offset>
+Parameters: <cipher> <key> <iv_offset> <device path> \
+              <offset> [<#opt_params> <opt_params>]
 
 <cipher>
     Encryption cipher and an optional IV generation mode.
@@ -37,6 +38,24 @@ Parameters: <cipher> <key> <iv_offset> <device path> <offset>
 <offset>
     Starting sector within the device where the encrypted data begins.
 
+<#opt_params>
+    Number of optional parameters. If there are no optional parameters,
+    the optional paramaters section can be skipped or #opt_params can be zero.
+    Otherwise #opt_params is the number of following arguments.
+
+    Example of optional parameters section:
+        1 allow_discards
+
+allow_discards
+    Block discard requests (a.k.a. TRIM) are passed through the crypt device.
+    The default is to ignore discard requests.
+
+    WARNING: Assess the specific security risks carefully before enabling this
+    option.  For example, allowing discards on encrypted devices may lead to
+    the leak of information about the ciphertext device (filesystem type,
+    used space etc.) if the discarded blocks can be located easily on the
+    device later.
+
 Example scripts
 ===============
 LUKS (Linux Unified Key Setup) is now the preferred way to set up disk
diff --git a/Documentation/device-mapper/dm-flakey.txt b/Documentation/device-mapper/dm-flakey.txt
index c8efdfd19a65..6ff5c2327227 100644
--- a/Documentation/device-mapper/dm-flakey.txt
+++ b/Documentation/device-mapper/dm-flakey.txt
@@ -1,17 +1,53 @@
 dm-flakey
 =========
 
-This target is the same as the linear target except that it returns I/O
-errors periodically.  It's been found useful in simulating failing
-devices for testing purposes.
+This target is the same as the linear target except that it exhibits
+unreliable behaviour periodically.  It's been found useful in simulating
+failing devices for testing purposes.
 
 Starting from the time the table is loaded, the device is available for
-<up interval> seconds, then returns errors for <down interval> seconds,
-and then this cycle repeats.
+<up interval> seconds, then exhibits unreliable behaviour for <down
+interval> seconds, and then this cycle repeats.
 
-Parameters: <dev path> <offset> <up interval> <down interval>
+Also, consider using this in combination with the dm-delay target too,
+which can delay reads and writes and/or send them to different
+underlying devices.
+
+Table parameters
+----------------
+  <dev path> <offset> <up interval> <down interval> \
+    [<num_features> [<feature arguments>]]
+
+Mandatory parameters:
     <dev path>: Full pathname to the underlying block-device, or a
                 "major:minor" device-number.
     <offset>: Starting sector within the device.
     <up interval>: Number of seconds device is available.
     <down interval>: Number of seconds device returns errors.
+
+Optional feature parameters:
+  If no feature parameters are present, during the periods of
+  unreliability, all I/O returns errors.
+
+  drop_writes:
+        All write I/O is silently ignored.
+        Read I/O is handled correctly.
+
+  corrupt_bio_byte <Nth_byte> <direction> <value> <flags>:
+        During <down interval>, replace <Nth_byte> of the data of
+        each matching bio with <value>.
+
+    <Nth_byte>: The offset of the byte to replace.
+                Counting starts at 1, to replace the first byte.
+    <direction>: Either 'r' to corrupt reads or 'w' to corrupt writes.
+                 'w' is incompatible with drop_writes.
+    <value>: The value (from 0-255) to write.
+    <flags>: Perform the replacement only if bio->bi_rw has all the
+             selected flags set.
+
+Examples:
+  corrupt_bio_byte 32 r 1 0
+        - replaces the 32nd byte of READ bios with the value 1
+
+  corrupt_bio_byte 224 w 0 32
+        - replaces the 224th byte of REQ_META (=32) bios with the value 0
diff --git a/Documentation/device-mapper/dm-raid.txt b/Documentation/device-mapper/dm-raid.txt
index 33b6b7071ac8..2a8c11331d2d 100644
--- a/Documentation/device-mapper/dm-raid.txt
+++ b/Documentation/device-mapper/dm-raid.txt
@@ -1,70 +1,108 @@
-Device-mapper RAID (dm-raid) is a bridge from DM to MD.  It
-provides a way to use device-mapper interfaces to access the MD RAID
-drivers.
+dm-raid
+-------
 
-As with all device-mapper targets, the nominal public interfaces are the
-constructor (CTR) tables and the status outputs (both STATUSTYPE_INFO
-and STATUSTYPE_TABLE).  The CTR table looks like the following:
+The device-mapper RAID (dm-raid) target provides a bridge from DM to MD.
+It allows the MD RAID drivers to be accessed using a device-mapper
+interface.
 
-1: <s> <l> raid \
-2:      <raid_type> <#raid_params> <raid_params> \
-3:      <#raid_devs> <meta_dev1> <dev1> .. <meta_devN> <devN>
-
-Line 1 contains the standard first three arguments to any device-mapper
-target - the start, length, and target type fields.  The target type in
-this case is "raid".
-
-Line 2 contains the arguments that define the particular raid
-type/personality/level, the required arguments for that raid type, and
-any optional arguments.  Possible raid types include: raid4, raid5_la,
-raid5_ls, raid5_rs, raid6_zr, raid6_nr, and raid6_nc.  (raid1 is
-planned for the future.)  The list of required and optional parameters
-is the same for all the current raid types.  The required parameters are
-positional, while the optional parameters are given as key/value pairs.
-The possible parameters are as follows:
- <chunk_size>           Chunk size in sectors.
- [[no]sync]             Force/Prevent RAID initialization
- [rebuild <idx>]        Rebuild the drive indicated by the index
- [daemon_sleep <ms>]    Time between bitmap daemon work to clear bits
- [min_recovery_rate <kB/sec/disk>]      Throttle RAID initialization
- [max_recovery_rate <kB/sec/disk>]      Throttle RAID initialization
- [max_write_behind <sectors>]           See '-write-behind=' (man mdadm)
- [stripe_cache <sectors>]               Stripe cache size for higher RAIDs
-
-Line 3 contains the list of devices that compose the array in
-metadata/data device pairs.  If the metadata is stored separately, a '-'
-is given for the metadata device position.  If a drive has failed or is
-missing at creation time, a '-' can be given for both the metadata and
-data drives for a given position.
-
-NB. Currently all metadata devices must be specified as '-'.
-
-Examples:
-# RAID4 - 4 data drives, 1 parity
+The target is named "raid" and it accepts the following parameters:
+
+  <raid_type> <#raid_params> <raid_params> \
+    <#raid_devs> <metadata_dev0> <dev0> [.. <metadata_devN> <devN>]
+
+<raid_type>:
+  raid1         RAID1 mirroring
+  raid4         RAID4 dedicated parity disk
+  raid5_la      RAID5 left asymmetric
+                - rotating parity 0 with data continuation
+  raid5_ra      RAID5 right asymmetric
+                - rotating parity N with data continuation
+  raid5_ls      RAID5 left symmetric
+                - rotating parity 0 with data restart
+  raid5_rs      RAID5 right symmetric
+                - rotating parity N with data restart
+  raid6_zr      RAID6 zero restart
+                - rotating parity zero (left-to-right) with data restart
+  raid6_nr      RAID6 N restart
+                - rotating parity N (right-to-left) with data restart
+  raid6_nc      RAID6 N continue
+                - rotating parity N (right-to-left) with data continuation
+
+  Refererence: Chapter 4 of
+  http://www.snia.org/sites/default/files/SNIA_DDF_Technical_Position_v2.0.pdf
+
+<#raid_params>: The number of parameters that follow.
+
+<raid_params> consists of
+    Mandatory parameters:
+        <chunk_size>: Chunk size in sectors.  This parameter is often known as
+                      "stripe size".  It is the only mandatory parameter and
+                      is placed first.
+
+    followed by optional parameters (in any order):
+        [sync|nosync]   Force or prevent RAID initialization.
+
+        [rebuild <idx>] Rebuild drive number idx (first drive is 0).
+
+        [daemon_sleep <ms>]
+                Interval between runs of the bitmap daemon that
+                clear bits.  A longer interval means less bitmap I/O but
+                resyncing after a failure is likely to take longer.
+
+        [min_recovery_rate <kB/sec/disk>]  Throttle RAID initialization
+        [max_recovery_rate <kB/sec/disk>]  Throttle RAID initialization
+        [write_mostly <idx>]               Drive index is write-mostly
+        [max_write_behind <sectors>]       See '-write-behind=' (man mdadm)
+        [stripe_cache <sectors>]           Stripe cache size (higher RAIDs only)
+        [region_size <sectors>]
+                The region_size multiplied by the number of regions is the
+                logical size of the array.  The bitmap records the device
+                synchronisation state for each region.
+
+<#raid_devs>: The number of devices composing the array.
+        Each device consists of two entries.  The first is the device
+        containing the metadata (if any); the second is the one containing the
+        data.
+
+        If a drive has failed or is missing at creation time, a '-' can be
+        given for both the metadata and data drives for a given position.
+
+
+Example tables
+--------------
+# RAID4 - 4 data drives, 1 parity (no metadata devices)
 # No metadata devices specified to hold superblock/bitmap info
 # Chunk size of 1MiB
 # (Lines separated for easy reading)
+
 0 1960893648 raid \
         raid4 1 2048 \
         5 - 8:17 - 8:33 - 8:49 - 8:65 - 8:81
 
-# RAID4 - 4 data drives, 1 parity (no metadata devices)
+# RAID4 - 4 data drives, 1 parity (with metadata devices)
 # Chunk size of 1MiB, force RAID initialization,
 #       min recovery rate at 20 kiB/sec/disk
+
 0 1960893648 raid \
-        raid4 4 2048 min_recovery_rate 20 sync\
-        5 - 8:17 - 8:33 - 8:49 - 8:65 - 8:81
+        raid4 4 2048 sync min_recovery_rate 20 \
+        5 8:17 8:18 8:33 8:34 8:49 8:50 8:65 8:66 8:81 8:82
 
-Performing a 'dmsetup table' should display the CTR table used to
-construct the mapping (with possible reordering of optional
-parameters).
+'dmsetup table' displays the table used to construct the mapping.
+The optional parameters are always printed in the order listed
+above with "sync" or "nosync" always output ahead of the other
+arguments, regardless of the order used when originally loading the table.
+Arguments that can be repeated are ordered by value.
 
-Performing a 'dmsetup status' will yield information on the state and
-health of the array.  The output is as follows:
+'dmsetup status' yields information on the state and health of the
+array.
+The output is as follows:
 1: <s> <l> raid \
 2:      <raid_type> <#devices> <1 health char for each dev> <resync_ratio>
 
-Line 1 is standard DM output.  Line 2 is best shown by example:
+Line 1 is the standard output produced by device-mapper.
+Line 2 is produced by the raid target, and best explained by example:
         0 1960893648 raid raid4 5 AAAAA 2/490221568
 Here we can see the RAID type is raid4, there are 5 devices - all of
 which are 'A'live, and the array is 2/490221568 complete with recovery.
+Faulty or missing devices are marked 'D'.  Devices that are out-of-sync
+are marked 'a'.