NAME

statvfs - file system statistics

SYNOPSIS

DESCRIPTION

The <sys/statvfs.h> header defines the structures and functions that return information about a mounted file system. The statvfs structure is defined as follows:
typedef struct { int32_t val[2]; } fsid_t;      /* file system id type */
        

#define VFS_NAMELEN 32 /* length of fs type name, including nul */ #define VFS_MNAMELEN 1024 /* length of buffer for returned name */

struct statvfs { unsigned long f_flag; /* copy of mount exported flags */ unsigned long f_bsize; /* system block size */ unsigned long f_frsize; /* system fragment size */ unsigned long f_iosize; /* optimal file system block size */

fsblkcnt_t f_blocks; /* number of blocks in file system */ fsblkcnt_t f_bfree; /* free blocks avail in file system */ fsblkcnt_t f_bavail; /* free blocks avail to non-root */ fsblkcnt_t f_bresvd; /* blocks reserved for root */

fsfilcnt_t f_files; /* total file nodes in file system */ fsfilcnt_t f_ffree; /* free file nodes in file system */ fsfilcnt_t f_favail; /* free file nodes avail to non-root */ fsfilcnt_t f_fresvd; /* file nodes reserved for root */

uint64_t f_syncreads; /* count of sync reads since mount */ uint64_t f_syncwrites; /* count of sync writes since mount */

uint64_t f_asyncreads; /* count of async reads since mount */ uint64_t f_asyncwrites; /* count of async writes since mount */

unsigned long f_fsid; /* POSIX compliant file system id */ fsid_t f_fsidx; /* NetBSD compatible file system id */

unsigned long f_namemax;/* maximum filename length */ uid_t f_owner; /* user that mounted the file system */

uint32_t f_spare[4]; /* spare space */

char f_fstypename[VFS_NAMELEN]; /* fs type name */ char f_mntonname[VFS_MNAMELEN]; /* directory on which mounted */ char f_mntfromname[VFS_MNAMELEN]; /* mounted file system */ };

The f_flag argument can have the following bits set:

ST_RDONLY
The filesystem is mounted read-only; Even the super-user may not write on it.

ST_NOEXEC
Files may not be executed from the filesystem.

ST_NOSUID
Setuid and setgid bits on files are not honored when they are executed.

ST_NODEV
Special files in the filesystem may not be opened.

ST_UNION
Union with underlying filesystem instead of obscuring it.

ST_SYNCHRONOUS
All I/O to the filesystem is done synchronously.

ST_ASYNC
No filesystem I/O is done synchronously.

ST_NOCOREDUMP
Don't write core dumps to this file system.

ST_NOATIME
Never update access times.

ST_SYMPERM
Recognize symbolic link permission.

ST_NODEVMTIME
Never update modification times for device files.

ST_SOFTDEP
Use soft dependencies.

ST_LOCAL
The filesystem resides locally.

ST_QUOTA
The filesystem has quotas enabled on it.

ST_ROOTFS
Identifies the root filesystem.

ST_EXRDONLY
The filesystem is exported read-only.

ST_EXPORTED
The filesystem is exported for both reading and writing.

ST_DEFEXPORTED
The filesystem is exported for both reading and writing to any Internet host.

ST_EXPORTANON
The filesystem maps all remote accesses to the anonymous user.

ST_EXKERB
The filesystem is exported with Kerberos uid mapping.

ST_EXNORESPORT
Don't enforce reserved ports (NFS).

ST_EXPUBLIC
Public export (WebNFS).

Fields that are undefined for a particular file system are set to -1.

NOTES

f_flag
The f_flag field is the same as the f_flags field in the 4.3BSD statfs(2) system call.

f_fsid
Is defined to be

unsigned long by the X/Open standard. Unfortunately this is not enough space to store our

fsid_t, so we define an additional f_fsidx field.

f_bavail
Could historically be negative (in the statfs(2) system call) when the used space has exceeded the non-superuser free space. In order to comply with the X/Open standard, we have to define

fsblkcnt_t as an unsigned type, so in all cases where f_bavail would have been negative, we set it to 0. In addition we provide f_bresvd which contains the amount of reserved blocks for the superuser, so the old value of f_bavail can be easily computed as:
        old_bavail = f_bfree - f_bresvd;

SEE ALSO

statvfs(2)

HISTORY

The <sys/statvfs.h> header first appeared in NetBSD3.0.