/*
* Modify inode page cache in such way:
* have - blocks with b_blocknr equal to oldb...oldb+count-1
* get - blocks with b_blocknr equal to newb...newb+count-1
* also we suppose that oldb...oldb+count-1 blocks
* situated at the end of file.
*
* We can come here from ufs_writepage or ufs_prepare_write,
* locked_page is argument of these functions, so we already lock it.
*/
static void ufs_change_blocknr(struct inode *inode, sector_t beg,
unsigned int count, sector_t oldb,
sector_t newb, struct page *locked_page)
{
const unsigned blks_per_page =
1 << (PAGE_CACHE_SHIFT - inode->i_blkbits);
const unsigned mask = blks_per_page - 1;
struct address_space * const mapping = inode->i_mapping;
pgoff_t index, cur_index, last_index;
unsigned pos, j, lblock;
sector_t end, i;
struct page *page;
struct buffer_head *head, *bh;
UFSD("ENTER, ino %lu, count %u, oldb %llu, newb %llu\n",
inode->i_ino, count,
(unsigned long long)oldb, (unsigned long long)newb);
BUG_ON(!locked_page);
BUG_ON(!PageLocked(locked_page));
cur_index = locked_page->index;
end = count + beg;
last_index = end >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
for (i = beg; i < end; i = (i | mask) + 1) {
index = i >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
if (likely(cur_index != index)) {
page = ufs_get_locked_page(mapping, index);
if (!page)/* it was truncated */
continue;
if (IS_ERR(page)) {/* or EIO */
ufs_error(inode->i_sb, __func__,
"read of page %llu failed\n",
(unsigned long long)index);
continue;
}
} else
page = locked_page;
head = page_buffers(page);
bh = head;
pos = i & mask;
for (j = 0; j < pos; ++j)
bh = bh->b_this_page;
if (unlikely(index == last_index))
lblock = end & mask;
else
lblock = blks_per_page;
do {
if (j >= lblock)
break;
pos = (i - beg) + j;
if (!buffer_mapped(bh))
map_bh(bh, inode->i_sb, oldb + pos);
if (!buffer_uptodate(bh)) {
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
ufs_error(inode->i_sb, __func__,
"read of block failed\n");
break;
}
}
UFSD(" change from %llu to %llu, pos %u\n",
(unsigned long long)(pos + oldb),
(unsigned long long)(pos + newb), pos);
bh->b_blocknr = newb + pos;
unmap_underlying_metadata(bh->b_bdev,
bh->b_blocknr);
mark_buffer_dirty(bh);
++j;
bh = bh->b_this_page;
} while (bh != head);
if (likely(cur_index != index))
ufs_put_locked_page(page);
}
UFSD("EXIT\n");
}
/*
* Modify inode page cache in such way:
* have - blocks with b_blocknr equal to oldb...oldb+count-1
* get - blocks with b_blocknr equal to newb...newb+count-1
* also we suppose that oldb...oldb+count-1 blocks
* situated at the end of file.
*
* We can come here from ufs_writepage or ufs_prepare_write,
* locked_page is argument of these functions, so we already lock it.
*/
static void ufs_change_blocknr(struct inode *inode, unsigned int beg,
unsigned int count, unsigned int oldb,
unsigned int newb, struct page *locked_page)
{
const unsigned mask = (1 << (PAGE_CACHE_SHIFT - inode->i_blkbits)) - 1;
struct address_space * const mapping = inode->i_mapping;
pgoff_t index, cur_index;
unsigned end, pos, j;
struct page *page;
struct buffer_head *head, *bh;
UFSD("ENTER, ino %lu, count %u, oldb %u, newb %u\n",
inode->i_ino, count, oldb, newb);
BUG_ON(!locked_page);
BUG_ON(!PageLocked(locked_page));
cur_index = locked_page->index;
for (end = count + beg; beg < end; beg = (beg | mask) + 1) {
index = beg >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
if (likely(cur_index != index)) {
page = ufs_get_locked_page(mapping, index);
if (!page || IS_ERR(page)) /* it was truncated or EIO */
continue;
} else
page = locked_page;
head = page_buffers(page);
bh = head;
pos = beg & mask;
for (j = 0; j < pos; ++j)
bh = bh->b_this_page;
j = 0;
do {
if (buffer_mapped(bh)) {
pos = bh->b_blocknr - oldb;
if (pos < count) {
UFSD(" change from %llu to %llu\n",
(unsigned long long)pos + oldb,
(unsigned long long)pos + newb);
bh->b_blocknr = newb + pos;
unmap_underlying_metadata(bh->b_bdev,
bh->b_blocknr);
mark_buffer_dirty(bh);
++j;
}
}
bh = bh->b_this_page;
} while (bh != head);
if (j)
set_page_dirty(page);
if (likely(cur_index != index))
ufs_put_locked_page(page);
}
UFSD("EXIT\n");
}