sbread(3) [freebsd man page]

SBREAD(3)						   BSD Library Functions Manual 						 SBREAD(3)

NAME

     sbread, sbwrite -- read and write superblocks of a UFS file system

LIBRARY

     UFS File System Access Library (libufs, -lufs)

SYNOPSIS

     #include <sys/param.h>
     #include <sys/mount.h>
     #include <ufs/ufs/ufsmount.h>
     #include <ufs/ufs/dinode.h>
     #include <ufs/ffs/fs.h>
     #include <libufs.h>

     int
     sbread(struct uufsd *disk);

     int
     sbwrite(struct uufsd *disk, int all);

DESCRIPTION

     The sbread() and sbwrite() functions provide superblock reads and writes for libufs(3) consumers.	The sbread() and sbwrite() functions oper-
     ate on the superblock field, d_sb, associated with a given userland UFS disk structure.  Additionally, the sbwrite() function will write to
     all superblock locations if the all value is non-zero.

RETURN VALUES

     The sbread() and sbwrite() functions return the value 0 if successful; otherwise the value -1 is returned and the global variable errno is
     set to indicate the error.

ERRORS

     The function sbread() may fail and set errno for any of the errors specified for the library function bread(3).  Additionally, it may follow
     the libufs(3) error methodologies in situations where no usable superblock could be found.

     The function sbwrite() may fail and set errno for any of the errors specified for the library function bwrite(3).

SEE ALSO

     bread(3), bwrite(3), libufs(3)

HISTORY

     These functions first appeared as part of libufs(3) in FreeBSD 5.0.

AUTHORS

     Juli Mallett <jmallett@FreeBSD.org>

BSD
								   June 4, 2003 							       BSD

BREAD(3)						   BSD Library Functions Manual 						  BREAD(3)

NAME

     bread, bwrite -- read and write blocks of a UFS file system

LIBRARY

     UFS File System Access Library (libufs, -lufs)

SYNOPSIS

     #include <sys/param.h>
     #include <sys/mount.h>
     #include <ufs/ufs/ufsmount.h>
     #include <ufs/ufs/dinode.h>
     #include <ufs/ffs/fs.h>
     #include <libufs.h>

     ssize_t
     bread(struct uufsd *disk, ufs2_daddr_t blockno, void *data, size_t size);

     ssize_t
     bwrite(struct uufsd *disk, ufs2_daddr_t blockno, const void *data, size_t size);

     int
     berase(struct uufsd *disk, ufs2_daddr_t blockno, ufs2_daddr_t size);

DESCRIPTION

     The bread(), bwrite() and berase() functions provide a block read, write and erase API for libufs(3) consumers.  They operate on a userland
     UFS disk structure, and perform the read and write at a given block address, which uses the current d_bsize value of the structure.

RETURN VALUES

     The bread() and bwrite() functions return the amount read or written, or -1 in case of any error, including short read.

     The berase() function returns non-zero on error.

ERRORS

     The function bread() may fail and set errno for any of the errors specified for the library functions ufs_disk_write(3) or pread(2).

     The function bwrite() may fail and set errno for any of the errors specified for the library function pwrite(2).

     The function berase() may fail and set errno for any of the errors specified for the library function ioctl(2).

     Additionally all three functions may follow the libufs(3) error methodologies in situations where the amount of data written is not equal to
     the amount requested, or in case of a device error.

SEE ALSO

     libufs(3), ufs_disk_write(3)

HISTORY

     These functions first appeared as part of libufs(3) in FreeBSD 5.0.

AUTHORS

     Juli Mallett <jmallett@FreeBSD.org>

BSD
								   June 4, 2003 							       BSD