Re: [PATCH] vfs: introduce FS_IOC_SYNCFS to sync a single super

[Jonathan Nieder <jrnieder-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Arnd Bergmann wrote:

> You need to add this to the compat_ioctl handling as well, otherwise
> it won't work when you run a 32 bit process in a 64 bit kernel.
> 
> Adding it to the ioctl_pointer[] array is probably the easiest way.

Here's a patch for squashing (plus another tweak: renumbering the
ioctl to avoid a conflict with EXT4_IOC_ALLOC_DA_BLKS).

-- 8< --
Subject: FS_IOC_SYNCFS: finishing touches

This ioctl has the same ABI for 32-bit and 64-bit use; record
that in compat_ioctl.c.

Change ioctl number from _IO('f', 12) to _IO('f', 16) since the
former is taken by EXT4_IOC_ALLOC_DA_BLKS.

Signed-off-by: Jonathan Nieder <jrnieder-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 Documentation/ioctl/ioctl-number.txt |    2 +-
 fs/compat_ioctl.c                    |    1 +
 fs/ext4/ext4.h                       |    1 +
 include/linux/fs.h                   |    3 ++-
 4 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 63ffd78..3644ba9 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -212,7 +212,7 @@ Code  Seq#(hex)	Include File		Comments
 'f'	00-1F	linux/ext3_fs.h		conflict!
 'f'	00-0F	fs/jfs/jfs_dinode.h	conflict!
 'f'	00-0F	fs/ext4/ext4.h		conflict!
-'f'	00-0F	linux/fs.h		conflict!
+'f'	00-1F	linux/fs.h		conflict!
 'f'	00-0F	fs/ocfs2/ocfs2_fs.h	conflict!
 'g'	00-0F	linux/usb/gadgetfs.h
 'g'	20-2F	linux/usb/g_printer.h
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index a60579b..0989acf 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -876,6 +876,7 @@ COMPATIBLE_IOCTL(FIOASYNC)
 COMPATIBLE_IOCTL(FIONBIO)
 COMPATIBLE_IOCTL(FIONREAD)  /* This is also TIOCINQ */
 COMPATIBLE_IOCTL(FS_IOC_FIEMAP)
+COMPATIBLE_IOCTL(FS_IOC_SYNCFS)
 /* 0x00 */
 COMPATIBLE_IOCTL(FIBMAP)
 COMPATIBLE_IOCTL(FIGETBSZ)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 6a5edea..178d70b 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -541,6 +541,7 @@ struct ext4_new_group_data {
  /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
 #define EXT4_IOC_ALLOC_DA_BLKS		_IO('f', 12)
 #define EXT4_IOC_MOVE_EXT		_IOWR('f', 15, struct move_extent)
+ /* note ioctls 16- reserved for filesystem-independent ioctls */
 
 #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
 /*
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 525ecdd..24c6d42 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -331,7 +331,8 @@ struct inodes_stat_t {
 #define	FS_IOC_GETVERSION		_IOR('v', 1, long)
 #define	FS_IOC_SETVERSION		_IOW('v', 2, long)
 #define FS_IOC_FIEMAP			_IOWR('f', 11, struct fiemap)
-#define FS_IOC_SYNCFS                   _IO('f', 12)
+ /* 12-15 are for filesystem-specific ioctls */
+#define FS_IOC_SYNCFS			_IO('f', 16)
 #define FS_IOC32_GETFLAGS		_IOR('f', 1, int)
 #define FS_IOC32_SETFLAGS		_IOW('f', 2, int)
 #define FS_IOC32_GETVERSION		_IOR('v', 1, int)
-- 
1.7.2.3