* fs/bfs/file.c
* BFS file operations.
* Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
+ *
+ * Make the file block allocation algorithm understand the size
+ * of the underlying block device.
+ * Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
+ *
*/
#include <linux/fs.h>
.splice_read = generic_file_splice_read,
};
-static int bfs_move_block(unsigned long from, unsigned long to, struct super_block *sb)
+static int bfs_move_block(unsigned long from, unsigned long to,
+ struct super_block *sb)
{
struct buffer_head *bh, *new;
}
static int bfs_move_blocks(struct super_block *sb, unsigned long start,
- unsigned long end, unsigned long where)
+ 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);
+ 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)
+static int bfs_get_block(struct inode *inode, sector_t block,
+ struct buffer_head *bh_result, int create)
{
unsigned long phys;
int err;
struct bfs_inode_info *bi = BFS_I(inode);
struct buffer_head *sbh = info->si_sbh;
- if (block > info->si_blocks)
- return -EIO;
-
phys = bi->i_sblock + block;
if (!create) {
if (phys <= bi->i_eblock) {
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) {
+ /*
+ * 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 (bi->i_sblock && (phys <= bi->i_eblock)) {
dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n",
create, (unsigned long)block, phys);
map_bh(bh_result, sb, phys);
return 0;
}
- /* the rest has to be protected against itself */
- lock_kernel();
+ /* The file will be extended, so let's see if there is enough space. */
+ if (phys >= info->si_blocks)
+ return -ENOSPC;
+
+ /* The rest has to be protected against itself. */
+ mutex_lock(&info->bfs_lock);
- /* if the last data block for this file is the last allocated
- block, we can extend the file trivially, without moving it
- anywhere */
+ /*
+ * 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, (unsigned long)block, phys);
goto out;
}
- /* Ok, we have to move this entire file to the next free block */
+ /* 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 */
+ if (phys + block >= info->si_blocks) {
+ err = -ENOSPC;
+ goto out;
+ }
+
+ if (bi->i_sblock) {
err = bfs_move_blocks(inode->i_sb, bi->i_sblock,
- bi->i_eblock, phys);
+ bi->i_eblock, phys);
if (err) {
- dprintf("failed to move ino=%08lx -> fs corruption\n", inode->i_ino);
+ dprintf("failed to move ino=%08lx -> fs corruption\n",
+ inode->i_ino);
goto out;
}
} else
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)*/
+ /*
+ * 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();
+ mutex_unlock(&info->bfs_lock);
return err;
}
return block_read_full_page(page, bfs_get_block);
}
-static int bfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
+static int bfs_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
{
- return block_prepare_write(page, from, to, bfs_get_block);
+ *pagep = NULL;
+ return block_write_begin(file, mapping, pos, len, flags,
+ pagep, fsdata, bfs_get_block);
}
static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
.readpage = bfs_readpage,
.writepage = bfs_writepage,
.sync_page = block_sync_page,
- .prepare_write = bfs_prepare_write,
- .commit_write = generic_commit_write,
+ .write_begin = bfs_write_begin,
+ .write_end = generic_write_end,
.bmap = bfs_bmap,
};
git.openpandora.org / pandora-kernel.git / blobdiff