In the current snapshot automount implementation, it is possible for
multiple mounts to attempted concurrently. Only one of the mounts will
succeed and the other will fail. The failed mounts will cause an EREMOTE
to be propagated back to the application.
This commit works around the problem by adding a new exit status,
MOUNT_BUSY to the mount.zfs program which is used when the underlying
mount(2) call returns EBUSY. The zfs code detects this condition and
treats it as if the mount had succeeded.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1819
A mount failure was accidentally introduced by commit 0c1171d
which reworked the parse_dataset() function to read pool names
from devices. The error case where a label is read from the
device but the pool name/value pair doesn't exist was not
handled properly. In this case we should fall back to the
previous behavior.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1560
To simplify integration with the xfstests test suite the
mount.zfs helper has been extended. When passed a block
device (/dev/sdX) to mount, instead of a pool/dataset,
the pool name will be read from any existing zfs label
and used. This allows you to mount the root dataset of
a zfs filesystem by specifing any of the member vdevs.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When calling mount(), care must be taken to avoid passing in flags
that are used only by the user space utilities. Otherwise we may
stomp on flags that are reserved for other purposes in the kernel.
In particular, openSUSE 12.3 kernels have added a new MS_RICHACL
super-block flag whose value conflicts with our MS_COMMENT flag. This
causes incorrect behavior such as the umask being ignored. The
MS_COMMENT flag essentially serves as a placeholder in the option_map
data structure of zfs_mount.c, but its value is never used. Therefore
we can avoid the conflict by defining it to 0.
The MS_USERS, MS_OWNER, and MS_GROUP flags also conflict with reserved
flags in the kernel. While this is not known to have caused any
problems, it is nevertheless incorrect. For the purposes of the
mount.zfs helper, the "users", "owner", and "group" options just serve
as hints to set additional implied options. Therefore we now define
their associated mount flags in terms of the options that they imply
rather than giving them unique values.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1457
Rather than just reporting the failure include the passed
mount point and error number.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1153
mountall in Debian depends on being able to pass the -f parameter to
mount, which specifies a fake mount and just updates the mtab. Currently
mount.zfs will fail such a request if it is not passed with -o zfsutil.
This patch allows a fake mount on a non-legacy filesystem to succeed in
the same manner as a -o remount does, thus enabling mountall to work
correctly.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1167
Canonicalize the mount point passed to the mount.zfs helper.
This way a clean path is always added to mtab which ensures
the umount can properly locate and remove the entry.
Test case:
$ mkdir /mnt/foo
$ mount -t zfs zpool/foo /mnt/../mnt/foo////
$ umount /mnt/foo
$ cat /etc/mtab | grep zpool/foo
zpool/foo /mnt/../mnt/foo//// zfs rw 0 0
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#573
This is done for compatibility with existing Linux infrastructure.
In particular, when using zfs as a root filesystem there are init
scripts which as part of shutdown remount root read-only. Also,
the new systemd infrastructure being used by Fedora expects to be
able to remount a file system read-write.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #847
When compiling ZFS with CFLAGS=-O0 it will trigger the following error.
Resolve the issue by properly including locale.h.
../../cmd/mount_zfs/mount_zfs.c: In function 'main':
../../cmd/mount_zfs/mount_zfs.c:318:2: warning: implicit declaration
of function 'setlocale' [-Wimplicit-function-declaration]
../../cmd/mount_zfs/mount_zfs.c:318:19: error: 'LC_ALL' undeclared
(first use in this function)
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#724
A cryptic error code is printed when mounting a legacy dataset to a
non-existent mountpoint. This patch changes this behavior to print
"mount point '%s' does not exist", which is similar to the error
message printed when mounting procfs.
The single quotes were added to be consistent with the existing EBUSY
error message, which is the only difference between this error message
and the one that is printed when the same condition occurs when mounting
procfs.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#633
The .get_sb callback has been replaced by a .mount callback
in the file_system_type structure. When using the new
interface the caller must now use the mount_nodev() helper.
Unfortunately, the new interface no longer passes the vfsmount
down to the zfs layers. This poses a problem for the existing
implementation because we currently save this pointer in the
super block for latter use. It provides our only entry point
in to the namespace layer for manipulating certain mount options.
This needed to be done originally to allow commands like
'zfs set atime=off tank' to work properly. It also allowed me
to keep more of the original Solaris code unmodified. Under
Solaris there is a 1-to-1 mapping between a mount point and a
file system so this is a fairly natural thing to do. However,
under Linux they many be multiple entries in the namespace
which reference the same filesystem. Thus keeping a back
reference from the filesystem to the namespace is complicated.
Rather than introduce some ugly hack to get the vfsmount and
continue as before. I'm leveraging this API change to update
the ZFS code to do things in a more natural way for Linux.
This has the upside that is resolves the compatibility issue
for the long term and fixes several other minor bugs which
have been reported.
This commit updates the code to remove this vfsmount back
reference entirely. All modifications to filesystem mount
options are now passed in to the kernel via a '-o remount'.
This is the expected Linux mechanism and allows the namespace
to properly handle any options which apply to it before passing
them on to the file system itself.
Aside from fixing the compatibility issue, removing the
vfsmount has had the benefit of simplifying the code. This
change which fairly involved has turned out nicely.
Closes#246Closes#217Closes#187Closes#248Closes#231
Under Fedora 15 /etc/mtab is now a symlink to /proc/mounts by
default. When /etc/mtab is a symlink the mount.zfs helper
should not update it. There was code in place to handle this
case but it used stat() which traverses the link and then issues
the stat on /proc/mounts. We need to use lstat() to prevent the
link traversal and instead stat /etc/mtab.
Closes#270
With the addition of the mount helper we accidentally regressed
the ability to manually mount snapshots. This commit updates
the mount helper to expect the possibility of a ZFS_TYPE_SNAPSHOT.
All snapshot will be automatically treated as 'legacy' type mounts
so they can be mounted manually.
When compiling ZFS in user space gcc-4.6.0 correctly identifies
the variable 'value' as being set but never used. This generates a
warning and a build failure when using --enable-debug. Once again
this is correct but I'm reluctant to remove 'value' because we are
breaking the string in to name/value pairs. While it is not used
now there's a good chance it will be soon and I'd rather not have
to reinvent this. To suppress the warning with just as a VERIFY().
This was observed under Fedora 15.
cmd/mount_zfs/mount_zfs.c: In function ‘parse_option’:
cmd/mount_zfs/mount_zfs.c:112:21: error: variable ‘value’ set but not
used [-Werror=unused-but-set-variable]
New versions glibc declare getcwd() with the warn_unused_result attribute.
This results in a warning because the updated mount helper was not
checking this return value. This issue was fixed by checking the return
type and in the case of an error simply returning the passed dataset.
One possible, but unlikely, error would be having your cwd directory
unlinked while the mount command was running.
cmd/mount_zfs/mount_zfs.c: In function ‘parse_dataset’:
cmd/mount_zfs/mount_zfs.c:223:2: error: ignoring return value of
‘getcwd’, declared with attribute warn_unused_result
When updating /etc/mtab we should be careful and strip certain
options. In particular, we need to strip 'zfsutil' because if
we don't the mount utility will helpfull provide it to the
mount helper when we issue mount(8) again. This subverts the
check that the caller is zfs(8) and not mount(8).
Allow the mount(8) utility to always operate on all datasets when
remounting them read-only. This critical for rc.sysinit/umountroot
which remounts the root filesystem read-only during shutdown to
ensure everything is correctly flushed to disk.
Fix minor typo, the check to set zfsutil should use the bitwise
'&'. I must have accidentally hit the adjacent '*' and obviously
neither the compiler or my code review caught this. Fix it now.
When run with a root '/' cwd the mount.zfs helper would strip not
only the '/' but also the next character from the dataset name.
For example, '/tank' was changed to 'ank' instead of just 'tank'.
Originally, this was done for the '/tmp' cwd case where we needed
to strip the '/' following the cwd. For example '/tmp/tank' needed
to remove the '/tmp' cwd plus 1 character for the '/'.
This change fixes the problem by checking the cwd and if it ends in
a '/' it does not strip and extra character. Otherwise it will strip
the next character. I believe this should only ever be true for the
root directory.
Closes#148
Several issues related to strange mount/umount behavior were reported
and this commit should address most of them. The original idea was
to put in place a zfs mount helper (mount.zfs). This helper is used
to enforce 'legacy' mount behavior, and perform any extra mount argument
processing (selinux, zfsutil, etc). This helper wasn't ready for the
0.6.0-rc1 release but with this change it's functional but needs to
extensively tested.
This change addresses the following open issues.
Closes#101Closes#107Closes#113Closes#115Closes#119
