The errors returned from Mount and Unmount functions are raw
syscall.Errno errors (like EPERM or EINVAL), which provides
no context about what has happened and why.
Similar to os.PathError type, introduce mount.Error type
with some context. The error messages will now look like this:
> mount /tmp/mount-tests/source:/tmp/mount-tests/target, flags: 0x1001: operation not permitted
or
> mount tmpfs:/tmp/mount-test-source-516297835: operation not permitted
Before this patch, it was just
> operation not permitted
[v2: add Cause()]
[v3: rename MountError to Error, document Cause()]
[v4: fixes; audited all users]
[v5: make Error type private; changes after @cpuguy83 reviews]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
(cherry picked from commit 65331369617e89ce54cc9be080dba70f3a883d1c)
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Upstream-commit: 7f1c6bf5a745c8faeba695d3556dff4c4ff5f473
Component: engine
It has been pointed out that we're ignoring EINVAL from umount(2)
everywhere, so let's move it to a lower-level function. Also, its
implementation should be the same for any UNIX incarnation, so
let's consolidate it.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
(cherry picked from commit 90be078fe59a8cfeff2bcc5dc2f34a00309837b6)
Upstream-commit: 47c51447e1b6dacf92b40574f6f929958ca9d621
Component: engine
Now, every Unmount() call takes a burden to parse the whole nine yards
of /proc/self/mountinfo to figure out whether the given mount point is
mounted or not (and returns an error in case parsing fails somehow).
Instead, let's just call umount() and ignore EINVAL, which results
in the same behavior, but much better performance.
Note that EINVAL is returned from umount(2) not only in the case when
`target` is not mounted, but also for invalid flags. As the flags are
hardcoded here, it can't be the case.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Upstream-commit: a1d095199ddb9b4811e1417b6adcdfadad7d73f4
Component: engine
The flow of getSourceMount was:
1 get all entries from /proc/self/mountinfo
2 do a linear search for the `source` directory
3 if found, return its data
4 get the parent directory of `source`, goto 2
The repeated linear search through the whole mountinfo (which can have
thousands of records) is inefficient. Instead, let's just
1 collect all the relevant records (only those mount points
that can be a parent of `source`)
2 find the record with the longest mountpath, return its data
This was tested manually with something like
```go
func TestGetSourceMount(t *testing.T) {
mnt, flags, err := getSourceMount("/sys/devices/msr/")
assert.NoError(t, err)
t.Logf("mnt: %v, flags: %v", mnt, flags)
}
```
...but it relies on having a specific mount points on the system
being used for testing.
[v2: add unit tests for ParentsFilter]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Upstream-commit: 871c957242df9f8c74faf751a2f14eb5178d4140
Component: engine
Functions `GetMounts()` and `parseMountTable()` return all the entries
as read and parsed from /proc/self/mountinfo. In many cases the caller
is only interested only one or a few entries, not all of them.
One good example is `Mounted()` function, which looks for a specific
entry only. Another example is `RecursiveUnmount()` which is only
interested in mount under a specific path.
This commit adds `filter` argument to `GetMounts()` to implement
two things:
1. filter out entries a caller is not interested in
2. stop processing if a caller is found what it wanted
`nil` can be passed to get a backward-compatible behavior, i.e. return
all the entries.
A few filters are implemented:
- `PrefixFilter`: filters out all entries not under `prefix`
- `SingleEntryFilter`: looks for a specific entry
Finally, `Mounted()` is modified to use `SingleEntryFilter()`, and
`RecursiveUnmount()` is using `PrefixFilter()`.
Unit tests are added to check filters are working.
[v2: ditch NoFilter, use nil]
[v3: ditch GetMountsFiltered()]
[v4: add unit test for filters]
[v5: switch to gotestyourself]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Upstream-commit: bb934c6aca3e77541dd4fd51b9ab2706294dadda
Component: engine
Sorting by mount point length can be implemented in a more
straightforward fashion since Go 1.8 introduced sort.Slice()
with an ability to provide a less() function in place.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Upstream-commit: a00310b54c0cdcafb402aeea92feca865da9fdf3
Component: engine
When a recursive unmount fails, don't bother parsing the mount table to check
if what we expected to be a mountpoint is still mounted. `EINVAL` is
returned when you try to unmount something that is not a mountpoint, the
other cases of `EINVAL` would not apply here unless everything is just
wrong. Parsing the mount table over and over is relatively expensive,
especially in the code path that it's in.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: dd2108766017c13a19bdbfd1a56cd1358580e0bb
Component: engine
Before this, if `forceRemove` is set the container data will be removed
no matter what, including if there are issues with removing container
on-disk state (rw layer, container root).
In practice this causes a lot of issues with leaked data sitting on
disk that users are not able to clean up themselves.
This is particularly a problem while the `EBUSY` errors on remove are so
prevalent. So for now let's not keep this behavior.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: 54dcbab25ea4771da303fa95e0c26f2d39487b49
Component: engine
This fixes issues where the underlying filesystem may be disconnected and
attempting to unmount may cause a hang.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Upstream-commit: acbfe6bc56b9357d40a452f6b3901cb2c2d40404
Component: engine
Fix the following warnings:
pkg/mount/mountinfo.go:5:6: type name will be used as mount.MountInfo by other packages, and that stutters; consider calling this Info
pkg/mount/mountinfo.go:7:2: struct field Id should be ID
Signed-off-by: Antonio Murdaca <runcom@linux.com>
Upstream-commit: 0f5c9d301b9b1cca66b3ea0f9dec3b5317d3686d
Component: engine
Without this line of code, if a volume is present in /proc/mounts,
it cannot be remounted with new mount options.
Docker-DCO-1.1-Signed-off-by: Peter Waller <p@pwaller.net> (github: pwaller)
Upstream-commit: f87afda12344b726c1bfb49b2dc8b5995f86f4ab
Component: engine
Mount is self contained and generic, it should be in pkg, to allow other pkg modules to use it.
Docker-DCO-1.1-Signed-off-by: Paul Nasrat <pnasrat@gmail.com> (github: pnasrat)
Upstream-commit: 2e094db6390dde57263c07665290b1477bb6df7e
Component: engine
