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Btrfs: Add a write ahead tree log to optimize synchronous operations
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File syncs and directory syncs are optimized by copying their
items into a special (copy-on-write) log tree.  There is one log tree per
subvolume and the btrfs super block points to a tree of log tree roots.

After a crash, items are copied out of the log tree and back into the
subvolume.  See tree-log.c for all the details.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
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@chrismason-xx
chrismason-xx committed Sep 25, 2008
1 parent a1b32a5 commit e02119d
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Showing 17 changed files with 3,408 additions and 205 deletions.
3 changes: 1 addition & 2 deletions fs/btrfs/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -7,8 +7,7 @@ btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
transaction.o bit-radix.o inode.o file.o tree-defrag.o \
extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \
ref-cache.o acl.o export.o

ref-cache.o export.o tree-log.o acl.o
else

# Normal Makefile
Expand Down
8 changes: 8 additions & 0 deletions fs/btrfs/btrfs_inode.h
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ struct btrfs_inode {
struct extent_io_tree io_failure_tree;
struct mutex csum_mutex;
struct mutex extent_mutex;
struct mutex log_mutex;
struct inode vfs_inode;
struct btrfs_ordered_inode_tree ordered_tree;

Expand All @@ -44,10 +45,17 @@ struct btrfs_inode {

struct list_head delalloc_inodes;

/* full 64 bit generation number */
u64 generation;

/*
* transid of the trans_handle that last modified this inode
*/
u64 last_trans;
/*
* transid that last logged this inode
*/
u64 logged_trans;
u64 delalloc_bytes;
u64 disk_i_size;
u32 flags;
Expand Down
15 changes: 15 additions & 0 deletions fs/btrfs/compat.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,21 @@ static inline struct dentry *d_obtain_alias(struct inode *inode)
}
#endif

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
static inline void btrfs_drop_nlink(struct inode *inode)
{
inode->i_nlink--;
}

static inline void btrfs_inc_nlink(struct inode *inode)
{
inode->i_nlink++;
}
#else
# define btrfs_drop_nlink(inode) drop_nlink(inode)
# define btrfs_inc_nlink(inode) inc_nlink(inode)
#endif

/*
* Even if AppArmor isn't enabled, it still has different prototypes.
* Add more distro/version pairs here to declare which has AppArmor applied.
Expand Down
73 changes: 54 additions & 19 deletions fs/btrfs/ctree.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ void btrfs_free_path(struct btrfs_path *p)
kmem_cache_free(btrfs_path_cachep, p);
}

void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
void noinline btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
{
int i;

Expand Down Expand Up @@ -176,7 +176,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
return 0;
}

int __btrfs_cow_block(struct btrfs_trans_handle *trans,
int noinline __btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
Expand Down Expand Up @@ -294,7 +294,7 @@ int __btrfs_cow_block(struct btrfs_trans_handle *trans,
return 0;
}

int btrfs_cow_block(struct btrfs_trans_handle *trans,
int noinline btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret, u64 prealloc_dest)
Expand Down Expand Up @@ -677,9 +677,10 @@ static int noinline check_block(struct btrfs_root *root,
*
* slot may point to max if the key is bigger than all of the keys
*/
static int generic_bin_search(struct extent_buffer *eb, unsigned long p,
int item_size, struct btrfs_key *key,
int max, int *slot)
static noinline int generic_bin_search(struct extent_buffer *eb,
unsigned long p,
int item_size, struct btrfs_key *key,
int max, int *slot)
{
int low = 0;
int high = max;
Expand Down Expand Up @@ -765,7 +766,7 @@ static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
return -1;
}

static struct extent_buffer *read_node_slot(struct btrfs_root *root,
static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
struct extent_buffer *parent, int slot)
{
int level = btrfs_header_level(parent);
Expand All @@ -781,7 +782,7 @@ static struct extent_buffer *read_node_slot(struct btrfs_root *root,
btrfs_node_ptr_generation(parent, slot));
}

static int balance_level(struct btrfs_trans_handle *trans,
static noinline int balance_level(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
Expand Down Expand Up @@ -1128,8 +1129,9 @@ static int noinline push_nodes_for_insert(struct btrfs_trans_handle *trans,
/*
* readahead one full node of leaves
*/
static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
int level, int slot, u64 objectid)
static noinline void reada_for_search(struct btrfs_root *root,
struct btrfs_path *path,
int level, int slot, u64 objectid)
{
struct extent_buffer *node;
struct btrfs_disk_key disk_key;
Expand Down Expand Up @@ -1201,7 +1203,8 @@ static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
}
}

static void unlock_up(struct btrfs_path *path, int level, int lowest_unlock)
static noinline void unlock_up(struct btrfs_path *path, int level,
int lowest_unlock)
{
int i;
int skip_level = level;
Expand Down Expand Up @@ -1759,8 +1762,9 @@ static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
*
* returns 0 on success and < 0 on failure
*/
static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, int level)
static noinline int split_node(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, int level)
{
u64 root_gen;
struct extent_buffer *c;
Expand Down Expand Up @@ -1874,7 +1878,8 @@ static int leaf_space_used(struct extent_buffer *l, int start, int nr)
* the start of the leaf data. IOW, how much room
* the leaf has left for both items and data
*/
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf)
int noinline btrfs_leaf_free_space(struct btrfs_root *root,
struct extent_buffer *leaf)
{
int nritems = btrfs_header_nritems(leaf);
int ret;
Expand Down Expand Up @@ -2283,9 +2288,11 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
*
* returns 0 if all went well and < 0 on failure.
*/
static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *ins_key,
struct btrfs_path *path, int data_size, int extend)
static noinline int split_leaf(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_key *ins_key,
struct btrfs_path *path, int data_size,
int extend)
{
u64 root_gen;
struct extent_buffer *l;
Expand Down Expand Up @@ -3079,6 +3086,7 @@ int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
* was nothing in the tree that matched the search criteria.
*/
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
struct btrfs_key *max_key,
struct btrfs_path *path, int cache_only,
u64 min_trans)
{
Expand All @@ -3093,6 +3101,7 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
again:
cur = btrfs_lock_root_node(root);
level = btrfs_header_level(cur);
WARN_ON(path->nodes[level]);
path->nodes[level] = cur;
path->locks[level] = 1;

Expand All @@ -3107,6 +3116,8 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,

/* at level = 0, we're done, setup the path and exit */
if (level == 0) {
if (slot >= nritems)
goto find_next_key;
ret = 0;
path->slots[level] = slot;
btrfs_item_key_to_cpu(cur, &found_key, slot);
Expand All @@ -3123,6 +3134,8 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
u64 blockptr;
u64 gen;
struct extent_buffer *tmp;
struct btrfs_disk_key disk_key;

blockptr = btrfs_node_blockptr(cur, slot);
gen = btrfs_node_ptr_generation(cur, slot);
if (gen < min_trans) {
Expand All @@ -3132,6 +3145,14 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
if (!cache_only)
break;

if (max_key) {
btrfs_node_key(cur, &disk_key, slot);
if (comp_keys(&disk_key, max_key) >= 0) {
ret = 1;
goto out;
}
}

tmp = btrfs_find_tree_block(root, blockptr,
btrfs_level_size(root, level - 1));

Expand All @@ -3143,14 +3164,16 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
free_extent_buffer(tmp);
slot++;
}
find_next_key:
/*
* we didn't find a candidate key in this node, walk forward
* and find another one
*/
if (slot >= nritems) {
ret = btrfs_find_next_key(root, path, min_key, level,
path->slots[level] = slot;
sret = btrfs_find_next_key(root, path, min_key, level,
cache_only, min_trans);
if (ret == 0) {
if (sret == 0) {
btrfs_release_path(root, path);
goto again;
} else {
Expand Down Expand Up @@ -3351,6 +3374,7 @@ int btrfs_previous_item(struct btrfs_root *root,
{
struct btrfs_key found_key;
struct extent_buffer *leaf;
u32 nritems;
int ret;

while(1) {
Expand All @@ -3362,9 +3386,20 @@ int btrfs_previous_item(struct btrfs_root *root,
path->slots[0]--;
}
leaf = path->nodes[0];
nritems = btrfs_header_nritems(leaf);
if (nritems == 0)
return 1;
if (path->slots[0] == nritems)
path->slots[0]--;

btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
if (found_key.type == type)
return 0;
if (found_key.objectid < min_objectid)
break;
if (found_key.objectid == min_objectid &&
found_key.type < type)
break;
}
return 1;
}
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