The patch titled
Subject: vfs,ext2: introduce IS_DAX(inode)
has been added to the -mm tree. Its filename is
vfsext2-introduce-is_daxinode.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/vfsext2-introduce-is_daxinode.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/vfsext2-introduce-is_daxinode.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
Subject: 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@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Andreas Dilger <andreas.dilger@xxxxxxxxx>
Cc: Boaz Harrosh <boaz@xxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ext2/inode.c | 9 ++++++---
fs/ext2/xip.h | 2 --
include/linux/fs.h | 6 ++++++
mm/filemap.c | 19 ++++++++++++-------
4 files changed, 24 insertions(+), 12 deletions(-)
diff -puN fs/ext2/inode.c~vfsext2-introduce-is_daxinode fs/ext2/inode.c
--- a/fs/ext2/inode.c~vfsext2-introduce-is_daxinode
+++ a/fs/ext2/inode.c
@@ -731,7 +731,7 @@ static int ext2_get_blocks(struct 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 *in
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 *
{
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->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 -puN fs/ext2/xip.h~vfsext2-introduce-is_daxinode fs/ext2/xip.h
--- a/fs/ext2/xip.h~vfsext2-introduce-is_daxinode
+++ a/fs/ext2/xip.h
@@ -16,9 +16,7 @@ static inline int ext2_use_xip (struct s
}
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
diff -puN include/linux/fs.h~vfsext2-introduce-is_daxinode include/linux/fs.h
--- a/include/linux/fs.h~vfsext2-introduce-is_daxinode
+++ a/include/linux/fs.h
@@ -1638,6 +1638,11 @@ 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
@@ -1675,6 +1680,7 @@ 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)
diff -puN mm/filemap.c~vfsext2-introduce-is_daxinode mm/filemap.c
--- a/mm/filemap.c~vfsext2-introduce-is_daxinode
+++ a/mm/filemap.c
@@ -1723,9 +1723,11 @@ generic_file_read_iter(struct kiocb *ioc
* 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;
}
@@ -2588,13 +2590,16 @@ ssize_t __generic_file_write_iter(struct
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;
_
Patches currently in -mm which might be from matthew.r.wilcox@xxxxxxxxx are
axonram-fix-bug-in-direct_access.patch
block-change-direct_access-calling-convention.patch
mm-fix-xip-fault-vs-truncate-race.patch
mm-fix-xip-fault-vs-truncate-race-fix.patch
mm-allow-page-fault-handlers-to-perform-the-cow.patch
mm-allow-page-fault-handlers-to-perform-the-cow-fix.patch
vfsext2-introduce-is_daxinode.patch
daxext2-replace-xip-read-and-write-with-dax-i-o.patch
daxext2-replace-ext2_clear_xip_target-with-dax_clear_blocks.patch
daxext2-replace-the-xip-page-fault-handler-with-the-dax-page-fault-handler.patch
daxext2-replace-the-xip-page-fault-handler-with-the-dax-page-fault-handler-fix.patch
daxext2-replace-xip_truncate_page-with-dax_truncate_page.patch
vfs-remove-get_xip_mem.patch
ext2-remove-ext2_xip_verify_sb.patch
ext2-remove-ext2_use_xip.patch
ext2-remove-xipc-and-xiph.patch
vfsext2-remove-config_ext2_fs_xip-and-rename-config_fs_xip-to-config_fs_dax.patch
ext2-remove-ext2_aops_xip.patch
ext2-get-rid-of-most-mentions-of-xip-in-ext2.patch
dax-add-dax_zero_page_range.patch
dax-add-dax_zero_page_range-fix.patch
ext4-add-dax-functionality.patch
brd-rename-xip-to-dax.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
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