Commit 5c521830 authored by Jiaying Zhang's avatar Jiaying Zhang Committed by Theodore Ts'o
Browse files

ext4: Support discard requests when running in no-journal mode 



Issue discard request in ext4_free_blocks() when ext4 has no journal and
is mounted with discard option.
    
Signed-off-by: default avatarJiaying Zhang <jiayingz@google.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 47def826

fs/ext4/mballoc.c

+21 −16
Original line number Diff line number Diff line
@@ -2558,6 +2558,22 @@ int ext4_mb_release(struct super_block *sb) 
	return 0;

}



static inline void ext4_issue_discard(struct super_block *sb,

		ext4_group_t block_group, ext4_grpblk_t block, int count)

{

	int ret;

	ext4_fsblk_t discard_block;



	discard_block = block + ext4_group_first_block_no(sb, block_group);

	trace_ext4_discard_blocks(sb,

			(unsigned long long) discard_block, count);

	ret = sb_issue_discard(sb, discard_block, count);

	if (ret == EOPNOTSUPP) {

		ext4_warning(sb, "discard not supported, disabling");

		clear_opt(EXT4_SB(sb)->s_mount_opt, DISCARD);

	}

}



/*

 * This function is called by the jbd2 layer once the commit has finished,

 * so we know we can free the blocks that were released with that commit.
@@ -2577,22 +2593,9 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn) 
		mb_debug(1, "gonna free %u blocks in group %u (0x%p):",

			 entry->count, entry->group, entry);



		if (test_opt(sb, DISCARD)) {

			int ret;

			ext4_fsblk_t discard_block;



			discard_block = entry->start_blk +

				ext4_group_first_block_no(sb, entry->group);

			trace_ext4_discard_blocks(sb,

					(unsigned long long)discard_block,

					entry->count);

			ret = sb_issue_discard(sb, discard_block, entry->count);

			if (ret == EOPNOTSUPP) {

				ext4_warning(sb,

					"discard not supported, disabling");

				clear_opt(EXT4_SB(sb)->s_mount_opt, DISCARD);

			}

		}

		if (test_opt(sb, DISCARD))

			ext4_issue_discard(sb, entry->group,

					entry->start_blk, entry->count);



		err = ext4_mb_load_buddy(sb, entry->group, &e4b);

		/* we expect to find existing buddy because it's pinned */
@@ -4639,6 +4642,8 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode, 
		mb_clear_bits(bitmap_bh->b_data, bit, count);

		mb_free_blocks(inode, &e4b, bit, count);

		ext4_mb_return_to_preallocation(inode, &e4b, block, count);

		if (test_opt(sb, DISCARD))

			ext4_issue_discard(sb, block_group, bit, count);

	}



	ret = ext4_free_blks_count(sb, gdp) + count;