ext4: stop issuing discards if not supported by device (a30eec2a) · Commits · 戴 / test

Turn off issuance of discard requests if the device does not support it - similar to the action we take for barriers. This will save a little computation time if a non-discardable device is mounted with -o discard, and also makes it obvious that it's not doing what was asked at mount time ... Signed-off-by:

Eric Sandeen <sandeen@redhat.com> Signed-off-by:

"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/mballoc.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -2534,6 +2534,7 @@ static void release_blocks_on_commit(journal_t journal, transaction_t txn)
		entry->count, entry->group, entry);

		if (test_opt(sb, DISCARD)) {
		int ret;
		ext4_fsblk_t discard_block;

		discard_block = entry->start_blk +
		@@ -2541,7 +2542,12 @@ static void release_blocks_on_commit(journal_t journal, transaction_t txn)
		trace_ext4_discard_blocks(sb,
		(unsigned long long)discard_block,
		entry->count);
		sb_issue_discard(sb, 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);
		}
		}

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

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