Login or Register to Ask a Question and Join Our Community

Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

fss(4) [netbsd man page]

FSS(4)							   BSD Kernel Interfaces Manual 						    FSS(4)

NAME

     fss -- file system snapshot device

SYNOPSIS

     pseudo-device fss 4

DESCRIPTION

     The fss driver provides a read-only interface to the snapshot of a currently mounted file system.	Reading from a fss device gives the view
     of the file system when the snapshot was taken.  It can be configured via ioctl(2).

IOCTLS

     The ioctl(2) command codes below are defined in <sys/dev/fssvar.h>.

     The (third) argument to ioctl(2) should be a pointer to the type indicated.

     FSSIOCSET(struct fss_set)
	       Configures a fss device.

		     struct fss_set {
			     char *fss_mount;
			     char *fss_bstore;
			     blksize_t fss_csize;
			     int fss_flags;
		     };

	       The struct element fss_mount is the mount point of the file system.  The struct element fss_bstore is either a regular file or a
	       raw disk device where data overwritten on the file system will be saved.  The struct element fss_csize is the preferred size of
	       this data.  The struct element fss_flags is the initial set of flags.

     FSSIOCGET(struct fss_get)
	       Gets the status of a fss device.

		     struct fss_get {
			     char fsg_mount[MNAMELEN];
			     struct timeval fsg_time;
			     blksize_t fsg_csize;
			     blkcnt_t fsg_mount_size;
			     blkcnt_t fsg_bs_size;
		     };
	       The struct element fsg_mount is the mount point of the file system.  The struct element fsg_time is the time this snapshot was
	       taken.  The struct element fsg_csize is the current size of data clusters.  The struct element fsg_mount_size is the number of
	       clusters of the file system.  The struct element fsg_bs_size is the number of clusters written to the backing store.

     FSSIOCCLR
	       Unconfigures a fss device.

     FSSIOFSET(int)
	       Sets the flags of a fss device.	Possible flags are:

	       FSS_UNCONFIG_ON_CLOSE
			     Unconfigure the fss device on the last close.

	       FSS_UNLINK_ON_CREATE
			     Unlink the backing file before the fss device is created.

     FSSIOFGET(int)
	       Gets the flags of a fss device.

KERNEL THREADS

     For each active snapshot device there is a kernel thread that handles the backing store.  This thread is named fssN where N is the device
     minor number.

FILES

     /dev/rfss?
     /dev/fss?

SEE ALSO

     fssconfig(8), mount(8), umount(8)

HISTORY

     The fss device appeared in NetBSD 2.0.

BSD
								 February 24, 2011							       BSD

Check Out this Related Man Page

STRUCT 
DEVICE_DRIVER(9) 				   Device drivers infrastructure				   STRUCT DEVICE_DRIVER(9)

NAME

       struct_device_driver - The basic device driver structure

SYNOPSIS

       struct device_driver {
	 const char * name;
	 struct bus_type * bus;
	 struct module * owner;
	 const char * mod_name;
	 bool suppress_bind_attrs;
	 const struct of_device_id * of_match_table;
	 const struct acpi_device_id * acpi_match_table;
	 int (* probe) (struct device *dev);
	 int (* remove) (struct device *dev);
	 void (* shutdown) (struct device *dev);
	 int (* suspend) (struct device *dev, pm_message_t state);
	 int (* resume) (struct device *dev);
	 const struct attribute_group ** groups;
	 const struct dev_pm_ops * pm;
	 struct driver_private * p;
       };

MEMBERS

       name
	   Name of the device driver.

       bus
	   The bus which the device of this driver belongs to.

       owner
	   The module owner.

       mod_name
	   Used for built-in modules.

       suppress_bind_attrs
	   Disables bind/unbind via sysfs.

       of_match_table
	   The open firmware table.

       acpi_match_table
	   The ACPI match table.

       probe
	   Called to query the existence of a specific device, whether this driver can work with it, and bind the driver to a specific device.

       remove
	   Called when the device is removed from the system to unbind a device from this driver.

       shutdown
	   Called at shut-down time to quiesce the device.

       suspend
	   Called to put the device to sleep mode. Usually to a low power state.

       resume
	   Called to bring a device from sleep mode.

       groups
	   Default attributes that get created by the driver core automatically.

       pm
	   Power management operations of the device which matched this driver.

       p
	   Driver core's private data, no one other than the driver core can touch this.

DESCRIPTION

       The device driver-model tracks all of the drivers known to the system. The main reason for this tracking is to enable the driver core to
       match up drivers with new devices. Once drivers are known objects within the system, however, a number of other things become possible.
       Device drivers can export information and configuration variables that are independent of any specific device.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   STRUCT DEVICE_DRIVER(9)
Man Page