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-rw-r--r--fs/btrfs/backref.c4
-rw-r--r--fs/btrfs/backref.h2
-rw-r--r--fs/btrfs/block-rsv.c2
-rw-r--r--fs/btrfs/ctree.c26
-rw-r--r--fs/btrfs/ctree.h25
-rw-r--r--fs/btrfs/disk-io.c13
-rw-r--r--fs/btrfs/extent-tree.c2
-rw-r--r--fs/btrfs/file.c2
-rw-r--r--fs/btrfs/inode.c17
-rw-r--r--fs/btrfs/ioctl.c2
-rw-r--r--fs/btrfs/relocation.c25
-rw-r--r--fs/btrfs/transaction.c14
-rw-r--r--fs/btrfs/tree-defrag.c2
13 files changed, 81 insertions, 55 deletions
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index ac3c34f47b56..41ef3fa91864 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -2702,7 +2702,7 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
root = btrfs_get_fs_root(fs_info, &root_key, false);
if (IS_ERR(root))
return PTR_ERR(root);
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
cur->cowonly = 1;
if (btrfs_root_level(&root->root_item) == cur->level) {
@@ -2789,7 +2789,7 @@ static int handle_indirect_tree_backref(struct btrfs_backref_cache *cache,
goto out;
}
upper->owner = btrfs_header_owner(eb);
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
upper->cowonly = 1;
/*
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 18393cc05ca2..ff705cc564a9 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -184,7 +184,7 @@ struct btrfs_backref_node {
struct extent_buffer *eb;
/* Level of the tree block */
unsigned int level:8;
- /* Is the block in non-reference counted tree */
+ /* Is the block in a non-shareable tree */
unsigned int cowonly:1;
/* 1 if no child node is in the cache */
unsigned int lowest:1;
diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c
index dbba53e712e6..7e1549a84fcc 100644
--- a/fs/btrfs/block-rsv.c
+++ b/fs/btrfs/block-rsv.c
@@ -458,7 +458,7 @@ static struct btrfs_block_rsv *get_block_rsv(
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_rsv *block_rsv = NULL;
- if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
+ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
(root == fs_info->csum_root && trans->adding_csums) ||
(root == fs_info->uuid_root))
block_rsv = trans->block_rsv;
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 746dec22f250..92775554d1cc 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -144,9 +144,10 @@ struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
return eb;
}
-/* cowonly root (everything not a reference counted cow subvolume), just get
- * put onto a simple dirty list. transaction.c walks this to make sure they
- * get properly updated on disk.
+/*
+ * Cowonly root (not-shareable trees, everything not subvolume or reloc roots),
+ * just get put onto a simple dirty list. Transaction walks this list to make
+ * sure they get properly updated on disk.
*/
static void add_root_to_dirty_list(struct btrfs_root *root)
{
@@ -185,9 +186,9 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
int level;
struct btrfs_disk_key disk_key;
- WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
+ WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
trans->transid != fs_info->running_transaction->transid);
- WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
+ WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
trans->transid != root->last_trans);
level = btrfs_header_level(buf);
@@ -826,12 +827,11 @@ int btrfs_block_can_be_shared(struct btrfs_root *root,
struct extent_buffer *buf)
{
/*
- * Tree blocks not in reference counted trees and tree roots
- * are never shared. If a block was allocated after the last
- * snapshot and the block was not allocated by tree relocation,
- * we know the block is not shared.
+ * Tree blocks not in shareable trees and tree roots are never shared.
+ * If a block was allocated after the last snapshot and the block was
+ * not allocated by tree relocation, we know the block is not shared.
*/
- if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
+ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
buf != root->node && buf != root->commit_root &&
(btrfs_header_generation(buf) <=
btrfs_root_last_snapshot(&root->root_item) ||
@@ -1024,9 +1024,9 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
btrfs_assert_tree_locked(buf);
- WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
+ WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
trans->transid != fs_info->running_transaction->transid);
- WARN_ON(test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
+ WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
trans->transid != root->last_trans);
level = btrfs_header_level(buf);
@@ -1065,7 +1065,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
return ret;
}
- if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
+ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
ret = btrfs_reloc_cow_block(trans, root, buf, cow);
if (ret) {
btrfs_abort_transaction(trans, ret);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0a1fa1526c43..bf46093be76e 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -969,7 +969,28 @@ enum {
* is used to tell us when more checks are required
*/
BTRFS_ROOT_IN_TRANS_SETUP,
- BTRFS_ROOT_REF_COWS,
+
+ /*
+ * Set if tree blocks of this root can be shared by other roots.
+ * Only subvolume trees and their reloc trees have this bit set.
+ * Conflicts with TRACK_DIRTY bit.
+ *
+ * This affects two things:
+ *
+ * - How balance works
+ * For shareable roots, we need to use reloc tree and do path
+ * replacement for balance, and need various pre/post hooks for
+ * snapshot creation to handle them.
+ *
+ * While for non-shareable trees, we just simply do a tree search
+ * with COW.
+ *
+ * - How dirty roots are tracked
+ * For shareable roots, btrfs_record_root_in_trans() is needed to
+ * track them, while non-subvolume roots have TRACK_DIRTY bit, they
+ * don't need to set this manually.
+ */
+ BTRFS_ROOT_SHAREABLE,
BTRFS_ROOT_TRACK_DIRTY,
BTRFS_ROOT_IN_RADIX,
BTRFS_ROOT_ORPHAN_ITEM_INSERTED,
@@ -1055,7 +1076,7 @@ struct btrfs_root {
struct btrfs_key defrag_progress;
struct btrfs_key defrag_max;
- /* the dirty list is only used by non-reference counted roots */
+ /* The dirty list is only used by non-shareable roots */
struct list_head dirty_list;
struct list_head root_list;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 714b57553ed6..248086cca124 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1273,12 +1273,13 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
/*
- * DON'T set REF_COWS for log trees
+ * DON'T set SHAREABLE bit for log trees.
*
- * log trees do not get reference counted because they go away
- * before a real commit is actually done. They do store pointers
- * to file data extents, and those reference counts still get
- * updated (along with back refs to the log tree).
+ * Log trees are not exposed to user space thus can't be snapshotted,
+ * and they go away before a real commit is actually done.
+ *
+ * They do store pointers to file data extents, and those reference
+ * counts still get updated (along with back refs to the log tree).
*/
leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,
@@ -1417,7 +1418,7 @@ static int btrfs_init_fs_root(struct btrfs_root *root)
goto fail;
if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
- set_bit(BTRFS_ROOT_REF_COWS, &root->state);
+ set_bit(BTRFS_ROOT_SHAREABLE, &root->state);
btrfs_check_and_init_root_item(&root->root_item);
}
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 140011edcad7..c0bc35f932bf 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2426,7 +2426,7 @@ static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
nritems = btrfs_header_nritems(buf);
level = btrfs_header_level(buf);
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0)
return 0;
if (full_backref)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 719e68ab552c..606c2f3c1a38 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -775,7 +775,7 @@ int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
if (start >= BTRFS_I(inode)->disk_i_size && !replace_extent)
modify_tree = 0;
- update_refs = (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
+ update_refs = (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
root == fs_info->tree_root);
while (1) {
recow = 0;
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3ea694ee1c90..08c02bd148a6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4100,11 +4100,12 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
/*
- * for non-free space inodes and ref cows, we want to back off from
- * time to time
+ * For non-free space inodes and non-shareable roots, we want to back
+ * off from time to time. This means all inodes in subvolume roots,
+ * reloc roots, and data reloc roots.
*/
if (!btrfs_is_free_space_inode(BTRFS_I(inode)) &&
- test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
be_nice = true;
path = btrfs_alloc_path();
@@ -4121,7 +4122,7 @@ int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
* not block aligned since we will be keeping the last block of the
* extent just the way it is.
*/
- if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
+ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
root == fs_info->tree_root)
btrfs_drop_extent_cache(BTRFS_I(inode), ALIGN(new_size,
fs_info->sectorsize),
@@ -4233,7 +4234,7 @@ search_again:
extent_num_bytes);
num_dec = (orig_num_bytes -
extent_num_bytes);
- if (test_bit(BTRFS_ROOT_REF_COWS,
+ if (test_bit(BTRFS_ROOT_SHAREABLE,
&root->state) &&
extent_start != 0)
inode_sub_bytes(inode, num_dec);
@@ -4249,7 +4250,7 @@ search_again:
num_dec = btrfs_file_extent_num_bytes(leaf, fi);
if (extent_start != 0) {
found_extent = 1;
- if (test_bit(BTRFS_ROOT_REF_COWS,
+ if (test_bit(BTRFS_ROOT_SHAREABLE,
&root->state))
inode_sub_bytes(inode, num_dec);
}
@@ -4285,7 +4286,7 @@ search_again:
clear_len = fs_info->sectorsize;
}
- if (test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
inode_sub_bytes(inode, item_end + 1 - new_size);
}
delete:
@@ -4326,7 +4327,7 @@ delete:
should_throttle = false;
if (found_extent &&
- (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
+ (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
root == fs_info->tree_root)) {
struct btrfs_ref ref = { 0 };
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 40b729dce91c..709d9446896a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -750,7 +750,7 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir,
int ret;
bool snapshot_force_cow = false;
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
return -EINVAL;
if (atomic_read(&root->nr_swapfiles)) {
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index f25deca18a5d..1dd7b5310ffd 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -321,7 +321,7 @@ int btrfs_should_ignore_reloc_root(struct btrfs_root *root)
{
struct btrfs_root *reloc_root;
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
return 0;
/* This root has been merged with its reloc tree, we can ignore it */
@@ -808,7 +808,7 @@ static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
BUG_ON(IS_ERR(reloc_root));
- set_bit(BTRFS_ROOT_REF_COWS, &reloc_root->state);
+ set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
reloc_root->last_trans = trans->transid;
return reloc_root;
}
@@ -2018,7 +2018,7 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
next = walk_up_backref(next, edges, &index);
root = next->root;
BUG_ON(!root);
- BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
+ BUG_ON(!test_bit(BTRFS_ROOT_SHAREABLE, &root->state));
if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
record_reloc_root_in_trans(trans, root);
@@ -2062,10 +2062,13 @@ struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
}
/*
- * select a tree root for relocation. return NULL if the block
- * is reference counted. we should use do_relocation() in this
- * case. return a tree root pointer if the block isn't reference
- * counted. return -ENOENT if the block is root of reloc tree.
+ * Select a tree root for relocation.
+ *
+ * Return NULL if the block is not shareable. We should use do_relocation() in
+ * this case.
+ *
+ * Return a tree root pointer if the block is shareable.
+ * Return -ENOENT if the block is root of reloc tree.
*/
static noinline_for_stack
struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
@@ -2083,8 +2086,8 @@ struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
root = next->root;
BUG_ON(!root);
- /* no other choice for non-references counted tree */
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ /* No other choice for non-shareable tree */
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
return root;
if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
@@ -2480,7 +2483,7 @@ static int relocate_tree_block(struct btrfs_trans_handle *trans,
}
if (root) {
- if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
+ if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
BUG_ON(node->new_bytenr);
BUG_ON(!list_empty(&node->list));
btrfs_record_root_in_trans(trans, root);
@@ -3765,7 +3768,7 @@ int btrfs_recover_relocation(struct btrfs_root *root)
goto out;
}
- set_bit(BTRFS_ROOT_REF_COWS, &reloc_root->state);
+ set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
list_add(&reloc_root->root_list, &reloc_roots);
if (btrfs_root_refs(&reloc_root->root_item) > 0) {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index f58d0fdc5078..a8cc2ddffc17 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -349,10 +349,10 @@ loop:
}
/*
- * this does all the record keeping required to make sure that a reference
- * counted root is properly recorded in a given transaction. This is required
- * to make sure the old root from before we joined the transaction is deleted
- * when the transaction commits
+ * This does all the record keeping required to make sure that a shareable root
+ * is properly recorded in a given transaction. This is required to make sure
+ * the old root from before we joined the transaction is deleted when the
+ * transaction commits.
*/
static int record_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
@@ -360,7 +360,7 @@ static int record_root_in_trans(struct btrfs_trans_handle *trans,
{
struct btrfs_fs_info *fs_info = root->fs_info;
- if ((test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
+ if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
root->last_trans < trans->transid) || force) {
WARN_ON(root == fs_info->extent_root);
WARN_ON(!force && root->commit_root != root->node);
@@ -439,7 +439,7 @@ int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
{
struct btrfs_fs_info *fs_info = root->fs_info;
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
return 0;
/*
@@ -504,7 +504,7 @@ static inline bool need_reserve_reloc_root(struct btrfs_root *root)
struct btrfs_fs_info *fs_info = root->fs_info;
if (!fs_info->reloc_ctl ||
- !test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
+ !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
root->reloc_root)
return false;
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index 5f9e2dd413af..16c3a6d2586d 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -35,7 +35,7 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
goto out;
}
- if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
+ if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
goto out;
path = btrfs_alloc_path();
generated by cgit v1.2.3 (git 2.39.1) at 2024-08-23 10:30:33 +0000