Signed-off-by: Li Wang <liw...@ubuntukylin.com>
Signed-off-by: Yunchuan Wen <yunchuan...@ubuntukylin.com>
---
fs/drop_caches.c | 45 +++++++++++++++++++++++++++++++++++++--------
1 file changed, 37 insertions(+), 8 deletions(-)
diff --git a/fs/drop_caches.c b/fs/drop_caches.c
index 9fd702f..ab31393 100644
--- a/fs/drop_caches.c
+++ b/fs/drop_caches.c
@@ -8,10 +8,11 @@
#include <linux/writeback.h>
#include <linux/sysctl.h>
#include <linux/gfp.h>
+#include <linux/fs_struct.h>
#include "internal.h"
/* A global variable is a bit ugly, but it keeps the code simple */
-int sysctl_drop_caches;
+char sysctl_drop_caches[PATH_MAX];
static void drop_pagecache_sb(struct super_block *sb, void *unused)
{
@@ -54,15 +55,43 @@ int drop_caches_sysctl_handler(ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
int ret;
+ int command;
+ struct path path;
+ struct path root;
- ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
- if (ret)
- return ret;
- if (write) {
- if (sysctl_drop_caches & 1)
+ ret = proc_dostring(table, write, buffer, length, ppos);
+ if (ret || !write)
+ goto out;
+ ret = -EINVAL;
+ command = sysctl_drop_caches[0] - '0';
+ if (command < 1 || command > 3)
+ goto out;
+ if (sysctl_drop_caches[1] == '\0') {
+ if (command & 1)
iterate_supers(drop_pagecache_sb, NULL);
- if (sysctl_drop_caches & 2)
+ if (command & 2)
drop_slab();
+ ret = 0;
+ goto out;
}
- return 0;
+ if (sysctl_drop_caches[1] != ':' || sysctl_drop_caches[2] == '\0')
+ goto out;
+ if (sysctl_drop_caches[2] == '/')
+ get_fs_root(current->fs, &root);
+ else
+ get_fs_pwd(current->fs, &root);
+ ret = vfs_path_lookup(root.dentry, root.mnt,
+ &sysctl_drop_caches[2], 0, &path);
+ path_put(&root);
+ if (ret)
+ goto out;
+ if (command & 1)
+ shrink_pagecache_parent(path.dentry);
+ if (command & 2)
+ shrink_dcache_parent(path.dentry);
+ path_put(&path);
+out:
+ if (ret)
+ memset(sysctl_drop_caches, 0, PATH_MAX);
+ return ret;
}
--
1.7.9.5
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