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Commit ad7fefb1 authored by Theodore Ts'o's avatar Theodore Ts'o
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Revert "ext4: fix suboptimal seek_{data,hole} extents traversial" 



This reverts commit 14516bb7.

This was causing regression test failures with generic/285 with an ext3
filesystem using CONFIG_EXT4_USE_FOR_EXT23.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 011fa994

fs/ext4/extents.c

+2 −2
Original line number Diff line number Diff line
@@ -5166,7 +5166,7 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 


	/* fallback to generic here if not in extents fmt */

	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))

		return __generic_block_fiemap(inode, fieinfo, start, len,

		return generic_block_fiemap(inode, fieinfo, start, len,

			ext4_get_block);



	if (fiemap_check_flags(fieinfo, EXT4_FIEMAP_FLAGS))

fs/ext4/file.c

+114 −106
Original line number Diff line number Diff line
@@ -273,19 +273,24 @@ static int ext4_file_open(struct inode * inode, struct file * filp) 
 * we determine this extent as a data or a hole according to whether the

 * page cache has data or not.

 */

static int ext4_find_unwritten_pgoff(struct inode *inode, int whence,

				     loff_t endoff, loff_t *offset)

static int ext4_find_unwritten_pgoff(struct inode *inode,

				     int whence,

				     struct ext4_map_blocks *map,

				     loff_t *offset)

{

	struct pagevec pvec;

	unsigned int blkbits;

	pgoff_t index;

	pgoff_t end;

	loff_t endoff;

	loff_t startoff;

	loff_t lastoff;

	int found = 0;



	blkbits = inode->i_sb->s_blocksize_bits;

	startoff = *offset;

	lastoff = startoff;



	endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits;



	index = startoff >> PAGE_CACHE_SHIFT;

	end = endoff >> PAGE_CACHE_SHIFT;
@@ -403,144 +408,147 @@ static int ext4_find_unwritten_pgoff(struct inode *inode, int whence, 
static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize)

{

	struct inode *inode = file->f_mapping->host;

	struct fiemap_extent_info fie;

	struct fiemap_extent ext[2];

	loff_t next;

	int i, ret = 0;

	struct ext4_map_blocks map;

	struct extent_status es;

	ext4_lblk_t start, last, end;

	loff_t dataoff, isize;

	int blkbits;

	int ret = 0;



	mutex_lock(&inode->i_mutex);

	if (offset >= inode->i_size) {



	isize = i_size_read(inode);

	if (offset >= isize) {

		mutex_unlock(&inode->i_mutex);

		return -ENXIO;

	}

	fie.fi_flags = 0;

	fie.fi_extents_max = 2;

	fie.fi_extents_start = (struct fiemap_extent __user *) &ext;

	while (1) {

		mm_segment_t old_fs = get_fs();



		fie.fi_extents_mapped = 0;

		memset(ext, 0, sizeof(*ext) * fie.fi_extents_max);

	blkbits = inode->i_sb->s_blocksize_bits;

	start = offset >> blkbits;

	last = start;

	end = isize >> blkbits;

	dataoff = offset;



		set_fs(get_ds());

		ret = ext4_fiemap(inode, &fie, offset, maxsize - offset);

		set_fs(old_fs);

		if (ret)

			break;



		/* No extents found, EOF */

		if (!fie.fi_extents_mapped) {

			ret = -ENXIO;

	do {

		map.m_lblk = last;

		map.m_len = end - last + 1;

		ret = ext4_map_blocks(NULL, inode, &map, 0);

		if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {

			if (last != start)

				dataoff = (loff_t)last << blkbits;

			break;

		}

		for (i = 0; i < fie.fi_extents_mapped; i++) {

			next = (loff_t)(ext[i].fe_length + ext[i].fe_logical);



			if (offset < (loff_t)ext[i].fe_logical)

				offset = (loff_t)ext[i].fe_logical;

		/*

			 * If extent is not unwritten, then it contains valid

			 * data, mapped or delayed.

		 * If there is a delay extent at this offset,

		 * it will be as a data.

		 */

			if (!(ext[i].fe_flags & FIEMAP_EXTENT_UNWRITTEN))

				goto out;

		ext4_es_find_delayed_extent_range(inode, last, last, &es);

		if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {

			if (last != start)

				dataoff = (loff_t)last << blkbits;

			break;

		}



		/*

		 * If there is a unwritten extent at this offset,

		 * it will be as a data or a hole according to page

		 * cache that has data or not.

		 */

			if (ext4_find_unwritten_pgoff(inode, SEEK_DATA,

						      next, &offset))

				goto out;



			if (ext[i].fe_flags & FIEMAP_EXTENT_LAST) {

				ret = -ENXIO;

				goto out;

			}

			offset = next;

		}

		if (map.m_flags & EXT4_MAP_UNWRITTEN) {

			int unwritten;

			unwritten = ext4_find_unwritten_pgoff(inode, SEEK_DATA,

							      &map, &dataoff);

			if (unwritten)

				break;

		}

	if (offset > inode->i_size)

		offset = inode->i_size;

out:



		last++;

		dataoff = (loff_t)last << blkbits;

	} while (last <= end);



	mutex_unlock(&inode->i_mutex);

	if (ret)

		return ret;



	return vfs_setpos(file, offset, maxsize);

	if (dataoff > isize)

		return -ENXIO;



	return vfs_setpos(file, dataoff, maxsize);

}



/*

 * ext4_seek_hole() retrieves the offset for SEEK_HOLE

 * ext4_seek_hole() retrieves the offset for SEEK_HOLE.

 */

static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize)

{

	struct inode *inode = file->f_mapping->host;

	struct fiemap_extent_info fie;

	struct fiemap_extent ext[2];

	loff_t next;

	int i, ret = 0;

	struct ext4_map_blocks map;

	struct extent_status es;

	ext4_lblk_t start, last, end;

	loff_t holeoff, isize;

	int blkbits;

	int ret = 0;



	mutex_lock(&inode->i_mutex);

	if (offset >= inode->i_size) {



	isize = i_size_read(inode);

	if (offset >= isize) {

		mutex_unlock(&inode->i_mutex);

		return -ENXIO;

	}



	fie.fi_flags = 0;

	fie.fi_extents_max = 2;

	fie.fi_extents_start = (struct fiemap_extent __user *)&ext;

	while (1) {

		mm_segment_t old_fs = get_fs();



		fie.fi_extents_mapped = 0;

		memset(ext, 0, sizeof(*ext));

	blkbits = inode->i_sb->s_blocksize_bits;

	start = offset >> blkbits;

	last = start;

	end = isize >> blkbits;

	holeoff = offset;



		set_fs(get_ds());

		ret = ext4_fiemap(inode, &fie, offset, maxsize - offset);

		set_fs(old_fs);

		if (ret)

			break;



		/* No extents found */

		if (!fie.fi_extents_mapped)

			break;

	do {

		map.m_lblk = last;

		map.m_len = end - last + 1;

		ret = ext4_map_blocks(NULL, inode, &map, 0);

		if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) {

			last += ret;

			holeoff = (loff_t)last << blkbits;

			continue;

		}



		for (i = 0; i < fie.fi_extents_mapped; i++) {

			next = (loff_t)(ext[i].fe_logical + ext[i].fe_length);

		/*

			 * If extent is not unwritten, then it contains valid

			 * data, mapped or delayed.

		 * If there is a delay extent at this offset,

		 * we will skip this extent.

		 */

			if (!(ext[i].fe_flags & FIEMAP_EXTENT_UNWRITTEN)) {

				if (offset < (loff_t)ext[i].fe_logical)

					goto out;

				offset = next;

		ext4_es_find_delayed_extent_range(inode, last, last, &es);

		if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) {

			last = es.es_lblk + es.es_len;

			holeoff = (loff_t)last << blkbits;

			continue;

		}



		/*

		 * If there is a unwritten extent at this offset,

		 * it will be as a data or a hole according to page

		 * cache that has data or not.

		 */

			if (ext4_find_unwritten_pgoff(inode, SEEK_HOLE,

						      next, &offset))

				goto out;



			offset = next;

			if (ext[i].fe_flags & FIEMAP_EXTENT_LAST)

				goto out;

		if (map.m_flags & EXT4_MAP_UNWRITTEN) {

			int unwritten;

			unwritten = ext4_find_unwritten_pgoff(inode, SEEK_HOLE,

							      &map, &holeoff);

			if (!unwritten) {

				last += ret;

				holeoff = (loff_t)last << blkbits;

				continue;

			}

		}

	if (offset > inode->i_size)

		offset = inode->i_size;

out:



		/* find a hole */

		break;

	} while (last <= end);



	mutex_unlock(&inode->i_mutex);

	if (ret)

		return ret;



	return vfs_setpos(file, offset, maxsize);

	if (holeoff > isize)

		holeoff = isize;



	return vfs_setpos(file, holeoff, maxsize);

}



/*