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>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6f042de..541a827 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1711,7 +1711,7 @@
}
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",
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 1cc8924..171057a 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -218,7 +218,7 @@
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 @@
* 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 @@
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 @@
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;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 09908f2..84c3b66 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -58,14 +58,15 @@
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 @@
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;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4d210a7..6672adc 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -47,7 +47,6 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
{
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index bdebe83..86c44e9 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -93,7 +93,6 @@
struct btrfs_fs_devices *seed;
int seeding;
- int sprouted;
int opened;
};
@@ -127,7 +126,7 @@
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);