On 10/30/20 9:51 AM, Naohiro Aota wrote:
This is the 1/4 patch to support device-replace in ZONED mode.
We have two types of I/Os during the device-replace process. One is an I/O
to "copy" (by the scrub functions) all the device extents on the source
device to the destination device. The other one is an I/O to "clone" (by
handle_ops_on_dev_replace()) new incoming write I/Os from users to the
source device into the target device.
Cloning incoming I/Os can break the sequential write rule in the target
device. When writing is mapped in the middle of a block group, the I/O is
directed in the middle of a target device zone, which breaks the sequential
write rule.
However, the cloning function cannot be merely disabled since incoming I/Os
targeting already copied device extents must be cloned so that the I/O is
executed on the target device.
We cannot use dev_replace->cursor_{left,right} to determine whether bio is
going to not yet copied region. Since we have a time gap between finishing
btrfs_scrub_dev() and rewriting the mapping tree in
btrfs_dev_replace_finishing(), we can have a newly allocated device extent
which is never cloned nor copied.
So the point is to copy only already existing device extents. This patch
introduces mark_block_group_to_copy() to mark existing block groups as a
target of copying. Then, handle_ops_on_dev_replace() and dev-replace can
check the flag to do their job.
Signed-off-by: Naohiro Aota <naohiro.aota@xxxxxxx>
---
fs/btrfs/block-group.h | 1 +
fs/btrfs/dev-replace.c | 175 +++++++++++++++++++++++++++++++++++++++++
fs/btrfs/dev-replace.h | 3 +
fs/btrfs/scrub.c | 17 ++++
4 files changed, 196 insertions(+)
diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index b2a8a3beceac..e91123495d68 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -95,6 +95,7 @@ struct btrfs_block_group {
unsigned int iref:1;
unsigned int has_caching_ctl:1;
unsigned int removed:1;
+ unsigned int to_copy:1;
int disk_cache_state;
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 5e3554482af1..e86aff38aea4 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -22,6 +22,7 @@
#include "dev-replace.h"
#include "sysfs.h"
#include "zoned.h"
+#include "block-group.h"
/*
* Device replace overview
@@ -437,6 +438,176 @@ static char* btrfs_dev_name(struct btrfs_device *device)
return rcu_str_deref(device->name);
}
+static int mark_block_group_to_copy(struct btrfs_fs_info *fs_info,
+ struct btrfs_device *src_dev)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct btrfs_root *root = fs_info->dev_root;
+ struct btrfs_dev_extent *dev_extent = NULL;
+ struct btrfs_block_group *cache;
+ struct extent_buffer *l;
+ struct btrfs_trans_handle *trans;
+ int slot;
+ int ret = 0;
+ u64 chunk_offset, length;
+
+ /* Do not use "to_copy" on non-ZONED for now */
+ if (!btrfs_fs_incompat(fs_info, ZONED))
+ return 0;
if (!btrfs_is_zoned())
+
+ mutex_lock(&fs_info->chunk_mutex);
+
+ /* ensulre we don't have pending new block group */
ensure.
+ while (fs_info->running_transaction &&
+ !list_empty(&fs_info->running_transaction->dev_update_list)) {
This is not safe to check, running_transaction can change without the trans_lock
held.
+ mutex_unlock(&fs_info->chunk_mutex);
+ trans = btrfs_attach_transaction(root);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ mutex_lock(&fs_info->chunk_mutex);
+ if (ret == -ENOENT)
+ continue;
+ else
+ goto out;
+ }
+
+ ret = btrfs_commit_transaction(trans);
+ mutex_lock(&fs_info->chunk_mutex);
+ if (ret)
+ goto out;
+ }
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ path->reada = READA_FORWARD;
+ path->search_commit_root = 1;
+ path->skip_locking = 1;
+
+ key.objectid = src_dev->devid;
+ key.offset = 0ull;
0 is fine here right?
+ key.type = BTRFS_DEV_EXTENT_KEY;
+
+ while (1) {
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ break;
+ if (ret > 0) {
+ if (path->slots[0] >=
+ btrfs_header_nritems(path->nodes[0])) {
+ ret = btrfs_next_leaf(root, path);
+ if (ret < 0)
+ break;
+ if (ret > 0) {
+ ret = 0;
+ break;
+ }
+ } else {
+ ret = 0;
+ }
+ }
+
+ l = path->nodes[0];
+ slot = path->slots[0];
+
+ btrfs_item_key_to_cpu(l, &found_key, slot);
+
+ if (found_key.objectid != src_dev->devid)
+ break;
+
+ if (found_key.type != BTRFS_DEV_EXTENT_KEY)
+ break;
+
+ if (found_key.offset < key.offset)
+ break;
+
+ dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
+ length = btrfs_dev_extent_length(l, dev_extent);
+
+ chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
+
+ cache = btrfs_lookup_block_group(fs_info, chunk_offset);
+ if (!cache)
+ goto skip;
+
+ spin_lock(&cache->lock);
+ cache->to_copy = 1;
+ spin_unlock(&cache->lock);
+
+ btrfs_put_block_group(cache);
+
+skip:
+ key.offset = found_key.offset + length;
+ btrfs_release_path(path);
Why are you releasing the path here?
This can be re-arranged into a loop that just uses btrfs_next_item().
+ }
+
+ btrfs_free_path(path);
+out:
+ mutex_unlock(&fs_info->chunk_mutex);
+
+ return ret;
+}
+
+bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
+ struct btrfs_block_group *cache,
+ u64 physical)
+{
+ struct btrfs_fs_info *fs_info = cache->fs_info;
+ struct extent_map *em;
+ struct map_lookup *map;
+ u64 chunk_offset = cache->start;
+ int num_extents, cur_extent;
+ int i;
+
+ /* Do not use "to_copy" on non-ZONED for now */
+ if (!btrfs_fs_incompat(fs_info, ZONED))
+ return true;
btrfs_is_zoned();
+
+ spin_lock(&cache->lock);
+ if (cache->removed) {
+ spin_unlock(&cache->lock);
+ return true;
+ }
+ spin_unlock(&cache->lock);
+
+ em = btrfs_get_chunk_map(fs_info, chunk_offset, 1);
+ BUG_ON(IS_ERR(em));
ASSERT(!IS_ERR(em));
+ map = em->map_lookup;
+
+ num_extents = cur_extent = 0;
+ for (i = 0; i < map->num_stripes; i++) {
+ /* we have more device extent to copy */
+ if (srcdev != map->stripes[i].dev)
+ continue;
+
+ num_extents++;
+ if (physical == map->stripes[i].physical)
+ cur_extent = i;
+ }
+
+ free_extent_map(em);
+
+ if (num_extents > 1 && cur_extent < num_extents - 1) {
+ /*
+ * Has more stripes on this device. Keep this BG
+ * readonly until we finish all the stripes.
+ */
+ return false;
+ }
+
+ /* last stripe on this device */
+ spin_lock(&cache->lock);
+ cache->to_copy = 0;
+ spin_unlock(&cache->lock);
+
+ return true;
+}
+
static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
const char *tgtdev_name, u64 srcdevid, const char *srcdev_name,
int read_src)
@@ -478,6 +649,10 @@ static int btrfs_dev_replace_start(struct btrfs_fs_info *fs_info,
if (ret)
return ret;
+ ret = mark_block_group_to_copy(fs_info, src_device);
+ if (ret)
+ return ret;
+
down_write(&dev_replace->rwsem);
switch (dev_replace->replace_state) {
case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h
index 60b70dacc299..3911049a5f23 100644
--- a/fs/btrfs/dev-replace.h
+++ b/fs/btrfs/dev-replace.h
@@ -18,5 +18,8 @@ int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info);
void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info);
int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info);
int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace);
+bool btrfs_finish_block_group_to_copy(struct btrfs_device *srcdev,
+ struct btrfs_block_group *cache,
+ u64 physical);
#endif
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index aa1b36cf5c88..d0d7db3c8b0b 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3500,6 +3500,17 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
if (!cache)
goto skip;
+
+ if (sctx->is_dev_replace && btrfs_fs_incompat(fs_info, ZONED)) {
btrfs_is_zoned(). Thanks,
Josef
