admin-guide/device-mapper/dm-dust.rst

15 in the "bad block list" will fail with EIO ("Input/output error").
17 Writes of blocks in the "bad block list will result in the following:
19 1. Remove the block from the "bad block list".
40         Path to the block device.
46         Block size in bytes
59 (For a device with a block size of 512 bytes)
65 (For a device with a block size of 4096 bytes)
73 bad block additions, removals, and remaps will be verbosely logged)::
89 At any time (i.e.: whether the device has the "bad block" emulation
94         kernel: device-mapper: dust: badblock added at block 60
97         kernel: device-mapper: dust: badblock added at block 67
100         kernel: device-mapper: dust: badblock added at block 72
102 These bad blocks will be stored in the "bad block list".
108 Enabling block read failures
111 To enable the "fail read on bad block" behavior, send the "enable" message::
119 With the device in "fail read on bad block" mode, attempting to read a
120 block will encounter an "Input/output error"::
135         kernel: device-mapper: dust: block 60 removed from badblocklist by write
136         kernel: device-mapper: dust: block 67 removed from badblocklist by write
137         kernel: device-mapper: dust: block 72 removed from badblocklist by write
138         kernel: device-mapper: dust: block 87 removed from badblocklist by write
140 Bad block add/remove error handling
143 Attempting to add a bad block that already exists in the list will
148         kernel: device-mapper: dust: block 88 already in badblocklist
150 Attempting to remove a bad block that doesn't exist in the list will
155         kernel: device-mapper: dust: block 87 not found in badblocklist
157 Counting the number of bad blocks in the bad block list
173 To find out if a specific block is in the bad block list, run the
178 The following message will print if the block is in the list::
180         dust_query_block: block 72 found in badblocklist
182 The following message will print if the block is not in the list::
184         dust_query_block: block 72 not found in badblocklist
187 and "disabled" modes, allowing the verification of whether a block
189 or having to "enable" the bad block emulation.
191 Clearing the bad block list
194 To clear the bad block list (without needing to individually run
195 a "removebadblock" message command for every block), run the
200 After clearing the bad block list, the following message will appear::
209 Listing the bad block list
212 To list all bad blocks in the bad block list (using an example device
213 with blocks 1 and 2 in the bad block list), run the following message
220 If there are no bad blocks in the bad block list, the command will
236 ...where <blknum> is a block number within range of the device
237 (corresponding to the block size of the device.)
290 dm-flakey fails all I/O from all block locations at a specified time