On 23/08/2019 12:10, Naohiro Aota wrote:
> HMZONED mode cannot be used together with the RAID5/6 profile for now.
> Introduce the function btrfs_check_hmzoned_mode() to check this. This
> function will also check if HMZONED flag is enabled on the file system and
> if the file system consists of zoned devices with equal zone size.
>
> Additionally, as updates to the space cache are in-place, the space cache
> cannot be located over sequential zones and there is no guarantees that the
> device will have enough conventional zones to store this cache. Resolve
> this problem by disabling completely the space cache. This does not
completely disabling ~^
> introduces any problems with sequential block groups: all the free space is
introduce ~^
> located after the allocation pointer and no free space before the pointer.
is located? ~^
> There is no need to have such cache.
>
> For the same reason, NODATACOW is also disabled.
>
> Also INODE_MAP_CACHE is also disabled to avoid preallocation in the
> INODE_MAP_CACHE inode.
>
> In summary, HMZONED will disable:
>
> | Disabled features | Reason |
> |-------------------+-----------------------------------------------------|
> | RAID5/6 | 1) Non-full stripe write cause overwriting of |
> | | parity block |
> | | 2) Rebuilding on high capacity volume (usually with |
> | | SMR) can lead to higher failure rate |
> |-------------------+-----------------------------------------------------|
> | space_cache (v1) | In-place updating |
> | NODATACOW | In-place updating |
> |-------------------+-----------------------------------------------------|
> | tree-log | Partial write out of metadata creates write holes |
> |-------------------+-----------------------------------------------------|
> | fallocate | Reserved extent will be a write hole |
> | INODE_MAP_CACHE | Need pre-allocation. (and will be deprecated?) |
> |-------------------+-----------------------------------------------------|
> | MIXED_BG | Allocated metadata region will be write holes for |
> | | data writes |
> | async checksum | Not to mix up bios by multiple workers |
>
> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
> Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
> ---
> fs/btrfs/ctree.h | 3 ++
> fs/btrfs/dev-replace.c | 8 +++++
> fs/btrfs/disk-io.c | 8 +++++
> fs/btrfs/hmzoned.c | 67 ++++++++++++++++++++++++++++++++++++++++++
> fs/btrfs/hmzoned.h | 18 ++++++++++++
> fs/btrfs/super.c | 1 +
> fs/btrfs/volumes.c | 5 ++++
> 7 files changed, 110 insertions(+)
>
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 94660063a162..221259737703 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -712,6 +712,9 @@ struct btrfs_fs_info {
> struct btrfs_root *uuid_root;
> struct btrfs_root *free_space_root;
>
> + /* Zone size when in HMZONED mode */
> + u64 zone_size;
> +
> /* the log root tree is a directory of all the other log roots */
> struct btrfs_root *log_root_tree;
>
> diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
> index 6b2e9aa83ffa..2cc3ac4d101d 100644
> --- a/fs/btrfs/dev-replace.c
> +++ b/fs/btrfs/dev-replace.c
> @@ -20,6 +20,7 @@
> #include "rcu-string.h"
> #include "dev-replace.h"
> #include "sysfs.h"
> +#include "hmzoned.h"
>
> static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
> int scrub_ret);
> @@ -201,6 +202,13 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
> return PTR_ERR(bdev);
> }
>
> + if (!btrfs_check_device_zone_type(fs_info, bdev)) {
> + btrfs_err(fs_info,
> + "zone type of target device mismatch with the filesystem!");
> + ret = -EINVAL;
> + goto error;
> + }
> +
> sync_blockdev(bdev);
>
> devices = &fs_info->fs_devices->devices;
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 97beb351a10c..3f5ea92f546c 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -40,6 +40,7 @@
> #include "compression.h"
> #include "tree-checker.h"
> #include "ref-verify.h"
> +#include "hmzoned.h"
>
> #define BTRFS_SUPER_FLAG_SUPP (BTRFS_HEADER_FLAG_WRITTEN |\
> BTRFS_HEADER_FLAG_RELOC |\
> @@ -3121,6 +3122,13 @@ int open_ctree(struct super_block *sb,
>
> btrfs_free_extra_devids(fs_devices, 1);
>
> + ret = btrfs_check_hmzoned_mode(fs_info);
> + if (ret) {
> + btrfs_err(fs_info, "failed to init hmzoned mode: %d",
> + ret);
> + goto fail_block_groups;
> + }
> +
> ret = btrfs_sysfs_add_fsid(fs_devices, NULL);
> if (ret) {
> btrfs_err(fs_info, "failed to init sysfs fsid interface: %d",
> diff --git a/fs/btrfs/hmzoned.c b/fs/btrfs/hmzoned.c
> index 23bf58d3d7bb..ca58eee08a70 100644
> --- a/fs/btrfs/hmzoned.c
> +++ b/fs/btrfs/hmzoned.c
> @@ -157,3 +157,70 @@ int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
>
> return 0;
> }
> +
> +int btrfs_check_hmzoned_mode(struct btrfs_fs_info *fs_info)
> +{
> + struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
> + struct btrfs_device *device;
> + u64 hmzoned_devices = 0;
> + u64 nr_devices = 0;
> + u64 zone_size = 0;
> + int incompat_hmzoned = btrfs_fs_incompat(fs_info, HMZONED);
> + int ret = 0;
> +
> + /* Count zoned devices */
> + list_for_each_entry(device, &fs_devices->devices, dev_list) {
> + if (!device->bdev)
> + continue;
> + if (bdev_zoned_model(device->bdev) == BLK_ZONED_HM ||
> + (bdev_zoned_model(device->bdev) == BLK_ZONED_HA &&
> + incompat_hmzoned)) {
> + hmzoned_devices++;
> + if (!zone_size) {
> + zone_size = device->zone_info->zone_size;
> + } else if (device->zone_info->zone_size != zone_size) {
> + btrfs_err(fs_info,
> + "Zoned block devices must have equal zone sizes");
> + ret = -EINVAL;
> + goto out;
> + }
> + }
> + nr_devices++;
> + }
> +
> + if (!hmzoned_devices && incompat_hmzoned) {
> + /* No zoned block device found on HMZONED FS */
> + btrfs_err(fs_info, "HMZONED enabled file system should have zoned devices");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + if (!hmzoned_devices && !incompat_hmzoned)
> + goto out;
> +
> + fs_info->zone_size = zone_size;
> +
> + if (hmzoned_devices != nr_devices) {
> + btrfs_err(fs_info,
> + "zoned devices cannot be mixed with regular devices");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + /*
> + * stripe_size is always aligned to BTRFS_STRIPE_LEN in
> + * __btrfs_alloc_chunk(). Since we want stripe_len == zone_size,
> + * check the alignment here.
> + */
> + if (!IS_ALIGNED(zone_size, BTRFS_STRIPE_LEN)) {
> + btrfs_err(fs_info,
> + "zone size is not aligned to BTRFS_STRIPE_LEN");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + btrfs_info(fs_info, "HMZONED mode enabled, zone size %llu B",
> + fs_info->zone_size);
> +out:
> + return ret;
> +}
> diff --git a/fs/btrfs/hmzoned.h b/fs/btrfs/hmzoned.h
> index ffc70842135e..29cfdcabff2f 100644
> --- a/fs/btrfs/hmzoned.h
> +++ b/fs/btrfs/hmzoned.h
> @@ -9,6 +9,8 @@
> #ifndef BTRFS_HMZONED_H
> #define BTRFS_HMZONED_H
>
> +#include <linux/blkdev.h>
> +
> struct btrfs_zoned_device_info {
> /*
> * Number of zones, zone size and types of zones if bdev is a
> @@ -25,6 +27,7 @@ int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
> struct blk_zone *zone, gfp_t gfp_mask);
> int btrfs_get_dev_zone_info(struct btrfs_device *device);
> void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
> +int btrfs_check_hmzoned_mode(struct btrfs_fs_info *fs_info);
While we're at it, shouldn't all the functions in hmzoned.[ch] have a
!CONFIG_BLK_DEV_ZONED compat wrapper and hmzoned.o is dependent on
CONFIG_BLK_DEV_ZONED?
--
Johannes Thumshirn SUSE Labs Filesystems
jthumshirn@xxxxxxx +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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HRB 21284 (AG Nürnberg)
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