1MOUNT(2) System Calls Manual MOUNT(2)
2
6 mount, umount - mount or remove file system
7
9 mount(special, name, flags)
10 char *special, *name;
11 int flags;
12 umount(special)
14 char *special;
15
17 Mount announces to the system that a removable file system has been
18 mounted on the block-structured special file special; from now on, ref‐
19 erences to file name will refer to the root file on the newly mounted
20 file system. Special and name are pointers to null-terminated strings
21 containing the appropriate path names.
22 Name must exist already. Name must be a directory. Its old contents
24 are inaccessible while the file system is mounted.
25 The following flags may be specified to suppress default semantics
27 which affect filesystem access.
28 MNT_RDONLY The filesystem should be treated as read-only; Even
30 the super-user may not write on it.
31 MNT_NOEXEC Do not allow files to be executed from the filesys‐
33 tem.
34 MNT_NOSUID Do not honor setuid or setgid bits on files when
36 executing them.
37 MNT_NODEV Do not interpret special files on the filesystem.
39 MNT_SYNCHRONOUS All I/O to the filesystem should be done syn‐
41 chronously.
42 Umount announces to the system that the special file is no longer to
44 contain a removable file system. The associated file reverts to its
45 ordinary interpretation.
46
48 Mount returns 0 if the action occurred, -1 if special is inaccessible
49 or not an appropriate file, if name does not exist, if special is
50 already mounted, if name is in use, or if there are already too many
51 file systems mounted.
52 Umount returns 0 if the action occurred; -1 if if the special file is
54 inaccessible or does not have a mounted file system, or if there are
55 active files in the mounted file system.
56
58 Mount will fail when one of the following occurs:
59 [ENAMETOOLONG] A component of either pathname exceeded 255 characters,
61 or the entire length of either path name exceeded 1023
62 characters.
63 [ELOOP] Too many symbolic links were encountered in translating
65 either pathname.
66 [EPERM] The caller is not the super-user.
68 [ENOENT] A component of name does not exist.
70 [ENODEV] A component of special does not exist.
72 [ENOTBLK] Special is not a block device.
74 [ENXIO] The major device number of special is out of range (this
76 indicates no device driver exists for the associated
77 hardware).
78 [ENOTDIR] A component of name is not a directory, or a path prefix
80 of special is not a directory.
81 [EINVAL] Either pathname contains a character with the high-order
83 bit set.
84 [EINVAL] The super block for the file system had a bad magic num‐
86 ber or an out of range block size.
87 [EBUSY] Another process currently holds a reference to name, or
89 special is already mounted.
90 [EMFILE] No space remains in the mount table.
92 [ENOMEM] Not enough memory was available to read the cylinder
94 group information for the file system.
95 [EIO] An I/O error occurred while reading the super block or
97 cylinder group information.
98 [EFAULT] Special or name points outside the process's allocated
100 address space.
101 Umount may fail with one of the following errors:
103 [ENOTDIR] A component of the path prefix is not a directory.
105 [EINVAL] The pathname contains a character with the high-order
107 bit set.
108 [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an
110 entire path name exceeded 1023 characters.
111 [ELOOP] Too many symbolic links were encountered in translating
113 the pathname.
114 [EPERM] The caller is not the super-user.
116 [ENODEV] Special does not exist.
118 [ENOTBLK] Special is not a block device.
120 [ENXIO] The major device number of special is out of range (this
122 indicates no device driver exists for the associated
123 hardware).
124 [EINVAL] The requested device is not in the mount table.
126 [EBUSY] A process is holding a reference to a file located on
128 the file system.
129 [EIO] An I/O error occurred while writing the super block or
131 other cached file system information.
132 [EFAULT] Special points outside the process's allocated address
134 space.
135
137 mount(8), umount(8)
138
140 Some of the error codes need translation to more obvious messages.
141 Physically write-protected and magnetic tape file systems must be
143 mounted read-only or errors will occur when access times are updated,
144 whether or not any explicit write is attempted.
145 MNT_SYNCHRONOUS is not currently implemented in the kernel but may be
147 specified because the kernel ignores it.
1484th Berkeley Distribution January 25, 1996 MOUNT(2)