vfs,ext2: introduce IS_DAX(inode)

Use an inode flag to tag inodes which should avoid using the page cache.
Convert ext2 to use it instead of mapping_is_xip().  Prevent I/Os to files
tagged with the DAX flag from falling back to buffered I/O.

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 6 insertions, 5 deletions

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index 36d35c36311d..0cb04486577d 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -731,7 +731,7 @@ static int ext2_get_blocks(struct inode *inode,
                 goto cleanup;
         }
 
-        if (ext2_use_xip(inode->i_sb)) {
+        if (IS_DAX(inode)) {
                 /*
                  * we need to clear the block
                  */
@@ -1201,7 +1201,7 @@ static int ext2_setsize(struct inode *inode, loff_t newsize)
 
         inode_dio_wait(inode);
 
-        if (mapping_is_xip(inode->i_mapping))
+        if (IS_DAX(inode))
                 error = xip_truncate_page(inode->i_mapping, newsize);
         else if (test_opt(inode->i_sb, NOBH))
                 error = nobh_truncate_page(inode->i_mapping,
@@ -1273,7 +1273,8 @@ void ext2_set_inode_flags(struct inode *inode)
 {
         unsigned int flags = EXT2_I(inode)->i_flags;
 
-        inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+        inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
+                                S_DIRSYNC | S_DAX);
         if (flags & EXT2_SYNC_FL)
                 inode->i_flags |= S_SYNC;
         if (flags & EXT2_APPEND_FL)
@@ -1284,6 +1285,8 @@ void ext2_set_inode_flags(struct inode *inode)
                 inode->i_flags |= S_NOATIME;
         if (flags & EXT2_DIRSYNC_FL)
                 inode->i_flags |= S_DIRSYNC;
+        if (test_opt(inode->i_sb, XIP))
+                inode->i_flags |= S_DAX;
 }
 
 /* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
diff --git a/fs/ext2/xip.h b/fs/ext2/xip.h
index 18b34d2f31b3..29be73781419 100644
--- a/fs/ext2/xip.h
+++ b/fs/ext2/xip.h
@@ -16,9 +16,7 @@ static inline int ext2_use_xip (struct super_block *sb)
 }
 int ext2_get_xip_mem(struct address_space *, pgoff_t, int,
                                 void **, unsigned long *);
-#define mapping_is_xip(map) unlikely(map->a_ops->get_xip_mem)
 #else
-#define mapping_is_xip(map)                     0
 #define ext2_xip_verify_sb(sb)                  do { } while (0)
 #define ext2_use_xip(sb)                        0
 #define ext2_clear_xip_target(inode, chain)     0