Re: New btrfs sub command: btrfs inspect physical-find
On 2016-07-14 23:45, Chris Mason wrote:
>
>
> On 07/12/2016 05:40 PM, Goffredo Baroncelli wrote:
>> Hi All,
>>
>> the enclosed patch adds a new btrfs sub command: "btrfs inspect
>> physical-find". The aim of this new command is to show the physical
>> placement on the disk of a file. Currently it handles all the
>> profiles (single, dup, raid1/10/5/6). I develop this command in
>> order to show some bug in btrfs RAID5 profile (see next email).
>
> I've done this manually from time to time, and love the idea of
> having a helper for it. Can I talk you into adding a way to save the
> contents of the block without having to use dd? btrfs-map-logical
> does this now, but not via the search ioctl and not by filename.
>
> say:
>
> btrfs inspect physical-find -c -o
> offset
I prefer to add another command to do that (like btrfs insp physical-dump). And
I will add as constraint like
offset % blocksize == 0
this in order to avoid handling data spread different stripes/chunks.
However has different meaning:
single/raid0 -> means nothing
raid1/raid10 -> means the copy #
raid5/raid6 -> could mean the parity: i.e.
-1 -> first parity (raid5/raid6)
-2 -> 2nd parity (raid6 only)
> Looks like you've open coded btrfs_map_logical() below, getting
> output from the search ioctl. Dave might want that in a more
> centralized place.
I will give a look
> Also, please turn:
>
> for(;;) if (foo) { statements }
>
> Into
>
> for(;;) { if (foo) { statements } }
>
> I find that much less error prone.
Ok
>
> -chris
>
BR
G.Baroncelli
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Re: New btrfs sub command: btrfs inspect physical-find
On Thu, Jul 14, 2016 at 04:05:00PM -0700, Liu Bo wrote: > On Tue, Jul 12, 2016 at 11:40:13PM +0200, Goffredo Baroncelli wrote: > > Hi All, > > > > the enclosed patch adds a new btrfs sub command: "btrfs inspect > > physical-find". The aim of this new command is to show the physical > > placement on the disk of a file. Currently it handles all the profiles > > (single, dup, raid1/10/5/6). > > I develop this command in order to show some bug in btrfs RAID5 profile > > (see next email). > > > > You can pull the code from: > > > > https://github.com/kreijack/btrfs-progs.git > > > > branch > > > > insp-phy > > The tool looks similar to the existing 'btrfs-map-logical', yes, > btrfs-map-logical has some problems on raid56, and a quick glance shows > that it's due to that btrfs_num_copies() can only return 2 copies for > raid5 and 3 copies for raid6. I was wrong about btrfs_num_copies(), for raid56 it returns certain value to control which stripe __btrfs_map_block() needs to be return. Thus, btrfs-map-logical doesn't work for raid56 since everytime it will return the required-offset data stripe and the parity stripe. Thanks, -liubo > > Thanks, > > -liubo > > > > > The syntax of this new command is simple: > > > > # btrfs inspect physical-find [] > > > > where: > >is the file to inspect > >is the offset of the file to inspect (default 0) > > > > Below some examples: > > > > ** Single > > > > $ sudo mkfs.btrfs -f -d single -m single /dev/loop0 > > $ sudo mount /dev/loop0 mnt/ > > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > > >/dev/null > > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > > mnt/out.txt: 0 > > devid 1, /dev/loop0 : 12582912 LINEAR > > $ dd 2>/dev/null if=/dev/loop0 skip=12582912 bs=1 count=5; echo > > adaaa > > > > ** Dup > > > > The command shows both the copies > > > > $ sudo mkfs.btrfs -f -d single -m single /dev/loop0 > > $ sudo mount /dev/loop0 mnt/ > > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > > >/dev/null > > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > > mnt/out.txt: 0 > > devid 1, /dev/loop0 : 71303168 DUP > > devid 1, /dev/loop0 : 104857600 DUP > > $ dd 2>/dev/null if=/dev/loop0 skip=104857600 bs=1 count=5 ; echo > > adaaa > > > > > > ** Raid1 > > > > The command shows both the copies > > > > $ sudo mkfs.btrfs -f -d raid1 -m raid1 /dev/loop0 /dev/loop1 > > $ sudo mount /dev/loop0 mnt/ > > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > > >/dev/null > > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt mnt/out.txt: 0 > > devid 2, /dev/loop1 : 61865984 RAID1 > > devid 1, /dev/loop0 : 81788928 RAID1 > > $ dd 2>/dev/null if=/dev/loop0 skip=81788928 bs=1 count=5; echo > > adaaa > > > > > > ** Raid10 > > > > The command show both the copies; if you set an offset to the next > > disk-stripe, you can see the next pair of disk-stripe > > > > $ sudo mkfs.btrfs -f -d raid10 -m raid10 /dev/loop[0123] > > $ sudo mount /dev/loop0 mnt/ > > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > > >/dev/null > > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt mnt/out.txt: 0 > > devid 4, /dev/loop3 : 61931520 RAID10 > > devid 3, /dev/loop2 : 61931520 RAID10 > > $ dd 2>/dev/null if=/dev/loop2 skip=61931520 bs=1 count=5; echo > > adaaa > > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt 65536 > > mnt/out.txt: 65536 > > devid 2, /dev/loop1 : 61931520 RAID10 > > devid 1, /dev/loop0 : 81854464 RAID10 > > $ dd 2>/dev/null if=/dev/loop0 skip=81854464 bs=1 count=5; echo > > bdbbb > > > > > > ** Raid5 > > > > Depending by the offset, you can see which disk-stripe is used. > > > > $ sudo mkfs.btrfs -f -d raid5 -m raid5 /dev/loop[012] > > $ sudo mount /dev/loop0 mnt/ > > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > > >/dev/null > > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > > mnt/out.txt: 0 > > devid 2, /dev/loop1 : 61931520 DATA > > d
Re: New btrfs sub command: btrfs inspect physical-find
On Tue, Jul 12, 2016 at 11:40:13PM +0200, Goffredo Baroncelli wrote: > Hi All, > > the enclosed patch adds a new btrfs sub command: "btrfs inspect > physical-find". The aim of this new command is to show the physical placement > on the disk of a file. Currently it handles all the profiles (single, dup, > raid1/10/5/6). > I develop this command in order to show some bug in btrfs RAID5 profile (see > next email). > > You can pull the code from: > > https://github.com/kreijack/btrfs-progs.git > > branch > > insp-phy The tool looks similar to the existing 'btrfs-map-logical', yes, btrfs-map-logical has some problems on raid56, and a quick glance shows that it's due to that btrfs_num_copies() can only return 2 copies for raid5 and 3 copies for raid6. Thanks, -liubo > > The syntax of this new command is simple: > > # btrfs inspect physical-find [] > > where: >is the file to inspect >is the offset of the file to inspect (default 0) > > Below some examples: > > ** Single > > $ sudo mkfs.btrfs -f -d single -m single /dev/loop0 > $ sudo mount /dev/loop0 mnt/ > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > >/dev/null > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > mnt/out.txt: 0 > devid 1, /dev/loop0 : 12582912 LINEAR > $ dd 2>/dev/null if=/dev/loop0 skip=12582912 bs=1 count=5; echo > adaaa > > ** Dup > > The command shows both the copies > > $ sudo mkfs.btrfs -f -d single -m single /dev/loop0 > $ sudo mount /dev/loop0 mnt/ > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > >/dev/null > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > mnt/out.txt: 0 > devid 1, /dev/loop0 : 71303168 DUP > devid 1, /dev/loop0 : 104857600 DUP > $ dd 2>/dev/null if=/dev/loop0 skip=104857600 bs=1 count=5 ; echo > adaaa > > > ** Raid1 > > The command shows both the copies > > $ sudo mkfs.btrfs -f -d raid1 -m raid1 /dev/loop0 /dev/loop1 > $ sudo mount /dev/loop0 mnt/ > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > >/dev/null > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt mnt/out.txt: 0 > devid 2, /dev/loop1 : 61865984 RAID1 > devid 1, /dev/loop0 : 81788928 RAID1 > $ dd 2>/dev/null if=/dev/loop0 skip=81788928 bs=1 count=5; echo > adaaa > > > ** Raid10 > > The command show both the copies; if you set an offset to the next > disk-stripe, you can see the next pair of disk-stripe > > $ sudo mkfs.btrfs -f -d raid10 -m raid10 /dev/loop[0123] > $ sudo mount /dev/loop0 mnt/ > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > >/dev/null > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt mnt/out.txt: 0 > devid 4, /dev/loop3 : 61931520 RAID10 > devid 3, /dev/loop2 : 61931520 RAID10 > $ dd 2>/dev/null if=/dev/loop2 skip=61931520 bs=1 count=5; echo > adaaa > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt 65536 > mnt/out.txt: 65536 > devid 2, /dev/loop1 : 61931520 RAID10 > devid 1, /dev/loop0 : 81854464 RAID10 > $ dd 2>/dev/null if=/dev/loop0 skip=81854464 bs=1 count=5; echo > bdbbb > > > ** Raid5 > > Depending by the offset, you can see which disk-stripe is used. > > $ sudo mkfs.btrfs -f -d raid5 -m raid5 /dev/loop[012] > $ sudo mount /dev/loop0 mnt/ > $ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt > >/dev/null > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > mnt/out.txt: 0 > devid 2, /dev/loop1 : 61931520 DATA > devid 1, /dev/loop0 : 81854464 OTHER > devid 3, /dev/loop2 : 61931520 PARITY > $ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt > 65536mnt/out.txt: 65536 > devid 2, /dev/loop1 : 61931520 OTHER > devid 1, /dev/loop0 : 81854464 DATA > devid 3, /dev/loop2 : 61931520 PARITY > $ dd 2>/dev/null if=/dev/loop1 skip=61931520 bs=1 count=5; echo > adaaa > $ dd 2>/dev/null if=/dev/loop0 skip=81854464 bs=1 count=5; echo > bdbbb > $ dd 2>/dev/null if=/dev/loop2 skip=61931520 bs=1 count=5 | xxd > : 0300 0303 03 . > > The parity is computed as: parity=disk1^disk2. So "adaa" ^ "bdbb" == > "\x03\x00\x03\x03 > > ** Raid6 > $ sudo mkfs.btrfs -f -mraid6 -draid6 /dev/loop[0-4]^C > $ sudo mount /dev/loop0 mnt/ > $ python -c "print 'ad'+'a'*65534
Re: New btrfs sub command: btrfs inspect physical-find
On 07/12/2016 05:40 PM, Goffredo Baroncelli wrote:
Hi All,
the enclosed patch adds a new btrfs sub command: "btrfs inspect physical-find".
The aim of this new command is to show the physical placement on the disk of a file.
Currently it handles all the profiles (single, dup, raid1/10/5/6).
I develop this command in order to show some bug in btrfs RAID5 profile (see
next email).
I've done this manually from time to time, and love the idea of having a
helper for it. Can I talk you into adding a way to save the contents of
the block without having to use dd? btrfs-map-logical does this now,
but not via the search ioctl and not by filename.
say:
btrfs inspect physical-find -c -o
offset
Looks like you've open coded btrfs_map_logical() below, getting output
from the search ioctl. Dave might want that in a more centralized place.
Also, please turn:
for(;;)
if (foo) {
statements
}
Into
for(;;) {
if (foo) {
statements
}
}
I find that much less error prone.
-chris
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To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
New btrfs sub command: btrfs inspect physical-find
Hi All,
the enclosed patch adds a new btrfs sub command: "btrfs inspect physical-find".
The aim of this new command is to show the physical placement on the disk of a
file. Currently it handles all the profiles (single, dup, raid1/10/5/6).
I develop this command in order to show some bug in btrfs RAID5 profile (see
next email).
You can pull the code from:
https://github.com/kreijack/btrfs-progs.git
branch
insp-phy
The syntax of this new command is simple:
# btrfs inspect physical-find []
where:
is the file to inspect
is the offset of the file to inspect (default 0)
Below some examples:
** Single
$ sudo mkfs.btrfs -f -d single -m single /dev/loop0
$ sudo mount /dev/loop0 mnt/
$ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt
>/dev/null
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt
mnt/out.txt: 0
devid 1, /dev/loop0 : 12582912 LINEAR
$ dd 2>/dev/null if=/dev/loop0 skip=12582912 bs=1 count=5; echo
adaaa
** Dup
The command shows both the copies
$ sudo mkfs.btrfs -f -d single -m single /dev/loop0
$ sudo mount /dev/loop0 mnt/
$ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt
>/dev/null
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt
mnt/out.txt: 0
devid 1, /dev/loop0 : 71303168 DUP
devid 1, /dev/loop0 : 104857600 DUP
$ dd 2>/dev/null if=/dev/loop0 skip=104857600 bs=1 count=5 ; echo
adaaa
** Raid1
The command shows both the copies
$ sudo mkfs.btrfs -f -d raid1 -m raid1 /dev/loop0 /dev/loop1
$ sudo mount /dev/loop0 mnt/
$ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt
>/dev/null
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt mnt/out.txt: 0
devid 2, /dev/loop1 : 61865984 RAID1
devid 1, /dev/loop0 : 81788928 RAID1
$ dd 2>/dev/null if=/dev/loop0 skip=81788928 bs=1 count=5; echo
adaaa
** Raid10
The command show both the copies; if you set an offset to the next disk-stripe,
you can see the next pair of disk-stripe
$ sudo mkfs.btrfs -f -d raid10 -m raid10 /dev/loop[0123]
$ sudo mount /dev/loop0 mnt/
$ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt
>/dev/null
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt mnt/out.txt: 0
devid 4, /dev/loop3 : 61931520 RAID10
devid 3, /dev/loop2 : 61931520 RAID10
$ dd 2>/dev/null if=/dev/loop2 skip=61931520 bs=1 count=5; echo
adaaa
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt 65536
mnt/out.txt: 65536
devid 2, /dev/loop1 : 61931520 RAID10
devid 1, /dev/loop0 : 81854464 RAID10
$ dd 2>/dev/null if=/dev/loop0 skip=81854464 bs=1 count=5; echo
bdbbb
** Raid5
Depending by the offset, you can see which disk-stripe is used.
$ sudo mkfs.btrfs -f -d raid5 -m raid5 /dev/loop[012]
$ sudo mount /dev/loop0 mnt/
$ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt
>/dev/null
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt
mnt/out.txt: 0
devid 2, /dev/loop1 : 61931520 DATA
devid 1, /dev/loop0 : 81854464 OTHER
devid 3, /dev/loop2 : 61931520 PARITY
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt 65536mnt/out.txt:
65536
devid 2, /dev/loop1 : 61931520 OTHER
devid 1, /dev/loop0 : 81854464 DATA
devid 3, /dev/loop2 : 61931520 PARITY
$ dd 2>/dev/null if=/dev/loop1 skip=61931520 bs=1 count=5; echo
adaaa
$ dd 2>/dev/null if=/dev/loop0 skip=81854464 bs=1 count=5; echo
bdbbb
$ dd 2>/dev/null if=/dev/loop2 skip=61931520 bs=1 count=5 | xxd
: 0300 0303 03 .
The parity is computed as: parity=disk1^disk2. So "adaa" ^ "bdbb" ==
"\x03\x00\x03\x03
** Raid6
$ sudo mkfs.btrfs -f -mraid6 -draid6 /dev/loop[0-4]^C
$ sudo mount /dev/loop0 mnt/
$ python -c "print 'ad'+'a'*65534+'bd'+'b'*65533" | sudo tee mnt/out.txt
>/dev/null
$ sudo ../btrfs-progs/btrfs inspect physical-find mnt/out.txt
mnt/out.txt: 0
devid 3, /dev/loop2 : 61931520 DATA
devid 2, /dev/loop1 : 61931520 OTHER
devid 1, /dev/loop0 : 81854464 PARITY
devid 4, /dev/loop3 : 61931520 PARITY
$ dd 2>/dev/null if=/dev/loop2 skip=61931520 bs=1 count=5 ; echo
adaaa
--
diff --git a/cmds-inspect.c b/cmds-inspect.c
index dd7b9dd..a604c2b 100644
--- a/cmds-inspect.c
+++ b/cmds-inspect.c
@@ -22,6 +22,11 @@
#include
#include
#include
+#include
+#include
+#include
+#include
+#include
#include "kerncompat.h"
#include "ioctl.h"
@@ -623,6 +628,450 @@ out:
return !!ret;
}
+
+static const char* const cmd_inspect_physical_find_usage[] = {
+ "btrfs inspect-internal physical-find [options] [...]",
+ "Show the physical address of each blocks"
