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-rw-r--r--fs/bfs/file.c62
1 files changed, 41 insertions, 21 deletions
diff --git a/fs/bfs/file.c b/fs/bfs/file.c
index 911b4cc..b11e63e 100644
--- a/fs/bfs/file.c
+++ b/fs/bfs/file.c
@@ -2,6 +2,11 @@
* 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>
@@ -27,7 +32,8 @@ const struct file_operations bfs_file_operations = {
.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;
@@ -43,21 +49,22 @@ static int bfs_move_block(unsigned long from, unsigned long to, struct super_blo
}
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;
@@ -66,9 +73,6 @@ static int bfs_get_block(struct inode * inode, sector_t block,
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) {
@@ -79,21 +83,29 @@ static int bfs_get_block(struct inode * inode, sector_t block,
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 */
+ /* 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. */
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 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);
@@ -106,13 +118,19 @@ static int bfs_get_block(struct inode * inode, sector_t block,
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
@@ -124,8 +142,10 @@ static int bfs_get_block(struct inode * inode, sector_t block,
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);
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