On Mon 13-04-20 21:00:27, ira.weiny@xxxxxxxxx wrote: > From: Ira Weiny <ira.weiny@xxxxxxxxx> > > We add 'always', 'never', and 'inode' (default). '-o dax' continue to > operate the same. > > Specifically we introduce a 2nd DAX mount flag EXT4_MOUNT_NODAX and set > it and EXT4_MOUNT_DAX appropriately. > > We also force EXT4_MOUNT_NODAX if !CONFIG_FS_DAX. > > https://lore.kernel.org/lkml/20200405061945.GA94792@xxxxxxxxxxxxxxxxxxxxxxxxx/ > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> ... > @@ -2303,6 +2325,13 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb, > if (DUMMY_ENCRYPTION_ENABLED(sbi)) > SEQ_OPTS_PUTS("test_dummy_encryption"); > > + if (test_opt2(sb, NODAX)) > + SEQ_OPTS_PUTS("dax=never"); > + else if (test_opt(sb, DAX)) > + SEQ_OPTS_PUTS("dax=always"); > + else > + SEQ_OPTS_PUTS("dax=inode"); > + We try to show only mount options that were explicitely set by the user, or that are different from defaults - e.g., see how 'data=' mount option printing is handled. > ext4_show_quota_options(seq, sb); > return 0; > } > @@ -5424,6 +5453,12 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) > sbi->s_mount_opt ^= EXT4_MOUNT_DAX; > } > > + if ((sbi->s_mount_opt2 ^ old_opts.s_mount_opt2) & EXT4_MOUNT2_NODAX) { > + ext4_msg(sb, KERN_WARNING, "warning: refusing change of " > + "non-dax flag with busy inodes while remounting"); > + sbi->s_mount_opt2 ^= EXT4_MOUNT2_NODAX; > + } > + > if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) > ext4_abort(sb, "Abort forced by user"); I'd just merge this with the check whether EXT4_MOUNT_DAX changed. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
