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![Nick Piggin](/assets/img/avatar_default.png)
Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
171 lines
4.5 KiB
C
171 lines
4.5 KiB
C
/*
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* fs/bfs/file.c
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* BFS file operations.
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* Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
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*/
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/smp_lock.h>
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#include "bfs.h"
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#undef DEBUG
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#ifdef DEBUG
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#define dprintf(x...) printf(x)
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#else
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#define dprintf(x...)
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#endif
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const struct file_operations bfs_file_operations = {
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.llseek = generic_file_llseek,
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.read = do_sync_read,
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.aio_read = generic_file_aio_read,
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.write = do_sync_write,
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.aio_write = generic_file_aio_write,
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.mmap = generic_file_mmap,
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.splice_read = generic_file_splice_read,
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};
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static int bfs_move_block(unsigned long from, unsigned long to, struct super_block *sb)
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{
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struct buffer_head *bh, *new;
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bh = sb_bread(sb, from);
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if (!bh)
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return -EIO;
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new = sb_getblk(sb, to);
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memcpy(new->b_data, bh->b_data, bh->b_size);
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mark_buffer_dirty(new);
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bforget(bh);
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brelse(new);
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return 0;
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}
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static int bfs_move_blocks(struct super_block *sb, unsigned long start,
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unsigned long end, unsigned long where)
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{
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unsigned long i;
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dprintf("%08lx-%08lx->%08lx\n", start, end, where);
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for (i = start; i <= end; i++)
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if(bfs_move_block(i, where + i, sb)) {
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dprintf("failed to move block %08lx -> %08lx\n", i, where + i);
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return -EIO;
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}
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return 0;
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}
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static int bfs_get_block(struct inode * inode, sector_t block,
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struct buffer_head * bh_result, int create)
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{
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unsigned long phys;
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int err;
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struct super_block *sb = inode->i_sb;
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struct bfs_sb_info *info = BFS_SB(sb);
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struct bfs_inode_info *bi = BFS_I(inode);
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struct buffer_head *sbh = info->si_sbh;
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if (block > info->si_blocks)
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return -EIO;
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phys = bi->i_sblock + block;
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if (!create) {
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if (phys <= bi->i_eblock) {
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dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
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create, (unsigned long)block, phys);
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map_bh(bh_result, sb, phys);
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}
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return 0;
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}
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/* if the file is not empty and the requested block is within the range
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of blocks allocated for this file, we can grant it */
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if (inode->i_size && phys <= bi->i_eblock) {
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dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
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create, (unsigned long)block, phys);
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map_bh(bh_result, sb, phys);
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return 0;
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}
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/* the rest has to be protected against itself */
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lock_kernel();
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/* if the last data block for this file is the last allocated
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block, we can extend the file trivially, without moving it
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anywhere */
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if (bi->i_eblock == info->si_lf_eblk) {
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dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n",
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create, (unsigned long)block, phys);
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map_bh(bh_result, sb, phys);
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info->si_freeb -= phys - bi->i_eblock;
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info->si_lf_eblk = bi->i_eblock = phys;
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mark_inode_dirty(inode);
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mark_buffer_dirty(sbh);
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err = 0;
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goto out;
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}
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/* Ok, we have to move this entire file to the next free block */
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phys = info->si_lf_eblk + 1;
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if (bi->i_sblock) { /* if data starts on block 0 then there is no data */
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err = bfs_move_blocks(inode->i_sb, bi->i_sblock,
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bi->i_eblock, phys);
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if (err) {
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dprintf("failed to move ino=%08lx -> fs corruption\n", inode->i_ino);
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goto out;
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}
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} else
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err = 0;
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dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
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create, (unsigned long)block, phys);
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bi->i_sblock = phys;
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phys += block;
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info->si_lf_eblk = bi->i_eblock = phys;
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/* this assumes nothing can write the inode back while we are here
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* and thus update inode->i_blocks! (XXX)*/
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info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
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mark_inode_dirty(inode);
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mark_buffer_dirty(sbh);
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map_bh(bh_result, sb, phys);
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out:
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unlock_kernel();
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return err;
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}
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static int bfs_writepage(struct page *page, struct writeback_control *wbc)
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{
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return block_write_full_page(page, bfs_get_block, wbc);
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}
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static int bfs_readpage(struct file *file, struct page *page)
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{
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return block_read_full_page(page, bfs_get_block);
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}
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static int bfs_write_begin(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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*pagep = NULL;
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return block_write_begin(file, mapping, pos, len, flags,
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pagep, fsdata, bfs_get_block);
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}
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static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
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{
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return generic_block_bmap(mapping, block, bfs_get_block);
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}
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const struct address_space_operations bfs_aops = {
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.readpage = bfs_readpage,
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.writepage = bfs_writepage,
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.sync_page = block_sync_page,
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.write_begin = bfs_write_begin,
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.write_end = generic_write_end,
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.bmap = bfs_bmap,
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};
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const struct inode_operations bfs_file_inops;
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