[RFC v1 05/11] vfs: add one new mount option '-o hottrack'

zwu.kernel
2012-09-17T07:19:30Z

Introduce one new mount option '-o hottrack',
and add its parsing support.
Its usage looks like:
mount -o hottrack
mount -o nouser,hottrack
mount -o nouser,hottrack,loop
mount -o hottrack,nouser

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
fs/hot_track.c | 34 ++++++++++++++++++++++++++++++++++
fs/hot_track.h | 1 +
fs/super.c | 5 +++++
include/linux/hot_track.h | 6 ++++++
4 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/fs/hot_track.c b/fs/hot_track.c
index 064c7dc..b3f01a1 100644
--- a/fs/hot_track.c
+++ b/fs/hot_track.c
@@ -16,6 +16,40 @@
#include "hot_track.h"

/*
+ * Regular mount options parser for -hottrack option.
+ * return false if no -hottrack is specified;
+ * otherwise return true. And the -hottrack will be
+ * removed from options.
+ */
+bool hot_track_parse_options(char *options)
+{
+ long len;
+ char *p;
+ static char opts_hot[] = "hottrack";
+
+ if (!options)
+ return false;
+
+ p = strstr(options, opts_hot);
+ if (!p)
+ return false;
+
+ while (p) {
+ len = options + strlen(options) - (p + strlen(opts_hot));
+ if (len == 0) {
+ options[0] = '\0';
+ break;
+ }
+
+ memmove(p, p + strlen(opts_hot) + 1, len);
+ p = strstr(options, opts_hot);
+ }
+
+ printk(KERN_INFO "vfs: turning on hot data tracking\n");
+ return true;
+}
+
+/*
* Initialize kmem cache for hot_inode_item
* and hot_range_item
*/
diff --git a/fs/hot_track.h b/fs/hot_track.h
index 9a52945..a099b43 100644
--- a/fs/hot_track.h
+++ b/fs/hot_track.h
@@ -15,6 +15,7 @@

#include "hot_rb.h"

+bool hot_track_parse_options(char *options);
void __init hot_track_kmem_cache_init(void);

#endif /* __HOT_TRACK__ */
diff --git a/fs/super.c b/fs/super.c
index 0902cfa..d5bc781 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -35,6 +35,7 @@
#include <linux/fsnotify.h>
#include <linux/lockdep.h>
#include "internal.h"
+#include "hot_track.h"

LIST_HEAD(super_blocks);
@@ -1125,6 +1126,7 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
struct dentry *root;
struct super_block *sb;
char *secdata = NULL;
+ bool hottrack = false;
int error = -ENOMEM;

if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
@@ -1137,6 +1139,9 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
goto out_free_secdata;
}

+ if (data && hot_track_parse_options(data))
+ hottrack = true;
+
root = type->mount(type, flags, name, data);
if (IS_ERR(root)) {
error = PTR_ERR(root);
diff --git a/include/linux/hot_track.h b/include/linux/hot_track.h
index 2256496..b56a467 100644
--- a/include/linux/hot_track.h
+++ b/include/linux/hot_track.h
@@ -20,6 +20,11 @@
#include <linux/rbtree.h>
#include <linux/kref.h>

+/*
+ * Flags for hot data tracking mount options.
+ */
+#define HOT_MOUNT_HOT_TRACK (1 << 0)
+
/* A tree that sits on the hot_info */
struct hot_inode_tree {
struct rb_root map;
@@ -89,6 +94,7 @@ struct hot_range_item {
};

struct hot_info {
+ unsigned long mount_opt;

/* red-black tree that keeps track of fs-wide hot data */
struct hot_inode_tree hot_inode_tree;
--
1.7.6.5