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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/Documentation/device-mapper/dm-flakey.txt
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
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+dm-flakey
+=========
+
+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 exhibits unreliable behaviour for <down
+interval> seconds, and then this cycle repeats.
+
+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