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Btrfs: implement online profile changing
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Profile changing is done by launching a balance with
BTRFS_BALANCE_CONVERT bits set and target fields of respective
btrfs_balance_args structs initialized.  Profile reducing code in this
case will pick restriper's target profile if it's available instead of
doing a blind reduce.  If target profile is not yet available it goes
back to a plain reduce.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
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Ilya Dryomov committed Jan 16, 2012
1 parent 7092261 commit e4d8ec0
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Showing 3 changed files with 129 additions and 1 deletion.
56 changes: 55 additions & 1 deletion fs/btrfs/extent-tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3030,7 +3030,9 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
/*
* @flags: available profiles in extended format (see ctree.h)
*
* Returns reduced profile in chunk format.
* Returns reduced profile in chunk format. If profile changing is in
* progress (either running or paused) picks the target profile (if it's
* already available), otherwise falls back to plain reducing.
*/
u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
{
Expand All @@ -3042,6 +3044,34 @@ u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
u64 num_devices = root->fs_info->fs_devices->rw_devices +
root->fs_info->fs_devices->missing_devices;

/* pick restriper's target profile if it's available */
spin_lock(&root->fs_info->balance_lock);
if (root->fs_info->balance_ctl) {
struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
u64 tgt = 0;

if ((flags & BTRFS_BLOCK_GROUP_DATA) &&
(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
(flags & bctl->data.target)) {
tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
} else if ((flags & BTRFS_BLOCK_GROUP_SYSTEM) &&
(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
(flags & bctl->sys.target)) {
tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
} else if ((flags & BTRFS_BLOCK_GROUP_METADATA) &&
(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
(flags & bctl->meta.target)) {
tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
}

if (tgt) {
spin_unlock(&root->fs_info->balance_lock);
flags = tgt;
goto out;
}
}
spin_unlock(&root->fs_info->balance_lock);

if (num_devices == 1)
flags &= ~(BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID0);
if (num_devices < 4)
Expand All @@ -3065,6 +3095,7 @@ u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags)
flags &= ~BTRFS_BLOCK_GROUP_RAID0;
}

out:
/* extended -> chunk profile */
flags &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
return flags;
Expand Down Expand Up @@ -6795,6 +6826,29 @@ static u64 update_block_group_flags(struct btrfs_root *root, u64 flags)
u64 stripped = BTRFS_BLOCK_GROUP_RAID0 |
BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;

if (root->fs_info->balance_ctl) {
struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
u64 tgt = 0;

/* pick restriper's target profile and return */
if (flags & BTRFS_BLOCK_GROUP_DATA &&
bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
tgt = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
} else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
tgt = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
} else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
tgt = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
}

if (tgt) {
/* extended -> chunk profile */
tgt &= ~BTRFS_AVAIL_ALLOC_BIT_SINGLE;
return tgt;
}
}

/*
* we add in the count of missing devices because we want
* to make sure that any RAID levels on a degraded FS
Expand Down
69 changes: 69 additions & 0 deletions fs/btrfs/volumes.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2438,6 +2438,75 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
}
}

/*
* Profile changing sanity checks. Skip them if a simple
* balance is requested.
*/
if (!((bctl->data.flags | bctl->sys.flags | bctl->meta.flags) &
BTRFS_BALANCE_ARGS_CONVERT))
goto do_balance;

allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
if (fs_info->fs_devices->num_devices == 1)
allowed |= BTRFS_BLOCK_GROUP_DUP;
else if (fs_info->fs_devices->num_devices < 4)
allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
else
allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
BTRFS_BLOCK_GROUP_RAID10);

if (!profile_is_valid(bctl->data.target, 1) ||
bctl->data.target & ~allowed) {
printk(KERN_ERR "btrfs: unable to start balance with target "
"data profile %llu\n",
(unsigned long long)bctl->data.target);
ret = -EINVAL;
goto out;
}
if (!profile_is_valid(bctl->meta.target, 1) ||
bctl->meta.target & ~allowed) {
printk(KERN_ERR "btrfs: unable to start balance with target "
"metadata profile %llu\n",
(unsigned long long)bctl->meta.target);
ret = -EINVAL;
goto out;
}
if (!profile_is_valid(bctl->sys.target, 1) ||
bctl->sys.target & ~allowed) {
printk(KERN_ERR "btrfs: unable to start balance with target "
"system profile %llu\n",
(unsigned long long)bctl->sys.target);
ret = -EINVAL;
goto out;
}

if (bctl->data.target & BTRFS_BLOCK_GROUP_DUP) {
printk(KERN_ERR "btrfs: dup for data is not allowed\n");
ret = -EINVAL;
goto out;
}

/* allow to reduce meta or sys integrity only if force set */
allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
BTRFS_BLOCK_GROUP_RAID10;
if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
(fs_info->avail_system_alloc_bits & allowed) &&
!(bctl->sys.target & allowed)) ||
((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
(fs_info->avail_metadata_alloc_bits & allowed) &&
!(bctl->meta.target & allowed))) {
if (bctl->flags & BTRFS_BALANCE_FORCE) {
printk(KERN_INFO "btrfs: force reducing metadata "
"integrity\n");
} else {
printk(KERN_ERR "btrfs: balance will reduce metadata "
"integrity, use force if you want this\n");
ret = -EINVAL;
goto out;
}
}

do_balance:
set_balance_control(bctl);

mutex_unlock(&fs_info->balance_mutex);
Expand Down
5 changes: 5 additions & 0 deletions fs/btrfs/volumes.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -196,6 +196,9 @@ struct map_lookup {
#define BTRFS_BALANCE_TYPE_MASK (BTRFS_BALANCE_DATA | \
BTRFS_BALANCE_SYSTEM | \
BTRFS_BALANCE_METADATA)

#define BTRFS_BALANCE_FORCE (1ULL << 3)

/*
* Balance filters
*/
Expand All @@ -205,6 +208,8 @@ struct map_lookup {
#define BTRFS_BALANCE_ARGS_DRANGE (1ULL << 3)
#define BTRFS_BALANCE_ARGS_VRANGE (1ULL << 4)

#define BTRFS_BALANCE_ARGS_CONVERT (1ULL << 8)

struct btrfs_balance_args;
struct btrfs_balance_control {
struct btrfs_fs_info *fs_info;
Expand Down

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