| Message ID | cover.1639766364.git.kreijack@inwind.it (mailing list archive) |
|---|---|
| Headers | show |
| Series | btrfs: allocation_hint mode | expand |
On Fri, Dec 17, 2021 at 07:47:16PM +0100, Goffredo Baroncelli wrote: > From: Goffredo Baroncelli <kreijack@inwind.it> > > Hi all, > > This patches set was born after some discussion between me, Zygo and Josef. > Some details can be found in https://github.com/btrfs/btrfs-todo/issues/19. > > Some further information about a real use case can be found in > https://lore.kernel.org/linux-btrfs/20210116002533.GE31381@hungrycats.org/ > > Reently Shafeeq told me that he is interested too, due to the performance gain. > > In V8 revision I switched away from an ioctl API in favor of a sysfs API ( > see patch #2 and #3). > > In V9 I renamed the sysfs interface from devinfo/type to devinfo/allocation_hint. > Moreover I renamed dev_info->type to dev_info->flags. > > The idea behind this patches set, is to dedicate some disks (the fastest one) > to the metadata chunk. My initial idea was a "soft" hint. However Zygo > asked an option for a "strong" hint (== mandatory). The result is that > each disk can be "tagged" by one of the following flags: > - BTRFS_DEV_ALLOCATION_METADATA_ONLY > - BTRFS_DEV_ALLOCATION_PREFERRED_METADATA > - BTRFS_DEV_ALLOCATION_PREFERRED_DATA > - BTRFS_DEV_ALLOCATION_DATA_ONLY > > When the chunk allocator search a disks to allocate a chunk, scans the disks > in an order decided by these tags. For metadata, the order is: > *_METADATA_ONLY > *_PREFERRED_METADATA > *_PREFERRED_DATA > > The *_DATA_ONLY are not eligible from metadata chunk allocation. > > For the data chunk, the order is reversed, and the *_METADATA_ONLY are > excluded. > > The exact sort logic is to sort first for the "tag", and then for the space > available. If there is no space available, the next "tag" disks set are > selected. > > To set these tags, a new property called "allocation_hint" was created. > There is a dedicated btrfs-prog patches set [[PATCH V9] btrfs-progs: > allocation_hint disk property]. > > $ sudo mount /dev/loop0 /mnt/test-btrfs/ > $ for i in /dev/loop[0-9]; do sudo ./btrfs prop get $i allocation_hint; done > devid=1, path=/dev/loop0: allocation_hint=PREFERRED_METADATA > devid=2, path=/dev/loop1: allocation_hint=PREFERRED_METADATA > devid=3, path=/dev/loop2: allocation_hint=PREFERRED_DATA > devid=4, path=/dev/loop3: allocation_hint=PREFERRED_DATA > devid=5, path=/dev/loop4: allocation_hint=PREFERRED_DATA > devid=6, path=/dev/loop5: allocation_hint=DATA_ONLY > devid=7, path=/dev/loop6: allocation_hint=METADATA_ONLY > devid=8, path=/dev/loop7: allocation_hint=METADATA_ONLY > > $ sudo ./btrfs fi us /mnt/test-btrfs/ > Overall: > Device size: 2.75GiB > Device allocated: 1.34GiB > Device unallocated: 1.41GiB > Device missing: 0.00B > Used: 400.89MiB > Free (estimated): 1.04GiB (min: 1.04GiB) > Data ratio: 2.00 > Metadata ratio: 1.00 > Global reserve: 3.25MiB (used: 0.00B) > Multiple profiles: no > > Data,RAID1: Size:542.00MiB, Used:200.25MiB (36.95%) > /dev/loop0 288.00MiB > /dev/loop1 288.00MiB > /dev/loop2 127.00MiB > /dev/loop3 127.00MiB > /dev/loop4 127.00MiB > /dev/loop5 127.00MiB > > Metadata,single: Size:256.00MiB, Used:384.00KiB (0.15%) > /dev/loop1 256.00MiB > > System,single: Size:32.00MiB, Used:16.00KiB (0.05%) > /dev/loop0 32.00MiB > > Unallocated: > /dev/loop0 704.00MiB > /dev/loop1 480.00MiB > /dev/loop2 1.00MiB > /dev/loop3 1.00MiB > /dev/loop4 1.00MiB > /dev/loop5 1.00MiB > /dev/loop6 128.00MiB > /dev/loop7 128.00MiB > > # change the tag of some disks > > $ sudo ./btrfs prop set /dev/loop0 allocation_hint DATA_ONLY > $ sudo ./btrfs prop set /dev/loop1 allocation_hint DATA_ONLY > $ sudo ./btrfs prop set /dev/loop5 allocation_hint METADATA_ONLY > > $ for i in /dev/loop[0-9]; do sudo ./btrfs prop get $i allocation_hint; done > devid=1, path=/dev/loop0: allocation_hint=DATA_ONLY > devid=2, path=/dev/loop1: allocation_hint=DATA_ONLY > devid=3, path=/dev/loop2: allocation_hint=PREFERRED_DATA > devid=4, path=/dev/loop3: allocation_hint=PREFERRED_DATA > devid=5, path=/dev/loop4: allocation_hint=PREFERRED_DATA > devid=6, path=/dev/loop5: allocation_hint=METADATA_ONLY > devid=7, path=/dev/loop6: allocation_hint=METADATA_ONLY > devid=8, path=/dev/loop7: allocation_hint=METADATA_ONLY > > $ sudo btrfs bal start --full-balance /mnt/test-btrfs/ > $ sudo ./btrfs fi us /mnt/test-btrfs/ > Overall: > Device size: 2.75GiB > Device allocated: 735.00MiB > Device unallocated: 2.03GiB > Device missing: 0.00B > Used: 400.72MiB > Free (estimated): 1.10GiB (min: 1.10GiB) > Data ratio: 2.00 > Metadata ratio: 1.00 > Global reserve: 3.25MiB (used: 0.00B) > Multiple profiles: no > > Data,RAID1: Size:288.00MiB, Used:200.19MiB (69.51%) > /dev/loop0 288.00MiB > /dev/loop1 288.00MiB > > Metadata,single: Size:127.00MiB, Used:336.00KiB (0.26%) > /dev/loop5 127.00MiB > > System,single: Size:32.00MiB, Used:16.00KiB (0.05%) > /dev/loop7 32.00MiB > > Unallocated: > /dev/loop0 736.00MiB > /dev/loop1 736.00MiB > /dev/loop2 128.00MiB > /dev/loop3 128.00MiB > /dev/loop4 128.00MiB > /dev/loop5 1.00MiB > /dev/loop6 128.00MiB > /dev/loop7 96.00MiB > > > #As you can see all the metadata were placed on the disk loop5/loop7 even if > #the most empty one are loop0 and loop1. > > > > TODO: > - more tests > - the tool which show the space available should consider the tagging (eg > the disks tagged by _METADATA_ONLY should be excluded from the data > availability) > - allow btrfs-prog to change the allocation_hint even when the filesystem > is not mounted. > > > Comments are welcome This is cool, thanks for building it! I'm playing with setting this up for a test I'm working on where I want to send data to a dm-zero device. To that end, I applied this patchset on top of misc-next and ran: $ mkfs.btrfs -f /dev/vg0/lv0 -dsingle -msingle $ mount /dev/vg0/lv0 /mnt/lol $ btrfs device add /dev/mapper/zero-data /mnt/lol $ btrfs fi usage /mnt/lol Overall: Device size: 50.01TiB Device allocated: 20.00MiB Device unallocated: 50.01TiB Device missing: 0.00B Used: 128.00KiB Free (estimated): 50.01TiB (min: 50.01TiB) Free (statfs, df): 50.01TiB Data ratio: 1.00 Metadata ratio: 1.00 Global reserve: 3.25MiB (used: 0.00B) Multiple profiles: no Data,single: Size:8.00MiB, Used:0.00B (0.00%) /dev/mapper/vg0-lv0 8.00MiB Metadata,single: Size:8.00MiB, Used:112.00KiB (1.37%) /dev/mapper/vg0-lv0 8.00MiB System,single: Size:4.00MiB, Used:16.00KiB (0.39%) /dev/mapper/vg0-lv0 4.00MiB Unallocated: /dev/mapper/vg0-lv0 9.98GiB /dev/mapper/zero-data 50.00TiB $ ./btrfs property set -t device /dev/mapper/zero-data allocation_hint DATA_ONLY $ ./btrfs property set -t device /dev/vg0/lv0 allocation_hint METADATA_ONLY $ btrfs balance start --full-balance /mnt/lol Done, had to relocate 3 out of 3 chunks $ btrfs fi usage /mnt/lol Overall: Device size: 50.01TiB Device allocated: 2.03GiB Device unallocated: 50.01TiB Device missing: 0.00B Used: 640.00KiB Free (estimated): 50.01TiB (min: 50.01TiB) Free (statfs, df): 50.01TiB Data ratio: 1.00 Metadata ratio: 1.00 Global reserve: 3.25MiB (used: 0.00B) Multiple profiles: no Data,single: Size:1.00GiB, Used:512.00KiB (0.05%) /dev/mapper/zero-data 1.00GiB Metadata,single: Size:1.00GiB, Used:112.00KiB (0.01%) /dev/mapper/zero-data 1.00GiB System,single: Size:32.00MiB, Used:16.00KiB (0.05%) /dev/mapper/zero-data 32.00MiB Unallocated: /dev/mapper/vg0-lv0 10.00GiB /dev/mapper/zero-data 50.00TiB I expected that I would have data on /dev/mapper/zero-data and metadata on /dev/mapper/vg0-lv0, but it seems both of them were written to the zero device. Attempting to actually use the file system eventually fails, since the metadata is black-holed :) Did I make some mistake in how I used it, or is this a bug? Thanks, Boris > BR > G.Baroncelli > > Revision: > V9: > - rename dev_item->type to dev_item->flags > - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint > > V8: > - drop the ioctl API, instead use a sysfs one > > V7: > - make more room in the struct btrfs_ioctl_dev_properties up to 1K > - leave in btrfs_tree.h only the costants > - removed the mount option (sic) > - correct an 'use before check' in the while loop (signaled > by Zygo) > - add a 2nd sort to be sure that the device_info array is in the > expected order > > V6: > - add further values to the hints: add the possibility to > exclude a disk for a chunk type > > > Goffredo Baroncelli (6): > btrfs: add flags to give an hint to the chunk allocator > btrfs: export the device allocation_hint property in sysfs > btrfs: change the device allocation_hint property via sysfs > btrfs: add allocation_hint mode > btrfs: rename dev_item->type to dev_item->flags > btrfs: add allocation_hint option. > > fs/btrfs/ctree.h | 18 +++++- > fs/btrfs/disk-io.c | 4 +- > fs/btrfs/super.c | 17 ++++++ > fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ > fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- > fs/btrfs/volumes.h | 7 ++- > include/uapi/linux/btrfs_tree.h | 20 +++++- > 7 files changed, 232 insertions(+), 12 deletions(-) > > -- > 2.34.1 >
Hi Boris, On 1/5/22 03:44, Boris Burkov wrote: [...] > > This is cool, thanks for building it! > > I'm playing with setting this up for a test I'm working on where I want > to send data to a dm-zero device. To that end, I applied this patchset > on top of misc-next and ran: > > $ mkfs.btrfs -f /dev/vg0/lv0 -dsingle -msingle > $ mount /dev/vg0/lv0 /mnt/lol You should mount the filesystem with $ mount -o allocation_hint=1 /dev/vg0/lv0 /mnt/lol In the previous iteration I missed the patch #6, which activates this option. You can drop patch #6 and avoid to pass this option. Please give me a feedback if this resolve. BR G.Baroncelli > $ btrfs device add /dev/mapper/zero-data /mnt/lol > $ btrfs fi usage /mnt/lol > Overall: > Device size: 50.01TiB > Device allocated: 20.00MiB > Device unallocated: 50.01TiB > Device missing: 0.00B > Used: 128.00KiB > Free (estimated): 50.01TiB (min: 50.01TiB) > Free (statfs, df): 50.01TiB > Data ratio: 1.00 > Metadata ratio: 1.00 > Global reserve: 3.25MiB (used: 0.00B) > Multiple profiles: no > > Data,single: Size:8.00MiB, Used:0.00B (0.00%) > /dev/mapper/vg0-lv0 8.00MiB > > Metadata,single: Size:8.00MiB, Used:112.00KiB (1.37%) > /dev/mapper/vg0-lv0 8.00MiB > > System,single: Size:4.00MiB, Used:16.00KiB (0.39%) > /dev/mapper/vg0-lv0 4.00MiB > > Unallocated: > /dev/mapper/vg0-lv0 9.98GiB > /dev/mapper/zero-data 50.00TiB > > $ ./btrfs property set -t device /dev/mapper/zero-data allocation_hint DATA_ONLY > $ ./btrfs property set -t device /dev/vg0/lv0 allocation_hint METADATA_ONLY > > $ btrfs balance start --full-balance /mnt/lol > Done, had to relocate 3 out of 3 chunks > > $ btrfs fi usage /mnt/lol > Overall: > Device size: 50.01TiB > Device allocated: 2.03GiB > Device unallocated: 50.01TiB > Device missing: 0.00B > Used: 640.00KiB > Free (estimated): 50.01TiB (min: 50.01TiB) > Free (statfs, df): 50.01TiB > Data ratio: 1.00 > Metadata ratio: 1.00 > Global reserve: 3.25MiB (used: 0.00B) > Multiple profiles: no > > Data,single: Size:1.00GiB, Used:512.00KiB (0.05%) > /dev/mapper/zero-data 1.00GiB > > Metadata,single: Size:1.00GiB, Used:112.00KiB (0.01%) > /dev/mapper/zero-data 1.00GiB > > System,single: Size:32.00MiB, Used:16.00KiB (0.05%) > /dev/mapper/zero-data 32.00MiB > > Unallocated: > /dev/mapper/vg0-lv0 10.00GiB > /dev/mapper/zero-data 50.00TiB > > > I expected that I would have data on /dev/mapper/zero-data and metadata > on /dev/mapper/vg0-lv0, but it seems both of them were written to the zero > device. Attempting to actually use the file system eventually fails, since > the metadata is black-holed :) > > Did I make some mistake in how I used it, or is this a bug? > > Thanks, > Boris > >> BR >> G.Baroncelli >> >> Revision: >> V9: >> - rename dev_item->type to dev_item->flags >> - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint >> >> V8: >> - drop the ioctl API, instead use a sysfs one >> >> V7: >> - make more room in the struct btrfs_ioctl_dev_properties up to 1K >> - leave in btrfs_tree.h only the costants >> - removed the mount option (sic) >> - correct an 'use before check' in the while loop (signaled >> by Zygo) >> - add a 2nd sort to be sure that the device_info array is in the >> expected order >> >> V6: >> - add further values to the hints: add the possibility to >> exclude a disk for a chunk type >> >> >> Goffredo Baroncelli (6): >> btrfs: add flags to give an hint to the chunk allocator >> btrfs: export the device allocation_hint property in sysfs >> btrfs: change the device allocation_hint property via sysfs >> btrfs: add allocation_hint mode >> btrfs: rename dev_item->type to dev_item->flags >> btrfs: add allocation_hint option. >> >> fs/btrfs/ctree.h | 18 +++++- >> fs/btrfs/disk-io.c | 4 +- >> fs/btrfs/super.c | 17 ++++++ >> fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ >> fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- >> fs/btrfs/volumes.h | 7 ++- >> include/uapi/linux/btrfs_tree.h | 20 +++++- >> 7 files changed, 232 insertions(+), 12 deletions(-) >> >> -- >> 2.34.1 >>
On Wed, Jan 05, 2022 at 10:16:08AM +0100, Goffredo Baroncelli wrote: > Hi Boris, > > > > On 1/5/22 03:44, Boris Burkov wrote: > [...] > > > > This is cool, thanks for building it! > > > > I'm playing with setting this up for a test I'm working on where I want > > to send data to a dm-zero device. To that end, I applied this patchset > > on top of misc-next and ran: > > > > $ mkfs.btrfs -f /dev/vg0/lv0 -dsingle -msingle > > $ mount /dev/vg0/lv0 /mnt/lol > > You should mount the filesystem with > > $ mount -o allocation_hint=1 /dev/vg0/lv0 /mnt/lol > With this option, I got the expected usage output: Data,single: Size:1.00GiB, Used:512.00KiB (0.05%) /dev/mapper/zero-data 1.00GiB Metadata,single: Size:1.00GiB, Used:112.00KiB (0.01%) /dev/mapper/vg0-lv0 1.00GiB Sorry I missed that, and thanks for the quick reply. > > In the previous iteration I missed the patch #6, which activates this option. You can drop patch #6 and avoid to pass this option. > > Please give me a feedback if this resolve. > > BR > G.Baroncelli > > > $ btrfs device add /dev/mapper/zero-data /mnt/lol > > $ btrfs fi usage /mnt/lol > > Overall: > > Device size: 50.01TiB > > Device allocated: 20.00MiB > > Device unallocated: 50.01TiB > > Device missing: 0.00B > > Used: 128.00KiB > > Free (estimated): 50.01TiB (min: 50.01TiB) > > Free (statfs, df): 50.01TiB > > Data ratio: 1.00 > > Metadata ratio: 1.00 > > Global reserve: 3.25MiB (used: 0.00B) > > Multiple profiles: no > > > > Data,single: Size:8.00MiB, Used:0.00B (0.00%) > > /dev/mapper/vg0-lv0 8.00MiB > > > > Metadata,single: Size:8.00MiB, Used:112.00KiB (1.37%) > > /dev/mapper/vg0-lv0 8.00MiB > > > > System,single: Size:4.00MiB, Used:16.00KiB (0.39%) > > /dev/mapper/vg0-lv0 4.00MiB > > > > Unallocated: > > /dev/mapper/vg0-lv0 9.98GiB > > /dev/mapper/zero-data 50.00TiB > > > > $ ./btrfs property set -t device /dev/mapper/zero-data allocation_hint DATA_ONLY > > $ ./btrfs property set -t device /dev/vg0/lv0 allocation_hint METADATA_ONLY > > > > $ btrfs balance start --full-balance /mnt/lol > > Done, had to relocate 3 out of 3 chunks > > > > $ btrfs fi usage /mnt/lol > > Overall: > > Device size: 50.01TiB > > Device allocated: 2.03GiB > > Device unallocated: 50.01TiB > > Device missing: 0.00B > > Used: 640.00KiB > > Free (estimated): 50.01TiB (min: 50.01TiB) > > Free (statfs, df): 50.01TiB > > Data ratio: 1.00 > > Metadata ratio: 1.00 > > Global reserve: 3.25MiB (used: 0.00B) > > Multiple profiles: no > > > > Data,single: Size:1.00GiB, Used:512.00KiB (0.05%) > > /dev/mapper/zero-data 1.00GiB > > > > Metadata,single: Size:1.00GiB, Used:112.00KiB (0.01%) > > /dev/mapper/zero-data 1.00GiB > > > > System,single: Size:32.00MiB, Used:16.00KiB (0.05%) > > /dev/mapper/zero-data 32.00MiB > > > > Unallocated: > > /dev/mapper/vg0-lv0 10.00GiB > > /dev/mapper/zero-data 50.00TiB > > > > > > I expected that I would have data on /dev/mapper/zero-data and metadata > > on /dev/mapper/vg0-lv0, but it seems both of them were written to the zero > > device. Attempting to actually use the file system eventually fails, since > > the metadata is black-holed :) > > > > Did I make some mistake in how I used it, or is this a bug? > > > > Thanks, > > Boris > > > > > BR > > > G.Baroncelli > > > > > > Revision: > > > V9: > > > - rename dev_item->type to dev_item->flags > > > - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint > > > > > > V8: > > > - drop the ioctl API, instead use a sysfs one > > > > > > V7: > > > - make more room in the struct btrfs_ioctl_dev_properties up to 1K > > > - leave in btrfs_tree.h only the costants > > > - removed the mount option (sic) > > > - correct an 'use before check' in the while loop (signaled > > > by Zygo) > > > - add a 2nd sort to be sure that the device_info array is in the > > > expected order > > > > > > V6: > > > - add further values to the hints: add the possibility to > > > exclude a disk for a chunk type > > > > > > > > > Goffredo Baroncelli (6): > > > btrfs: add flags to give an hint to the chunk allocator > > > btrfs: export the device allocation_hint property in sysfs > > > btrfs: change the device allocation_hint property via sysfs > > > btrfs: add allocation_hint mode > > > btrfs: rename dev_item->type to dev_item->flags > > > btrfs: add allocation_hint option. > > > > > > fs/btrfs/ctree.h | 18 +++++- > > > fs/btrfs/disk-io.c | 4 +- > > > fs/btrfs/super.c | 17 ++++++ > > > fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ > > > fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- > > > fs/btrfs/volumes.h | 7 ++- > > > include/uapi/linux/btrfs_tree.h | 20 +++++- > > > 7 files changed, 232 insertions(+), 12 deletions(-) > > > > > > -- > > > 2.34.1 > > > > > > -- > gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> > Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
On Wed, Jan 05, 2022 at 10:16:08AM +0100, Goffredo Baroncelli wrote: > Hi Boris, > > > > On 1/5/22 03:44, Boris Burkov wrote: > [...] > > > > This is cool, thanks for building it! > > > > I'm playing with setting this up for a test I'm working on where I want > > to send data to a dm-zero device. To that end, I applied this patchset > > on top of misc-next and ran: > > > > $ mkfs.btrfs -f /dev/vg0/lv0 -dsingle -msingle > > $ mount /dev/vg0/lv0 /mnt/lol > > You should mount the filesystem with > > $ mount -o allocation_hint=1 /dev/vg0/lv0 /mnt/lol > > In the previous iteration I missed the patch #6, which activates this option. You can drop patch #6 and avoid to pass this option. Can we drop the mount option from the series? It isn't needed. Or, if we must have it (and I am in no way conceding that we do), at least make it default to enabled. Or turn the mount option into a disable flag under the 'rescue=' option to make it clear this option is not intended to be used in normal operation. > Please give me a feedback if this resolve. > > BR > G.Baroncelli > > > $ btrfs device add /dev/mapper/zero-data /mnt/lol > > $ btrfs fi usage /mnt/lol > > Overall: > > Device size: 50.01TiB > > Device allocated: 20.00MiB > > Device unallocated: 50.01TiB > > Device missing: 0.00B > > Used: 128.00KiB > > Free (estimated): 50.01TiB (min: 50.01TiB) > > Free (statfs, df): 50.01TiB > > Data ratio: 1.00 > > Metadata ratio: 1.00 > > Global reserve: 3.25MiB (used: 0.00B) > > Multiple profiles: no > > > > Data,single: Size:8.00MiB, Used:0.00B (0.00%) > > /dev/mapper/vg0-lv0 8.00MiB > > > > Metadata,single: Size:8.00MiB, Used:112.00KiB (1.37%) > > /dev/mapper/vg0-lv0 8.00MiB > > > > System,single: Size:4.00MiB, Used:16.00KiB (0.39%) > > /dev/mapper/vg0-lv0 4.00MiB > > > > Unallocated: > > /dev/mapper/vg0-lv0 9.98GiB > > /dev/mapper/zero-data 50.00TiB > > > > $ ./btrfs property set -t device /dev/mapper/zero-data allocation_hint DATA_ONLY > > $ ./btrfs property set -t device /dev/vg0/lv0 allocation_hint METADATA_ONLY > > > > $ btrfs balance start --full-balance /mnt/lol > > Done, had to relocate 3 out of 3 chunks > > > > $ btrfs fi usage /mnt/lol > > Overall: > > Device size: 50.01TiB > > Device allocated: 2.03GiB > > Device unallocated: 50.01TiB > > Device missing: 0.00B > > Used: 640.00KiB > > Free (estimated): 50.01TiB (min: 50.01TiB) > > Free (statfs, df): 50.01TiB > > Data ratio: 1.00 > > Metadata ratio: 1.00 > > Global reserve: 3.25MiB (used: 0.00B) > > Multiple profiles: no > > > > Data,single: Size:1.00GiB, Used:512.00KiB (0.05%) > > /dev/mapper/zero-data 1.00GiB > > > > Metadata,single: Size:1.00GiB, Used:112.00KiB (0.01%) > > /dev/mapper/zero-data 1.00GiB > > > > System,single: Size:32.00MiB, Used:16.00KiB (0.05%) > > /dev/mapper/zero-data 32.00MiB > > > > Unallocated: > > /dev/mapper/vg0-lv0 10.00GiB > > /dev/mapper/zero-data 50.00TiB > > > > > > I expected that I would have data on /dev/mapper/zero-data and metadata > > on /dev/mapper/vg0-lv0, but it seems both of them were written to the zero > > device. Attempting to actually use the file system eventually fails, since > > the metadata is black-holed :) > > > > Did I make some mistake in how I used it, or is this a bug? > > > > Thanks, > > Boris > > > > > BR > > > G.Baroncelli > > > > > > Revision: > > > V9: > > > - rename dev_item->type to dev_item->flags > > > - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint > > > > > > V8: > > > - drop the ioctl API, instead use a sysfs one > > > > > > V7: > > > - make more room in the struct btrfs_ioctl_dev_properties up to 1K > > > - leave in btrfs_tree.h only the costants > > > - removed the mount option (sic) > > > - correct an 'use before check' in the while loop (signaled > > > by Zygo) > > > - add a 2nd sort to be sure that the device_info array is in the > > > expected order > > > > > > V6: > > > - add further values to the hints: add the possibility to > > > exclude a disk for a chunk type > > > > > > > > > Goffredo Baroncelli (6): > > > btrfs: add flags to give an hint to the chunk allocator > > > btrfs: export the device allocation_hint property in sysfs > > > btrfs: change the device allocation_hint property via sysfs > > > btrfs: add allocation_hint mode > > > btrfs: rename dev_item->type to dev_item->flags > > > btrfs: add allocation_hint option. > > > > > > fs/btrfs/ctree.h | 18 +++++- > > > fs/btrfs/disk-io.c | 4 +- > > > fs/btrfs/super.c | 17 ++++++ > > > fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ > > > fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- > > > fs/btrfs/volumes.h | 7 ++- > > > include/uapi/linux/btrfs_tree.h | 20 +++++- > > > 7 files changed, 232 insertions(+), 12 deletions(-) > > > > > > -- > > > 2.34.1 > > > > > > -- > gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> > Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
On 05/01/2022 19.07, Zygo Blaxell wrote: > On Wed, Jan 05, 2022 at 10:16:08AM +0100, Goffredo Baroncelli wrote: >> Hi Boris, >> >> >> >> On 1/5/22 03:44, Boris Burkov wrote: >> [...] >>> >>> This is cool, thanks for building it! >>> >>> I'm playing with setting this up for a test I'm working on where I want >>> to send data to a dm-zero device. To that end, I applied this patchset >>> on top of misc-next and ran: >>> >>> $ mkfs.btrfs -f /dev/vg0/lv0 -dsingle -msingle >>> $ mount /dev/vg0/lv0 /mnt/lol >> >> You should mount the filesystem with >> >> $ mount -o allocation_hint=1 /dev/vg0/lv0 /mnt/lol >> >> In the previous iteration I missed the patch #6, which activates this option. You can drop patch #6 and avoid to pass this option. > > Can we drop the mount option from the series? It isn't needed. > > Or, if we must have it (and I am in no way conceding that we do), > at least make it default to enabled. Or turn the mount option into a > disable flag under the 'rescue=' option to make it clear this option is > not intended to be used in normal operation. Frankly speaking it was a my mistake to add this patch. It was in the queue, but in the last patches sets I dropped it. However in the last one I forgot to drop it manually so it reappeared :-) However I like your suggestion to add as 'rescue' option, where the default is "enabled". @Josef, do you started to play with this patch ? If not can I send an update where the main change is the renaming of the properties from PREFERRED_<X> to <X>_PREFERRED (e.g. PREFERRED_DATA to DATA_PREFERRED) which are more correct ? BR G.Baroncelli > >> Please give me a feedback if this resolve. >> >> BR >> G.Baroncelli >> >>> $ btrfs device add /dev/mapper/zero-data /mnt/lol >>> $ btrfs fi usage /mnt/lol >>> Overall: >>> Device size: 50.01TiB >>> Device allocated: 20.00MiB >>> Device unallocated: 50.01TiB >>> Device missing: 0.00B >>> Used: 128.00KiB >>> Free (estimated): 50.01TiB (min: 50.01TiB) >>> Free (statfs, df): 50.01TiB >>> Data ratio: 1.00 >>> Metadata ratio: 1.00 >>> Global reserve: 3.25MiB (used: 0.00B) >>> Multiple profiles: no >>> >>> Data,single: Size:8.00MiB, Used:0.00B (0.00%) >>> /dev/mapper/vg0-lv0 8.00MiB >>> >>> Metadata,single: Size:8.00MiB, Used:112.00KiB (1.37%) >>> /dev/mapper/vg0-lv0 8.00MiB >>> >>> System,single: Size:4.00MiB, Used:16.00KiB (0.39%) >>> /dev/mapper/vg0-lv0 4.00MiB >>> >>> Unallocated: >>> /dev/mapper/vg0-lv0 9.98GiB >>> /dev/mapper/zero-data 50.00TiB >>> >>> $ ./btrfs property set -t device /dev/mapper/zero-data allocation_hint DATA_ONLY >>> $ ./btrfs property set -t device /dev/vg0/lv0 allocation_hint METADATA_ONLY >>> >>> $ btrfs balance start --full-balance /mnt/lol >>> Done, had to relocate 3 out of 3 chunks >>> >>> $ btrfs fi usage /mnt/lol >>> Overall: >>> Device size: 50.01TiB >>> Device allocated: 2.03GiB >>> Device unallocated: 50.01TiB >>> Device missing: 0.00B >>> Used: 640.00KiB >>> Free (estimated): 50.01TiB (min: 50.01TiB) >>> Free (statfs, df): 50.01TiB >>> Data ratio: 1.00 >>> Metadata ratio: 1.00 >>> Global reserve: 3.25MiB (used: 0.00B) >>> Multiple profiles: no >>> >>> Data,single: Size:1.00GiB, Used:512.00KiB (0.05%) >>> /dev/mapper/zero-data 1.00GiB >>> >>> Metadata,single: Size:1.00GiB, Used:112.00KiB (0.01%) >>> /dev/mapper/zero-data 1.00GiB >>> >>> System,single: Size:32.00MiB, Used:16.00KiB (0.05%) >>> /dev/mapper/zero-data 32.00MiB >>> >>> Unallocated: >>> /dev/mapper/vg0-lv0 10.00GiB >>> /dev/mapper/zero-data 50.00TiB >>> >>> >>> I expected that I would have data on /dev/mapper/zero-data and metadata >>> on /dev/mapper/vg0-lv0, but it seems both of them were written to the zero >>> device. Attempting to actually use the file system eventually fails, since >>> the metadata is black-holed :) >>> >>> Did I make some mistake in how I used it, or is this a bug? >>> >>> Thanks, >>> Boris >>> >>>> BR >>>> G.Baroncelli >>>> >>>> Revision: >>>> V9: >>>> - rename dev_item->type to dev_item->flags >>>> - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint >>>> >>>> V8: >>>> - drop the ioctl API, instead use a sysfs one >>>> >>>> V7: >>>> - make more room in the struct btrfs_ioctl_dev_properties up to 1K >>>> - leave in btrfs_tree.h only the costants >>>> - removed the mount option (sic) >>>> - correct an 'use before check' in the while loop (signaled >>>> by Zygo) >>>> - add a 2nd sort to be sure that the device_info array is in the >>>> expected order >>>> >>>> V6: >>>> - add further values to the hints: add the possibility to >>>> exclude a disk for a chunk type >>>> >>>> >>>> Goffredo Baroncelli (6): >>>> btrfs: add flags to give an hint to the chunk allocator >>>> btrfs: export the device allocation_hint property in sysfs >>>> btrfs: change the device allocation_hint property via sysfs >>>> btrfs: add allocation_hint mode >>>> btrfs: rename dev_item->type to dev_item->flags >>>> btrfs: add allocation_hint option. >>>> >>>> fs/btrfs/ctree.h | 18 +++++- >>>> fs/btrfs/disk-io.c | 4 +- >>>> fs/btrfs/super.c | 17 ++++++ >>>> fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ >>>> fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- >>>> fs/btrfs/volumes.h | 7 ++- >>>> include/uapi/linux/btrfs_tree.h | 20 +++++- >>>> 7 files changed, 232 insertions(+), 12 deletions(-) >>>> >>>> -- >>>> 2.34.1 >>>> >> >> >> -- >> gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> >> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
On Wed, Jan 05, 2022 at 07:16:04PM +0100, Goffredo Baroncelli wrote: > On 05/01/2022 19.07, Zygo Blaxell wrote: > > On Wed, Jan 05, 2022 at 10:16:08AM +0100, Goffredo Baroncelli wrote: > > > Hi Boris, > > > > > > > > > > > > On 1/5/22 03:44, Boris Burkov wrote: > > > [...] > > > > > > > > This is cool, thanks for building it! > > > > > > > > I'm playing with setting this up for a test I'm working on where I want > > > > to send data to a dm-zero device. To that end, I applied this patchset > > > > on top of misc-next and ran: > > > > > > > > $ mkfs.btrfs -f /dev/vg0/lv0 -dsingle -msingle > > > > $ mount /dev/vg0/lv0 /mnt/lol > > > > > > You should mount the filesystem with > > > > > > $ mount -o allocation_hint=1 /dev/vg0/lv0 /mnt/lol > > > > > > In the previous iteration I missed the patch #6, which activates this option. You can drop patch #6 and avoid to pass this option. > > > > Can we drop the mount option from the series? It isn't needed. > > > > Or, if we must have it (and I am in no way conceding that we do), > > at least make it default to enabled. Or turn the mount option into a > > disable flag under the 'rescue=' option to make it clear this option is > > not intended to be used in normal operation. > > Frankly speaking it was a my mistake to add this patch. It was in the > queue, but in the last patches sets I dropped it. However in the last > one I forgot to drop it manually so it reappeared :-) > > However I like your suggestion to add as 'rescue' option, where the > default is "enabled". A mount option adds a lot of testing burden: enabling it where it was disabled disabling it where it was enabled does the above work on remount does it always print what's expected in /proc/mounts etc.. So I think it should have a strong justification for adding it, and the xfstests will need to reflect the above. Unless it's the best way to support some otherwise impossible recovery for a realistic failure mode, I would personally suggest just skipping it. However, I only skimmed through the discussion about recovery in the older thread, FWIW. > > @Josef, > do you started to play with this patch ? If not can I send an update > where the main change is the renaming of the properties from > > PREFERRED_<X> to <X>_PREFERRED > > (e.g. PREFERRED_DATA to DATA_PREFERRED) which are more correct ? > > BR > G.Baroncelli > > > > > Please give me a feedback if this resolve. > > > > > > BR > > > G.Baroncelli > > > > > > > $ btrfs device add /dev/mapper/zero-data /mnt/lol > > > > $ btrfs fi usage /mnt/lol > > > > Overall: > > > > Device size: 50.01TiB > > > > Device allocated: 20.00MiB > > > > Device unallocated: 50.01TiB > > > > Device missing: 0.00B > > > > Used: 128.00KiB > > > > Free (estimated): 50.01TiB (min: 50.01TiB) > > > > Free (statfs, df): 50.01TiB > > > > Data ratio: 1.00 > > > > Metadata ratio: 1.00 > > > > Global reserve: 3.25MiB (used: 0.00B) > > > > Multiple profiles: no > > > > > > > > Data,single: Size:8.00MiB, Used:0.00B (0.00%) > > > > /dev/mapper/vg0-lv0 8.00MiB > > > > > > > > Metadata,single: Size:8.00MiB, Used:112.00KiB (1.37%) > > > > /dev/mapper/vg0-lv0 8.00MiB > > > > > > > > System,single: Size:4.00MiB, Used:16.00KiB (0.39%) > > > > /dev/mapper/vg0-lv0 4.00MiB > > > > > > > > Unallocated: > > > > /dev/mapper/vg0-lv0 9.98GiB > > > > /dev/mapper/zero-data 50.00TiB > > > > > > > > $ ./btrfs property set -t device /dev/mapper/zero-data allocation_hint DATA_ONLY > > > > $ ./btrfs property set -t device /dev/vg0/lv0 allocation_hint METADATA_ONLY > > > > > > > > $ btrfs balance start --full-balance /mnt/lol > > > > Done, had to relocate 3 out of 3 chunks > > > > > > > > $ btrfs fi usage /mnt/lol > > > > Overall: > > > > Device size: 50.01TiB > > > > Device allocated: 2.03GiB > > > > Device unallocated: 50.01TiB > > > > Device missing: 0.00B > > > > Used: 640.00KiB > > > > Free (estimated): 50.01TiB (min: 50.01TiB) > > > > Free (statfs, df): 50.01TiB > > > > Data ratio: 1.00 > > > > Metadata ratio: 1.00 > > > > Global reserve: 3.25MiB (used: 0.00B) > > > > Multiple profiles: no > > > > > > > > Data,single: Size:1.00GiB, Used:512.00KiB (0.05%) > > > > /dev/mapper/zero-data 1.00GiB > > > > > > > > Metadata,single: Size:1.00GiB, Used:112.00KiB (0.01%) > > > > /dev/mapper/zero-data 1.00GiB > > > > > > > > System,single: Size:32.00MiB, Used:16.00KiB (0.05%) > > > > /dev/mapper/zero-data 32.00MiB > > > > > > > > Unallocated: > > > > /dev/mapper/vg0-lv0 10.00GiB > > > > /dev/mapper/zero-data 50.00TiB > > > > > > > > > > > > I expected that I would have data on /dev/mapper/zero-data and metadata > > > > on /dev/mapper/vg0-lv0, but it seems both of them were written to the zero > > > > device. Attempting to actually use the file system eventually fails, since > > > > the metadata is black-holed :) > > > > > > > > Did I make some mistake in how I used it, or is this a bug? > > > > > > > > Thanks, > > > > Boris > > > > > > > > > BR > > > > > G.Baroncelli > > > > > > > > > > Revision: > > > > > V9: > > > > > - rename dev_item->type to dev_item->flags > > > > > - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint > > > > > > > > > > V8: > > > > > - drop the ioctl API, instead use a sysfs one > > > > > > > > > > V7: > > > > > - make more room in the struct btrfs_ioctl_dev_properties up to 1K > > > > > - leave in btrfs_tree.h only the costants > > > > > - removed the mount option (sic) > > > > > - correct an 'use before check' in the while loop (signaled > > > > > by Zygo) > > > > > - add a 2nd sort to be sure that the device_info array is in the > > > > > expected order > > > > > > > > > > V6: > > > > > - add further values to the hints: add the possibility to > > > > > exclude a disk for a chunk type > > > > > > > > > > > > > > > Goffredo Baroncelli (6): > > > > > btrfs: add flags to give an hint to the chunk allocator > > > > > btrfs: export the device allocation_hint property in sysfs > > > > > btrfs: change the device allocation_hint property via sysfs > > > > > btrfs: add allocation_hint mode > > > > > btrfs: rename dev_item->type to dev_item->flags > > > > > btrfs: add allocation_hint option. > > > > > > > > > > fs/btrfs/ctree.h | 18 +++++- > > > > > fs/btrfs/disk-io.c | 4 +- > > > > > fs/btrfs/super.c | 17 ++++++ > > > > > fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ > > > > > fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- > > > > > fs/btrfs/volumes.h | 7 ++- > > > > > include/uapi/linux/btrfs_tree.h | 20 +++++- > > > > > 7 files changed, 232 insertions(+), 12 deletions(-) > > > > > > > > > > -- > > > > > 2.34.1 > > > > > > > > > > > > > > -- > > > gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> > > > Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 > > > -- > gpg @keyserver.linux.it: Goffredo Baroncelli <kreijackATinwind.it> > Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5
I noticed this patchset still suffers from some checkpatch failures with stuff like spaces around parens and minus signs, tabs vs spaces, etc. We generally try to keep checkpatch happy in btrfs, though of course reason should always prevail. FWIW, I have it rebased on kdave/misc-next and ran: checkpatch.pl -g kdave/misc-next..
From: Goffredo Baroncelli <kreijack@inwind.it> Hi all, This patches set was born after some discussion between me, Zygo and Josef. Some details can be found in https://github.com/btrfs/btrfs-todo/issues/19. Some further information about a real use case can be found in https://lore.kernel.org/linux-btrfs/20210116002533.GE31381@hungrycats.org/ Reently Shafeeq told me that he is interested too, due to the performance gain. In V8 revision I switched away from an ioctl API in favor of a sysfs API ( see patch #2 and #3). In V9 I renamed the sysfs interface from devinfo/type to devinfo/allocation_hint. Moreover I renamed dev_info->type to dev_info->flags. The idea behind this patches set, is to dedicate some disks (the fastest one) to the metadata chunk. My initial idea was a "soft" hint. However Zygo asked an option for a "strong" hint (== mandatory). The result is that each disk can be "tagged" by one of the following flags: - BTRFS_DEV_ALLOCATION_METADATA_ONLY - BTRFS_DEV_ALLOCATION_PREFERRED_METADATA - BTRFS_DEV_ALLOCATION_PREFERRED_DATA - BTRFS_DEV_ALLOCATION_DATA_ONLY When the chunk allocator search a disks to allocate a chunk, scans the disks in an order decided by these tags. For metadata, the order is: *_METADATA_ONLY *_PREFERRED_METADATA *_PREFERRED_DATA The *_DATA_ONLY are not eligible from metadata chunk allocation. For the data chunk, the order is reversed, and the *_METADATA_ONLY are excluded. The exact sort logic is to sort first for the "tag", and then for the space available. If there is no space available, the next "tag" disks set are selected. To set these tags, a new property called "allocation_hint" was created. There is a dedicated btrfs-prog patches set [[PATCH V9] btrfs-progs: allocation_hint disk property]. $ sudo mount /dev/loop0 /mnt/test-btrfs/ $ for i in /dev/loop[0-9]; do sudo ./btrfs prop get $i allocation_hint; done devid=1, path=/dev/loop0: allocation_hint=PREFERRED_METADATA devid=2, path=/dev/loop1: allocation_hint=PREFERRED_METADATA devid=3, path=/dev/loop2: allocation_hint=PREFERRED_DATA devid=4, path=/dev/loop3: allocation_hint=PREFERRED_DATA devid=5, path=/dev/loop4: allocation_hint=PREFERRED_DATA devid=6, path=/dev/loop5: allocation_hint=DATA_ONLY devid=7, path=/dev/loop6: allocation_hint=METADATA_ONLY devid=8, path=/dev/loop7: allocation_hint=METADATA_ONLY $ sudo ./btrfs fi us /mnt/test-btrfs/ Overall: Device size: 2.75GiB Device allocated: 1.34GiB Device unallocated: 1.41GiB Device missing: 0.00B Used: 400.89MiB Free (estimated): 1.04GiB (min: 1.04GiB) Data ratio: 2.00 Metadata ratio: 1.00 Global reserve: 3.25MiB (used: 0.00B) Multiple profiles: no Data,RAID1: Size:542.00MiB, Used:200.25MiB (36.95%) /dev/loop0 288.00MiB /dev/loop1 288.00MiB /dev/loop2 127.00MiB /dev/loop3 127.00MiB /dev/loop4 127.00MiB /dev/loop5 127.00MiB Metadata,single: Size:256.00MiB, Used:384.00KiB (0.15%) /dev/loop1 256.00MiB System,single: Size:32.00MiB, Used:16.00KiB (0.05%) /dev/loop0 32.00MiB Unallocated: /dev/loop0 704.00MiB /dev/loop1 480.00MiB /dev/loop2 1.00MiB /dev/loop3 1.00MiB /dev/loop4 1.00MiB /dev/loop5 1.00MiB /dev/loop6 128.00MiB /dev/loop7 128.00MiB # change the tag of some disks $ sudo ./btrfs prop set /dev/loop0 allocation_hint DATA_ONLY $ sudo ./btrfs prop set /dev/loop1 allocation_hint DATA_ONLY $ sudo ./btrfs prop set /dev/loop5 allocation_hint METADATA_ONLY $ for i in /dev/loop[0-9]; do sudo ./btrfs prop get $i allocation_hint; done devid=1, path=/dev/loop0: allocation_hint=DATA_ONLY devid=2, path=/dev/loop1: allocation_hint=DATA_ONLY devid=3, path=/dev/loop2: allocation_hint=PREFERRED_DATA devid=4, path=/dev/loop3: allocation_hint=PREFERRED_DATA devid=5, path=/dev/loop4: allocation_hint=PREFERRED_DATA devid=6, path=/dev/loop5: allocation_hint=METADATA_ONLY devid=7, path=/dev/loop6: allocation_hint=METADATA_ONLY devid=8, path=/dev/loop7: allocation_hint=METADATA_ONLY $ sudo btrfs bal start --full-balance /mnt/test-btrfs/ $ sudo ./btrfs fi us /mnt/test-btrfs/ Overall: Device size: 2.75GiB Device allocated: 735.00MiB Device unallocated: 2.03GiB Device missing: 0.00B Used: 400.72MiB Free (estimated): 1.10GiB (min: 1.10GiB) Data ratio: 2.00 Metadata ratio: 1.00 Global reserve: 3.25MiB (used: 0.00B) Multiple profiles: no Data,RAID1: Size:288.00MiB, Used:200.19MiB (69.51%) /dev/loop0 288.00MiB /dev/loop1 288.00MiB Metadata,single: Size:127.00MiB, Used:336.00KiB (0.26%) /dev/loop5 127.00MiB System,single: Size:32.00MiB, Used:16.00KiB (0.05%) /dev/loop7 32.00MiB Unallocated: /dev/loop0 736.00MiB /dev/loop1 736.00MiB /dev/loop2 128.00MiB /dev/loop3 128.00MiB /dev/loop4 128.00MiB /dev/loop5 1.00MiB /dev/loop6 128.00MiB /dev/loop7 96.00MiB #As you can see all the metadata were placed on the disk loop5/loop7 even if #the most empty one are loop0 and loop1. TODO: - more tests - the tool which show the space available should consider the tagging (eg the disks tagged by _METADATA_ONLY should be excluded from the data availability) - allow btrfs-prog to change the allocation_hint even when the filesystem is not mounted. Comments are welcome BR G.Baroncelli Revision: V9: - rename dev_item->type to dev_item->flags - rename /sys/fs/btrfs/$UUID/devinfo/type -> allocation_hint V8: - drop the ioctl API, instead use a sysfs one V7: - make more room in the struct btrfs_ioctl_dev_properties up to 1K - leave in btrfs_tree.h only the costants - removed the mount option (sic) - correct an 'use before check' in the while loop (signaled by Zygo) - add a 2nd sort to be sure that the device_info array is in the expected order V6: - add further values to the hints: add the possibility to exclude a disk for a chunk type Goffredo Baroncelli (6): btrfs: add flags to give an hint to the chunk allocator btrfs: export the device allocation_hint property in sysfs btrfs: change the device allocation_hint property via sysfs btrfs: add allocation_hint mode btrfs: rename dev_item->type to dev_item->flags btrfs: add allocation_hint option. fs/btrfs/ctree.h | 18 +++++- fs/btrfs/disk-io.c | 4 +- fs/btrfs/super.c | 17 ++++++ fs/btrfs/sysfs.c | 73 ++++++++++++++++++++++ fs/btrfs/volumes.c | 105 ++++++++++++++++++++++++++++++-- fs/btrfs/volumes.h | 7 ++- include/uapi/linux/btrfs_tree.h | 20 +++++- 7 files changed, 232 insertions(+), 12 deletions(-)