Kernel 3.17.2 and RO snapshots
Hi there,
I'm a little lost with latest kernel issues, and would like to know if the "data corruption" with RO snapshots is fixed in 3.17.2, or not yet ?
Also about this issuse, I'd like to know if :
- Data corruption occurs when creating RO snapshots,
- Or if it can occur with just using a FS that already has RO snapshots ?
- Or if it can occur when deleting existing RO snapshots with 3.17 ?
Which means : If I have mistakenty upgraded to 3.17.2 a system containing RO snapshots and cannot downgrade (big distro and drivers mess...), what is the safest way to go ?
And if data corruption occurs, should I expect it to affect snapshots only, or the whole system ?
TIA for any insight.
Signature · 1 line
Swâmi Petaramesh <[email protected]> http://petaramesh.org PGP 9076E32E
Quoted 4 lines · Swâmi Petaramesh
Hi there,
I'm a little lost with latest kernel issues, and would like to know if the "data corruption" with RO snapshots is fixed in 3.17.2, or not yet ?
Yes, it is.
Quoted 3 lines
Also about this issuse, I'd like to know if :
- Data corruption occurs when creating RO snapshots,
Yes.
Quoted 1 line
- Or if it can occur with just using a FS that already has RO snapshots ?
No.
Quoted 1 line
- Or if it can occur when deleting existing RO snapshots with 3.17 ?
Not that I'm aware of.
Quoted 3 lines
Which means : If I have mistakenty upgraded to 3.17.2 a system containing RO snapshots and cannot downgrade (big distro and drivers mess...), what is the safest way to go ?
Leave it as it is. :)
Quoted 2 lines
And if data corruption occurs, should I expect it to affect snapshots only, or the whole system ?
I _think_ it only affects the snapshots, but could bring the system
down if you access the broken data. But you're safe with 3.17.2, so it's a moot point for you right now.
Hugo.
Signature · 4 lines
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
--- If it's December 1941 in Casablanca, what time is it ---
in New York? Quoted 4 lines · Le dimanche 2 novembre 2014 10:49:52 Hugo Mills a écrit :
Quoted 2 lines
I'm a little lost with latest kernel issues, and would like to know if the "data corruption" with RO snapshots is fixed in 3.17.2, or not yet ?
Yes, it is.
Thank you Hugo :-)
Signature · 4 lines
Swâmi Petaramesh <[email protected]> http://petaramesh.org PGP 9076E32E Je ne suis pas assez jeune pour tout savoir. -- James Matthew Barrie
Quoted 6 lines · Hugo Mills
Quoted 4 lines · Swâmi Petaramesh
Hi there,
I'm a little lost with latest kernel issues, and would like to know if the "data corruption" with RO snapshots is fixed in 3.17.2, or not yet ?
Quoted 7 lines
Yes, it is.
Quoted 3 lines
Also about this issuse, I'd like to know if :
- Data corruption occurs when creating RO snapshots,
Yes.
More specifically, you won't lose your data or get it modified in some way. The problem was that when a ro snapshot was created under specific timings, the fs metadata on disk would never end up pointing to the current (most recent) root of the snapshot. And this caused all sorts of errors when accessing the snapshot after a umount + mount / reboot.
Code to fix the issue (correct the metadata to point to the correct roots) went into btrfs' check command (btrfs-progs v3.17).
Quoted 29 lines
Quoted 2 lines
- Or if it can occur with just using a FS that already has RO snapshots ?
No.Quoted 1 line
- Or if it can occur when deleting existing RO snapshots with 3.17 ?
Not that I'm aware of.
Quoted 3 lines
Which means : If I have mistakenty upgraded to 3.17.2 a system containing RO snapshots and cannot downgrade (big distro and drivers mess...), what is the safest way to go ?
Leave it as it is. :)
Quoted 2 lines
And if data corruption occurs, should I expect it to affect snapshots only, or the whole system ?
I _think_ it only affects the snapshots, but could bring the system
down if you access the broken data. But you're safe with 3.17.2, so it's a moot point for you right now.Hugo.
--
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
PGP key: 65E74AC0 from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
--- If it's December 1941 in Casablanca, what time is it ---
in New York?
Signature · 5 lines
Filipe David Manana, "Reasonable men adapt themselves to the world. Unreasonable men adapt the world to themselves. That's why all progress depends on unreasonable men."