Commit 10e5dce0 authored by Evgeniy Dushistov's avatar Evgeniy Dushistov Committed by Linus Torvalds
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[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: default avatarEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent eb28931e

fs/ufs/balloc.c

+2 −46
Original line number Diff line number Diff line
@@ -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");

}

fs/ufs/file.c

+0 −4
Original line number Diff line number Diff line
@@ -60,7 +60,3 @@ const struct file_operations ufs_file_operations = { 
	.fsync		= ufs_sync_file,

	.sendfile	= generic_file_sendfile,

};
 


struct inode_operations ufs_file_inode_operations = {

	.truncate	= ufs_truncate,

};

fs/ufs/inode.c

+5 −2
Original line number Diff line number Diff line
@@ -843,14 +843,17 @@ int ufs_sync_inode (struct inode *inode) 


void ufs_delete_inode (struct inode * inode)

{

	loff_t old_i_size;



	truncate_inode_pages(&inode->i_data, 0);

	/*UFS_I(inode)->i_dtime = CURRENT_TIME;*/

	lock_kernel();

	mark_inode_dirty(inode);

	ufs_update_inode(inode, IS_SYNC(inode));

	old_i_size = inode->i_size;

	inode->i_size = 0;

	if (inode->i_blocks)

		ufs_truncate (inode);

	if (inode->i_blocks && ufs_truncate(inode, old_i_size))

		ufs_warning(inode->i_sb, __FUNCTION__, "ufs_truncate failed\n");

	ufs_free_inode (inode);

	unlock_kernel();

}

fs/ufs/truncate.c

+135 −13
Original line number Diff line number Diff line
@@ -370,21 +370,94 @@ static int ufs_trunc_tindirect (struct inode * inode) 
	return retry;

}



void ufs_truncate (struct inode * inode)

static int ufs_alloc_lastblock(struct inode *inode)

{

	int err = 0;

	struct address_space *mapping = inode->i_mapping;

	struct ufs_sb_private_info *uspi = UFS_SB(inode->i_sb)->s_uspi;

	struct ufs_inode_info *ufsi = UFS_I(inode);

	struct super_block * sb;

	struct ufs_sb_private_info * uspi;

	int retry;

	unsigned lastfrag, i, end;

	struct page *lastpage;

	struct buffer_head *bh;



	lastfrag = (i_size_read(inode) + uspi->s_fsize - 1) >> uspi->s_fshift;



	if (!lastfrag) {

		ufsi->i_lastfrag = 0;

		goto out;

	}

	lastfrag--;



	lastpage = ufs_get_locked_page(mapping, lastfrag >>

				       (PAGE_CACHE_SHIFT - inode->i_blkbits));

       if (IS_ERR(lastpage)) {

               err = -EIO;

               goto out;

       }



       end = lastfrag & ((1 << (PAGE_CACHE_SHIFT - inode->i_blkbits)) - 1);

       bh = page_buffers(lastpage);

       for (i = 0; i < end; ++i)

               bh = bh->b_this_page;



       if (!buffer_mapped(bh)) {

               err = ufs_getfrag_block(inode, lastfrag, bh, 1);



               if (unlikely(err))

                       goto out_unlock;



               if (buffer_new(bh)) {

                       clear_buffer_new(bh);

                       unmap_underlying_metadata(bh->b_bdev,

						 bh->b_blocknr);

		       /*

			* we do not zeroize fragment, because of

			* if it maped to hole, it already contains zeroes

			*/

                       set_buffer_uptodate(bh);

                       mark_buffer_dirty(bh);

                       set_page_dirty(lastpage);

               }

       }

out_unlock:

       ufs_put_locked_page(lastpage);

out:

       return err;

}



int ufs_truncate(struct inode *inode, loff_t old_i_size)

{

	struct ufs_inode_info *ufsi = UFS_I(inode);

	struct super_block *sb = inode->i_sb;

	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;

	int retry, err = 0;

	

	UFSD("ENTER\n");

	sb = inode->i_sb;

	uspi = UFS_SB(sb)->s_uspi;



	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)))

		return;

	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||

	      S_ISLNK(inode->i_mode)))

		return -EINVAL;

	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))

		return;

		return -EPERM;



	if (inode->i_size > old_i_size) {

		/*

		 * if we expand file we should care about

		 * allocation of block for last byte first of all

		 */

		err = ufs_alloc_lastblock(inode);



		if (err) {

			i_size_write(inode, old_i_size);

			goto out;

		}

		/*

		 * go away, because of we expand file, and we do not

		 * need free blocks, and zeroizes page

		 */

		lock_kernel();

		goto almost_end;

	}



	block_truncate_page(inode->i_mapping, inode->i_size, ufs_getfrag_block);
@@ -404,9 +477,58 @@ void ufs_truncate (struct inode * inode) 
		yield();

	}



	if (inode->i_size < old_i_size) {

		/*

		 * now we should have enough space

		 * to allocate block for last byte

		 */

		err = ufs_alloc_lastblock(inode);

		if (err)

			/*

			 * looks like all the same - we have no space,

			 * but we truncate file already

			 */

			inode->i_size = (ufsi->i_lastfrag - 1) * uspi->s_fsize;

	}

almost_end:

	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;

	ufsi->i_lastfrag = DIRECT_FRAGMENT;

	unlock_kernel();

	mark_inode_dirty(inode);

	UFSD("EXIT\n");

out:

	UFSD("EXIT: err %d\n", err);

	return err;

}





/*

 * We don't define our `inode->i_op->truncate', and call it here,

 * because of:

 * - there is no way to know old size

 * - there is no way inform user about error, if it happens in `truncate'

 */

static int ufs_setattr(struct dentry *dentry, struct iattr *attr)

{

	struct inode *inode = dentry->d_inode;

	unsigned int ia_valid = attr->ia_valid;

	int error;



	error = inode_change_ok(inode, attr);

	if (error)

		return error;



	if (ia_valid & ATTR_SIZE &&

	    attr->ia_size != i_size_read(inode)) {

		loff_t old_i_size = inode->i_size;

		error = vmtruncate(inode, attr->ia_size);

		if (error)

			return error;

		error = ufs_truncate(inode, old_i_size);

		if (error)

			return error;

	}

	return inode_setattr(inode, attr);

}



struct inode_operations ufs_file_inode_operations = {

	.setattr = ufs_setattr,

};

fs/ufs/util.c

+54 −0
Original line number Diff line number Diff line
@@ -233,3 +233,57 @@ ufs_set_inode_dev(struct super_block *sb, struct ufs_inode_info *ufsi, dev_t dev 
	else

		ufsi->i_u1.i_data[0] = fs32;

}



/**

 * ufs_get_locked_page() - locate, pin and lock a pagecache page, if not exist

 * read it from disk.

 * @mapping: the address_space to search

 * @index: the page index

 *

 * Locates the desired pagecache page, if not exist we'll read it,

 * locks it, increments its reference

 * count and returns its address.

 *

 */



struct page *ufs_get_locked_page(struct address_space *mapping,

				 pgoff_t 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;

}

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