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Commit e4a7b7b0 authored by Benjamin Marzinski's avatar Benjamin Marzinski Committed by Steven Whitehouse
Browse files

GFS2: fix block allocation check for fallocate 



GFS2 fallocate wasn't properly checking if a blocks were already allocated.
In write_empty_blocks(), if a page didn't have buffer_heads attached, GFS2
was always treating it as if there were no blocks allocated for that page.
GFS2 now calls gfs2_block_map() to check if the blocks are allocated before
writing them out.

Signed-off-by: default avatarBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent fa1bbdea

fs/gfs2/file.c

+31 −25
Original line number Diff line number Diff line
@@ -622,8 +622,7 @@ static void empty_write_end(struct page *page, unsigned from, 
{

	struct gfs2_inode *ip = GFS2_I(page->mapping->host);



	page_zero_new_buffers(page, from, to);

	flush_dcache_page(page);

	zero_user(page, from, to-from);

	mark_page_accessed(page);



	if (!gfs2_is_writeback(ip))
@@ -632,36 +631,43 @@ static void empty_write_end(struct page *page, unsigned from, 
	block_commit_write(page, from, to);

}



static int write_empty_blocks(struct page *page, unsigned from, unsigned to)

static int needs_empty_write(sector_t block, struct inode *inode)

{

	unsigned start, end, next;

	struct buffer_head *bh, *head;

	int error;

	struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };



	if (!page_has_buffers(page)) {

		error = __block_write_begin(page, from, to - from, gfs2_block_map);

	bh_map.b_size = 1 << inode->i_blkbits;

	error = gfs2_block_map(inode, block, &bh_map, 0);

	if (unlikely(error))

		return error;



		empty_write_end(page, from, to);

		return 0;

	return !buffer_mapped(&bh_map);

}



	bh = head = page_buffers(page);

static int write_empty_blocks(struct page *page, unsigned from, unsigned to)

{

	struct inode *inode = page->mapping->host;

	unsigned start, end, next, blksize;

	sector_t block = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);

	int ret;



	blksize = 1 << inode->i_blkbits;

	next = end = 0;

	while (next < from) {

		next += bh->b_size;

		bh = bh->b_this_page;

		next += blksize;

		block++;

	}

	start = next;

	do {

		next += bh->b_size;

		if (buffer_mapped(bh)) {

		next += blksize;

		ret = needs_empty_write(block, inode);

		if (unlikely(ret < 0))

			return ret;

		if (ret == 0) {

			if (end) {

				error = __block_write_begin(page, start, end - start,

				ret = __block_write_begin(page, start, end - start,

							  gfs2_block_map);

				if (unlikely(error))

					return error;

				if (unlikely(ret))

					return ret;

				empty_write_end(page, start, end);

				end = 0;

			}
@@ -669,13 +675,13 @@ static int write_empty_blocks(struct page *page, unsigned from, unsigned to) 
		}

		else

			end = next;

		bh = bh->b_this_page;

		block++;

	} while (next < to);



	if (end) {

		error = __block_write_begin(page, start, end - start, gfs2_block_map);

		if (unlikely(error))

			return error;

		ret = __block_write_begin(page, start, end - start, gfs2_block_map);

		if (unlikely(ret))

			return ret;

		empty_write_end(page, start, end);

	}