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Commit b767e78a authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o
Browse files

ext4: Don't look at buffer_heads outside i_size. 



Buffer heads outside i_size will be unmapped. So when we
are doing "walk_page_buffers" limit ourself to i_size.

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: default avatarJosef Bacik <jbacik@redhat.com>
Acked-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
----
parent e6462869

fs/ext4/inode.c

+16 −12
Original line number Diff line number Diff line
@@ -2578,7 +2578,7 @@ static int ext4_da_writepage(struct page *page, 
		 * all are mapped and non delay. We don't want to

		 * do block allocation here.

		 */

		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,

		ret = block_prepare_write(page, 0, len,

					  noalloc_get_block_write);

		if (!ret) {

			page_bufs = page_buffers(page);
@@ -2600,7 +2600,7 @@ static int ext4_da_writepage(struct page *page, 
			return 0;

		}

		/* now mark the buffer_heads as dirty and uptodate */

		block_commit_write(page, 0, PAGE_CACHE_SIZE);

		block_commit_write(page, 0, len);

	}



	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
@@ -3246,6 +3246,8 @@ static int ext4_normal_writepage(struct page *page, 
static int __ext4_journalled_writepage(struct page *page,

				       struct writeback_control *wbc)

{

	loff_t size;

	unsigned int len;

	struct address_space *mapping = page->mapping;

	struct inode *inode = mapping->host;

	struct buffer_head *page_bufs;
@@ -3253,14 +3255,17 @@ static int __ext4_journalled_writepage(struct page *page, 
	int ret = 0;

	int err;



	ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,

				  noalloc_get_block_write);

	size = i_size_read(inode);

	if (page->index == size >> PAGE_CACHE_SHIFT)

		len = size & ~PAGE_CACHE_MASK;

	else

		len = PAGE_CACHE_SIZE;

	ret = block_prepare_write(page, 0, len, noalloc_get_block_write);

	if (ret != 0)

		goto out_unlock;



	page_bufs = page_buffers(page);

	walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,

								bget_one);

	walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);

	/* As soon as we unlock the page, it can go away, but we have

	 * references to buffers so we are safe */

	unlock_page(page);
@@ -3271,19 +3276,18 @@ static int __ext4_journalled_writepage(struct page *page, 
		goto out;

	}



	ret = walk_page_buffers(handle, page_bufs, 0,

			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);

	ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,

				do_journal_get_write_access);



	err = walk_page_buffers(handle, page_bufs, 0,

				PAGE_CACHE_SIZE, NULL, write_end_fn);

	err = walk_page_buffers(handle, page_bufs, 0, len, NULL,

				write_end_fn);

	if (ret == 0)

		ret = err;

	err = ext4_journal_stop(handle);

	if (!ret)

		ret = err;



	walk_page_buffers(handle, page_bufs, 0,

				PAGE_CACHE_SIZE, NULL, bput_one);

	walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);

	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;

	goto out;