Tree manipulating operations like merging nodes often release
once-allocated tree nodes. Btrfs cleans such nodes so that pages in the
node are not uselessly written out. On ZONED drives, however, such
optimization blocks the following IOs as the cancellation of the write
out of the freed blocks breaks the sequential write sequence expected by
the device.
Check if next dirty extent buffer is continuous to a previously written
one. If not, it redirty extent buffers between the previous one and the
next one, so that all dirty buffers are written sequentially.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A zoned filesystem must allocate blocks at the zones' write pointer. The
device's write pointer position can be mapped to a logical address
within a block group. To facilitate this, add an "alloc_offset" to the
block group to track the logical addresses of the write pointer.
This logical address is populated in btrfs_load_block_group_zone_info()
from the write pointers of corresponding zones.
For now, zoned filesystems the single profile. Supporting non-single
profile with zone append writing is not trivial. For example, in the DUP
profile, we send a zone append writing IO to two zones on a device. The
device reply with written LBAs for the IOs. If the offsets of the
returned addresses from the beginning of the zone are different, then it
results in different logical addresses.
We need fine-grained logical to physical mapping to support such
separated physical address issue. Since it should require additional
metadata type, disable non-single profiles for now.
This commit supports the case all the zones in a block group are
sequential. The next patch will handle the case having a conventional
zone.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The zone append write command has a maximum IO size restriction it
accepts. This is because a zone append write command cannot be split, as
we ask the device to place the data into a specific target zone and the
device responds with the actual written location of the data.
Introduce max_zone_append_size to zone_info and fs_info to track the
value, so we can limit all I/O to a zoned block device that we want to
write using the zone append command to the device's limits.
Zone append command is mandatory for zoned btrfs. So, reject a device
with max_zone_append_size == 0.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Introduce function btrfs_check_zoned_mode() to check if ZONED flag is
enabled on the file system and if the file system consists of zoned
devices with equal zone size.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With the zoned feature enabled, a zoned block device-aware btrfs
allocates block groups aligned to the device zones and always written in
sequential zones at the zone write pointer position.
It also supports "emulated" zoned mode on a non-zoned device. In the
emulated mode, btrfs emulates conventional zones by slicing the device
into fixed-size zones.
We don't support conversion from the ext4 volume with the zoned feature
because we can't be sure all the converted block groups are aligned to
zone boundaries.
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This function exists in kernel side but using the _item suffix, and
objectid argument is placed before the name argument. Change the
function to reflect the kernel version.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
