A number of workloads do not require copy on write data or checksumming.
mount -o nodatasum to disable checksums and -o nodatacow to disable
both copy on write and checksumming.
In nodatacow mode, copy on write is still performed when a given extent
is under snapshot.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
memset(p, 0, sizeof(*p));
}
-static int __btrfs_cow_block(struct btrfs_trans_handle *trans,
+int btrfs_copy_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf,
+ struct extent_buffer **cow_ret, u64 new_root_objectid)
+{
+ struct extent_buffer *cow;
+ u32 nritems;
+ int ret = 0;
+ int level;
+ struct btrfs_key first_key;
+ struct btrfs_root new_root;
+
+ memcpy(&new_root, root, sizeof(new_root));
+ new_root.root_key.objectid = new_root_objectid;
+
+ WARN_ON(root->ref_cows && trans->transid !=
+ root->fs_info->running_transaction->transid);
+ WARN_ON(root->ref_cows && trans->transid != root->last_trans);
+
+ level = btrfs_header_level(buf);
+ nritems = btrfs_header_nritems(buf);
+ if (nritems) {
+ if (level == 0)
+ btrfs_item_key_to_cpu(buf, &first_key, 0);
+ else
+ btrfs_node_key_to_cpu(buf, &first_key, 0);
+ } else {
+ first_key.objectid = 0;
+ }
+ cow = __btrfs_alloc_free_block(trans, &new_root, buf->len,
+ new_root_objectid,
+ trans->transid, first_key.objectid,
+ level, buf->start, 0);
+ if (IS_ERR(cow))
+ return PTR_ERR(cow);
+
+ copy_extent_buffer(cow, buf, 0, 0, cow->len);
+ btrfs_set_header_bytenr(cow, cow->start);
+ btrfs_set_header_generation(cow, trans->transid);
+ btrfs_set_header_owner(cow, new_root_objectid);
+
+ WARN_ON(btrfs_header_generation(buf) > trans->transid);
+ ret = btrfs_inc_ref(trans, &new_root, buf);
+ if (ret)
+ return ret;
+
+ btrfs_mark_buffer_dirty(cow);
+ *cow_ret = cow;
+ return 0;
+}
+
+int __btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
#define BTRFS_STRING_ITEM_KEY 253
#define BTRFS_MOUNT_NODATASUM 0x1
+#define BTRFS_MOUNT_NODATACOW 0x2
#define btrfs_clear_opt(o, opt) ((o) &= ~BTRFS_MOUNT_##opt)
#define btrfs_set_opt(o, opt) ((o) |= BTRFS_MOUNT_##opt)
btrfs_item_offset_nr(leaf, slot)))
/* extent-tree.c */
+u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
+ struct btrfs_path *count_path,
+ u64 first_extent);
int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy);
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret);
+int btrfs_copy_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf,
+ struct extent_buffer **cow_ret, u64 new_root_objectid);
int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, u32 data_size);
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
return 0;
}
+u32 btrfs_count_snapshots_in_path(struct btrfs_root *root,
+ struct btrfs_path *count_path,
+ u64 first_extent)
+{
+ struct btrfs_root *extent_root = root->fs_info->extent_root;
+ struct btrfs_path *path;
+ u64 bytenr;
+ u64 found_objectid;
+ u64 root_objectid = 0;
+ u32 total_count = 0;
+ u32 cur_count;
+ u32 refs;
+ u32 nritems;
+ int ret;
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct extent_buffer *l;
+ struct btrfs_extent_item *item;
+ struct btrfs_extent_ref *ref_item;
+ int level = -1;
+
+ path = btrfs_alloc_path();
+again:
+ if (level == -1)
+ bytenr = first_extent;
+ else
+ bytenr = count_path->nodes[level]->start;
+
+ cur_count = 0;
+ key.objectid = bytenr;
+ key.offset = 0;
+
+ btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
+ ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ BUG_ON(ret == 0);
+
+ l = path->nodes[0];
+ btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
+
+ if (found_key.objectid != bytenr ||
+ found_key.type != BTRFS_EXTENT_ITEM_KEY) {
+ goto out;
+ }
+
+ item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
+ refs = btrfs_extent_refs(l, item);
+ while (1) {
+ nritems = btrfs_header_nritems(l);
+ if (path->slots[0] >= nritems) {
+ ret = btrfs_next_leaf(extent_root, path);
+ if (ret == 0)
+ continue;
+ break;
+ }
+ btrfs_item_key_to_cpu(l, &found_key, path->slots[0]);
+ if (found_key.objectid != bytenr)
+ break;
+ if (found_key.type != BTRFS_EXTENT_REF_KEY) {
+ path->slots[0]++;
+ continue;
+ }
+
+ cur_count++;
+ ref_item = btrfs_item_ptr(l, path->slots[0],
+ struct btrfs_extent_ref);
+ found_objectid = btrfs_ref_root(l, ref_item);
+
+ if (found_objectid != root_objectid)
+ total_count++;
+
+ if (total_count > 1)
+ goto out;
+
+ if (root_objectid == 0)
+ root_objectid = found_objectid;
+
+ path->slots[0]++;
+ }
+ if (cur_count == 0) {
+ total_count = 0;
+ goto out;
+ }
+ if (total_count > 1)
+ goto out;
+ if (level >= 0 && root->node == count_path->nodes[level])
+ goto out;
+ level++;
+ btrfs_release_path(root, path);
+ goto again;
+
+out:
+ btrfs_free_path(path);
+ return total_count;
+
+}
+
int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 owner_objectid)
{
if (!path)
return -ENOMEM;
- if (ref_generation && owner_objectid == 0 && root_objectid == 3) {
-//printk("drop backref root %Lu gen %Lu byte %Lu\n", root_objectid, ref_generation, bytenr );
- }
ret = lookup_extent_backref(trans, extent_root, path,
bytenr, root_objectid,
ref_generation,
[S_IFLNK >> S_SHIFT] = BTRFS_FT_SYMLINK,
};
-static int run_delalloc_range(struct inode *inode, u64 start, u64 end)
+static int cow_file_range(struct inode *inode, u64 start, u64 end)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_trans_handle *trans;
- struct btrfs_key ins;
u64 alloc_hint = 0;
u64 num_bytes;
- int ret;
u64 blocksize = root->sectorsize;
+ struct btrfs_key ins;
+ int ret;
- mutex_lock(&root->fs_info->fs_mutex);
trans = btrfs_start_transaction(root, 1);
- btrfs_set_trans_block_group(trans, inode);
BUG_ON(!trans);
+ btrfs_set_trans_block_group(trans, inode);
+
num_bytes = (end - start + blocksize) & ~(blocksize - 1);
+ num_bytes = max(blocksize, num_bytes);
ret = btrfs_drop_extents(trans, root, inode,
start, start + num_bytes, start, &alloc_hint);
ins.offset);
out:
btrfs_end_transaction(trans, root);
+ return ret;
+}
+
+static int run_delalloc_nocow(struct inode *inode, u64 start, u64 end)
+{
+ u64 extent_start;
+ u64 extent_end;
+ u64 bytenr;
+ u64 cow_end;
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct extent_buffer *leaf;
+ int found_type;
+ struct btrfs_path *path;
+ struct btrfs_file_extent_item *item;
+ int ret;
+ int err;
+ struct btrfs_key found_key;
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+again:
+ ret = btrfs_lookup_file_extent(NULL, root, path,
+ inode->i_ino, start, 0);
+ if (ret < 0) {
+ btrfs_free_path(path);
+ return ret;
+ }
+
+ cow_end = end;
+ if (ret != 0) {
+ if (path->slots[0] == 0)
+ goto not_found;
+ path->slots[0]--;
+ }
+
+ leaf = path->nodes[0];
+ item = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+
+ /* are we inside the extent that was found? */
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ found_type = btrfs_key_type(&found_key);
+ if (found_key.objectid != inode->i_ino ||
+ found_type != BTRFS_EXTENT_DATA_KEY) {
+ goto not_found;
+ }
+
+ found_type = btrfs_file_extent_type(leaf, item);
+ extent_start = found_key.offset;
+ if (found_type == BTRFS_FILE_EXTENT_REG) {
+ extent_end = extent_start +
+ btrfs_file_extent_num_bytes(leaf, item);
+ err = 0;
+
+ if (start < extent_start || start >= extent_end)
+ goto not_found;
+
+ cow_end = min(end, extent_end - 1);
+ bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
+ if (bytenr == 0)
+ goto not_found;
+
+ bytenr += btrfs_file_extent_offset(leaf, item);
+ if (btrfs_count_snapshots_in_path(root, path, bytenr) != 1) {
+ goto not_found;
+ }
+
+ start = extent_end;
+ } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+ goto not_found;
+ }
+loop:
+ if (start > end) {
+ btrfs_free_path(path);
+ return 0;
+ }
+ btrfs_release_path(root, path);
+ goto again;
+
+not_found:
+ cow_file_range(inode, start, cow_end);
+ start = cow_end + 1;
+ goto loop;
+}
+
+static int run_delalloc_range(struct inode *inode, u64 start, u64 end)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ int ret;
+
+ mutex_lock(&root->fs_info->fs_mutex);
+ if (btrfs_test_opt(root, NODATACOW))
+ ret = run_delalloc_nocow(inode, start, end);
+ else
+ ret = cow_file_range(inode, start, end);
mutex_unlock(&root->fs_info->fs_mutex);
return ret;
}
btrfs_cow_one_page(inode, page, PAGE_CACHE_SIZE);
- set_page_extent_mapped(page);
- set_page_dirty(page);
-
if (pos > inode->i_size) {
i_size_write(inode, pos);
mark_inode_dirty(inode);
key.objectid = objectid;
key.offset = 1;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+
extent_buffer_get(root->node);
btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
free_extent_buffer(tmp);
- btrfs_set_root_bytenr(&new_root_item, root->node->start);
- btrfs_set_root_level(&new_root_item, btrfs_header_level(root->node));
+
+ btrfs_copy_root(trans, root, root->node, &tmp, objectid);
+
+ btrfs_set_root_bytenr(&new_root_item, tmp->start);
+ btrfs_set_root_level(&new_root_item, btrfs_header_level(tmp));
ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
&new_root_item);
+ free_extent_buffer(tmp);
if (ret)
goto fail;
if (ret)
goto fail;
-
- ret = btrfs_inc_root_ref(trans, root, objectid);
- if (ret)
- goto fail;
fail:
nr = trans->blocks_used;
err = btrfs_commit_transaction(trans, root);
}
enum {
- Opt_subvol, Opt_nodatasum, Opt_err,
+ Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_err,
};
static match_table_t tokens = {
{Opt_subvol, "subvol=%s"},
{Opt_nodatasum, "nodatasum"},
+ {Opt_nodatacow, "nodatacow"},
{Opt_err, NULL}
};
struct btrfs_fs_info *info = NULL;
substring_t args[MAX_OPT_ARGS];
- if (root)
- info = root->fs_info;
-
if (!options)
return 1;
+ /*
+ * strsep changes the string, duplicate it because parse_options
+ * gets called twice
+ */
+ options = kstrdup(options, GFP_NOFS);
+ if (!options)
+ return -ENOMEM;
+
+ if (root)
+ info = root->fs_info;
+
while ((p = strsep (&options, ",")) != NULL) {
int token;
if (!*p)
token = match_token(p, tokens, args);
switch (token) {
case Opt_subvol:
- if (subvol_name)
+ if (subvol_name) {
*subvol_name = match_strdup(&args[0]);
+ }
break;
case Opt_nodatasum:
- if (root)
+ if (info) {
+ printk("btrfs: setting nodatacsum\n");
btrfs_set_opt(info->mount_opt, NODATASUM);
+ }
+ break;
+ case Opt_nodatacow:
+ if (info) {
+ printk("btrfs: setting nodatacow\n");
+ btrfs_set_opt(info->mount_opt, NODATACOW);
+ btrfs_set_opt(info->mount_opt, NODATASUM);
+ }
break;
default:
- return 0;
+ break;
}
}
+ kfree(options);
return 1;
}
projects / platform / kernel / linux-rpi.git / commitdiff