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Commit 7cb476f8 authored by Jan Kara's avatar Jan Kara Committed by Theodore Ts'o
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ext4: handle transient ENOSPC properly for DAX 



ext4_dax_get_blocks() was accidentally omitted fixing get blocks
handlers to properly handle transient ENOSPC errors. Fix it now to use
ext4_get_blocks_trans() helper which takes care of these errors.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent aef39ab1

fs/ext4/inode.c

+20 −55
Original line number Diff line number Diff line
@@ -3232,72 +3232,37 @@ static int ext4_releasepage(struct page *page, gfp_t wait) 
int ext4_dax_mmap_get_block(struct inode *inode, sector_t iblock,

			    struct buffer_head *bh_result, int create)

{

	int ret, err;

	int credits;

	struct ext4_map_blocks map;

	handle_t *handle = NULL;

	int flags = 0;

	int ret;



	ext4_debug("ext4_dax_mmap_get_block: inode %lu, create flag %d\n",

		   inode->i_ino, create);

	map.m_lblk = iblock;

	map.m_len = bh_result->b_size >> inode->i_blkbits;

	credits = ext4_chunk_trans_blocks(inode, map.m_len);

	if (create) {

		flags |= EXT4_GET_BLOCKS_PRE_IO | EXT4_GET_BLOCKS_CREATE_ZERO;

		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);

		if (IS_ERR(handle)) {

			ret = PTR_ERR(handle);

			return ret;

		}

	}

	if (!create)

		return _ext4_get_block(inode, iblock, bh_result, 0);



	ret = ext4_map_blocks(handle, inode, &map, flags);

	if (create) {

		err = ext4_journal_stop(handle);

		if (ret >= 0 && err < 0)

			ret = err;

	}

	if (ret <= 0)

		goto out;

	if (map.m_flags & EXT4_MAP_UNWRITTEN) {

		int err2;

	ret = ext4_get_block_trans(inode, iblock, bh_result,

				   EXT4_GET_BLOCKS_PRE_IO |

				   EXT4_GET_BLOCKS_CREATE_ZERO);

	if (ret < 0)

		return ret;



	if (buffer_unwritten(bh_result)) {

		/*

		 * We are protected by i_mmap_sem so we know block cannot go

		 * away from under us even though we dropped i_data_sem.

		 * Convert extent to written and write zeros there.

		 *

		 * Note: We may get here even when create == 0.

		 */

		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, credits);

		if (IS_ERR(handle)) {

			ret = PTR_ERR(handle);

			goto out;

		}



		err = ext4_map_blocks(handle, inode, &map,

		      EXT4_GET_BLOCKS_CONVERT | EXT4_GET_BLOCKS_CREATE_ZERO);

		if (err < 0)

			ret = err;

		err2 = ext4_journal_stop(handle);

		if (err2 < 0 && ret > 0)

			ret = err2;

		ret = ext4_get_block_trans(inode, iblock, bh_result,

					   EXT4_GET_BLOCKS_CONVERT |

					   EXT4_GET_BLOCKS_CREATE_ZERO);

		if (ret < 0)

			return ret;

	}

out:

	WARN_ON_ONCE(ret == 0 && create);

	if (ret > 0) {

		map_bh(bh_result, inode->i_sb, map.m_pblk);

	/*

	 * At least for now we have to clear BH_New so that DAX code

	 * doesn't attempt to zero blocks again in a racy way.

	 */

		map.m_flags &= ~EXT4_MAP_NEW;

		ext4_update_bh_state(bh_result, map.m_flags);

		bh_result->b_size = map.m_len << inode->i_blkbits;

		ret = 0;

	}

	return ret;

	clear_buffer_new(bh_result);

	return 0;

}

#endif