[PATCH V1 5/9] fs/ext4: Update ext4_should_use_dax()

ira.weiny
2020-05-14T06:53:40Z

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>

---
Changes from RFC
Change function name to 'should enable'
Clean up bool conversion
Reorder this for better bisect-ability
---
fs/ext4/inode.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

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;
--
2.25.1