Re: [PATCH v2] ext2: Remove deprecated DAX support

[Ashwin Gundarapu]

Thanks for the review, Jan. All the style issues you mentioned have
been addressed in v3 and v4:

v3: https://lore.kernel.org/linux-ext4/19e595ac3d0.1a0dcfbe128078.1031782761444069401@xxxxxxxxxxx/
v4: https://lore.kernel.org/linux-ext4/19e5aa07c9b.3a2e576d130187.5289857983023045470@xxxxxxxxxxx/

v3 fixed the spaces-to-tabs indentation issues in inode.c, super.c,
and file.c. It also restored Opt_dax for a graceful mount error message.

v4 changed Opt_xip and Opt_dax from -EINVAL to break with a warning,
per Sashiko AI review, to avoid potential boot failures on systems
with these options in /etc/fstab.

The stray empty lines and tab indentation are all cleaned up in the
latest version (v4).

Thanks,
Ashwin


From: Jan Kara <jack@xxxxxxx>
To: "Ashwin Gundarapu"<linuxuser509@xxxxxxxxxxx>
Cc: "jack"<jack@xxxxxxxx>, "linux-ext4"<linux-ext4@xxxxxxxxxxxxxxx>, "linux-kernel"<linux-kernel@xxxxxxxxxxxxxxx>
Date: Mon, 25 May 2026 22:00:40 +0530
Subject: Re: [PATCH v2] ext2: Remove deprecated DAX support

 > On Sun 24-05-26 11:08:53, Ashwin Gundarapu wrote: 
 > > 
 > > DAX support in ext2 was deprecated in commit d5a2693f93e4 
 > > ("ext2: Deprecate DAX") with a removal deadline of end of 2025. 
 > > Remove all DAX code from ext2 as scheduled. 
 > > 
 > > This removes the DAX mount option, IOMAP DAX support, DAX file 
 > > operations, DAX address_space_operations, and the DAX fault handler. 
 > > 
 > > Signed-off-by: Ashwin Gundarapu <linuxuser509@xxxxxxxxxxx> 
 > > --- 
 > > v2: Removed unused sbi variable and fixed indentation as reported 
 > >     by kernel test robot. 
 >  
 > Thanks for the patch. Some style nits below. 
 >  
 > >  static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 
 > >  { 
 > > -#ifdef CONFIG_FS_DAX 
 > > -    if (IS_DAX(iocb->ki_filp->f_mapping->host)) 
 > > -        return ext2_dax_read_iter(iocb, to); 
 > > -#endif 
 > > + 
 >  
 > Stray empty line here. 
 >  
 > >      if (iocb->ki_flags & IOCB_DIRECT) 
 > >          return ext2_dio_read_iter(iocb, to); 
 > > 
 > > @@ -297,10 +188,7 @@ static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to) 
 > > 
 > >  static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 
 > >  { 
 > > -#ifdef CONFIG_FS_DAX 
 > > -    if (IS_DAX(iocb->ki_filp->f_mapping->host)) 
 > > -        return ext2_dax_write_iter(iocb, from); 
 > > -#endif 
 > > + 
 >  
 > ... and here. 
 >  
 > >      if (iocb->ki_flags & IOCB_DIRECT) 
 > >          return ext2_dio_write_iter(iocb, from); 
 > > 
 > > @@ -321,7 +209,7 @@ const struct file_operations ext2_file_operations = { 
 > >  #ifdef CONFIG_COMPAT 
 > >      .compat_ioctl    = ext2_compat_ioctl, 
 > >  #endif 
 > > -    .mmap_prepare    = ext2_file_mmap_prepare, 
 > > +    .mmap_prepare = generic_file_mmap_prepare, 
 >  
 > Please indent this with tab the same way as other methods. 
 >  
 > > @@ -841,10 +818,7 @@ static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length, 
 > > 
 > >      iomap->flags = 0; 
 > >      iomap->offset = (u64)first_block << blkbits; 
 > > -    if (flags & IOMAP_DAX) 
 > > -        iomap->dax_dev = sbi->s_daxdev; 
 > > -    else 
 > > -        iomap->bdev = inode->i_sb->s_bdev; 
 > > +        iomap->bdev = inode->i_sb->s_bdev; 
 >  
 > Indented with spaces instead of tabs. 
 >  
 > > @@ -1290,12 +1248,8 @@ static int ext2_setsize(struct inode *inode, loff_t newsize) 
 > > 
 > >      inode_dio_wait(inode); 
 > > 
 > > -    if (IS_DAX(inode)) 
 > > -        error = dax_truncate_page(inode, newsize, NULL, 
 > > -                      &ext2_iomap_ops); 
 > > -    else 
 > > -        error = block_truncate_page(inode->i_mapping, 
 > > -                newsize, ext2_get_block); 
 > > +        error = block_truncate_page(inode->i_mapping, 
 > > +                                newsize, ext2_get_block); 
 >  
 > Indented with spaces instead of tabs. 
 >  
 > >      if (error) 
 > >          return error; 
 > > 
 >  
 > ... 
 > > +        case Opt_xip: 
 > > +                ext2_msg_fc(fc, KERN_ERR, "DAX support has been removed. Please use ext4 instead."); 
 > > +                return -EINVAL; 
 >  
 > Indented with spaces instead of tabs. 
 >  
 > > @@ -992,16 +974,8 @@ static int ext2_fill_super(struct super_block *sb, struct fs_context *fc) 
 > >      } 
 > >      blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size); 
 > > 
 > > -    if (test_opt(sb, DAX)) { 
 > > -        if (!sbi->s_daxdev) { 
 > > -            ext2_msg(sb, KERN_ERR, 
 > > -                "DAX unsupported by block device. Turning off DAX."); 
 > > -            clear_opt(sbi->s_mount_opt, DAX); 
 > > -        } else if (blocksize != PAGE_SIZE) { 
 > > -            ext2_msg(sb, KERN_ERR, "unsupported blocksize for DAX\n"); 
 > > -            clear_opt(sbi->s_mount_opt, DAX); 
 > > -        } 
 > > -    } 
 > > + 
 > > + 
 >  
 > Stray empty lines. 
 >  
 >                                 Honza 
 > -- 
 > Jan Kara <jack@xxxxxxxx> 
 > SUSE Labs, CR 
 >  
 >