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btrfs_get_block, file read/write 

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2007-03-26 16:00:06 -04:00 committed by David Woodhouse
parent 4730a4bc5b
commit dee26a9f7a
5 changed files with 230 additions and 41 deletions
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1
fs/btrfs/TODO
View File

@ -8,6 +8,7 @@
* Add block mapping tree (simple dm layer)
* Add simple tree locking (semaphore per tree)
* Make allocator smarter
* Make directory hashing work on 32 bit
* Do actual block accounting
* Check compat and incompat flags on the inode
* Add virtual filesystems, mountable snapshots

26
fs/btrfs/ctree.h
View File

@ -198,7 +198,7 @@ struct btrfs_file_extent_item {
__le64 disk_blocknr;
__le64 disk_num_blocks;
/*
* the logical offset in file bytes (no csums)
* the logical offset in file blocks (no csums)
* this extent record is for. This allows a file extent to point
* into the middle of an existing extent on disk, sharing it
* between two snapshots (useful if some bytes in the middle of the
@ -812,12 +812,19 @@ static inline struct btrfs_root *btrfs_sb(struct super_block *sb)
((type *)(btrfs_leaf_data(leaf) + \
btrfs_item_offset((leaf)->items + (slot))))
/* extent-item.c */
struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root);
int btrfs_alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 num_blocks, u64 search_start, u64
search_end, u64 owner, struct btrfs_key *ins);
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct buffer_head *buf);
int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 blocknr, u64 num_blocks, int pin);
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
btrfs_root *root);
/* ctree.c */
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_key *key, struct btrfs_path *p, int
ins_len, int cow);
@ -834,8 +841,7 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
int btrfs_leaf_free_space(struct btrfs_root *root, struct btrfs_leaf *leaf);
int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct buffer_head *snap);
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
btrfs_root *root);
/* root-item.c */
int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
struct btrfs_key *key);
int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
@ -846,6 +852,7 @@ int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
*item);
int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
btrfs_root_item *item, struct btrfs_key *key);
/* dir-item.c */
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, const char *name, int name_len, u64 dir, u64
objectid, u8 type);
@ -854,6 +861,7 @@ int btrfs_lookup_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
const char *name, int name_len, int mod);
int btrfs_match_dir_item_name(struct btrfs_root *root, struct btrfs_path *path,
const char *name, int name_len);
/* inode-map.c */
int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
struct btrfs_root *fs_root,
u64 dirid, u64 *objectid);
@ -863,9 +871,21 @@ int btrfs_insert_inode_map(struct btrfs_trans_handle *trans,
int btrfs_lookup_inode_map(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct btrfs_path *path,
u64 objectid, int mod);
/* inode-item.c */
int btrfs_insert_inode(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 objectid, struct btrfs_inode_item
*inode_item);
int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
*root, struct btrfs_path *path, u64 objectid, int mod);
/* file-item.c */
int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
u64 num_blocks, u64 hint_block,
u64 *result);
int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid,
u64 blocknr, u64 num_blocks, int mod);
#endif

4
fs/btrfs/extent-tree.c
View File

@ -403,7 +403,7 @@ error:
*
* returns 0 if everything worked, non-zero otherwise.
*/
static int alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
int btrfs_alloc_extent(struct btrfs_trans_handle *trans, struct btrfs_root
*root, u64 num_blocks, u64 search_start, u64
search_end, u64 owner, struct btrfs_key *ins)
{
@ -458,7 +458,7 @@ struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
int ret;
struct buffer_head *buf;
ret = alloc_extent(trans, root, 1, 0, (unsigned long)-1,
ret = btrfs_alloc_extent(trans, root, 1, 0, (unsigned long)-1,
btrfs_header_parentid(btrfs_buffer_header(root->node)), &ins);
if (ret) {
BUG();

52
fs/btrfs/file-item.c
View File

@ -1,9 +1,57 @@
#include <linux/module.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
int btrfs_create_file(struct btrfs_trans_handle *trans,
struct btrfs_root *root, u64 dirid, u64 *objectid)
int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
u64 num_blocks, u64 hint_block,
u64 *result)
{
struct btrfs_key ins;
int ret = 0;
struct btrfs_file_extent_item *item;
struct btrfs_key file_key;
struct btrfs_path path;
btrfs_init_path(&path);
ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
(u64)-1, objectid, &ins);
BUG_ON(ret);
file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
sizeof(*item));
item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
btrfs_set_file_extent_offset(item, 0);
btrfs_set_file_extent_num_blocks(item, ins.offset);
mark_buffer_dirty(path.nodes[0]);
*result = ins.objectid;
btrfs_release_path(root, &path);
return 0;
}
int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid,
u64 blocknr, u64 num_blocks, int mod)
{
int ret;
struct btrfs_key file_key;
int ins_len = mod < 0 ? -1 : 0;
int cow = mod != 0;
file_key.objectid = objectid;
file_key.offset = blocknr;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
return ret;
}

188
fs/btrfs/super.c
View File

@ -8,6 +8,7 @@
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
@ -17,6 +18,9 @@
static struct inode_operations btrfs_dir_inode_operations;
static struct super_operations btrfs_super_ops;
static struct file_operations btrfs_dir_file_operations;
static struct inode_operations btrfs_file_inode_operations;
static struct address_space_operations btrfs_aops;
static struct file_operations btrfs_file_operations;
static void btrfs_read_locked_inode(struct inode *inode)
{
@ -57,6 +61,9 @@ static void btrfs_read_locked_inode(struct inode *inode)
break;
#endif
case S_IFREG:
inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
break;
case S_IFDIR:
inode->i_op = &btrfs_dir_inode_operations;
@ -214,35 +221,6 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
return d_splice_alias(inode, dentry);
}
static void reada_leaves(struct btrfs_root *root, struct btrfs_path *path)
{
struct buffer_head *bh;
struct btrfs_node *node;
int i;
int nritems;
u64 objectid;
u64 item_objectid;
u64 blocknr;
int slot;
if (!path->nodes[1])
return;
node = btrfs_buffer_node(path->nodes[1]);
slot = path->slots[1];
objectid = btrfs_disk_key_objectid(&node->ptrs[slot].key);
nritems = btrfs_header_nritems(&node->header);
for (i = slot; i < nritems; i++) {
item_objectid = btrfs_disk_key_objectid(&node->ptrs[i].key);
if (item_objectid != objectid)
break;
blocknr = btrfs_node_blockptr(node, i);
bh = sb_getblk(root->fs_info->sb, blocknr);
ll_rw_block(READ, 1, &bh);
brelse(bh);
}
}
static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct inode *inode = filp->f_path.dentry->d_inode;
@ -269,21 +247,18 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
goto err;
}
advance = 0;
reada_leaves(root, &path);
while(1) {
leaf = btrfs_buffer_leaf(path.nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
slot = path.slots[0];
if (advance) {
if (slot == nritems -1) {
if (advance || slot >= nritems) {
if (slot >= nritems -1) {
ret = btrfs_next_leaf(root, &path);
if (ret)
break;
leaf = btrfs_buffer_leaf(path.nodes[0]);
nritems = btrfs_header_nritems(&leaf->header);
slot = path.slots[0];
if (path.nodes[1] && path.slots[1] == 0)
reada_leaves(root, &path);
} else {
slot++;
path.slots[0]++;
@ -297,6 +272,8 @@ static int btrfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
continue;
if (btrfs_disk_key_offset(&item->key) < filp->f_pos)
continue;
advance = 1;
di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
over = filldir(dirent, (const char *)(di + 1),
btrfs_dir_name_len(di),
@ -524,6 +501,11 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
err = btrfs_add_nondir(trans, dentry, inode);
if (err)
drop_inode = 1;
else {
inode->i_mapping->a_ops = &btrfs_aops;
inode->i_fop = &btrfs_file_operations;
inode->i_op = &btrfs_file_inode_operations;
}
dir->i_sb->s_dirt = 1;
btrfs_end_transaction(trans, root);
out_unlock:
@ -623,11 +605,124 @@ printk("btrfs sync_fs\n");
return 0;
}
static int btrfs_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *result, int create)
{
int ret;
int err = 0;
u64 blocknr;
u64 extent_start = 0;
u64 extent_end = 0;
u64 objectid = inode->i_ino;
struct btrfs_path path;
struct btrfs_root *root = btrfs_sb(inode->i_sb);
struct btrfs_trans_handle *trans = NULL;
struct btrfs_file_extent_item *item;
struct btrfs_leaf *leaf;
struct btrfs_disk_key *found_key;
btrfs_init_path(&path);
mutex_lock(&root->fs_info->fs_mutex);
if (create)
trans = btrfs_start_transaction(root, 1);
ret = btrfs_lookup_file_extent(trans, root, &path,
inode->i_ino, iblock, 1, 0);
if (ret < 0) {
btrfs_release_path(root, &path);
err = ret;
goto out;
}
if (ret != 0) {
if (path.slots[0] == 0) {
btrfs_release_path(root, &path);
goto allocate;
}
path.slots[0]--;
}
item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
struct btrfs_file_extent_item);
leaf = btrfs_buffer_leaf(path.nodes[0]);
blocknr = btrfs_file_extent_disk_blocknr(item);
blocknr += btrfs_file_extent_offset(item);
/* exact match found, use it */
if (ret == 0) {
err = 0;
map_bh(result, inode->i_sb, blocknr);
btrfs_release_path(root, &path);
goto out;
}
/* are we inside the extent that was found? */
found_key = &leaf->items[path.slots[0]].key;
if (btrfs_disk_key_objectid(found_key) != objectid ||
btrfs_disk_key_type(found_key) != BTRFS_EXTENT_DATA_KEY) {
extent_end = 0;
extent_start = 0;
btrfs_release_path(root, &path);
goto allocate;
}
extent_start = btrfs_disk_key_offset(&leaf->items[path.slots[0]].key);
extent_start += btrfs_file_extent_offset(item);
extent_end = extent_start + btrfs_file_extent_num_blocks(item);
btrfs_release_path(root, &path);
if (iblock >= extent_start && iblock < extent_end) {
err = 0;
map_bh(result, inode->i_sb, blocknr + iblock - extent_start);
goto out;
}
allocate:
/* ok, create a new extent */
if (!create) {
err = 0;
goto out;
}
ret = btrfs_alloc_file_extent(trans, root, objectid, iblock,
1, extent_end, &blocknr);
if (ret) {
err = ret;
goto out;
}
map_bh(result, inode->i_sb, blocknr);
out:
if (trans)
btrfs_end_transaction(trans, root);
mutex_unlock(&root->fs_info->fs_mutex);
return err;
}
static int btrfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
return block_prepare_write(page, from, to, btrfs_get_block);
}
static void btrfs_write_super(struct super_block *sb)
{
btrfs_sync_fs(sb, 1);
}
static int btrfs_readpage(struct file *file, struct page *page)
{
return mpage_readpage(page, btrfs_get_block);
}
static int btrfs_readpages(struct file *file, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, btrfs_get_block);
}
static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, btrfs_get_block, wbc);
}
static int btrfs_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
@ -667,6 +762,31 @@ static struct file_operations btrfs_dir_file_operations = {
.readdir = btrfs_readdir,
};
static struct address_space_operations btrfs_aops = {
.readpage = btrfs_readpage,
.readpages = btrfs_readpages,
.writepage = btrfs_writepage,
.sync_page = block_sync_page,
.prepare_write = btrfs_prepare_write,
.commit_write = generic_commit_write,
};
static struct inode_operations btrfs_file_inode_operations = {
.truncate = NULL,
};
static struct file_operations btrfs_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = generic_file_aio_read,
.aio_write = generic_file_aio_write,
.mmap = generic_file_mmap,
.open = generic_file_open,
.sendfile = generic_file_sendfile,
.splice_read = generic_file_splice_read,
.splice_write = generic_file_splice_write,
};
static int __init init_btrfs_fs(void)
{