| Message ID | 20200520055753.3733520-5-ira.weiny@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Enable ext4 support for per-file/directory DAX operations | expand |
On Tue 19-05-20 22:57:49, ira.weiny@intel.com wrote: > From: Ira Weiny <ira.weiny@intel.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@suse.cz> > Signed-off-by: Ira Weiny <ira.weiny@intel.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, ...). Honza
On Wed, May 20, 2020 at 03:37:28PM +0200, Jan Kara wrote: > On Tue 19-05-20 22:57:49, ira.weiny@intel.com wrote: > > From: Ira Weiny <ira.weiny@intel.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@suse.cz> > > Signed-off-by: Ira Weiny <ira.weiny@intel.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? 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) {
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@intel.com wrote: > > > From: Ira Weiny <ira.weiny@intel.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@suse.cz> > > > Signed-off-by: Ira Weiny <ira.weiny@intel.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) > { >
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index a10ff12194db..d3a4c2ed7a1c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4398,10 +4398,8 @@ int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) !ext4_test_inode_state(inode, EXT4_STATE_XATTR)); } -static bool ext4_should_use_dax(struct inode *inode) +static bool ext4_should_enable_dax(struct inode *inode) { - if (!test_opt(inode->i_sb, DAX_ALWAYS)) - return false; if (!S_ISREG(inode->i_mode)) return false; if (ext4_should_journal_data(inode)) @@ -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; } void ext4_set_inode_flags(struct inode *inode) @@ -4430,7 +4434,7 @@ void ext4_set_inode_flags(struct inode *inode) new_fl |= S_NOATIME; if (flags & EXT4_DIRSYNC_FL) new_fl |= S_DIRSYNC; - if (ext4_should_use_dax(inode)) + if (ext4_should_enable_dax(inode)) new_fl |= S_DAX; if (flags & EXT4_ENCRYPT_FL) new_fl |= S_ENCRYPTED;