mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 11:19:37 +00:00
![Nick Piggin](/assets/img/avatar_default.png)
Use a seqlock in the fs_struct to enable us to take an atomic copy of the complete cwd and root paths. Use this in the RCU lookup path to avoid a thread-shared spinlock in RCU lookup operations. Multi-threaded apps may now perform path lookups with scalability matching multi-process apps. Operations such as stat(2) become very scalable for multi-threaded workload. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
#ifndef _LINUX_FS_STRUCT_H
|
|
#define _LINUX_FS_STRUCT_H
|
|
|
|
#include <linux/path.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/seqlock.h>
|
|
|
|
struct fs_struct {
|
|
int users;
|
|
spinlock_t lock;
|
|
seqcount_t seq;
|
|
int umask;
|
|
int in_exec;
|
|
struct path root, pwd;
|
|
};
|
|
|
|
extern struct kmem_cache *fs_cachep;
|
|
|
|
extern void exit_fs(struct task_struct *);
|
|
extern void set_fs_root(struct fs_struct *, struct path *);
|
|
extern void set_fs_pwd(struct fs_struct *, struct path *);
|
|
extern struct fs_struct *copy_fs_struct(struct fs_struct *);
|
|
extern void free_fs_struct(struct fs_struct *);
|
|
extern void daemonize_fs_struct(void);
|
|
extern int unshare_fs_struct(void);
|
|
|
|
static inline void get_fs_root(struct fs_struct *fs, struct path *root)
|
|
{
|
|
spin_lock(&fs->lock);
|
|
*root = fs->root;
|
|
path_get(root);
|
|
spin_unlock(&fs->lock);
|
|
}
|
|
|
|
static inline void get_fs_pwd(struct fs_struct *fs, struct path *pwd)
|
|
{
|
|
spin_lock(&fs->lock);
|
|
*pwd = fs->pwd;
|
|
path_get(pwd);
|
|
spin_unlock(&fs->lock);
|
|
}
|
|
|
|
static inline void get_fs_root_and_pwd(struct fs_struct *fs, struct path *root,
|
|
struct path *pwd)
|
|
{
|
|
spin_lock(&fs->lock);
|
|
*root = fs->root;
|
|
path_get(root);
|
|
*pwd = fs->pwd;
|
|
path_get(pwd);
|
|
spin_unlock(&fs->lock);
|
|
}
|
|
|
|
#endif /* _LINUX_FS_STRUCT_H */
|