3:20 p.m.
The current IS_DAX() helper that checks the S_DAX inode flag is
ambiguous, and currently has the broken assumption that the S_DAX flag
is only non-zero in the CONFIG_FS_DAX=y case. In preparation for
defining S_DAX to non-zero in the CONFIG_FS_DAX=n + CONFIG_DEV_DAX=y
case, introduce two explicit helpers to replace IS_DAX().
Cc: "Theodore Ts'o" <tytso(a)mit.edu>
Cc: Andreas Dilger <adilger.kernel(a)dilger.ca>
Cc: Alexander Viro <viro(a)zeniv.linux.org.uk>
Cc: "Darrick J. Wong" <darrick.wong(a)oracle.com>
Cc: linux-xfs(a)vger.kernel.org (supporter:XFS FILESYSTEM)
Cc: Matthew Wilcox <mawilcox(a)microsoft.com>
Cc: Ross Zwisler <ross.zwisler(a)linux.intel.com>
Cc: <stable(a)vger.kernel.org>
Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap")
Reported-by: Jan Kara <jack(a)suse.cz>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
---
include/linux/fs.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 79c413985305..bd0c46880572 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1909,6 +1909,28 @@ static inline bool sb_rdonly(const struct super_block *sb) { return
sb->s_flags
#define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \
(inode)->i_rdev == WHITEOUT_DEV)
+static inline bool IS_DEVDAX(struct inode *inode)
+{
+ if (!IS_ENABLED(CONFIG_DEV_DAX))
+ return false;
+ if ((inode->i_flags & S_DAX) == 0)
+ return false;
+ if (!S_ISCHR(inode->i_mode))
+ return false;
+ return true;
+}
+
+static inline bool IS_FSDAX(struct inode *inode)
+{
+ if (!IS_ENABLED(CONFIG_FS_DAX))
+ return false;
+ if ((inode->i_flags & S_DAX) == 0)
+ return false;
+ if (S_ISCHR(inode->i_mode))
+ return false;
+ return true;
+}
+
static inline bool HAS_UNMAPPED_ID(struct inode *inode)
{
return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);