Re: [RFC] FS_IOC_SYNCFS

From: Jan Kara
Date: Fri Jul 23 2010 - 12:25:17 EST


On Tue 20-07-10 16:48:26, Sage Weil wrote:
> As far as I can see, currently the only way to sync a single file system
> (and not _all_ mounted file systems) is via the BLKFLSBUF ioctl, which
> will sync_filesystem() and then invalidate_bdev(). If you _just_ want to
> sync, though, the invalidate_bdev() is unnecessary and potentially
> counter-productive.
>
> Would it be reasonable to add a simple call like so? Then you could
>
> fd = open("/path/for/some/mount", O_RDONLY);
> ioctl(fd, FS_IOC_SYNCFS);
> close(fd);
>
> or something along those lines.
Looks reasonable to me...

Honza

> diff --git a/fs/ioctl.c b/fs/ioctl.c
> index 2d140a7..0bc9f7a 100644
> --- a/fs/ioctl.c
> +++ b/fs/ioctl.c
> @@ -593,6 +593,9 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
> case FS_IOC_FIEMAP:
> return ioctl_fiemap(filp, arg);
>
> + case FS_IOC_SYNCFS:
> + return sync_filesystem(filp->f_dentry->d_sb);
> +
> case FIGETBSZ:
> {
> struct inode *inode = filp->f_path.dentry->d_inode;
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 471e1ff..4a84d78 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -321,6 +321,7 @@ 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('S', 12)
> #define FS_IOC32_GETFLAGS _IOR('f', 1, int)
> #define FS_IOC32_SETFLAGS _IOW('f', 2, int)
> #define FS_IOC32_GETVERSION _IOR('v', 1, int)
> --
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--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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