lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 21 May 2020 12:24:34 +0200 From: Jan Kara <jack@...e.cz> To: Ira Weiny <ira.weiny@...el.com> Cc: Jan Kara <jack@...e.cz>, linux-ext4@...r.kernel.org, Andreas Dilger <adilger.kernel@...ger.ca>, "Theodore Y. Ts'o" <tytso@....edu>, Eric Biggers <ebiggers@...nel.org>, Al Viro <viro@...iv.linux.org.uk>, Dan Williams <dan.j.williams@...el.com>, Dave Chinner <david@...morbit.com>, Christoph Hellwig <hch@....de>, Jeff Moyer <jmoyer@...hat.com>, "Darrick J. Wong" <darrick.wong@...cle.com>, linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH V3 4/8] fs/ext4: Update ext4_should_use_dax() On Wed 20-05-20 12:40:50, Ira Weiny wrote: > On Wed, May 20, 2020 at 03:37:28PM +0200, Jan Kara wrote: > > On Tue 19-05-20 22:57:49, ira.weiny@...el.com wrote: > > > From: Ira Weiny <ira.weiny@...el.com> > > > > > > S_DAX should only be enabled when the underlying block device supports > > > dax. > > > > > > Change ext4_should_use_dax() to check for device support prior to the > > > over riding mount option. > > > > > > While we are at it change the function to ext4_should_enable_dax() as > > > this better reflects the ask as well as matches xfs. > > > > > > Reviewed-by: Jan Kara <jack@...e.cz> > > > Signed-off-by: Ira Weiny <ira.weiny@...el.com> > > > > ... > > > > > @@ -4412,7 +4410,13 @@ static bool ext4_should_use_dax(struct inode *inode) > > > return false; > > > if (ext4_test_inode_flag(inode, EXT4_INODE_VERITY)) > > > return false; > > > - return true; > > > + if (!bdev_dax_supported(inode->i_sb->s_bdev, > > > + inode->i_sb->s_blocksize)) > > > + return false; > > > + if (test_opt(inode->i_sb, DAX_ALWAYS)) > > > + return true; > > > + > > > + return false; > > > } > > > > Now that I think about it - shouldn't we rather cache the result of > > bdev_dax_supported() in sb on mount and then just check the flag here? > > Because bdev_dax_supported() isn't exactly cheap (it does a lot of checks > > and mappings, tries to read from the pmem, ...). > > Sounds reasonable. > > Not sure which flags are appropriate. So add it here? Yes, sounds good. Thanks! Honza > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 1a3daf2d18ef..0b4db9ce7756 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -1979,6 +1979,7 @@ static inline bool ext4_has_incompat_features(struct super_block *sb) > */ > #define EXT4_FLAGS_RESIZING 0 > #define EXT4_FLAGS_SHUTDOWN 1 > +#define EXT4_FLAGS_BDEV_IS_DAX 2 > > static inline int ext4_forced_shutdown(struct ext4_sb_info *sbi) > { > -- Jan Kara <jack@...e.com> SUSE Labs, CR
Powered by blists - more mailing lists