最終更新:2015-02-02 (月) 14:04:43 (3364d)  

super_block
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ファイルシステムを表す構造体

メモ

  • typically contains a pointer to super block operations, information on block size, identifiers to the block device, and file-specific information.
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定義 

struct super_block {
        struct list_head        s_list;         /* Keep this first */
        dev_t                   s_dev;          /* search index; _not_ kdev_t */
        unsigned char           s_blocksize_bits;
        unsigned long           s_blocksize;
        loff_t                  s_maxbytes;     /* Max file size */
        struct file_system_type *s_type;
        const struct super_operations   *s_op;
        const struct dquot_operations   *dq_op;
        const struct quotactl_ops       *s_qcop;
        const struct export_operations *s_export_op;
        unsigned long           s_flags;
        unsigned long           s_magic;
        struct dentry           *s_root;
        struct rw_semaphore     s_umount;
        int                     s_count;
        atomic_t                s_active;
#ifdef CONFIG_SECURITY
        void                    *s_security;
#endif
        const struct xattr_handler **s_xattr;

        struct list_head        s_inodes;       /* all inodes */
        struct hlist_bl_head    s_anon;         /* anonymous dentries for (nfs) exporting */
        struct list_head        s_mounts;       /* list of mounts; _not_ for fs use */
        struct block_device     *s_bdev;
        struct backing_dev_info *s_bdi;
        struct mtd_info         *s_mtd;
        struct hlist_node       s_instances;
        struct quota_info       s_dquot;        /* Diskquota specific options */

        struct sb_writers       s_writers;

        char s_id[32];                          /* Informational name */
        u8 s_uuid[16];                          /* UUID */

        void                    *s_fs_info;     /* Filesystem private info */
        unsigned int            s_max_links;
        fmode_t                 s_mode;

        /* Granularity of c/m/atime in ns.
           Cannot be worse than a second */
        u32                s_time_gran;

        /*
         * The next field is for VFS *only*. No filesystems have any business
         * even looking at it. You had been warned.
         */
        struct mutex s_vfs_rename_mutex;        /* Kludge */

        /*
         * Filesystem subtype.  If non-empty the filesystem type field
         * in /proc/mounts will be "type.subtype"
         */
        char *s_subtype;

        /*
         * Saved mount options for lazy filesystems using
         * generic_show_options()
         */
        char __rcu *s_options;
        const struct dentry_operations *s_d_op; /* default d_op for dentries */

        /*
         * Saved pool identifier for cleancache (-1 means none)
         */
        int cleancache_poolid;

        struct shrinker s_shrink;       /* per-sb shrinker handle */

        /* Number of inodes with nlink == 0 but still referenced */
        atomic_long_t s_remove_count;

        /* Being remounted read-only */
        int s_readonly_remount;

        /* AIO completions deferred from interrupt context */
        struct workqueue_struct *s_dio_done_wq;
        struct hlist_head s_pins;

        /*
         * Keep the lru lists last in the structure so they always sit on their
         * own individual cachelines.
         */
        struct list_lru         s_dentry_lru ____cacheline_aligned_in_smp;
        struct list_lru         s_inode_lru ____cacheline_aligned_in_smp;
        struct rcu_head         rcu;

        /*
         * Indicates how deep in a filesystem stack this SB is
         */
        int s_stack_depth;
};
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関連

  • Linux/VFS
  • super_operations - provides methods to manage an inode, beyond methods that manage the super block and collect statistics.



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