[PATCH] ufs: truncate should allocate block for last byte

This patch fixes buggy behaviour of UFS
in such kind of scenario:
open(, O_TRUNC...)
ftruncate(, 1024)
ftruncate(, 0)

Such a scenario causes ufs_panic and remount read-only.  This happen
because of according to specification UFS should always allocate block for
last byte, and many parts of our implementation rely on this, but
`ufs_truncate' doesn't care about this.

To make possible return error code and to know about old size, this patch
removes `truncate' from ufs inode_operations and uses `setattr' method to
call ufs_truncate.

Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 46 deletions

diff --git a/fs/ufs/balloc.c b/fs/ufs/balloc.c
index 95b878e..b01804b 100644
--- a/fs/ufs/balloc.c
+++ b/fs/ufs/balloc.c
@@ -217,48 +217,6 @@ failed:
 	return;
 }
 
-static struct page *ufs_get_locked_page(struct address_space *mapping,
-				  unsigned long index)
-{
-	struct page *page;
-
-try_again:
-	page = find_lock_page(mapping, index);
-	if (!page) {
-		page = read_cache_page(mapping, index,
-				       (filler_t*)mapping->a_ops->readpage,
-				       NULL);
-		if (IS_ERR(page)) {
-			printk(KERN_ERR "ufs_change_blocknr: "
-			       "read_cache_page error: ino %lu, index: %lu\n",
-			       mapping->host->i_ino, index);
-			goto out;
-		}
-
-		lock_page(page);
-
-		if (!PageUptodate(page) || PageError(page)) {
-			unlock_page(page);
-			page_cache_release(page);
-
-			printk(KERN_ERR "ufs_change_blocknr: "
-			       "can not read page: ino %lu, index: %lu\n",
-			       mapping->host->i_ino, index);
-
-			page = ERR_PTR(-EIO);
-			goto out;
-		}
-	}
-
-	if (unlikely(!page->mapping || !page_has_buffers(page))) {
-		unlock_page(page);
-		page_cache_release(page);
-		goto try_again;/*we really need these buffers*/
-	}
-out:
-	return page;
-}
-
 /*
  * Modify inode page cache in such way:
  * have - blocks with b_blocknr equal to oldb...oldb+count-1
@@ -311,10 +269,8 @@ static void ufs_change_blocknr(struct inode *inode, unsigned int baseblk,
 
 		set_page_dirty(page);
 
-		if (likely(cur_index != index)) {
-			unlock_page(page);
-			page_cache_release(page);
-		}
+		if (likely(cur_index != index))
+			ufs_put_locked_page(page);
  	}
 	UFSD("EXIT\n");
 }