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Btrfs: shared seed device 

This patch makes seed device possible to be shared by
multiple mounted file systems. The sharing is achieved
by cloning seed device's btrfs_fs_devices structure.
Thanks you,

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
This commit is contained in:
Yan Zheng 2008-12-12 10:03:26 -05:00 committed by Chris Mason
parent d2fb3437e4
commit e4404d6e8d
5 changed files with 156 additions and 134 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/btrfs/disk-io.c
View File

@ -1711,7 +1711,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
}
mutex_lock(&fs_info->chunk_mutex);
ret = btrfs_read_sys_array(tree_root, btrfs_super_bytenr(disk_super));
ret = btrfs_read_sys_array(tree_root);
mutex_unlock(&fs_info->chunk_mutex);
if (ret) {
printk("btrfs: failed to read the system array on %s\n",

37
fs/btrfs/extent-tree.c
View File

@ -218,7 +218,7 @@ static int cache_block_group(struct btrfs_root *root,
struct btrfs_key key;
struct extent_buffer *leaf;
int slot;
u64 last = block_group->key.objectid;
u64 last;
if (!block_group)
return 0;
@ -239,7 +239,8 @@ static int cache_block_group(struct btrfs_root *root,
* skip the locking here
*/
path->skip_locking = 1;
key.objectid = max_t(u64, last, BTRFS_SUPER_INFO_OFFSET);
last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
key.objectid = last;
key.offset = 0;
btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
@ -5335,8 +5336,20 @@ static int noinline relocate_one_extent(struct btrfs_root *extent_root,
prev_block = block_start;
}
if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID &&
pass >= 2) {
btrfs_record_root_in_trans(found_root);
if (ref_path->owner_objectid >= BTRFS_FIRST_FREE_OBJECTID) {
/*
* try to update data extent references while
* keeping metadata shared between snapshots.
*/
if (pass == 1) {
ret = relocate_one_path(trans, found_root,
path, &first_key, ref_path,
group, reloc_inode);
if (ret < 0)
goto out;
continue;
}
/*
* use fallback method to process the remaining
* references.
@ -5359,23 +5372,9 @@ static int noinline relocate_one_extent(struct btrfs_root *extent_root,
path, extent_key,
&first_key, ref_path,
new_extents, nr_extents);
if (ret < 0)
goto out;
continue;
}
btrfs_record_root_in_trans(found_root);
if (ref_path->owner_objectid < BTRFS_FIRST_FREE_OBJECTID) {
} else {
ret = relocate_tree_block(trans, found_root, path,
&first_key, ref_path);
} else {
/*
* try to update data extent references while
* keeping metadata shared between snapshots.
*/
ret = relocate_one_path(trans, found_root, path,
&first_key, ref_path,
group, reloc_inode);
}
if (ret < 0)
goto out;

8
fs/btrfs/super.c
View File

@ -58,14 +58,15 @@ static struct super_operations btrfs_super_ops;
static void btrfs_put_super (struct super_block * sb)
{
struct btrfs_root *root = btrfs_sb(sb);
struct btrfs_fs_info *fs = root->fs_info;
int ret;
ret = close_ctree(root);
if (ret) {
printk("close ctree returns %d\n", ret);
}
btrfs_sysfs_del_super(fs);
#if 0
btrfs_sysfs_del_super(root->fs_info);
#endif
sb->s_fs_info = NULL;
}
@ -349,11 +350,12 @@ static int btrfs_fill_super(struct super_block * sb,
err = -ENOMEM;
goto fail_close;
}
#if 0
/* this does the super kobj at the same time */
err = btrfs_sysfs_add_super(tree_root->fs_info);
if (err)
goto fail_close;
#endif
sb->s_root = root_dentry;

240
fs/btrfs/volumes.c
View File

@ -47,7 +47,6 @@ static int init_first_rw_device(struct btrfs_trans_handle *trans,
struct btrfs_device *device);
static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
#define map_lookup_size(n) (sizeof(struct map_lookup) + \
(sizeof(struct btrfs_bio_stripe) * (n)))
@ -74,34 +73,29 @@ static void unlock_chunks(struct btrfs_root *root)
mutex_unlock(&root->fs_info->chunk_mutex);
}
static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
{
struct btrfs_device *device;
WARN_ON(fs_devices->opened);
while (!list_empty(&fs_devices->devices)) {
device = list_entry(fs_devices->devices.next,
struct btrfs_device, dev_list);
list_del(&device->dev_list);
kfree(device->name);
kfree(device);
}
kfree(fs_devices);
}
int btrfs_cleanup_fs_uuids(void)
{
struct btrfs_fs_devices *fs_devices;
struct btrfs_device *dev;
while (!list_empty(&fs_uuids)) {
fs_devices = list_entry(fs_uuids.next,
struct btrfs_fs_devices, list);
list_del(&fs_devices->list);
while(!list_empty(&fs_devices->devices)) {
dev = list_entry(fs_devices->devices.next,
struct btrfs_device, dev_list);
if (dev->bdev) {
close_bdev_exclusive(dev->bdev, dev->mode);
fs_devices->open_devices--;
}
fs_devices->num_devices--;
if (dev->writeable)
fs_devices->rw_devices--;
list_del(&dev->dev_list);
list_del(&dev->dev_alloc_list);
kfree(dev->name);
kfree(dev);
}
WARN_ON(fs_devices->num_devices);
WARN_ON(fs_devices->open_devices);
WARN_ON(fs_devices->rw_devices);
kfree(fs_devices);
free_fs_devices(fs_devices);
}
return 0;
}
@ -304,12 +298,55 @@ static noinline int device_list_add(const char *path,
return 0;
}
static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
{
struct btrfs_fs_devices *fs_devices;
struct btrfs_device *device;
struct btrfs_device *orig_dev;
fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
if (!fs_devices)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&fs_devices->devices);
INIT_LIST_HEAD(&fs_devices->alloc_list);
INIT_LIST_HEAD(&fs_devices->list);
fs_devices->latest_devid = orig->latest_devid;
fs_devices->latest_trans = orig->latest_trans;
memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
list_for_each_entry(orig_dev, &orig->devices, dev_list) {
device = kzalloc(sizeof(*device), GFP_NOFS);
if (!device)
goto error;
device->name = kstrdup(orig_dev->name, GFP_NOFS);
if (!device->name)
goto error;
device->devid = orig_dev->devid;
device->work.func = pending_bios_fn;
memcpy(device->uuid, orig_dev->uuid, sizeof(device->uuid));
device->barriers = 1;
spin_lock_init(&device->io_lock);
INIT_LIST_HEAD(&device->dev_list);
INIT_LIST_HEAD(&device->dev_alloc_list);
list_add(&device->dev_list, &fs_devices->devices);
device->fs_devices = fs_devices;
fs_devices->num_devices++;
}
return fs_devices;
error:
free_fs_devices(fs_devices);
return ERR_PTR(-ENOMEM);
}
int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
{
struct list_head *tmp;
struct list_head *cur;
struct btrfs_device *device;
int seed_devices = 0;
mutex_lock(&uuid_mutex);
again:
@ -328,17 +365,14 @@ int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
device->writeable = 0;
fs_devices->rw_devices--;
}
if (!seed_devices) {
list_del_init(&device->dev_list);
fs_devices->num_devices--;
kfree(device->name);
kfree(device);
}
list_del_init(&device->dev_list);
fs_devices->num_devices--;
kfree(device->name);
kfree(device);
}
if (fs_devices->seed) {
fs_devices = fs_devices->seed;
seed_devices = 1;
goto again;
}
@ -348,10 +382,9 @@ int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
struct btrfs_fs_devices *seed_devices;
struct list_head *cur;
struct btrfs_device *device;
again:
if (--fs_devices->opened > 0)
return 0;
@ -370,31 +403,38 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
device->writeable = 0;
device->in_fs_metadata = 0;
}
WARN_ON(fs_devices->open_devices);
WARN_ON(fs_devices->rw_devices);
fs_devices->opened = 0;
fs_devices->seeding = 0;
fs_devices->sprouted = 0;
seed_devices = fs_devices->seed;
fs_devices->seed = NULL;
if (seed_devices) {
fs_devices = seed_devices;
goto again;
}
return 0;
}
int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
struct btrfs_fs_devices *seed_devices = NULL;
int ret;
mutex_lock(&uuid_mutex);
ret = __btrfs_close_devices(fs_devices);
if (!fs_devices->opened) {
seed_devices = fs_devices->seed;
fs_devices->seed = NULL;
}
mutex_unlock(&uuid_mutex);
while (seed_devices) {
fs_devices = seed_devices;
seed_devices = fs_devices->seed;
__btrfs_close_devices(fs_devices);
free_fs_devices(fs_devices);
}
return ret;
}
int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
fmode_t flags, void *holder)
static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
fmode_t flags, void *holder)
{
struct block_device *bdev;
struct list_head *head = &fs_devices->devices;
@ -490,12 +530,8 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
mutex_lock(&uuid_mutex);
if (fs_devices->opened) {
if (fs_devices->sprouted) {
ret = -EBUSY;
} else {
fs_devices->opened++;
ret = 0;
}
fs_devices->opened++;
ret = 0;
} else {
ret = __btrfs_open_devices(fs_devices, flags, holder);
}
@ -1043,12 +1079,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
goto error_brelse;
device->in_fs_metadata = 0;
if (device->fs_devices == root->fs_info->fs_devices) {
list_del_init(&device->dev_list);
root->fs_info->fs_devices->num_devices--;
if (device->bdev)
device->fs_devices->open_devices--;
}
list_del_init(&device->dev_list);
device->fs_devices->num_devices--;
next_device = list_entry(root->fs_info->fs_devices->devices.next,
struct btrfs_device, dev_list);
@ -1057,34 +1089,27 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
if (device->bdev == root->fs_info->fs_devices->latest_bdev)
root->fs_info->fs_devices->latest_bdev = next_device->bdev;
if (device->bdev) {
close_bdev_exclusive(device->bdev, device->mode);
device->bdev = NULL;
device->fs_devices->open_devices--;
}
num_devices = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
btrfs_set_super_num_devices(&root->fs_info->super_copy, num_devices);
if (device->fs_devices != root->fs_info->fs_devices) {
BUG_ON(device->writeable);
brelse(bh);
if (bdev)
close_bdev_exclusive(bdev, FMODE_READ);
if (device->bdev) {
close_bdev_exclusive(device->bdev, device->mode);
device->bdev = NULL;
device->fs_devices->open_devices--;
if (device->fs_devices->open_devices == 0) {
struct btrfs_fs_devices *fs_devices;
fs_devices = root->fs_info->fs_devices;
while (fs_devices) {
if (fs_devices->seed == device->fs_devices)
break;
fs_devices = fs_devices->seed;
}
if (device->fs_devices->open_devices == 0) {
struct btrfs_fs_devices *fs_devices;
fs_devices = root->fs_info->fs_devices;
while (fs_devices) {
if (fs_devices->seed == device->fs_devices)
break;
fs_devices = fs_devices->seed;
}
fs_devices->seed = device->fs_devices->seed;
device->fs_devices->seed = NULL;
__btrfs_close_devices(device->fs_devices);
}
ret = 0;
goto out;
fs_devices->seed = device->fs_devices->seed;
device->fs_devices->seed = NULL;
__btrfs_close_devices(device->fs_devices);
free_fs_devices(device->fs_devices);
}
/*
@ -1099,20 +1124,10 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
set_buffer_dirty(bh);
sync_dirty_buffer(bh);
}
brelse(bh);
if (device->bdev) {
/* one close for the device struct or super_block */
close_bdev_exclusive(device->bdev, device->mode);
}
if (bdev) {
/* one close for us */
close_bdev_exclusive(bdev, FMODE_READ);
}
kfree(device->name);
kfree(device);
ret = 0;
goto out;
error_brelse:
brelse(bh);
@ -1133,34 +1148,41 @@ static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
{
struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
struct btrfs_fs_devices *old_devices;
struct btrfs_fs_devices *seed_devices;
struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
struct btrfs_device *device;
u64 super_flags;
BUG_ON(!mutex_is_locked(&uuid_mutex));
if (!fs_devices->seeding || fs_devices->opened != 1)
if (!fs_devices->seeding)
return -EINVAL;
old_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
if (!old_devices)
seed_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
if (!seed_devices)
return -ENOMEM;
memcpy(old_devices, fs_devices, sizeof(*old_devices));
old_devices->opened = 1;
old_devices->sprouted = 1;
INIT_LIST_HEAD(&old_devices->devices);
INIT_LIST_HEAD(&old_devices->alloc_list);
list_splice_init(&fs_devices->devices, &old_devices->devices);
list_splice_init(&fs_devices->alloc_list, &old_devices->alloc_list);
list_for_each_entry(device, &old_devices->devices, dev_list) {
device->fs_devices = old_devices;
old_devices = clone_fs_devices(fs_devices);
if (IS_ERR(old_devices)) {
kfree(seed_devices);
return PTR_ERR(old_devices);
}
list_add(&old_devices->list, &fs_uuids);
memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
seed_devices->opened = 1;
INIT_LIST_HEAD(&seed_devices->devices);
INIT_LIST_HEAD(&seed_devices->alloc_list);
list_splice_init(&fs_devices->devices, &seed_devices->devices);
list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
list_for_each_entry(device, &seed_devices->devices, dev_list) {
device->fs_devices = seed_devices;
}
fs_devices->seeding = 0;
fs_devices->num_devices = 0;
fs_devices->open_devices = 0;
fs_devices->seed = old_devices;
fs_devices->seed = seed_devices;
generate_random_uuid(fs_devices->fsid);
memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
@ -2642,7 +2664,6 @@ int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
NULL, 0, page);
}
static void end_bio_multi_stripe(struct bio *bio, int err)
{
struct btrfs_multi_bio *multi = bio->bi_private;
@ -2840,6 +2861,7 @@ static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
device->dev_root = root->fs_info->dev_root;
device->devid = devid;
device->work.func = pending_bios_fn;
device->fs_devices = fs_devices;
fs_devices->num_devices++;
spin_lock_init(&device->io_lock);
INIT_LIST_HEAD(&device->dev_alloc_list);
@ -2980,8 +3002,10 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
ret = -ENOENT;
goto out;
}
if (fs_devices->opened) {
ret = -EBUSY;
fs_devices = clone_fs_devices(fs_devices);
if (IS_ERR(fs_devices)) {
ret = PTR_ERR(fs_devices);
goto out;
}
@ -2992,13 +3016,13 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid)
if (!fs_devices->seeding) {
__btrfs_close_devices(fs_devices);
free_fs_devices(fs_devices);
ret = -EINVAL;
goto out;
}
fs_devices->seed = root->fs_info->fs_devices->seed;
root->fs_info->fs_devices->seed = fs_devices;
fs_devices->sprouted = 1;
out:
mutex_unlock(&uuid_mutex);
return ret;
@ -3011,7 +3035,6 @@ static int read_one_dev(struct btrfs_root *root,
struct btrfs_device *device;
u64 devid;
int ret;
int seed_devices = 0;
u8 fs_uuid[BTRFS_UUID_SIZE];
u8 dev_uuid[BTRFS_UUID_SIZE];
@ -3025,14 +3048,13 @@ static int read_one_dev(struct btrfs_root *root,
if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
ret = open_seed_devices(root, fs_uuid);
if (ret)
if (ret && !btrfs_test_opt(root, DEGRADED))
return ret;
seed_devices = 1;
}
device = btrfs_find_device(root, devid, dev_uuid, fs_uuid);
if (!device || !device->bdev) {
if (!btrfs_test_opt(root, DEGRADED) || seed_devices)
if (!btrfs_test_opt(root, DEGRADED))
return -EIO;
if (!device) {
@ -3074,7 +3096,7 @@ int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
return read_one_dev(root, buf, dev_item);
}
int btrfs_read_sys_array(struct btrfs_root *root, u64 sb_bytenr)
int btrfs_read_sys_array(struct btrfs_root *root)
{
struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
struct extent_buffer *sb;
@ -3089,7 +3111,7 @@ int btrfs_read_sys_array(struct btrfs_root *root, u64 sb_bytenr)
u32 cur;
struct btrfs_key key;
sb = btrfs_find_create_tree_block(root, sb_bytenr,
sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
BTRFS_SUPER_INFO_SIZE);
if (!sb)
return -ENOMEM;

3
fs/btrfs/volumes.h
View File

@ -93,7 +93,6 @@ struct btrfs_fs_devices {
struct btrfs_fs_devices *seed;
int seeding;
int sprouted;
int opened;
};
@ -127,7 +126,7 @@ int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
u64 chunk_start, u64 physical, u64 devid,
u64 **logical, int *naddrs, int *stripe_len);
int btrfs_read_sys_array(struct btrfs_root *root, u64 sb_bytenr);
int btrfs_read_sys_array(struct btrfs_root *root);
int btrfs_read_chunk_tree(struct btrfs_root *root);
int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
struct btrfs_root *extent_root, u64 type);