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-rw-r--r--fs/bfs/file.c162
1 files changed, 162 insertions, 0 deletions
diff --git a/fs/bfs/file.c b/fs/bfs/file.c
new file mode 100644
index 00000000000..747fd1ea55e
--- /dev/null
+++ b/fs/bfs/file.c
@@ -0,0 +1,162 @@
+/*
+ * fs/bfs/file.c
+ * BFS file operations.
+ * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
+#include "bfs.h"
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define dprintf(x...) printf(x)
+#else
+#define dprintf(x...)
+#endif
+
+struct file_operations bfs_file_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_file_read,
+ .write = generic_file_write,
+ .mmap = generic_file_mmap,
+ .sendfile = generic_file_sendfile,
+};
+
+static int bfs_move_block(unsigned long from, unsigned long to, struct super_block *sb)
+{
+ struct buffer_head *bh, *new;
+
+ bh = sb_bread(sb, from);
+ if (!bh)
+ return -EIO;
+ new = sb_getblk(sb, to);
+ memcpy(new->b_data, bh->b_data, bh->b_size);
+ mark_buffer_dirty(new);
+ bforget(bh);
+ brelse(new);
+ return 0;
+}
+
+static int bfs_move_blocks(struct super_block *sb, unsigned long start, unsigned long end,
+ unsigned long where)
+{
+ unsigned long i;
+
+ dprintf("%08lx-%08lx->%08lx\n", start, end, where);
+ for (i = start; i <= end; i++)
+ if(bfs_move_block(i, where + i, sb)) {
+ dprintf("failed to move block %08lx -> %08lx\n", i, where + i);
+ return -EIO;
+ }
+ return 0;
+}
+
+static int bfs_get_block(struct inode * inode, sector_t block,
+ struct buffer_head * bh_result, int create)
+{
+ long phys;
+ int err;
+ struct super_block *sb = inode->i_sb;
+ struct bfs_sb_info *info = BFS_SB(sb);
+ struct bfs_inode_info *bi = BFS_I(inode);
+ struct buffer_head *sbh = info->si_sbh;
+
+ if (block < 0 || block > info->si_blocks)
+ return -EIO;
+
+ phys = bi->i_sblock + block;
+ if (!create) {
+ if (phys <= bi->i_eblock) {
+ dprintf("c=%d, b=%08lx, phys=%08lx (granted)\n", create, block, phys);
+ map_bh(bh_result, sb, phys);
+ }
+ return 0;
+ }
+
+ /* if the file is not empty and the requested block is within the range
+ of blocks allocated for this file, we can grant it */
+ if (inode->i_size && phys <= bi->i_eblock) {
+ dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
+ create, block, phys);
+ map_bh(bh_result, sb, phys);
+ return 0;
+ }
+
+ /* the rest has to be protected against itself */
+ lock_kernel();
+
+ /* if the last data block for this file is the last allocated block, we can
+ extend the file trivially, without moving it anywhere */
+ if (bi->i_eblock == info->si_lf_eblk) {
+ dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n",
+ create, block, phys);
+ map_bh(bh_result, sb, phys);
+ info->si_freeb -= phys - bi->i_eblock;
+ info->si_lf_eblk = bi->i_eblock = phys;
+ mark_inode_dirty(inode);
+ mark_buffer_dirty(sbh);
+ err = 0;
+ goto out;
+ }
+
+ /* Ok, we have to move this entire file to the next free block */
+ phys = info->si_lf_eblk + 1;
+ if (bi->i_sblock) { /* if data starts on block 0 then there is no data */
+ err = bfs_move_blocks(inode->i_sb, bi->i_sblock,
+ bi->i_eblock, phys);
+ if (err) {
+ dprintf("failed to move ino=%08lx -> fs corruption\n", inode->i_ino);
+ goto out;
+ }
+ } else
+ err = 0;
+
+ dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n", create, block, phys);
+ bi->i_sblock = phys;
+ phys += block;
+ info->si_lf_eblk = bi->i_eblock = phys;
+
+ /* this assumes nothing can write the inode back while we are here
+ * and thus update inode->i_blocks! (XXX)*/
+ info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
+ mark_inode_dirty(inode);
+ mark_buffer_dirty(sbh);
+ map_bh(bh_result, sb, phys);
+out:
+ unlock_kernel();
+ return err;
+}
+
+static int bfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+ return block_write_full_page(page, bfs_get_block, wbc);
+}
+
+static int bfs_readpage(struct file *file, struct page *page)
+{
+ return block_read_full_page(page, bfs_get_block);
+}
+
+static int bfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
+{
+ return block_prepare_write(page, from, to, bfs_get_block);
+}
+
+static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
+{
+ return generic_block_bmap(mapping, block, bfs_get_block);
+}
+
+struct address_space_operations bfs_aops = {
+ .readpage = bfs_readpage,
+ .writepage = bfs_writepage,
+ .sync_page = block_sync_page,
+ .prepare_write = bfs_prepare_write,
+ .commit_write = generic_commit_write,
+ .bmap = bfs_bmap,
+};
+
+struct inode_operations bfs_file_inops;