Subject: add metadata_readahead ioctl in vfs
Add metadata readahead ioctl in vfs. Filesystem can hook to
super_operations.metadata_readahead to handle filesystem specific task.
Next patch will give an example how btrfs implements it.
Signed-off-by: Shaohua Li
<shaohua.li-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Reviewed-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
---
fs/compat_ioctl.c | 2 ++
fs/ioctl.c | 21 +++++++++++++++++++++
include/linux/fs.h | 8 ++++++++
3 files changed, 31 insertions(+)
Index: linux/fs/ioctl.c
==================================================================---
linux.orig/fs/ioctl.c 2011-01-18 10:39:40.000000000 +0800
+++ linux/fs/ioctl.c 2011-01-18 10:41:37.000000000 +0800
@@ -568,6 +568,24 @@ static int ioctl_metadata_incore(struct
return 1;
}
+static int ioctl_metadata_readahead(struct file *filp, void __user *argp)
+{
+ struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
+ struct metadata_readahead_args args;
+
+ if (!sb->s_op->metadata_readahead)
+ return -EINVAL;
+
+ if (copy_from_user(&args, argp, sizeof(args)))
+ return -EFAULT;
+
+ /* readahead in page unit */
+ if ((args.offset & ~PAGE_CACHE_MASK) || (args.size &
~PAGE_CACHE_MASK))
+ return -EINVAL;
+
+ return sb->s_op->metadata_readahead(sb, args.offset, args.size);
+}
+
/*
* When you add any new common ioctls to the switches above and below
* please update compat_sys_ioctl() too.
@@ -631,6 +649,9 @@ int do_vfs_ioctl(struct file *filp, unsi
case FIMETADATA_INCORE:
return ioctl_metadata_incore(filp, argp);
+ case FIMETADATA_READAHEAD:
+ return ioctl_metadata_readahead(filp, argp);
+
default:
if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
error = file_ioctl(filp, cmd, arg);
Index: linux/include/linux/fs.h
==================================================================---
linux.orig/include/linux/fs.h 2011-01-18 10:39:40.000000000 +0800
+++ linux/include/linux/fs.h 2011-01-18 10:41:37.000000000 +0800
@@ -60,6 +60,11 @@ struct metadata_incore_args {
__u32 unused;
};
+struct metadata_readahead_args {
+ __u64 offset;
+ __u64 size;
+};
+
#define NR_FILE 8192 /* this can well be larger on a larger system */
#define MAY_EXEC 1
@@ -335,6 +340,7 @@ struct metadata_incore_args {
#define FITHAW _IOWR(''X'', 120, int) /* Thaw */
#define FITRIM _IOWR(''X'', 121, struct fstrim_range) /* Trim
*/
#define FIMETADATA_INCORE _IOWR(''X'', 122, struct
metadata_incore_args)
+#define FIMETADATA_READAHEAD _IOW(''X'', 123, struct
metadata_readahead_args)
#define FS_IOC_GETFLAGS _IOR(''f'', 1, long)
#define FS_IOC_SETFLAGS _IOW(''f'', 2, long)
@@ -1636,6 +1642,8 @@ struct super_operations {
int (*bdev_try_to_free_page)(struct super_block*, struct page*, gfp_t);
int (*metadata_incore)(struct super_block*, loff_t *offset,
ssize_t *size);
+ int (*metadata_readahead)(struct super_block*, loff_t offset,
+ ssize_t size);
};
/*
Index: linux/fs/compat_ioctl.c
==================================================================---
linux.orig/fs/compat_ioctl.c 2011-01-18 10:39:40.000000000 +0800
+++ linux/fs/compat_ioctl.c 2011-01-18 10:41:37.000000000 +0800
@@ -884,6 +884,7 @@ COMPATIBLE_IOCTL(FIGETBSZ)
COMPATIBLE_IOCTL(FIFREEZE)
COMPATIBLE_IOCTL(FITHAW)
COMPATIBLE_IOCTL(FIMETADATA_INCORE)
+COMPATIBLE_IOCTL(FIMETADATA_READAHEAD)
COMPATIBLE_IOCTL(KDGETKEYCODE)
COMPATIBLE_IOCTL(KDSETKEYCODE)
COMPATIBLE_IOCTL(KDGKBTYPE)
@@ -1580,6 +1581,7 @@ asmlinkage long compat_sys_ioctl(unsigne
case FIOASYNC:
case FIOQSIZE:
case FIMETADATA_INCORE:
+ case FIMETADATA_READAHEAD:
break;
#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)