[v2,14/27] libbtrfsutil: add btrfs_util_deleted_subvolumes()
diff mbox

Message ID e4d08b0c-7438-32d8-e076-90fc4c4f6c79@jp.fujitsu.com
State New
Headers show

Commit Message

Misono Tomohiro Feb. 28, 2018, 4:11 a.m. UTC
On 2018/02/24 8:33, Omar Sandoval wrote:
> On Fri, Feb 23, 2018 at 11:12:56AM +0900, Misono, Tomohiro wrote:
>>
>> On 2018/02/16 4:04, Omar Sandoval wrote:
>>> From: Omar Sandoval <osandov@fb.com>
>>>
>>> Signed-off-by: Omar Sandoval <osandov@fb.com>
>>> ---
>>>  libbtrfsutil/btrfsutil.h                    | 21 +++++++
>>>  libbtrfsutil/python/btrfsutilpy.h           |  3 +
>>>  libbtrfsutil/python/module.c                | 30 ++++++++++
>>>  libbtrfsutil/python/qgroup.c                | 17 +-----
>>>  libbtrfsutil/python/subvolume.c             | 30 ++++++++++
>>>  libbtrfsutil/python/tests/test_subvolume.py |  8 +++
>>>  libbtrfsutil/subvolume.c                    | 89 +++++++++++++++++++++++++++++
>>>  7 files changed, 183 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/libbtrfsutil/btrfsutil.h b/libbtrfsutil/btrfsutil.h
>>> index 00c86174..677ab3c1 100644
>>> --- a/libbtrfsutil/btrfsutil.h
>>> +++ b/libbtrfsutil/btrfsutil.h
>>> @@ -534,6 +534,27 @@ enum btrfs_util_error btrfs_util_subvolume_iterator_next_info(struct btrfs_util_
>>>  							      char **path_ret,
>>>  							      struct btrfs_util_subvolume_info *subvol);
>>>  
>>> +/**
>>> + * btrfs_util_deleted_subvolumes() - Get a list of subvolume which have been
>>> + * deleted but not yet cleaned up.
>>> + * @path: Path on a Btrfs filesystem.
>>> + * @ids: Returned array of subvolume IDs.
>>> + * @n: Returned number of IDs in the @ids array.
>>> + *
>>> + * This requires appropriate privilege (CAP_SYS_ADMIN).
>>> + *
>>> + * Return: %BTRFS_UTIL_OK on success, non-zero error code on failure.
>>> + */
>>> +enum btrfs_util_error btrfs_util_deleted_subvolumes(const char *path,
>>> +						    uint64_t **ids,
>>> +						    size_t *n);
>>> +
>>> +/**
>>> + * btrfs_util_deleted_subvolumes_fd() - See btrfs_util_deleted_subvolumes().
>>> + */
>>> +enum btrfs_util_error btrfs_util_deleted_subvolumes_fd(int fd, uint64_t **ids,
>>> +						       size_t *n);
>>> +
>>>  /**
>>>   * btrfs_util_create_qgroup_inherit() - Create a qgroup inheritance specifier
>>>   * for btrfs_util_create_subvolume() or btrfs_util_create_snapshot().
>>> diff --git a/libbtrfsutil/python/btrfsutilpy.h b/libbtrfsutil/python/btrfsutilpy.h
>>> index b3ec047f..be5122e2 100644
>>> --- a/libbtrfsutil/python/btrfsutilpy.h
>>> +++ b/libbtrfsutil/python/btrfsutilpy.h
>>> @@ -54,6 +54,8 @@ struct path_arg {
>>>  int path_converter(PyObject *o, void *p);
>>>  void path_cleanup(struct path_arg *path);
>>>  
>>> +PyObject *list_from_uint64_array(const uint64_t *arr, size_t n);
>>> +
>>>  void SetFromBtrfsUtilError(enum btrfs_util_error err);
>>>  void SetFromBtrfsUtilErrorWithPath(enum btrfs_util_error err,
>>>  				   struct path_arg *path);
>>> @@ -72,6 +74,7 @@ PyObject *set_default_subvolume(PyObject *self, PyObject *args, PyObject *kwds);
>>>  PyObject *create_subvolume(PyObject *self, PyObject *args, PyObject *kwds);
>>>  PyObject *create_snapshot(PyObject *self, PyObject *args, PyObject *kwds);
>>>  PyObject *delete_subvolume(PyObject *self, PyObject *args, PyObject *kwds);
>>> +PyObject *deleted_subvolumes(PyObject *self, PyObject *args, PyObject *kwds);
>>>  
>>>  void add_module_constants(PyObject *m);
>>>  
>>> diff --git a/libbtrfsutil/python/module.c b/libbtrfsutil/python/module.c
>>> index e995a1be..eaa062ac 100644
>>> --- a/libbtrfsutil/python/module.c
>>> +++ b/libbtrfsutil/python/module.c
>>> @@ -125,6 +125,29 @@ err:
>>>  	return 0;
>>>  }
>>>  
>>> +PyObject *list_from_uint64_array(const uint64_t *arr, size_t n)
>>> +{
>>> +    PyObject *ret;
>>> +    size_t i;
>>> +
>>> +    ret = PyList_New(n);
>>> +    if (!ret)
>>> +	    return NULL;
>>> +
>>> +    for (i = 0; i < n; i++) {
>>> +	    PyObject *tmp;
>>> +
>>> +	    tmp = PyLong_FromUnsignedLongLong(arr[i]);
>>> +	    if (!tmp) {
>>> +		    Py_DECREF(ret);
>>> +		    return NULL;
>>> +	    }
>>> +	    PyList_SET_ITEM(ret, i, tmp);
>>> +    }
>>> +
>>> +    return ret;
>>> +}
>>> +
>>>  void path_cleanup(struct path_arg *path)
>>>  {
>>>  	Py_CLEAR(path->object);
>>> @@ -214,6 +237,13 @@ static PyMethodDef btrfsutil_methods[] = {
>>>  	 "path -- string, bytes, or path-like object\n"
>>>  	 "recursive -- if the given subvolume has child subvolumes, delete\n"
>>>  	 "them instead of failing"},
>>> +	{"deleted_subvolumes", (PyCFunction)deleted_subvolumes,
>>> +	 METH_VARARGS | METH_KEYWORDS,
>>> +	 "deleted_subvolumes(path)\n\n"
>>> +	 "Get the list of subvolume IDs which have been deleted but not yet\n"
>>> +	 "cleaned up\n\n"
>>> +	 "Arguments:\n"
>>> +	 "path -- string, bytes, path-like object, or open file descriptor"},
>>>  	{},
>>>  };
>>>  
>>> diff --git a/libbtrfsutil/python/qgroup.c b/libbtrfsutil/python/qgroup.c
>>> index 69716d92..44ac5ebc 100644
>>> --- a/libbtrfsutil/python/qgroup.c
>>> +++ b/libbtrfsutil/python/qgroup.c
>>> @@ -55,25 +55,12 @@ static PyObject *QgroupInherit_getattro(QgroupInherit *self, PyObject *nameobj)
>>>      }
>>>  
>>>      if (strcmp(name, "groups") == 0) {
>>> -	    PyObject *ret, *tmp;
>>>  	    const uint64_t *arr;
>>> -	    size_t n, i;
>>> +	    size_t n;
>>>  
>>>  	    btrfs_util_qgroup_inherit_get_groups(self->inherit, &arr, &n);
>>> -	    ret = PyList_New(n);
>>> -	    if (!ret)
>>> -		    return NULL;
>>> -
>>> -	    for (i = 0; i < n; i++) {
>>> -		    tmp = PyLong_FromUnsignedLongLong(arr[i]);
>>> -		    if (!tmp) {
>>> -			    Py_DECREF(ret);
>>> -			    return NULL;
>>> -		    }
>>> -		    PyList_SET_ITEM(ret, i, tmp);
>>> -	    }
>>>  
>>> -	    return ret;
>>> +	    return list_from_uint64_array(arr, n);
>>>      } else {
>>>  	    return PyObject_GenericGetAttr((PyObject *)self, nameobj);
>>>      }
>>> diff --git a/libbtrfsutil/python/subvolume.c b/libbtrfsutil/python/subvolume.c
>>> index eb3f6e27..069e606b 100644
>>> --- a/libbtrfsutil/python/subvolume.c
>>> +++ b/libbtrfsutil/python/subvolume.c
>>> @@ -425,6 +425,36 @@ PyObject *delete_subvolume(PyObject *self, PyObject *args, PyObject *kwds)
>>>  	Py_RETURN_NONE;
>>>  }
>>>  
>>> +PyObject *deleted_subvolumes(PyObject *self, PyObject *args, PyObject *kwds)
>>> +{
>>> +	static char *keywords[] = {"path", NULL};
>>> +	struct path_arg path = {.allow_fd = true};
>>> +	PyObject *ret;
>>> +	uint64_t *ids;
>>> +	size_t n;
>>> +	enum btrfs_util_error err;
>>> +
>>> +	if (!PyArg_ParseTupleAndKeywords(args, kwds, "O&:deleted_subvolumes",
>>> +					 keywords, &path_converter, &path))
>>> +		return NULL;
>>> +
>>> +	if (path.path)
>>> +		err = btrfs_util_deleted_subvolumes(path.path, &ids, &n);
>>> +	else
>>> +		err = btrfs_util_deleted_subvolumes_fd(path.fd, &ids, &n);
>>> +	if (err) {
>>> +		SetFromBtrfsUtilErrorWithPath(err, &path);
>>> +		path_cleanup(&path);
>>> +		return NULL;
>>> +	}
>>> +
>>> +	path_cleanup(&path);
>>> +
>>> +	ret = list_from_uint64_array(ids, n);
>>> +	free(ids);
>>> +	return ret;
>>> +}
>>> +
>>>  typedef struct {
>>>  	PyObject_HEAD
>>>  	struct btrfs_util_subvolume_iterator *iter;
>>> diff --git a/libbtrfsutil/python/tests/test_subvolume.py b/libbtrfsutil/python/tests/test_subvolume.py
>>> index 08083abe..a46d4a34 100644
>>> --- a/libbtrfsutil/python/tests/test_subvolume.py
>>> +++ b/libbtrfsutil/python/tests/test_subvolume.py
>>> @@ -318,6 +318,14 @@ class TestSubvolume(BtrfsTestCase):
>>>          btrfsutil.delete_subvolume(subvol + '5', recursive=True)
>>>          self.assertFalse(os.path.exists(subvol + '5'))
>>>  
>>> +    def test_deleted_subvolumes(self):
>>> +        subvol = os.path.join(self.mountpoint, 'subvol')
>>> +        btrfsutil.create_subvolume(subvol + '1')
>>> +        btrfsutil.delete_subvolume(subvol + '1')
>>> +        for arg in self.path_or_fd(self.mountpoint):
>>> +            with self.subTest(type=type(arg)):
>>> +                self.assertEqual(btrfsutil.deleted_subvolumes(arg), [256])
>>> +
>>>      def test_subvolume_iterator(self):
>>>          pwd = os.getcwd()
>>>          try:
>>> diff --git a/libbtrfsutil/subvolume.c b/libbtrfsutil/subvolume.c
>>> index 908e71db..4ae581b2 100644
>>> --- a/libbtrfsutil/subvolume.c
>>> +++ b/libbtrfsutil/subvolume.c
>>> @@ -1277,3 +1277,92 @@ PUBLIC enum btrfs_util_error btrfs_util_subvolume_iterator_next_info(struct btrf
>>>  
>>>  	return btrfs_util_subvolume_info_fd(iter->fd, id, subvol);
>>>  }
>>> +
>>> +PUBLIC enum btrfs_util_error btrfs_util_deleted_subvolumes(const char *path,
>>> +							   uint64_t **ids,
>>> +							   size_t *n)
>>> +{
>>> +	enum btrfs_util_error err;
>>> +	int fd;
>>> +
>>> +	fd = open(path, O_RDONLY);
>>> +	if (fd == -1)
>>> +		return BTRFS_UTIL_ERROR_OPEN_FAILED;
>>> +
>>> +	err = btrfs_util_deleted_subvolumes_fd(fd, ids, n);
>>> +	SAVE_ERRNO_AND_CLOSE(fd);
>>> +	return err;
>>> +}
>>> +
>>> +PUBLIC enum btrfs_util_error btrfs_util_deleted_subvolumes_fd(int fd,
>>> +							      uint64_t **ids,
>>> +							      size_t *n)
>>> +{
>>> +	size_t capacity = 0;
>>> +	struct btrfs_ioctl_search_args search = {
>>> +		.key = {
>>> +			.tree_id = BTRFS_ROOT_TREE_OBJECTID,
>>> +			.min_objectid = BTRFS_ORPHAN_OBJECTID,
>>> +			.max_objectid = BTRFS_ORPHAN_OBJECTID,
>>> +			.min_type = BTRFS_ORPHAN_ITEM_KEY,
>>> +			.max_type = BTRFS_ORPHAN_ITEM_KEY,
>>> +			.min_offset = 0,
>>> +			.max_offset = UINT64_MAX,
>>> +			.min_transid = 0,
>>> +			.max_transid = UINT64_MAX,
>>> +			.nr_items = 0,
>>> +		},
>>> +	};
>> It seems btrfs_util_deleted_subvolume() does not works perfectly.
>>
>> Above search will return all ORPHAN_ITEM but some may be of free space cache inode (correct me if I'm wrong).
>> Since this is a public function, we should filter those non-subvolume objectid by checking root tree again.
>> I think this is the reason of failure of misc-test/013 after merging 26th patch.
> 
> So looking at the code that this replaces, I don't see the difference:
> 
> static int enumerate_dead_subvols(int fd, u64 **ids)
> {
> 	int ret;
> 	struct btrfs_ioctl_search_args args;
> 	struct btrfs_ioctl_search_key *sk = &args.key;
> 	int idx = 0;
> 	int count = 0;
> 
> 	memset(&args, 0, sizeof(args));
> 
> 	sk->tree_id = BTRFS_ROOT_TREE_OBJECTID;
> 	sk->min_objectid = BTRFS_ORPHAN_OBJECTID;
> 	sk->max_objectid = BTRFS_ORPHAN_OBJECTID;
> 	sk->min_type = BTRFS_ORPHAN_ITEM_KEY;
> 	sk->max_type = BTRFS_ORPHAN_ITEM_KEY;
> 	sk->min_offset = 0;
> 	sk->max_offset = (u64)-1;
> 	sk->min_transid = 0;
> 	sk->max_transid = (u64)-1;
> 	sk->nr_items = 4096;
> 
> 	*ids = NULL;
> 	while (1) {
> 		struct btrfs_ioctl_search_header *sh;
> 		unsigned long off;
> 		int i;
> 
> 		ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
> 		if (ret < 0)
> 			return -errno;
> 
> 		if (!sk->nr_items)
> 			return idx;
> 
> 		off = 0;
> 		for (i = 0; i < sk->nr_items; i++) {
> 			sh = (struct btrfs_ioctl_search_header*)(args.buf + off);
> 			off += sizeof(*sh);
> 
> 			if (btrfs_search_header_type(sh)
> 			    == BTRFS_ORPHAN_ITEM_KEY) {
> 				if (idx >= count) {
> 					u64 *newids;
> 
> 					count += SUBVOL_ID_BATCH;
> 					newids = (u64*)realloc(*ids,
> 							count * sizeof(u64));
> 					if (!newids)
> 						return -ENOMEM;
> 					*ids = newids;
> 				}
> 				(*ids)[idx] = btrfs_search_header_offset(sh);
> 				idx++;
> 			}
> 			off += btrfs_search_header_len(sh);
> 
> 			sk->min_objectid = btrfs_search_header_objectid(sh);
> 			sk->min_type = btrfs_search_header_type(sh);
> 			sk->min_offset = btrfs_search_header_offset(sh);
> 		}
> 		if (sk->min_offset < (u64)-1)
> 			sk->min_offset++;
> 		else
> 			break;
> 		if (sk->min_type != BTRFS_ORPHAN_ITEM_KEY)
> 			break;
> 		if (sk->min_objectid != BTRFS_ORPHAN_OBJECTID)
> 			break;
> 	}
> 
> 	return idx;
> }
> 
> This function does the same exact search, as far as I can tell. What does the
> test failure look like? I'll try to reproduce it on my side.
> 

Hello, sorry for late replay.

Actually this is not a problem for functionality of "sub list -d" or "sub sync",
because after this function is called we check root tree to see if ROOT_ITEM
for deleted subvolume still exists or not. If the returned id is not related subvolume,
there is no ROOT_ITEM at first.

Since your github branch (libbtrfs) is updated to skip BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND as I said
in 26th patch, there is no test failure anymore.

But if I run misc-test/013 (on 4.16-rc3) with following diff[1] on libbtrfs branch to show
which objectid returns BTRFS_UTIL_ERROR_SUBVOLUME_NOT_FOUND after btrfs_util_subvolume_info_fd(),
I can see the garbage id in tests/misc-tests-result.txt:
---

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Patch
diff mbox

===
[snip]

 ID 291 gen 78 top level 5 path snap34
 ID 293 gen 78 top level 5 path snap35

[snip]
 
 Subvolume id 291 is gone
 Subvolume id 293 is gone

[snip]

############### /home/misono/src/btrfs-progs/btrfs subvolum list -d .
 cleaned: 292  <- there was no subvolume with objectid 292

[snip]
===

I'm not sure where this number comes from, but isn't it better to filter them?

---
 cmds-subvolume.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index 5fa390ff..b034bb77 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -1112,6 +1112,7 @@  static struct subvol_list *btrfs_list_deleted_subvols(int fd,
 			 * The subvolume might have been cleaned up since it was
 			 * returned.
 			 */
+			printf("cleaned: %ld\n", ids[i]);
 			continue;
 		} else if (err) {
 			error_btrfs_util(err);