VFS四大对象之一 struct super_block

 1 struct super_block {
 2     struct list_head    s_list;        /* Keep this first */
 3     dev_t            s_dev;        /* search index; _not_ kdev_t */
 4     unsigned char        s_dirt;
 5     unsigned char        s_blocksize_bits;
 6     unsigned long        s_blocksize;
 7     loff_t            s_maxbytes;    /* Max file size */
 8     struct file_system_type    *s_type;
 9     const struct super_operations    *s_op;
10     const struct dquot_operations    *dq_op;
11     const struct quotactl_ops    *s_qcop;
12     const struct export_operations *s_export_op;
13     unsigned long        s_flags;
14     unsigned long        s_magic;
15     struct dentry        *s_root;
16     struct rw_semaphore    s_umount;
17     struct mutex        s_lock;
18     int            s_count;
19     atomic_t        s_active;
20 #ifdef CONFIG_SECURITY
21     void                    *s_security;
22 #endif
23     const struct xattr_handler **s_xattr;
24 
25     struct list_head    s_inodes;    /* all inodes */
26     struct hlist_bl_head    s_anon;        /* anonymous dentries for (nfs) exporting */
27 #ifdef CONFIG_SMP
28     struct list_head __percpu *s_files;
29 #else
30     struct list_head    s_files;
31 #endif
32     struct list_head    s_mounts;    /* list of mounts; _not_ for fs use */
33     /* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */
34     struct list_head    s_dentry_lru;    /* unused dentry lru */
35     int            s_nr_dentry_unused;    /* # of dentry on lru */
36 
37     /* s_inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */
38     spinlock_t        s_inode_lru_lock ____cacheline_aligned_in_smp;
39     struct list_head    s_inode_lru;        /* unused inode lru */
40     int            s_nr_inodes_unused;    /* # of inodes on lru */
41 
42     struct block_device    *s_bdev;
43     struct backing_dev_info *s_bdi;
44     struct mtd_info        *s_mtd;
45     struct hlist_node    s_instances;
46     struct quota_info    s_dquot;    /* Diskquota specific options */
47 
48     int            s_frozen;
49     wait_queue_head_t    s_wait_unfrozen;
50 
51     char s_id[32];                /* Informational name */
52     u8 s_uuid[16];                /* UUID */
53 
54     void             *s_fs_info;    /* Filesystem private info */
55     unsigned int        s_max_links;
56     fmode_t            s_mode;
57 
58     /* Granularity of c/m/atime in ns.
59        Cannot be worse than a second */
60     u32           s_time_gran;
61 
62     /*
63      * The next field is for VFS *only*. No filesystems have any business
64      * even looking at it. You had been warned.
65      */
66     struct mutex s_vfs_rename_mutex;    /* Kludge */
67 
68     /*
69      * Filesystem subtype.  If non-empty the filesystem type field
70      * in /proc/mounts will be "type.subtype"
71      */
72     char *s_subtype;
73 
74     /*
75      * Saved mount options for lazy filesystems using
76      * generic_show_options()
77      */
78     char __rcu *s_options;
79     const struct dentry_operations *s_d_op; /* default d_op for dentries */
80 
81     /*
82      * Saved pool identifier for cleancache (-1 means none)
83      */
84     int cleancache_poolid;
85 
86     struct shrinker s_shrink;    /* per-sb shrinker handle */
87 
88     /* Number of inodes with nlink == 0 but still referenced */
89     atomic_long_t s_remove_count;
90 
91     /* Being remounted read-only */
92     int s_readonly_remount;
93 };

1 struct list_head    s_list;

1 dev_t s_dev;

1 unsigned char        s_dirt;
2 unsigned char        s_blocksize_bits;
3 unsigned long        s_blocksize;
4 loff_t            s_maxbytes;    /* Max file size */

1 loff_t            s_maxbytes;    /* Max file size */

1 struct file_system_type    *s_type;

1 const struct super_operations    *s_op;
2 const struct dquot_operations    *dq_op;

1 const struct quotactl_ops    *s_qcop;

1 const struct export_operations *s_export_op;

1 unsigned long        s_flags;

1 unsigned long        s_magic;

1 struct dentry        *s_root;

1 struct rw_semaphore    s_umount;

1 struct mutex        s_lock;

1 int            s_count;

1 atomic_t        s_active;