mirror of https://gitee.com/openkylin/linux.git
Btrfs: early inline file data code
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
David Woodhouse
parent
9d64272cd3
commit
df24a2b9c9
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@ -16,21 +16,26 @@ static int balance_node_right(struct btrfs_trans_handle *trans, struct
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static int del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
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struct btrfs_path *path, int level, int slot);
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inline void btrfs_init_path(struct btrfs_path *p)
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{
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memset(p, 0, sizeof(*p));
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}
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struct btrfs_path *btrfs_alloc_path(void)
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{
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return kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
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struct btrfs_path *path;
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path = kmem_cache_alloc(btrfs_path_cachep, GFP_NOFS);
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if (path)
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btrfs_init_path(path);
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return path;
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}
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void btrfs_free_path(struct btrfs_path *p)
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{
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btrfs_release_path(NULL, p);
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kmem_cache_free(btrfs_path_cachep, p);
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}
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inline void btrfs_init_path(struct btrfs_path *p)
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{
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memset(p, 0, sizeof(*p));
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}
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void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p)
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{
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int i;
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@ -77,6 +82,7 @@ static int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
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btrfs_free_extent(trans, root, buf->b_blocknr, 1, 1);
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}
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btrfs_block_release(root, buf);
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mark_buffer_dirty(cow);
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*cow_ret = cow;
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return 0;
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}
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240
fs/btrfs/super.c
240
fs/btrfs/super.c
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@ -816,6 +816,73 @@ printk("btrfs sync_fs\n");
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return 0;
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}
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static int btrfs_get_block_inline(struct inode *inode, sector_t iblock,
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struct buffer_head *result, int create)
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{
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struct btrfs_root *root = btrfs_sb(inode->i_sb);
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struct btrfs_path *path;
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struct btrfs_key key;
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struct btrfs_leaf *leaf;
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int num_bytes = result->b_size;
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int item_size;
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int ret;
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u64 pos;
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char *ptr;
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int copy_size;
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int err = 0;
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char *safe_ptr;
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char *data_ptr;
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path = btrfs_alloc_path();
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BUG_ON(!path);
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WARN_ON(create);
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if (create) {
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return 0;
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}
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pos = iblock << inode->i_blkbits;
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key.objectid = inode->i_ino;
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key.flags = 0;
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btrfs_set_key_type(&key, BTRFS_INLINE_DATA_KEY);
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ptr = kmap(result->b_page);
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safe_ptr = ptr;
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ptr += (pos & (PAGE_CACHE_SIZE -1));
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again:
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key.offset = pos;
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ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
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if (ret) {
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if (ret < 0)
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err = ret;
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else
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err = 0;
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goto out;
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}
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leaf = btrfs_buffer_leaf(path->nodes[0]);
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item_size = btrfs_item_size(leaf->items + path->slots[0]);
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copy_size = min(num_bytes, item_size);
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data_ptr = btrfs_item_ptr(leaf, path->slots[0], char);
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WARN_ON(safe_ptr + PAGE_CACHE_SIZE < ptr + copy_size);
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memcpy(ptr, data_ptr, copy_size);
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pos += copy_size;
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num_bytes -= copy_size;
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WARN_ON(num_bytes < 0);
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ptr += copy_size;
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btrfs_release_path(root, path);
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if (num_bytes != 0) {
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if (pos >= i_size_read(inode))
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memset(ptr, 0, num_bytes);
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else
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goto again;
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}
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set_buffer_uptodate(result);
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map_bh(result, inode->i_sb, 0);
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err = 0;
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out:
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btrfs_free_path(path);
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kunmap(result->b_page);
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return err;
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}
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static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
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struct buffer_head *result, int create)
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{
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@ -918,7 +985,8 @@ static int btrfs_get_block(struct inode *inode, sector_t iblock,
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int err;
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struct btrfs_root *root = btrfs_sb(inode->i_sb);
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mutex_lock(&root->fs_info->fs_mutex);
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err = btrfs_get_block_lock(inode, iblock, result, create);
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// err = btrfs_get_block_lock(inode, iblock, result, create);
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err = btrfs_get_block_inline(inode, iblock, result, create);
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mutex_unlock(&root->fs_info->fs_mutex);
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return err;
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}
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@ -1177,6 +1245,170 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
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return num_written ? num_written : err;
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}
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static ssize_t inline_one_page(struct btrfs_root *root, struct inode *inode,
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struct page *page, loff_t pos,
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size_t offset, size_t write_bytes)
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{
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struct btrfs_path *path;
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struct btrfs_trans_handle *trans;
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struct btrfs_key key;
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struct btrfs_leaf *leaf;
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struct btrfs_key found_key;
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int ret;
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size_t copy_size = 0;
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char *dst = NULL;
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int err = 0;
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size_t num_written = 0;
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path = btrfs_alloc_path();
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BUG_ON(!path);
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mutex_lock(&root->fs_info->fs_mutex);
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trans = btrfs_start_transaction(root, 1);
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key.objectid = inode->i_ino;
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key.flags = 0;
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btrfs_set_key_type(&key, BTRFS_INLINE_DATA_KEY);
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again:
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key.offset = pos;
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ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
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if (ret < 0) {
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err = ret;
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goto out;
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}
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if (ret == 0) {
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leaf = btrfs_buffer_leaf(path->nodes[0]);
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btrfs_disk_key_to_cpu(&found_key,
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&leaf->items[path->slots[0]].key);
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copy_size = btrfs_item_size(leaf->items + path->slots[0]);
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dst = btrfs_item_ptr(leaf, path->slots[0], char);
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copy_size = min(write_bytes, copy_size);
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goto copyit;
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} else {
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int slot = path->slots[0];
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if (slot > 0) {
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slot--;
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}
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// FIXME find max key
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leaf = btrfs_buffer_leaf(path->nodes[0]);
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btrfs_disk_key_to_cpu(&found_key,
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&leaf->items[slot].key);
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if (found_key.objectid != inode->i_ino)
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goto insert;
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if (btrfs_key_type(&found_key) != BTRFS_INLINE_DATA_KEY)
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goto insert;
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copy_size = btrfs_item_size(leaf->items + slot);
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if (found_key.offset + copy_size <= pos)
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goto insert;
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dst = btrfs_item_ptr(leaf, path->slots[0], char);
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dst += pos - found_key.offset;
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copy_size = copy_size - (pos - found_key.offset);
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BUG_ON(copy_size < 0);
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copy_size = min(write_bytes, copy_size);
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WARN_ON(copy_size == 0);
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goto copyit;
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}
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insert:
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btrfs_release_path(root, path);
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copy_size = min(write_bytes, (size_t)512);
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ret = btrfs_insert_empty_item(trans, root, path, &key, copy_size);
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BUG_ON(ret);
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dst = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
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path->slots[0], char);
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copyit:
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WARN_ON(copy_size == 0);
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WARN_ON(dst + copy_size >
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btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
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path->slots[0], char) +
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btrfs_item_size(btrfs_buffer_leaf(path->nodes[0])->items +
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path->slots[0]));
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btrfs_memcpy(root, path->nodes[0]->b_data, dst,
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page_address(page) + offset, copy_size);
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mark_buffer_dirty(path->nodes[0]);
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btrfs_release_path(root, path);
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pos += copy_size;
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offset += copy_size;
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num_written += copy_size;
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write_bytes -= copy_size;
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if (write_bytes)
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goto again;
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out:
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btrfs_free_path(path);
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ret = btrfs_end_transaction(trans, root);
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BUG_ON(ret);
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mutex_unlock(&root->fs_info->fs_mutex);
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return num_written ? num_written : err;
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}
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static ssize_t btrfs_file_inline_write(struct file *file,
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const char __user *buf,
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size_t count, loff_t *ppos)
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{
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loff_t pos;
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size_t num_written = 0;
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int err = 0;
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int ret = 0;
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struct inode *inode = file->f_path.dentry->d_inode;
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struct btrfs_root *root = btrfs_sb(inode->i_sb);
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unsigned long page_index;
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if (file->f_flags & O_DIRECT)
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return -EINVAL;
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pos = *ppos;
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vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
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current->backing_dev_info = inode->i_mapping->backing_dev_info;
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err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
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if (err)
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goto out;
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if (count == 0)
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goto out;
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err = remove_suid(file->f_path.dentry);
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if (err)
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goto out;
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file_update_time(file);
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mutex_lock(&inode->i_mutex);
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while(count > 0) {
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size_t offset = pos & (PAGE_CACHE_SIZE - 1);
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size_t write_bytes = min(count, PAGE_CACHE_SIZE - offset);
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struct page *page;
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page_index = pos >> PAGE_CACHE_SHIFT;
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page = grab_cache_page(inode->i_mapping, page_index);
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if (!PageUptodate(page)) {
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ret = mpage_readpage(page, btrfs_get_block);
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BUG_ON(ret);
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lock_page(page);
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}
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ret = btrfs_copy_from_user(pos, 1,
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write_bytes, &page, buf);
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BUG_ON(ret);
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write_bytes = inline_one_page(root, inode, page, pos,
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offset, write_bytes);
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SetPageUptodate(page);
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if (write_bytes > 0 && pos + write_bytes > inode->i_size) {
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i_size_write(inode, pos + write_bytes);
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mark_inode_dirty(inode);
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}
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page_cache_release(page);
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unlock_page(page);
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if (write_bytes < 0)
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goto out_unlock;
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buf += write_bytes;
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count -= write_bytes;
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pos += write_bytes;
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num_written += write_bytes;
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balance_dirty_pages_ratelimited(inode->i_mapping);
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cond_resched();
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}
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out_unlock:
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mutex_unlock(&inode->i_mutex);
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out:
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*ppos = pos;
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current->backing_dev_info = NULL;
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return num_written ? num_written : err;
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}
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static int btrfs_read_actor(read_descriptor_t *desc, struct page *page,
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unsigned long offset, unsigned long size)
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{
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@ -1420,7 +1652,7 @@ static struct file_operations btrfs_dir_file_operations = {
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static struct address_space_operations btrfs_aops = {
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.readpage = btrfs_readpage,
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.readpages = btrfs_readpages,
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// .readpages = btrfs_readpages,
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.writepage = btrfs_writepage,
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.sync_page = block_sync_page,
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.prepare_write = btrfs_prepare_write,
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@ -1434,8 +1666,8 @@ static struct inode_operations btrfs_file_inode_operations = {
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static struct file_operations btrfs_file_operations = {
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.llseek = generic_file_llseek,
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.read = do_sync_read,
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.aio_read = btrfs_file_aio_read,
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.write = btrfs_file_write,
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.aio_read = generic_file_aio_read,
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.write = btrfs_file_inline_write,
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.mmap = generic_file_mmap,
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.open = generic_file_open,
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};
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