From: Theodore Ts'o Subject: [PATCH 2/2] ext4: Automatically enable journal_async_commit on ext4 file systems Date: Sat, 5 Sep 2009 18:32:43 -0400 Message-ID: <1252189963-23868-2-git-send-email-tytso@mit.edu> References: <1252189963-23868-1-git-send-email-tytso@mit.edu> Cc: Theodore Ts'o To: Ext4 Developers List Return-path: Received: from THUNK.ORG ([69.25.196.29]:35495 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751914AbZIEWco (ORCPT ); Sat, 5 Sep 2009 18:32:44 -0400 In-Reply-To: <1252189963-23868-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Now that we have cleaned up journal_async_commit, it's safe to enable it all the time. But we only want to do so if ext4-specific INCOMPAT features are enabled, since otherwise we will prevent the filesystem from being mounted using ext3. Signed-off-by: "Theodore Ts'o" --- Documentation/filesystems/ext4.txt | 8 ++++++-- fs/ext4/super.c | 26 ++++++++++++++++++++++++-- 2 files changed, 30 insertions(+), 4 deletions(-) diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 3e329db..4f8d73a 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -135,8 +135,12 @@ ro Mount filesystem read only. Note that ext4 will writes to the filesystem. journal_async_commit Commit block can be written to disk without waiting - for descriptor blocks. If enabled older kernels cannot - mount the device. + for descriptor blocks. This mount option will be + automatically enabled if ext4-specific INCOMPAT + features are present in the file system. + +nojournal_async_commit Disable the journal_async_commit option, even + for ext4 filesystems. journal=update Update the ext4 file system's journal to the current format. diff --git a/fs/ext4/super.c b/fs/ext4/super.c index f1815d3..f644a5c 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -75,6 +75,15 @@ static int ext4_unfreeze(struct super_block *sb); static void ext4_write_super(struct super_block *sb); static int ext4_freeze(struct super_block *sb); +/* + * If ext4 filesystem features are enabled, then enable async_commits + * by default. + */ +#define ASYNC_COMMIT_DEFAULT(sb) (EXT4_HAS_INCOMPAT_FEATURE(sb, \ + (EXT4_FEATURE_INCOMPAT_EXTENTS| \ + EXT4_FEATURE_INCOMPAT_64BIT| \ + EXT4_FEATURE_INCOMPAT_FLEX_BG))) + ext4_fsblk_t ext4_block_bitmap(struct super_block *sb, struct ext4_group_desc *bg) @@ -845,8 +854,13 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs) */ seq_puts(seq, ",barrier="); seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0"); - if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) - seq_puts(seq, ",journal_async_commit"); + if (ASYNC_COMMIT_DEFAULT(sb)) { + if (!test_opt(sb, JOURNAL_ASYNC_COMMIT)) + seq_puts(seq, ",nojournal_async_commit"); + } else { + if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) + seq_puts(seq, ",journal_async_commit"); + } if (test_opt(sb, NOBH)) seq_puts(seq, ",nobh"); if (test_opt(sb, I_VERSION)) @@ -1050,6 +1064,7 @@ enum { Opt_commit, Opt_min_batch_time, Opt_max_batch_time, Opt_journal_update, Opt_journal_dev, Opt_journal_checksum, Opt_journal_async_commit, + Opt_nojournal_async_commit, Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback, Opt_data_err_abort, Opt_data_err_ignore, Opt_mb_history_length, Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota, @@ -1092,6 +1107,7 @@ static const match_table_t tokens = { {Opt_journal_dev, "journal_dev=%u"}, {Opt_journal_checksum, "journal_checksum"}, {Opt_journal_async_commit, "journal_async_commit"}, + {Opt_nojournal_async_commit, "nojournal_async_commit"}, {Opt_abort, "abort"}, {Opt_data_journal, "data=journal"}, {Opt_data_ordered, "data=ordered"}, @@ -1284,6 +1300,9 @@ static int parse_options(char *options, struct super_block *sb, case Opt_journal_async_commit: set_opt(sbi->s_mount_opt, JOURNAL_ASYNC_COMMIT); break; + case Opt_nojournal_async_commit: + clear_opt(sbi->s_mount_opt, JOURNAL_ASYNC_COMMIT); + break; case Opt_noload: set_opt(sbi->s_mount_opt, NOLOAD); break; @@ -2422,6 +2441,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) */ set_opt(sbi->s_mount_opt, DELALLOC); + if (ASYNC_COMMIT_DEFAULT(sb)) + set_opt(sbi->s_mount_opt, JOURNAL_ASYNC_COMMIT); + if (!parse_options((char *) data, sb, &journal_devnum, &journal_ioprio, NULL, 0)) goto failed_mount; -- 1.6.3.2.1.gb9f7d.dirty