Superblock

Mountable filesystem. More...

Data Structures
struct	superblock_t
	Superblock structure. More...
struct	superblock_ops_t
	Superblock operations structure. More...

Typedefs
typedef uint64_t	superblock_id_t
	Superblock ID type.

Functions
superblock_t *	superblock_new (const filesystem_t *fs, const char *deviceName, const superblock_ops_t *ops, const dentry_ops_t *dentryOps)
	Create a new superblock.
void	superblock_inc_mount_count (superblock_t *superblock)
	Increment the mount count of a superblock.
void	superblock_dec_mount_count (superblock_t *superblock)
	Decrement the mount count of a superblock.

Detailed Description

Mountable filesystem.

A superblock represents a mounted filesystem, it can be thought of as "filesystem + device". The filesystem is just the format of the data, e.g. fat32, ramfs, sysfs, etc the device provides the data and the superblock is the combination of both, e.g. a fat32 filesystem on /dev/sda1.

In the case of certain special filesystems like ramfs or sysfs there is no underlying device, in this case the device name is simply set to VFS_DEVICE_NAME_NONE.

Typedef Documentation

superblock_id_t

typedef uint64_t superblock_id_t

Superblock ID type.

Definition at line 35 of file superblock.h.

Function Documentation

superblock_dec_mount_count()

void superblock_dec_mount_count

(

superblock_t *

superblock

)

Decrement the mount count of a superblock.

If the mount count reaches zero, the unmount operation is called if its not NULL.

Parameters

superblock

Pointer to the superblock.

Definition at line 62 of file superblock.c.

References atomic_fetch_sub, superblock_t::mountCount, NULL, superblock_t::ops, and superblock_ops_t::unmount.

Referenced by mount_free().

superblock_inc_mount_count()

void superblock_inc_mount_count

(

superblock_t *

superblock

)

Increment the mount count of a superblock.

Parameters

superblock

Pointer to the superblock.

Definition at line 57 of file superblock.c.

References atomic_fetch_add, and superblock_t::mountCount.

Referenced by mount_new().

superblock_new()

superblock_t * superblock_new	(	const filesystem_t *	fs,
		const char *	deviceName,
		const superblock_ops_t *	ops,
		const dentry_ops_t *	dentryOps
	)

Create a new superblock.

This does not add the superblock to the superblock cache, the vfs_mount() function will do that using vfs_add_superblock().

There is no superblock_free() instead use DEREF().

Note that the superblock's root dentry must be created and assigned after calling this function.

Parameters

fs	The filesystem type of the superblock.
deviceName	The device name, or VFS_DEVICE_NAME_NONE for no device.
ops	The superblock operations, can be NULL.
dentryOps	The dentry operations for dentries in this superblock, can be NULL.

Returns

On success, the new superblock. On failure, returns NULL and errno is set.

Definition at line 32 of file superblock.c.

References atomic_init, superblock_t::blockSize, superblock_t::dentryOps, dentryOps, superblock_t::deviceName, superblock_t::entry, superblock_t::fs, superblock_t::id, list_entry_init(), malloc(), MAX_NAME, superblock_t::maxFileSize, superblock_t::mountCount, NULL, superblock_t::ops, ops, PAGE_SIZE, superblock_t::private, superblock_t::ref, ref_init(), superblock_t::root, strncpy(), superblock_free(), UINT64_MAX, and vfs_get_new_id().

Referenced by ramfs_mount(), and sysfs_mount().