| Message ID | 530DF8D5.7010808@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 02/26/2014 09:23 AM, Austin S Hemmelgarn wrote: > Currently, btrfs balance start fails when trying to convert > metadata or system chunks to dup profile on filesystems with > multiple devices. This requires that a conversion from a > multi-device filesystem to a single device filesystem use the > following methodology: 1. btrfs balance start -dconvert=single > -mconvert=single \ -sconvert=single -f / 2. btrfs device delete / > /dev/sdx 3. btrfs balance start -mconvert=dup -sconvert=dup / This > results in a period of time (possibly very long if the devices are > big) where you don't have the protection guarantees of multiple > copies of metadata chunks. > > After applying this patch, one can instead use the following > methodology for conversion from a multi-device filesystem to a > single device filesystem: 1. btrfs balance start -dconvert=single > -mconvert=dup \ -sconvert=dup -f / 2. btrfs device delete / > /dev/sdx This greatly reduces the chances of the operation causing > data loss due to a read error during the device delete. > > Signed-off-by: Austin S. Hemmelgarn <ahferroin7@gmail.com> --- Fails to build, wait for me to push an updated btrfs-next and rebase and resubmit fs/btrfs/volumes.c: In function ‘btrfs_balance’: fs/btrfs/volumes.c:3223:55: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) && ^ fs/btrfs/volumes.c:3227:8: error: ‘num_devs’ undeclared (first use in this function) (num_devs > 1)) { ^ fs/btrfs/volumes.c:3227:8: note: each undeclared identifier is reported only once for each function it appears in make[1]: *** [fs/btrfs/volumes.o] Error 1 make: *** [_module_fs/btrfs] Error 2 Thanks, Josef -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTGgp0AAoJEANb+wAKly3BrkkQANOaAAk6LJ4VO86f9/N7Hkom Hf4FK5lQiMkzlLc8pz+RxHeIHSXScXdrVKPv8bIPoGwd171OIrMA1HZa/9iuez8z OInjO6Zwj6l/+N3/QckAJKkNmbInNH2wgdhUrFyUw+gDFvVnl1YGUcTwx6/udqTB kfsls2ivD7S9kfSXyaM4oxVMN+tZWpZtOs1TMpf7BDMIz92gr87VADKIocrlu5qh EZ2YyWGyIP87jz+7zzNPUQ00/BAgC1lPnbZf+ei0L1KQbDtjII3Rl1/rlg78Zdtb VQfYMBz0hpaOE+UNfVsClgDgMjAkphob7BXTrkzJaChOagJ5tIlSGZRUaHPt3qaz so1R/3BaPzlTdv7gPCpMg+nSYdNl0x3w5CauCB4EX3L8PtbxK9tQdFtKmpl5GNrZ gBADD+AAbyPoz4GO2lfQyIN6Hd5FA+drK6cErF/rY+dPlieyihdYfBWRU+nao9RY ju07FN2UHJaAlSh/K8ZLv4lZUULDObr/tOdg5M1h5piSL9H9jOHUdaLmRzSx+7hZ j96qRY9/W4L6avEQQLphGbgn3v+aOHcgxLS0MyO/fhXANah2z69PjpS5J7GOXGZ5 UDGTneQIeRqueYms1yqpmZA0Ctwavq0TGoDvYsOlf/x7vucJE6a02qMRitUJbuvV 6m+8a6PFRudGng7zQYef =KCPn -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 07629e9..38a9522 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -3152,10 +3152,8 @@ int btrfs_balance(struct btrfs_balance_control *bctl, num_devices--; } btrfs_dev_replace_unlock(&fs_info->dev_replace); - allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE; - if (num_devices == 1) - allowed |= BTRFS_BLOCK_GROUP_DUP; - else if (num_devices > 1) + allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE | BTRFS_BLOCK_GROUP_DUP; + if (num_devices > 1) allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1); if (num_devices > 2) allowed |= BTRFS_BLOCK_GROUP_RAID5; @@ -3221,6 +3219,21 @@ int btrfs_balance(struct btrfs_balance_control *bctl, goto out; } } + if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) && + (bctl->sys.target & ~BTRFS_BLOCK_GROUP_DUP) || + (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) && + (bctl->meta.target & ~BTRFS_BLOCK_GROUP_DUP)) && + (num_devs > 1)) { + if (bctl->flags & BTRFS_BALANCE_FORCE) { + btrfs_info(fs_info, "force conversion of metadata " + "to dup profile on multiple devices"); + } else { + btrfs_err(fs_info, "balance will reduce metadata " + "integrity, use force if you want this"); + ret = -EINVAL; + goto out; + } + } } while (read_seqretry(&fs_info->profiles_lock, seq)); if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
Currently, btrfs balance start fails when trying to convert metadata or system chunks to dup profile on filesystems with multiple devices. This requires that a conversion from a multi-device filesystem to a single device filesystem use the following methodology: 1. btrfs balance start -dconvert=single -mconvert=single \ -sconvert=single -f / 2. btrfs device delete / /dev/sdx 3. btrfs balance start -mconvert=dup -sconvert=dup / This results in a period of time (possibly very long if the devices are big) where you don't have the protection guarantees of multiple copies of metadata chunks. After applying this patch, one can instead use the following methodology for conversion from a multi-device filesystem to a single device filesystem: 1. btrfs balance start -dconvert=single -mconvert=dup \ -sconvert=dup -f / 2. btrfs device delete / /dev/sdx This greatly reduces the chances of the operation causing data loss due to a read error during the device delete. Signed-off-by: Austin S. Hemmelgarn <ahferroin7@gmail.com> --- fs/btrfs/volumes.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html