diff mbox series

[V1,7/9] fs/ext4: Make DAX mount option a tri-state

Message ID 20200514065316.2500078-8-ira.weiny@intel.com
State New
Headers show
Series Enable ext4 support for per-file/directory DAX operations | expand

Commit Message

Ira Weiny May 14, 2020, 6:53 a.m. UTC
From: Ira Weiny <ira.weiny@intel.com>

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@iweiny-DESK2.sc.intel.com/

Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
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(-)

Comments

Jan Kara May 14, 2020, 11:25 a.m. UTC | #1
On Wed 13-05-20 23:53:13, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> 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@iweiny-DESK2.sc.intel.com/
> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> 
> ---
> Changes from RFC:
> 	Combine remount check for DAX_NEVER with DAX_ALWAYS
> 	Update ext4_should_enable_dax()

...

> @@ -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);

As I wrote in my reply to previous version of this patch, I'd prefer if we
handled this like e.g. 'data=' mount option. I don't think any unification
in option parsing with XFS makes sence and I'd rather keep consistent how
ext4 handles these 'enum' options.

								Honza
Ira Weiny May 14, 2020, 2:27 p.m. UTC | #2
On Thu, May 14, 2020 at 01:25:53PM +0200, Jan Kara wrote:
> On Wed 13-05-20 23:53:13, ira.weiny@intel.com wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > 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@iweiny-DESK2.sc.intel.com/
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > 
> > ---
> > Changes from RFC:
> > 	Combine remount check for DAX_NEVER with DAX_ALWAYS
> > 	Update ext4_should_enable_dax()
> 
> ...
> 
> > @@ -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);
> 
> As I wrote in my reply to previous version of this patch, I'd prefer if we
> handled this like e.g. 'data=' mount option. I don't think any unification
> in option parsing with XFS makes sence and I'd rather keep consistent how
> ext4 handles these 'enum' options.

Ok...  I'm sorry I'll change this.  Thanks for all the reviews!
Ira

> 
> 								Honza
> 
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
Darrick J. Wong May 14, 2020, 3:08 p.m. UTC | #3
On Wed, May 13, 2020 at 11:53:13PM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> 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@iweiny-DESK2.sc.intel.com/
> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> 
> ---
> 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"},
>  	{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");

dax=inode is the default; do you need to show it?

(Especially since xfs doesn't...)

--D

> +
>  	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
>
Ira Weiny May 15, 2020, 3:38 a.m. UTC | #4
On Thu, May 14, 2020 at 08:08:39AM -0700, Darrick J. Wong wrote:
> On Wed, May 13, 2020 at 11:53:13PM -0700, ira.weiny@intel.com wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > 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@iweiny-DESK2.sc.intel.com/
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > 
> > ---
> > 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"},
> >  	{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");
> 
> dax=inode is the default; do you need to show it?
> 
> (Especially since xfs doesn't...)

I'll only show it if -o dax or -o dax=inode was actually specified per earlier
comments regarding ext4 behavior.

Ira

> 
> --D
> 
> > +
> >  	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
> >
diff mbox series

Patch

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"},
 	{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)