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Commit fbbbad4b authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

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: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarMathieu 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2e4cdab0

fs/ext2/inode.c

+6 −3
Original line number Diff line number Diff line
@@ -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 */

fs/ext2/xip.h

+0 −2
Original line number Diff line number Diff line
@@ -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

include/linux/fs.h

+6 −0
Original line number Diff line number Diff line
@@ -1677,6 +1677,11 @@ struct super_operations { 
#define S_IMA		1024	/* Inode has an associated IMA struct */

#define S_AUTOMOUNT	2048	/* Automount/referral quasi-directory */

#define S_NOSEC		4096	/* no suid or xattr security attributes */

#ifdef CONFIG_FS_XIP

#define S_DAX		8192	/* Direct Access, avoiding the page cache */

#else

#define S_DAX		0	/* Make all the DAX code disappear */

#endif



/*

 * Note that nosuid etc flags are inode-specific: setting some file-system
@@ -1714,6 +1719,7 @@ struct super_operations { 
#define IS_IMA(inode)		((inode)->i_flags & S_IMA)

#define IS_AUTOMOUNT(inode)	((inode)->i_flags & S_AUTOMOUNT)

#define IS_NOSEC(inode)		((inode)->i_flags & S_NOSEC)

#define IS_DAX(inode)		((inode)->i_flags & S_DAX)



#define IS_WHITEOUT(inode)	(S_ISCHR(inode->i_mode) && \

				 (inode)->i_rdev == WHITEOUT_DEV)

mm/filemap.c

+12 −7
Original line number Diff line number Diff line
@@ -1723,9 +1723,11 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
		 * we've already read everything we wanted to, or if

		 * there was a short read because we hit EOF, go ahead

		 * and return.  Otherwise fallthrough to buffered io for

		 * the rest of the read.

		 * the rest of the read.  Buffered reads will not work for

		 * DAX files, so don't bother trying.

		 */

		if (retval < 0 || !iov_iter_count(iter) || *ppos >= size) {

		if (retval < 0 || !iov_iter_count(iter) || *ppos >= size ||

		    IS_DAX(inode)) {

			file_accessed(file);

			goto out;

		}
@@ -2587,13 +2589,16 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) 
		loff_t endbyte;



		written = generic_file_direct_write(iocb, from, pos);

		if (written < 0 || written == count)

			goto out;



		/*

		 * direct-io write to a hole: fall through to buffered I/O

		 * for completing the rest of the request.

		 * If the write stopped short of completing, fall back to

		 * buffered writes.  Some filesystems do this for writes to

		 * holes, for example.  For DAX files, a buffered write will

		 * not succeed (even if it did, DAX does not handle dirty

		 * page-cache pages correctly).

		 */

		if (written < 0 || written == count || IS_DAX(inode))

			goto out;



		pos += written;

		count -= written;