On Tue 12-05-20 22:43:22, 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_MOUNT2_DAX_NEVER and set > it and EXT4_MOUNT_DAX_ALWAYS appropriately. > > We also force EXT4_MOUNT2_DAX_NEVER if !CONFIG_FS_DAX. > > https://lore.kernel.org/lkml/20200405061945.GA94792@xxxxxxxxxxxxxxxxxxxxxxxxx/ > > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > --- > Changes from RFC: > Combine remount check for DAX_NEVER with DAX_ALWAYS > Update ext4_should_enable_dax() > --- > fs/ext4/ext4.h | 1 + > fs/ext4/inode.c | 2 ++ > fs/ext4/super.c | 43 +++++++++++++++++++++++++++++++++++++------ > 3 files changed, 40 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 86a0994332ce..01d1de838896 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -1168,6 +1168,7 @@ struct ext4_inode_info { > blocks */ > #define EXT4_MOUNT2_HURD_COMPAT 0x00000004 /* Support HURD-castrated > file systems */ > +#define EXT4_MOUNT2_DAX_NEVER 0x00000008 /* Do not allow Direct Access */ > > #define EXT4_MOUNT2_EXPLICIT_JOURNAL_CHECKSUM 0x00000008 /* User explicitly > specified journal checksum */ > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 23e42a223235..140b1930e2f4 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -4400,6 +4400,8 @@ int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) > > static bool ext4_should_enable_dax(struct inode *inode) > { > + if (test_opt2(inode->i_sb, DAX_NEVER)) > + return false; > if (!S_ISREG(inode->i_mode)) > return false; > if (ext4_should_journal_data(inode)) > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 5ec900fdf73c..e01a040a58a9 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -1505,6 +1505,7 @@ enum { > Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota, > Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err, > Opt_usrquota, Opt_grpquota, Opt_prjquota, Opt_i_version, Opt_dax, > + Opt_dax_str, > Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_warn_on_error, > Opt_nowarn_on_error, Opt_mblk_io_submit, > Opt_lazytime, Opt_nolazytime, Opt_debug_want_extra_isize, > @@ -1570,6 +1571,7 @@ static const match_table_t tokens = { > {Opt_barrier, "barrier"}, > {Opt_nobarrier, "nobarrier"}, > {Opt_i_version, "i_version"}, > + {Opt_dax_str, "dax=%s"}, Hum, maybe it would be easier to handle this like we do with e.g. 'data=' mount option? I.e. like: {Opt_dax_always, "dax=always"}, {Opt_dax_never, "dax=never"}, {Opt_dax_inode, "dax=inode"), and then handle these three tokens... Not that it would be a big difference but that's why we usually handle mount options with small "enums" in ext4. Honza > {Opt_dax, "dax"}, > {Opt_stripe, "stripe=%u"}, > {Opt_delalloc, "delalloc"}, > @@ -1767,6 +1769,7 @@ static const struct mount_opts { > {Opt_min_batch_time, 0, MOPT_GTE0}, > {Opt_inode_readahead_blks, 0, MOPT_GTE0}, > {Opt_init_itable, 0, MOPT_GTE0}, > + {Opt_dax_str, 0, MOPT_STRING}, > {Opt_dax, EXT4_MOUNT_DAX_ALWAYS, MOPT_SET}, > {Opt_stripe, 0, MOPT_GTE0}, > {Opt_resuid, 0, MOPT_GTE0}, > @@ -2076,13 +2079,32 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, > } > sbi->s_jquota_fmt = m->mount_opt; > #endif > - } else if (token == Opt_dax) { > + } else if (token == Opt_dax || token == Opt_dax_str) { > #ifdef CONFIG_FS_DAX > - ext4_msg(sb, KERN_WARNING, > - "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); > - sbi->s_mount_opt |= m->mount_opt; > + char *tmp = match_strdup(&args[0]); > + > + if (!tmp || !strcmp(tmp, "always")) { > + ext4_msg(sb, KERN_WARNING, > + "DAX enabled. Warning: EXPERIMENTAL, use at your own risk"); > + sbi->s_mount_opt |= EXT4_MOUNT_DAX_ALWAYS; > + sbi->s_mount_opt2 &= ~EXT4_MOUNT2_DAX_NEVER; > + } else if (!strcmp(tmp, "never")) { > + sbi->s_mount_opt2 |= EXT4_MOUNT2_DAX_NEVER; > + sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS; > + } else if (!strcmp(tmp, "inode")) { > + sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS; > + sbi->s_mount_opt2 &= ~EXT4_MOUNT2_DAX_NEVER; > + } else { > + ext4_msg(sb, KERN_WARNING, "DAX invalid option."); > + kfree(tmp); > + return -1; > + } > + > + kfree(tmp); > #else > ext4_msg(sb, KERN_INFO, "dax option not supported"); > + sbi->s_mount_opt2 |= EXT4_MOUNT2_DAX_NEVER; > + sbi->s_mount_opt &= ~EXT4_MOUNT_DAX_ALWAYS; > return -1; > #endif > } else if (token == Opt_data_err_abort) { > @@ -2306,6 +2328,13 @@ 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, DAX_NEVER)) > + SEQ_OPTS_PUTS("dax=never"); > + else if (test_opt(sb, DAX_ALWAYS)) > + SEQ_OPTS_PUTS("dax=always"); > + else > + SEQ_OPTS_PUTS("dax=inode"); > + > ext4_show_quota_options(seq, sb); > return 0; > } > @@ -5425,10 +5454,12 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) > goto restore_opts; > } > > - if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_DAX_ALWAYS) { > + if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT4_MOUNT_DAX_ALWAYS || > + (sbi->s_mount_opt2 ^ old_opts.s_mount_opt2) & EXT4_MOUNT2_DAX_NEVER) { > ext4_msg(sb, KERN_WARNING, "warning: refusing change of " > - "dax flag with busy inodes while remounting"); > + "dax mount option with busy inodes while remounting"); > sbi->s_mount_opt ^= EXT4_MOUNT_DAX_ALWAYS; > + sbi->s_mount_opt2 ^= EXT4_MOUNT2_DAX_NEVER; > } > > if (sbi->s_mount_flags & EXT4_MF_FS_ABORTED) > -- > 2.25.1 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
