From: Goffredo Baroncelli <kreijack@xxxxxxxxx>
When this mode is enabled, the allocation policy of the chunk
is so modified:
- allocation of metadata chunk: priority is given to preferred_metadata
disks.
- allocation of data chunk: priority is given to a non preferred_metadata
disk.
When a striped profile is involved (like RAID0,5,6), the logic
is a bit more complex. If there are enough disks, the data profiles
are stored on the non preferred_metadata disks; instead the metadata
profiles are stored on the preferred_metadata disk.
If the disks are not enough, then the profile is allocated on all
the disks.
Example: assuming that sda, sdb, sdc are ssd disks, and sde, sdf are
non preferred_metadata ones.
A data profile raid6, will be stored on sda, sdb, sdc, sde, sdf (sde
and sdf are not enough to host a raid5 profile).
A metadata profile raid6, will be stored on sda, sdb, sdc (these
are enough to host a raid6 profile).
To enable this mode pass -o dedicated_metadata at mount time.
Signed-off-by: Goffredo Baroncelli <kreijack@xxxxxxxxx>
---
fs/btrfs/ctree.h | 1 +
fs/btrfs/super.c | 8 +++++
fs/btrfs/volumes.c | 89 ++++++++++++++++++++++++++++++++++++++++++++--
fs/btrfs/volumes.h | 1 +
4 files changed, 97 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 03ea7370aea7..779760fd27b1 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1239,6 +1239,7 @@ static inline u32 BTRFS_MAX_XATTR_SIZE(const struct btrfs_fs_info *info)
#define BTRFS_MOUNT_NOLOGREPLAY (1 << 27)
#define BTRFS_MOUNT_REF_VERIFY (1 << 28)
#define BTRFS_MOUNT_DISCARD_ASYNC (1 << 29)
+#define BTRFS_MOUNT_PREFERRED_METADATA (1 << 30)
#define BTRFS_DEFAULT_COMMIT_INTERVAL (30)
#define BTRFS_DEFAULT_MAX_INLINE (2048)
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 438ecba26557..80700dc9dcf8 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -359,6 +359,7 @@ enum {
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
Opt_ref_verify,
#endif
+ Opt_preferred_metadata,
Opt_err,
};
@@ -430,6 +431,7 @@ static const match_table_t tokens = {
#ifdef CONFIG_BTRFS_FS_REF_VERIFY
{Opt_ref_verify, "ref_verify"},
#endif
+ {Opt_preferred_metadata, "preferred_metadata"},
{Opt_err, NULL},
};
@@ -881,6 +883,10 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
btrfs_set_opt(info->mount_opt, REF_VERIFY);
break;
#endif
+ case Opt_preferred_metadata:
+ btrfs_set_and_info(info, PREFERRED_METADATA,
+ "enabling preferred_metadata");
+ break;
case Opt_err:
btrfs_err(info, "unrecognized mount option '%s'", p);
ret = -EINVAL;
@@ -1403,6 +1409,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
#endif
if (btrfs_test_opt(info, REF_VERIFY))
seq_puts(seq, ",ref_verify");
+ if (btrfs_test_opt(info, PREFERRED_METADATA))
+ seq_puts(seq, ",preferred_metadata");
seq_printf(seq, ",subvolid=%llu",
BTRFS_I(d_inode(dentry))->root->root_key.objectid);
seq_puts(seq, ",subvol=");
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 5265f54c2931..c68efb15e473 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4770,6 +4770,56 @@ static int btrfs_cmp_device_info(const void *a, const void *b)
return 0;
}
+/*
+ * sort the devices in descending order by preferred_metadata,
+ * max_avail, total_avail
+ */
+static int btrfs_cmp_device_info_metadata(const void *a, const void *b)
+{
+ const struct btrfs_device_info *di_a = a;
+ const struct btrfs_device_info *di_b = b;
+
+ /* metadata -> preferred_metadata first */
+ if (di_a->preferred_metadata && !di_b->preferred_metadata)
+ return -1;
+ if (!di_a->preferred_metadata && di_b->preferred_metadata)
+ return 1;
+ if (di_a->max_avail > di_b->max_avail)
+ return -1;
+ if (di_a->max_avail < di_b->max_avail)
+ return 1;
+ if (di_a->total_avail > di_b->total_avail)
+ return -1;
+ if (di_a->total_avail < di_b->total_avail)
+ return 1;
+ return 0;
+}
+
+/*
+ * sort the devices in descending order by !preferred_metadata,
+ * max_avail, total_avail
+ */
+static int btrfs_cmp_device_info_data(const void *a, const void *b)
+{
+ const struct btrfs_device_info *di_a = a;
+ const struct btrfs_device_info *di_b = b;
+
+ /* data -> preferred_metadata last */
+ if (di_a->preferred_metadata && !di_b->preferred_metadata)
+ return 1;
+ if (!di_a->preferred_metadata && di_b->preferred_metadata)
+ return -1;
+ if (di_a->max_avail > di_b->max_avail)
+ return -1;
+ if (di_a->max_avail < di_b->max_avail)
+ return 1;
+ if (di_a->total_avail > di_b->total_avail)
+ return -1;
+ if (di_a->total_avail < di_b->total_avail)
+ return 1;
+ return 0;
+}
+
static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
{
if (!(type & BTRFS_BLOCK_GROUP_RAID56_MASK))
@@ -4885,6 +4935,7 @@ static int gather_device_info(struct btrfs_fs_devices *fs_devices,
int ndevs = 0;
u64 max_avail;
u64 dev_offset;
+ int nr_preferred_metadata = 0;
/*
* in the first pass through the devices list, we gather information
@@ -4937,15 +4988,49 @@ static int gather_device_info(struct btrfs_fs_devices *fs_devices,
devices_info[ndevs].max_avail = max_avail;
devices_info[ndevs].total_avail = total_avail;
devices_info[ndevs].dev = device;
+ devices_info[ndevs].preferred_metadata = !!(device->type &
+ BTRFS_DEV_PREFERRED_METADATA);
+ if (devices_info[ndevs].preferred_metadata)
+ nr_preferred_metadata++;
++ndevs;
}
ctl->ndevs = ndevs;
+ BUG_ON(nr_preferred_metadata > ndevs);
/*
* now sort the devices by hole size / available space
*/
- sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
- btrfs_cmp_device_info, NULL);
+ if (((ctl->type & BTRFS_BLOCK_GROUP_DATA) &&
+ (ctl->type & BTRFS_BLOCK_GROUP_METADATA)) ||
+ !btrfs_test_opt(info, PREFERRED_METADATA)) {
+ /* mixed bg or PREFERRED_METADATA not set */
+ sort(devices_info, ctl->ndevs, sizeof(struct btrfs_device_info),
+ btrfs_cmp_device_info, NULL);
+ } else {
+ /*
+ * if PREFERRED_METADATA is set, sort the device considering
+ * also the kind (preferred_metadata or not). Limit the
+ * availables devices to the ones of the same kind, to avoid
+ * that a striped profile, like raid5, spreads to all kind of
+ * devices.
+ * It is allowed to use different kinds of devices if the ones
+ * of the same kind are not enough alone.
+ */
+ if (ctl->type & BTRFS_BLOCK_GROUP_DATA) {
+ int nr_data = ctl->ndevs - nr_preferred_metadata;
+ sort(devices_info, ctl->ndevs,
+ sizeof(struct btrfs_device_info),
+ btrfs_cmp_device_info_data, NULL);
+ if (nr_data >= ctl->devs_min)
+ ctl->ndevs = nr_data;
+ } else { /* non data -> metadata and system */
+ sort(devices_info, ctl->ndevs,
+ sizeof(struct btrfs_device_info),
+ btrfs_cmp_device_info_metadata, NULL);
+ if (nr_preferred_metadata >= ctl->devs_min)
+ ctl->ndevs = nr_preferred_metadata;
+ }
+ }
return 0;
}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 0ac5bf2b95e6..d39c3b0e7569 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -347,6 +347,7 @@ struct btrfs_device_info {
u64 dev_offset;
u64 max_avail;
u64 total_avail;
+ int preferred_metadata:1;
};
struct btrfs_raid_attr {
--
2.27.0.rc2
