alterddumbfs manual page

Synopsis

alterddumbfs [options] <parent-directory>

Description

alterddumbfs create anomalies in an offline ddumbfs filesystem, for testing only.

The parent-directory is the directory containing the ddfs.cfg file and ddfsroot directory.

Options

-h, --help

show this help message and exit

-v, --verbose

be more verbose and display progress

-l, --lock_index

lock index into memory (increase speed)

-f, --file

create funny file

-n, --random-seed=<VAL>

initialize random seed

-i, --index=<NUM>

alter index

-s, --swap-consecutive=<NUM>

swap non empty consecutive nodes in the index

-S, --swap-random=<NUM>

swap non empty random nodes in the index

-r, --reset-node=<NUM>

reset to zero non empty nodes in the index

-d, --duplicate-node=<NUM>

duplicate non empty nodes in empty random place

-p, --duplicate-inplace=<NUM>

duplicate non empty nodes just after itself

-a, --swap-addr=<NUM>

exchange addresses of two non empty nodes in the index

-c, --corrupt-node=<NUM>

write one random byte anywhere in the index

-u, --unexpected_shutdown

simulate a crash or a powercut

-I, --index-ops=<OPS>

alter index file

• OPS = delete: delete the file
• OPS = magic: put MAGIC at blank
• OPS = truncate: truncate the file at mid size
• OPS = empty: truncate file

-B, --block-ops=<OPS>

alter block file, see –index-ops for possible operations

Example

For example, to test if fsckddumbfs will detect and correct addresses the swap of some addresses inside the index:

# umount /l0/ddumbfs/
# alterddumbfs -a 2 /l0/ddumbfs/
# fsckddumbfs -C /l0/ddumbfs
use asynchronous io
root directory: /l0/ddumbfs/ddfsroot
blockfile: /l0/ddumbfs/ddfsblocks
indexfile: /l0/ddumbfs/ddfsidx
== Check index
== Checked 983 nodes in 0.0s
== Check block hash
== Checked 12 blocks in 0.0s
== Check unmatching 2 block
== Checked 2 unmatching blocks in 0.0s
== Read files
== Read 1 files in 0.0s
== Summary
Used blocks          :       12
Free blocks          :      148
Index errors         :        0 OK
Index blocks         :       12
Index blocks dup     :        0 OK
Block errors         :        2 ERR
Files                :        1
Files errors         :        2 ERR
Files blocks         :       12
Files lost blocks    :        0 OK
Tested hashes        :        0
Wrong hashes         :        0 OK
Diff index vs files  :        0 OK
Diff blocks vs files :        0 OK
Filesystem status    : ERROR
# fsckddumbfs -n /l0/ddumbfs
use asynchronous io
root directory: /l0/ddumbfs/ddfsroot
blockfile: /l0/ddumbfs/ddfsblocks
indexfile: /l0/ddumbfs/ddfsidx
02:40:45 INF Repair node order, fixed 0 errors.
02:40:45 INF Update index from files.
02:40:45 INF calculate hash for block addr=2
02:40:45 INF calculate hash for block addr=5
02:40:45 INF Read 1 files in 0.0s.
02:40:45 INF 12 blocks used in files.
02:40:45 INF 2 blocks have been added to index.
02:40:45 INF ddfs_load_usedblocks
02:40:45 INF 12 blocks used in nodes.
02:40:45 INF 2 suspect blocks in nodes.
02:40:45 INF Resolve Index conflicts.
02:40:45 INF 2 nodes fixed.
02:40:45 INF Fix files.
02:40:45 INF Fixed:0  Corrupted:0  Total:1 files in 0.0s.
02:40:45 INF Deleted 0 useless nodes.
02:40:45 INF blocks in use: 12   blocks free: 148.
# fsckddumbfs -C /l0/ddumbfs
use asynchronous io
root directory: /l0/ddumbfs/ddfsroot
blockfile: /l0/ddumbfs/ddfsblocks
indexfile: /l0/ddumbfs/ddfsidx
== Check index
== Checked 983 nodes in 0.0s
== Check block hash
== Checked 12 blocks in 0.0s
== Check unmatching 0 block
== Checked 0 unmatching blocks in 0.0s
== Read files
== Read 1 files in 0.0s
== Check 'unexpected shutdown' blocks: 0.
== Summary
Used blocks          :       12
Free blocks          :      148
Index errors         :        0 OK
Index blocks         :       12
Index blocks dup     :        0 OK
Block errors         :        0 OK
Files                :        1
Files errors         :        0 OK
Files blocks         :       12
Files lost blocks    :        0 OK
Tested hashes        :        0
Wrong hashes         :        0 OK
Diff index vs files  :        0 OK

See also

ddumbfs(1), fsckddumbfs(8)

Author

Alain Spineux <alain.spineux@gmail.com>