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authorYan Zheng <zheng.yan@oracle.com>2008-12-12 10:03:26 -0500
committerChris Mason <chris.mason@oracle.com>2008-12-12 10:03:26 -0500
commite4404d6e8da678d852b7f767f665f8edf76c9e9f (patch)
treeaf6b52e5251d8e939f91e1feab760c1f06021410 /fs/btrfs/volumes.c
parentd2fb3437e4d8d12c73c587615ad187d5288547ec (diff)
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>
Diffstat (limited to 'fs/btrfs/volumes.c')
-rw-r--r--fs/btrfs/volumes.c240
1 files changed, 131 insertions, 109 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 4d210a731d40..6672adcec9f8 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -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 @@ again:
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 @@ again:
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 @@ again:
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;
- }
- fs_devices->seed = device->fs_devices->seed;
- device->fs_devices->seed = NULL;
- __btrfs_close_devices(device->fs_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;
}
- 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;