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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>
hifive-unleashed-5.1
Matthew Wilcox 2015-02-16 15:58:53 -08:00 committed by Linus Torvalds
parent 2e4cdab058
commit fbbbad4bc2
4 changed files with 24 additions and 12 deletions
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9
fs/ext2/inode.c
View File

@ -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 */

2
fs/ext2/xip.h
View File

@ -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

6
include/linux/fs.h
View File

@ -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)

19
mm/filemap.c
View File

@ -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)
/*
* 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;
/*
* direct-io write to a hole: fall through to buffered I/O
* for completing the rest of the request.
*/
pos += written;
count -= written;