1statvfs(3) Library Functions Manual statvfs(3)
2
6 statvfs, fstatvfs - get filesystem statistics
7
9 Standard C library (libc, -lc)
10
12 #include <sys/statvfs.h>
13 int statvfs(const char *restrict path, struct statvfs *restrict buf);
15 int fstatvfs(int fd, struct statvfs *buf);
16
18 The function statvfs() returns information about a mounted filesystem.
19 path is the pathname of any file within the mounted filesystem. buf is
20 a pointer to a statvfs structure defined approximately as follows:
21 struct statvfs {
23 unsigned long f_bsize; /* Filesystem block size */
24 unsigned long f_frsize; /* Fragment size */
25 fsblkcnt_t f_blocks; /* Size of fs in f_frsize units */
26 fsblkcnt_t f_bfree; /* Number of free blocks */
27 fsblkcnt_t f_bavail; /* Number of free blocks for
28 unprivileged users */
29 fsfilcnt_t f_files; /* Number of inodes */
30 fsfilcnt_t f_ffree; /* Number of free inodes */
31 fsfilcnt_t f_favail; /* Number of free inodes for
32 unprivileged users */
33 unsigned long f_fsid; /* Filesystem ID */
34 unsigned long f_flag; /* Mount flags */
35 unsigned long f_namemax; /* Maximum filename length */
36 };
37 Here the types fsblkcnt_t and fsfilcnt_t are defined in <sys/types.h>.
39 Both used to be unsigned long.
40 The field f_flag is a bit mask indicating various options that were em‐
42 ployed when mounting this filesystem. It contains zero or more of the
43 following flags:
44 ST_MANDLOCK
46 Mandatory locking is permitted on the filesystem (see fcntl(2)).
47 ST_NOATIME
49 Do not update access times; see mount(2).
50 ST_NODEV
52 Disallow access to device special files on this filesystem.
53 ST_NODIRATIME
55 Do not update directory access times; see mount(2).
56 ST_NOEXEC
58 Execution of programs is disallowed on this filesystem.
59 ST_NOSUID
61 The set-user-ID and set-group-ID bits are ignored by exec(3) for
62 executable files on this filesystem
63 ST_RDONLY
65 This filesystem is mounted read-only.
66 ST_RELATIME
68 Update atime relative to mtime/ctime; see mount(2).
69 ST_SYNCHRONOUS
71 Writes are synched to the filesystem immediately (see the de‐
72 scription of O_SYNC in open(2)).
73 It is unspecified whether all members of the returned struct have mean‐
75 ingful values on all filesystems.
76 fstatvfs() returns the same information about an open file referenced
78 by descriptor fd.
79
81 On success, zero is returned. On error, -1 is returned, and errno is
82 set to indicate the error.
83
85 EACCES (statvfs()) Search permission is denied for a component of the
86 path prefix of path. (See also path_resolution(7).)
87 EBADF (fstatvfs()) fd is not a valid open file descriptor.
89 EFAULT Buf or path points to an invalid address.
91 EINTR This call was interrupted by a signal; see signal(7).
93 EIO An I/O error occurred while reading from the filesystem.
95 ELOOP (statvfs()) Too many symbolic links were encountered in trans‐
97 lating path.
98 ENAMETOOLONG
100 (statvfs()) path is too long.
101 ENOENT (statvfs()) The file referred to by path does not exist.
103 ENOMEM Insufficient kernel memory was available.
105 ENOSYS The filesystem does not support this call.
107 ENOTDIR
109 (statvfs()) A component of the path prefix of path is not a di‐
110 rectory.
111 EOVERFLOW
113 Some values were too large to be represented in the returned
114 struct.
115
117 For an explanation of the terms used in this section, see at‐
118 tributes(7).
119 ┌────────────────────────────────────────────┬───────────────┬─────────┐
121 │Interface │ Attribute │ Value │
122 ├────────────────────────────────────────────┼───────────────┼─────────┤
123 │statvfs(), fstatvfs() │ Thread safety │ MT-Safe │
124 └────────────────────────────────────────────┴───────────────┴─────────┘
125
127 Only the ST_NOSUID and ST_RDONLY flags of the f_flag field are
128 specified in POSIX.1. To obtain definitions of the remaining flags,
129 one must define _GNU_SOURCE.
130
132 The Linux kernel has system calls statfs(2) and fstatfs(2) to support
133 this library call.
134 The glibc implementations of
136 pathconf(path, _PC_REC_XFER_ALIGN);
138 pathconf(path, _PC_ALLOC_SIZE_MIN);
139 pathconf(path, _PC_REC_MIN_XFER_SIZE);
140 respectively use the f_frsize, f_frsize, and f_bsize fields returned by
142 a call to statvfs() with the argument path.
143 Under Linux, f_favail is always the same as f_ffree, and there's no way
145 for a filesystem to report otherwise. This is not an issue, since no
146 filesystems with an inode root reservation exist.
147
149 POSIX.1-2008.
150
152 POSIX.1-2001.
153 Before glibc 2.13, statvfs() populated the bits of the f_flag field by
155 scanning the mount options shown in /proc/mounts. However, starting
156 with Linux 2.6.36, the underlying statfs(2) system call provides the
157 necessary information via the f_flags field, and since glibc 2.13, the
158 statvfs() function will use information from that field rather than
159 scanning /proc/mounts.
160
162 statfs(2)
163Linux man-pages 6.05 2023-07-20 statvfs(3)