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mount: (new) be more pedantic about --make-* 

Signed-off-by: Karel Zak <kzak@redhat.com>
This commit is contained in:
Karel Zak 2012-04-18 10:09:49 +02:00
parent 5d451abbbf
commit d789077846
2 changed files with 31 additions and 11 deletions
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14
sys-utils/mount.8
View File

@ -398,6 +398,15 @@ command (then mount(8) does not read /etc/mtab), then you have to use bind flag
.B mount -o remount,ro,bind
.I olddir newdir
.RE
Note that
.I remount,ro,bind
will create a read-only mountpoint (VFS entry), but the original filesystem suberblock
will be still writable, it means that the
.I olddir
will be writable, but the
.I newdir
will be read-only.
.RE
.B The move operation.
@ -434,6 +443,11 @@ unbindable mount is a private mount which cannot be cloned through a bind
operation. Detailed semantics is documented in Documentation/filesystems/sharedsubtree.txt
file in the kernel source tree.
Note that Linux kernel does not allow to change more propagation flags by one
.B mount (2)
syscall and the flags cannot be mixed with another mount options. It means that
more --make-* options cannot be used together or with another mount options.
.RS
.nf
.BI "mount --make-shared " mountpoint

28
sys-utils/mount.c
View File

@ -789,37 +789,37 @@ int main(int argc, char **argv)
mnt_context_enable_sloppy(cxt, TRUE);
break;
case 'B':
oper = MS_BIND;
oper |= MS_BIND;
break;
case 'M':
oper = MS_MOVE;
oper |= MS_MOVE;
break;
case 'R':
oper = (MS_BIND | MS_REC);
oper |= (MS_BIND | MS_REC);
break;
case MOUNT_OPT_SHARED:
oper = MS_SHARED;
oper |= MS_SHARED;
break;
case MOUNT_OPT_SLAVE:
oper = MS_SLAVE;
oper |= MS_SLAVE;
break;
case MOUNT_OPT_PRIVATE:
oper = MS_PRIVATE;
oper |= MS_PRIVATE;
break;
case MOUNT_OPT_UNBINDABLE:
oper = MS_UNBINDABLE;
oper |= MS_UNBINDABLE;
break;
case MOUNT_OPT_RSHARED:
oper = (MS_SHARED | MS_REC);
oper |= (MS_SHARED | MS_REC);
break;
case MOUNT_OPT_RSLAVE:
oper = (MS_SLAVE | MS_REC);
oper |= (MS_SLAVE | MS_REC);
break;
case MOUNT_OPT_RPRIVATE:
oper = (MS_PRIVATE | MS_REC);
oper |= (MS_PRIVATE | MS_REC);
break;
case MOUNT_OPT_RUNBINDABLE:
oper = (MS_UNBINDABLE | MS_REC);
oper |= (MS_UNBINDABLE | MS_REC);
break;
default:
usage(stderr);
@ -885,6 +885,12 @@ int main(int argc, char **argv)
usage(stderr);
if (oper) {
if (!is_power_of_2(oper))
errx(MOUNT_EX_USAGE, _("propagation flags (--make-* or --bind options) are mutually exclusive"));
if (oper != MS_BIND && mnt_context_get_options(cxt))
errx(MOUNT_EX_USAGE, _("propagation flags (--make-* options) cannot be mixed with another mount options"));
/* MS_PROPAGATION operations, let's set the mount flags */
mnt_context_set_mflags(cxt, oper);