- 根目录:
- fs
- reiserfs
- tail_conversion.c
/*
* Copyright 1999 Hans Reiser, see reiserfs/README for licensing and copyright
* details
*/
#include <linux/time.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include "reiserfs.h"
/*
* access to tail : when one is going to read tail it must make sure, that is
* not running. direct2indirect and indirect2direct can not run concurrently
*/
/*
* Converts direct items to an unformatted node. Panics if file has no
* tail. -ENOSPC if no disk space for conversion
*/
/*
* path points to first direct item of the file regardless of how many of
* them are there
*/
int direct2indirect(struct reiserfs_transaction_handle *th, struct inode *inode,
struct treepath *path, struct buffer_head *unbh,
loff_t tail_offset)
{
struct super_block *sb = inode->i_sb;
struct buffer_head *up_to_date_bh;
struct item_head *p_le_ih = tp_item_head(path);
unsigned long total_tail = 0;
/* Key to search for the last byte of the converted item. */
struct cpu_key end_key;
/*
* new indirect item to be inserted or key
* of unfm pointer to be pasted
*/
struct item_head ind_ih;
int blk_size;
/* returned value for reiserfs_insert_item and clones */
int retval;
/* Handle on an unformatted node that will be inserted in the tree. */
unp_t unfm_ptr;
BUG_ON(!th->t_trans_id);
REISERFS_SB(sb)->s_direct2indirect++;
blk_size = sb->s_blocksize;
/*
* and key to search for append or insert pointer to the new
* unformatted node.
*/
copy_item_head(&ind_ih, p_le_ih);
set_le_ih_k_offset(&ind_ih, tail_offset);
set_le_ih_k_type(&ind_ih, TYPE_INDIRECT);
/* Set the key to search for the place for new unfm pointer */
make_cpu_key(&end_key, inode, tail_offset, TYPE_INDIRECT, 4);
/* FIXME: we could avoid this */
if (search_for_position_by_key(sb, &end_key, path) == POSITION_FOUND) {
reiserfs_error(sb, "PAP-14030",
"pasted or inserted byte exists in "
"the tree %K. Use fsck to repair.", &end_key);
pathrelse(path);
return -EIO;
}
p_le_ih = tp_item_head(path);
unfm_ptr = cpu_to_le32(unbh->b_blocknr);
if (is_statdata_le_ih(p_le_ih)) {
/* Insert new indirect item. */
set_ih_free_space(&ind_ih, 0); /* delete at nearest future */
put_ih_item_len(&ind_ih, UNFM_P_SIZE);
PATH_LAST_POSITION(path)++;
retval =
reiserfs_insert_item(th, path, &end_key, &ind_ih, inode,
(char *)&unfm_ptr);
} else {
/* Paste into last indirect item of an object. */
retval = reiserfs_paste_into_item(th, path, &end_key, inode,
(char *)&unfm_ptr,
UNFM_P_SIZE);
}
if (retval) {
return retval;
}
/*
* note: from here there are two keys which have matching first
* three key components. They only differ by the fourth one.
*/
/* Set the key to search for the direct items of the file */
make_cpu_key(&end_key, inode, max_reiserfs_offset(inode), TYPE_DIRECT,
4);
/*
* Move bytes from the direct items to the new unformatted node
* and delete them.
*/
while (1) {
int tail_size;
/*
* end_key.k_offset is set so, that we will always have found
* last item of the file
*/
if (search_for_position_by_key(sb, &end_key, path) ==
POSITION_FOUND)
reiserfs_panic(sb, "PAP-14050",
"direct item (%K) not found", &end_key);
p_le_ih = tp_item_head(path);
RFALSE(!is_direct_le_ih(p_le_ih),
"vs-14055: direct item expected(%K), found %h",
&end_key, p_le_ih);
tail_size = (le_ih_k_offset(p_le_ih) & (blk_size - 1))
+ ih_item_len(p_le_ih) - 1;
/*
* we only send the unbh pointer if the buffer is not
* up to date. this avoids overwriting good data from
* writepage() with old data from the disk or buffer cache
* Special case: unbh->b_page will be NULL if we are coming
* through DIRECT_IO handler here.
*/
if (!unbh->b_page || buffer_uptodate(unbh)
|| PageUptodate(unbh->b_page)) {
up_to_date_bh = NULL;
} else {
up_to_date_bh = unbh;
}
retval = reiserfs_delete_item(th, path, &end_key, inode,
up_to_date_bh);
total_tail += retval;
/* done: file does not have direct items anymore */
if (tail_size == retval)
break;
}
/*
* if we've copied bytes from disk into the page, we need to zero
* out the unused part of the block (it was not up to date before)
*/
if (up_to_date_bh) {
unsigned pgoff =
(tail_offset + total_tail - 1) & (PAGE_CACHE_SIZE - 1);
char *kaddr = kmap_atomic(up_to_date_bh->b_page);
memset(kaddr + pgoff, 0, blk_size - total_tail);
kunmap_atomic(kaddr);
}
REISERFS_I(inode)->i_first_direct_byte = U32_MAX;
return 0;
}
/* stolen from fs/buffer.c */
void reiserfs_unmap_buffer(struct buffer_head *bh)
{
lock_buffer(bh);
if (buffer_journaled(bh) || buffer_journal_dirty(bh)) {
BUG();
}
clear_buffer_dirty(bh);
/*
* Remove the buffer from whatever list it belongs to. We are mostly
* interested in removing it from per-sb j_dirty_buffers list, to avoid
* BUG() on attempt to write not mapped buffer
*/
if ((!list_empty(&bh->b_assoc_buffers) || bh->b_private) && bh->b_page) {
struct inode *inode = bh->b_page->mapping->host;
struct reiserfs_journal *j = SB_JOURNAL(inode->i_sb);
spin_lock(&j->j_dirty_buffers_lock);
list_del_init(&bh->b_assoc_buffers);
reiserfs_free_jh(bh);
spin_unlock(&j->j_dirty_buffers_lock);
}
clear_buffer_mapped(bh);
clear_buffer_req(bh);
clear_buffer_new(bh);
bh->b_bdev = NULL;
unlock_buffer(bh);
}
/*
* this first locks inode (neither reads nor sync are permitted),
* reads tail through page cache, insert direct item. When direct item
* inserted successfully inode is left locked. Return value is always
* what we expect from it (number of cut bytes). But when tail remains
* in the unformatted node, we set mode to SKIP_BALANCING and unlock
* inode
*/
int indirect2direct(struct reiserfs_transaction_handle *th,
struct inode *inode, struct page *page,
struct treepath *path, /* path to the indirect item. */
const struct cpu_key *item_key, /* Key to look for
* unformatted node
* pointer to be cut. */
loff_t n_new_file_size, /* New file size. */
char *mode)
{
struct super_block *sb = inode->i_sb;
struct item_head s_ih;
unsigned long block_size = sb->s_blocksize;
char *tail;
int tail_len, round_tail_len;
loff_t pos, pos1; /* position of first byte of the tail */
struct cpu_key key;
BUG_ON(!th->t_trans_id);
REISERFS_SB(sb)->s_indirect2direct++;
*mode = M_SKIP_BALANCING;
/* store item head path points to. */
copy_item_head(&s_ih, tp_item_head(path));
tail_len = (n_new_file_size & (block_size - 1));
if (get_inode_sd_version(inode) == STAT_DATA_V2)
round_tail_len = ROUND_UP(tail_len);
else
round_tail_len = tail_len;
pos =
le_ih_k_offset(&s_ih) - 1 + (ih_item_len(&s_ih) / UNFM_P_SIZE -
1) * sb->s_blocksize;
pos1 = pos;
/*
* we are protected by i_mutex. The tail can not disapper, not
* append can be done either
* we are in truncate or packing tail in file_release
*/
tail = (char *)kmap(page); /* this can schedule */
if (path_changed(&s_ih, path)) {
/* re-search indirect item */
if (search_for_position_by_key(sb, item_key, path)
== POSITION_NOT_FOUND)
reiserfs_panic(sb, "PAP-5520",
"item to be converted %K does not exist",
item_key);
copy_item_head(&s_ih, tp_item_head(path));
#ifdef CONFIG_REISERFS_CHECK
pos = le_ih_k_offset(&s_ih) - 1 +
(ih_item_len(&s_ih) / UNFM_P_SIZE -
1) * sb->s_blocksize;
if (pos != pos1)
reiserfs_panic(sb, "vs-5530", "tail position "
"changed while we were reading it");
#endif
}
/* Set direct item header to insert. */
make_le_item_head(&s_ih, NULL, get_inode_item_key_version(inode),
pos1 + 1, TYPE_DIRECT, round_tail_len,
0xffff /*ih_free_space */ );
/*
* we want a pointer to the first byte of the tail in the page.
* the page was locked and this part of the page was up to date when
* indirect2direct was called, so we know the bytes are still valid
*/
tail = tail + (pos & (PAGE_CACHE_SIZE - 1));
PATH_LAST_POSITION(path)++;
key = *item_key;
set_cpu_key_k_type(&key, TYPE_DIRECT);
key.key_length = 4;
/* Insert tail as new direct item in the tree */
if (reiserfs_insert_item(th, path, &key, &s_ih, inode,
tail ? tail : NULL) < 0) {
/*
* No disk memory. So we can not convert last unformatted node
* to the direct item. In this case we used to adjust
* indirect items's ih_free_space. Now ih_free_space is not
* used, it would be ideal to write zeros to corresponding
* unformatted node. For now i_size is considered as guard for
* going out of file size
*/
kunmap(page);
return block_size - round_tail_len;
}
kunmap(page);
/* make sure to get the i_blocks changes from reiserfs_insert_item */
reiserfs_update_sd(th, inode);
/*
* note: we have now the same as in above direct2indirect
* conversion: there are two keys which have matching first three
* key components. They only differ by the fourth one.
*/
/*
* We have inserted new direct item and must remove last
* unformatted node.
*/
*mode = M_CUT;
/* we store position of first direct item in the in-core inode */
/* mark_file_with_tail (inode, pos1 + 1); */
REISERFS_I(inode)->i_first_direct_byte = pos1 + 1;
return block_size - round_tail_len;
}