Commit 9a950d52 authored by Fan Li's avatar Fan Li Committed by Jaegeuk Kim
Browse files

f2fs: fix bugs and simplify codes of f2fs_fiemap 



fix bugs:
1. len could be updated incorrectly when start+len is beyond isize.
2. If there is a hole consisting of more than two blocks, it could
   fail to add FIEMAP_EXTENT_LAST flag for the last extent.
3. If there is an extent beyond isize, when we search extents in a range
   that ends at isize, it will also return the extent beyond isize,
   which is outside the range.

Signed-off-by: default avatarFan li <fanofcode.li@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 6d5a1495

fs/f2fs/data.c

+27 −53
Original line number Diff line number Diff line
@@ -783,7 +783,6 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
	loff_t isize = i_size_read(inode);

	u64 logical = 0, phys = 0, size = 0;

	u32 flags = 0;

	bool past_eof = false, whole_file = false;

	int ret = 0;



	ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
@@ -797,17 +796,18 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
	}



	mutex_lock(&inode->i_mutex);

	if (start >= isize)

		goto out;



	if (len >= isize) {

		whole_file = true;

		len = isize;

	}

	if (start + len > isize)

		len = isize - start;



	if (logical_to_blk(inode, len) == 0)

		len = blk_to_logical(inode, 1);



	start_blk = logical_to_blk(inode, start);

	last_blk = logical_to_blk(inode, start + len - 1);



next:

	memset(&map_bh, 0, sizeof(struct buffer_head));

	map_bh.b_size = len;
@@ -819,41 +819,22 @@ next: 


	/* HOLE */

	if (!buffer_mapped(&map_bh)) {

		start_blk++;



		if (!past_eof && blk_to_logical(inode, start_blk) >= isize)

			past_eof = 1;



		if (past_eof && size) {

		/* Go through holes util pass the EOF */

		if (blk_to_logical(inode, start_blk++) < isize)

			goto prep_next;

		/* Found a hole beyond isize means no more extents.

		 * Note that the premise is that filesystems don't

		 * punch holes beyond isize and keep size unchanged.

		 */

		flags |= FIEMAP_EXTENT_LAST;

			ret = fiemap_fill_next_extent(fieinfo, logical,

					phys, size, flags);

		} else if (size) {

			ret = fiemap_fill_next_extent(fieinfo, logical,

					phys, size, flags);

			size = 0;

	}



		/* if we have holes up to/past EOF then we're done */

		if (start_blk > last_blk || past_eof || ret)

			goto out;

	} else {

		if (start_blk > last_blk && !whole_file) {

	if (size)

		ret = fiemap_fill_next_extent(fieinfo, logical,

				phys, size, flags);

			goto out;

		}



		/*

		 * if size != 0 then we know we already have an extent

		 * to add, so add it.

		 */

		if (size) {

			ret = fiemap_fill_next_extent(fieinfo, logical,

					phys, size, flags);

			if (ret)

	if (start_blk > last_blk || ret)

		goto out;

		}



	logical = blk_to_logical(inode, start_blk);

	phys = blk_to_logical(inode, map_bh.b_blocknr);
@@ -864,14 +845,7 @@ next: 


	start_blk += logical_to_blk(inode, size);



		/*

		 * If we are past the EOF, then we need to make sure as

		 * soon as we find a hole that the last extent we found

		 * is marked with FIEMAP_EXTENT_LAST

		 */

		if (!past_eof && logical + size >= isize)

			past_eof = true;

	}

prep_next:

	cond_resched();

	if (fatal_signal_pending(current))

		ret = -EINTR;

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