[PATCH v3 0/2] btrfs-progs: make sure "mkfs --rootdir" copies all the attributes for the rootdir

[PATCH v3 0/2] btrfs-progs: make sure "mkfs --rootdir" copies all the attributes for the rootdir

[Qu Wenruo]

[CHANGELOG]
v3:
- Use 'stat()' instead pf 'lstate()' for the rootdir
  This would follow a softlink for the rootdir.

v2:
- Add more attributes to be copied for rootdir, including:
  * mode
  * uid
  * gid
  * timestamps

- Update the test case
  * Use two loopback devices
    One to store the source directory, so that we're ensured to have
    xattr support.
  * Add checks for all the uid/gid/mode attributes

We got a bug report that "mkfs.btrfs --rootdir" copies all the xattr but
the xattr of the source directory.

It turns out that we only do the regular xattr/gid/uid/mode/timestamps
copy for all the child inodes, not the source directory itself.

Fix it and create a test case for it.

Qu Wenruo (2):
  btrfs-progs: mkfs/rootdir: copy missing attributes for the rootdir
    inode
  btrfs-progs: tests/mkfs: make sure rootdir inode got its attributes
    copied

 mkfs/rootdir.c                             | 88 ++++++++++++++++------
 tests/mkfs-tests/027-rootdir-inode/test.sh | 60 +++++++++++++++
 2 files changed, 127 insertions(+), 21 deletions(-)
 create mode 100755 tests/mkfs-tests/027-rootdir-inode/test.sh

--
2.42.0

[PATCH v3 1/2] btrfs-progs: mkfs/rootdir: copy missing attributes for the rootdir inode

[Qu Wenruo]

[BUG]
When using "mkfs.btrfs" with "--rootdir" option, the top level inode
(rootdir) will not get the same xattr from the source dir:

  mkdir -p source_dir/
  touch source_dir/file
  setfattr -n user.rootdir_xattr source_dir/
  setfattr -n user.regular_xattr source_dir/file
  mkfs.btrfs -f --rootdir source_dir $dev
  mount $dev $mnt
  getfattr $mnt
  # Nothing <<<
  getfattr $mnt/file
  # file: $mnt/file
  user.regular_xattr <<<

[CAUSE]
In function traverse_directory(), we only call add_xattr_item() for all
the child inodes, not really for the rootdir inode itself, leading to
the missing xattr items.

Not only xattr, in fact we also miss the uid/gid/timestamps/mode for the
rootdir inode.

[FIX]
Extract a dedicated function, copy_rootdir_inode(), to handle every
needed attributes for the rootdir inode, including:

- xattr
- uid
- gid
- mode
- timestamps

Issue: #688
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 mkfs/rootdir.c | 88 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 67 insertions(+), 21 deletions(-)

diff --git a/mkfs/rootdir.c b/mkfs/rootdir.c
index a413a31eb2d6..24e26cdf50e0 100644
--- a/mkfs/rootdir.c
+++ b/mkfs/rootdir.c
@@ -429,6 +429,69 @@ end:
 	return ret;
 }
 
+static int copy_rootdir_inode(struct btrfs_trans_handle *trans,
+			      struct btrfs_root *root, const char *dir_name)
+{
+	u64 root_dir_inode_size;
+	struct btrfs_inode_item *inode_item;
+	struct btrfs_path path = { 0 };
+	struct btrfs_key key;
+	struct extent_buffer *leaf;
+	struct stat st;
+	int ret;
+
+	ret = stat(dir_name, &st);
+	if (ret < 0) {
+		ret = -errno;
+		error("lstat failed for direcotry %s: $m", dir_name);
+		return ret;
+	}
+
+	ret = add_xattr_item(trans, root, btrfs_root_dirid(&root->root_item),
+			     dir_name);
+	if (ret < 0) {
+		errno = -ret;
+		error("failed to add xattr item for the top level inode: %m");
+		return ret;
+	}
+
+	key.objectid = btrfs_root_dirid(&root->root_item);
+	key.offset = 0;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	ret = btrfs_lookup_inode(trans, root, &path, &key, 1);
+	if (ret > 0)
+		ret = -ENOENT;
+	if (ret) {
+		error("failed to lookup root dir: %d", ret);
+		goto error;
+	}
+
+	leaf = path.nodes[0];
+	inode_item = btrfs_item_ptr(leaf, path.slots[0],
+				    struct btrfs_inode_item);
+
+	root_dir_inode_size = calculate_dir_inode_size(dir_name);
+	btrfs_set_inode_size(leaf, inode_item, root_dir_inode_size);
+
+	/* Unlike fill_inode_item, we only need to copy part of the attributes. */
+	btrfs_set_inode_uid(leaf, inode_item, st.st_uid);
+	btrfs_set_inode_gid(leaf, inode_item, st.st_gid);
+	btrfs_set_inode_mode(leaf, inode_item, st.st_mode);
+	btrfs_set_timespec_sec(leaf, &inode_item->atime, st.st_atime);
+	btrfs_set_timespec_nsec(leaf, &inode_item->atime, 0);
+	btrfs_set_timespec_sec(leaf, &inode_item->ctime, st.st_ctime);
+	btrfs_set_timespec_nsec(leaf, &inode_item->ctime, 0);
+	btrfs_set_timespec_sec(leaf, &inode_item->mtime, st.st_mtime);
+	btrfs_set_timespec_nsec(leaf, &inode_item->mtime, 0);
+	btrfs_set_timespec_sec(leaf, &inode_item->otime, 0);
+	btrfs_set_timespec_nsec(leaf, &inode_item->otime, 0);
+	btrfs_mark_buffer_dirty(leaf);
+
+error:
+	btrfs_release_path(&path);
+	return ret;
+}
+
 static int traverse_directory(struct btrfs_trans_handle *trans,
 			      struct btrfs_root *root, const char *dir_name,
 			      struct directory_name_entry *dir_head)
@@ -436,7 +499,6 @@ static int traverse_directory(struct btrfs_trans_handle *trans,
 	int ret = 0;
 
 	struct btrfs_inode_item cur_inode;
-	struct btrfs_inode_item *inode_item;
 	int count, i, dir_index_cnt;
 	struct dirent **files;
 	struct stat st;
@@ -445,10 +507,6 @@ static int traverse_directory(struct btrfs_trans_handle *trans,
 	ino_t parent_inum, cur_inum;
 	ino_t highest_inum = 0;
 	const char *parent_dir_name;
-	struct btrfs_path path = { 0 };
-	struct extent_buffer *leaf;
-	struct btrfs_key root_dir_key;
-	u64 root_dir_inode_size = 0;
 
 	/* Add list for source directory */
 	dir_entry = malloc(sizeof(struct directory_name_entry));
@@ -466,25 +524,13 @@ static int traverse_directory(struct btrfs_trans_handle *trans,
 	dir_entry->inum = parent_inum;
 	list_add_tail(&dir_entry->list, &dir_head->list);
 
-	root_dir_key.objectid = btrfs_root_dirid(&root->root_item);
-	root_dir_key.offset = 0;
-	root_dir_key.type = BTRFS_INODE_ITEM_KEY;
-	ret = btrfs_lookup_inode(trans, root, &path, &root_dir_key, 1);
-	if (ret) {
-		error("failed to lookup root dir: %d", ret);
+	ret = copy_rootdir_inode(trans, root, dir_name);
+	if (ret < 0) {
+		errno = -ret;
+		error("failed to copy rootdir inode: %m");
 		goto fail_no_dir;
 	}
 
-	leaf = path.nodes[0];
-	inode_item = btrfs_item_ptr(leaf, path.slots[0],
-				    struct btrfs_inode_item);
-
-	root_dir_inode_size = calculate_dir_inode_size(dir_name);
-	btrfs_set_inode_size(leaf, inode_item, root_dir_inode_size);
-	btrfs_mark_buffer_dirty(leaf);
-
-	btrfs_release_path(&path);
-
 	do {
 		parent_dir_entry = list_entry(dir_head->list.next,
 					      struct directory_name_entry,
-- 
2.42.0

Re: [PATCH v3 1/2] btrfs-progs: mkfs/rootdir: copy missing attributes for the rootdir inode

[David Sterba]

On Thu, Oct 12, 2023 at 07:19:25AM +1030, Qu Wenruo wrote:
> [BUG]
> When using "mkfs.btrfs" with "--rootdir" option, the top level inode
> (rootdir) will not get the same xattr from the source dir:
> 
>   mkdir -p source_dir/
>   touch source_dir/file
>   setfattr -n user.rootdir_xattr source_dir/
>   setfattr -n user.regular_xattr source_dir/file
>   mkfs.btrfs -f --rootdir source_dir $dev
>   mount $dev $mnt
>   getfattr $mnt
>   # Nothing <<<
>   getfattr $mnt/file
>   # file: $mnt/file
>   user.regular_xattr <<<
> 
> [CAUSE]
> In function traverse_directory(), we only call add_xattr_item() for all
> the child inodes, not really for the rootdir inode itself, leading to
> the missing xattr items.
> 
> Not only xattr, in fact we also miss the uid/gid/timestamps/mode for the
> rootdir inode.
> 
> [FIX]
> Extract a dedicated function, copy_rootdir_inode(), to handle every
> needed attributes for the rootdir inode, including:
> 
> - xattr
> - uid
> - gid
> - mode
> - timestamps
> 
> Issue: #688
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  mkfs/rootdir.c | 88 ++++++++++++++++++++++++++++++++++++++------------
>  1 file changed, 67 insertions(+), 21 deletions(-)
> 
> diff --git a/mkfs/rootdir.c b/mkfs/rootdir.c
> index a413a31eb2d6..24e26cdf50e0 100644
> --- a/mkfs/rootdir.c
> +++ b/mkfs/rootdir.c
> @@ -429,6 +429,69 @@ end:
>  	return ret;
>  }
>  
> +static int copy_rootdir_inode(struct btrfs_trans_handle *trans,
> +			      struct btrfs_root *root, const char *dir_name)
> +{
> +	u64 root_dir_inode_size;
> +	struct btrfs_inode_item *inode_item;
> +	struct btrfs_path path = { 0 };
> +	struct btrfs_key key;
> +	struct extent_buffer *leaf;
> +	struct stat st;
> +	int ret;
> +
> +	ret = stat(dir_name, &st);

According to the v3 changelog this should be lstat(), right?

> +	if (ret < 0) {
> +		ret = -errno;
> +		error("lstat failed for direcotry %s: $m", dir_name);
                       ^^^^^

like here.

> +		return ret;
> +	}

Re: [PATCH v3 1/2] btrfs-progs: mkfs/rootdir: copy missing attributes for the rootdir inode

[Qu Wenruo]

On 2023/10/14 02:25, David Sterba wrote:
> On Thu, Oct 12, 2023 at 07:19:25AM +1030, Qu Wenruo wrote:
>> [BUG]
>> When using "mkfs.btrfs" with "--rootdir" option, the top level inode
>> (rootdir) will not get the same xattr from the source dir:
>>
>>    mkdir -p source_dir/
>>    touch source_dir/file
>>    setfattr -n user.rootdir_xattr source_dir/
>>    setfattr -n user.regular_xattr source_dir/file
>>    mkfs.btrfs -f --rootdir source_dir $dev
>>    mount $dev $mnt
>>    getfattr $mnt
>>    # Nothing <<<
>>    getfattr $mnt/file
>>    # file: $mnt/file
>>    user.regular_xattr <<<
>>
>> [CAUSE]
>> In function traverse_directory(), we only call add_xattr_item() for all
>> the child inodes, not really for the rootdir inode itself, leading to
>> the missing xattr items.
>>
>> Not only xattr, in fact we also miss the uid/gid/timestamps/mode for the
>> rootdir inode.
>>
>> [FIX]
>> Extract a dedicated function, copy_rootdir_inode(), to handle every
>> needed attributes for the rootdir inode, including:
>>
>> - xattr
>> - uid
>> - gid
>> - mode
>> - timestamps
>>
>> Issue: #688
>> Signed-off-by: Qu Wenruo <wqu@suse.com>
>> ---
>>   mkfs/rootdir.c | 88 ++++++++++++++++++++++++++++++++++++++------------
>>   1 file changed, 67 insertions(+), 21 deletions(-)
>>
>> diff --git a/mkfs/rootdir.c b/mkfs/rootdir.c
>> index a413a31eb2d6..24e26cdf50e0 100644
>> --- a/mkfs/rootdir.c
>> +++ b/mkfs/rootdir.c
>> @@ -429,6 +429,69 @@ end:
>>   	return ret;
>>   }
>>
>> +static int copy_rootdir_inode(struct btrfs_trans_handle *trans,
>> +			      struct btrfs_root *root, const char *dir_name)
>> +{
>> +	u64 root_dir_inode_size;
>> +	struct btrfs_inode_item *inode_item;
>> +	struct btrfs_path path = { 0 };
>> +	struct btrfs_key key;
>> +	struct extent_buffer *leaf;
>> +	struct stat st;
>> +	int ret;
>> +
>> +	ret = stat(dir_name, &st);
>
> According to the v3 changelog this should be lstat(), right?

It should be stat(), not lstat() of v2.

The reason is, the end user may pass a softlink pointing to a directory.
In that case, lstat() would not follow the softlink.

>
>> +	if (ret < 0) {
>> +		ret = -errno;
>> +		error("lstat failed for direcotry %s: $m", dir_name);
>                         ^^^^^
>
> like here.

I'll update it along with other fixes to address the comments.

Thanks,
Qu
>
>> +		return ret;
>> +	}

Re: [PATCH v3 1/2] btrfs-progs: mkfs/rootdir: copy missing attributes for the rootdir inode

[David Sterba]

On Sat, Oct 14, 2023 at 06:25:03AM +1030, Qu Wenruo wrote:
> 
> 
> On 2023/10/14 02:25, David Sterba wrote:
> > On Thu, Oct 12, 2023 at 07:19:25AM +1030, Qu Wenruo wrote:
> >> [BUG]
> >> When using "mkfs.btrfs" with "--rootdir" option, the top level inode
> >> (rootdir) will not get the same xattr from the source dir:
> >>
> >>    mkdir -p source_dir/
> >>    touch source_dir/file
> >>    setfattr -n user.rootdir_xattr source_dir/
> >>    setfattr -n user.regular_xattr source_dir/file
> >>    mkfs.btrfs -f --rootdir source_dir $dev
> >>    mount $dev $mnt
> >>    getfattr $mnt
> >>    # Nothing <<<
> >>    getfattr $mnt/file
> >>    # file: $mnt/file
> >>    user.regular_xattr <<<
> >>
> >> [CAUSE]
> >> In function traverse_directory(), we only call add_xattr_item() for all
> >> the child inodes, not really for the rootdir inode itself, leading to
> >> the missing xattr items.
> >>
> >> Not only xattr, in fact we also miss the uid/gid/timestamps/mode for the
> >> rootdir inode.
> >>
> >> [FIX]
> >> Extract a dedicated function, copy_rootdir_inode(), to handle every
> >> needed attributes for the rootdir inode, including:
> >>
> >> - xattr
> >> - uid
> >> - gid
> >> - mode
> >> - timestamps
> >>
> >> Issue: #688
> >> Signed-off-by: Qu Wenruo <wqu@suse.com>
> >> ---
> >>   mkfs/rootdir.c | 88 ++++++++++++++++++++++++++++++++++++++------------
> >>   1 file changed, 67 insertions(+), 21 deletions(-)
> >>
> >> diff --git a/mkfs/rootdir.c b/mkfs/rootdir.c
> >> index a413a31eb2d6..24e26cdf50e0 100644
> >> --- a/mkfs/rootdir.c
> >> +++ b/mkfs/rootdir.c
> >> @@ -429,6 +429,69 @@ end:
> >>   	return ret;
> >>   }
> >>
> >> +static int copy_rootdir_inode(struct btrfs_trans_handle *trans,
> >> +			      struct btrfs_root *root, const char *dir_name)
> >> +{
> >> +	u64 root_dir_inode_size;
> >> +	struct btrfs_inode_item *inode_item;
> >> +	struct btrfs_path path = { 0 };
> >> +	struct btrfs_key key;
> >> +	struct extent_buffer *leaf;
> >> +	struct stat st;
> >> +	int ret;
> >> +
> >> +	ret = stat(dir_name, &st);
> >
> > According to the v3 changelog this should be lstat(), right?
> 
> It should be stat(), not lstat() of v2.
> 
> The reason is, the end user may pass a softlink pointing to a directory.
> In that case, lstat() would not follow the softlink.

Ok, I've changed it to stat().

> 
> >
> >> +	if (ret < 0) {
> >> +		ret = -errno;
> >> +		error("lstat failed for direcotry %s: $m", dir_name);
> >                         ^^^^^
> >
> > like here.
> 
> I'll update it along with other fixes to address the comments.

Unless it's just the l/stat references no need to resend, I've updated
the commit.

Re: [PATCH v3 1/2] btrfs-progs: mkfs/rootdir: copy missing attributes for the rootdir inode

[David Sterba]

On Thu, Oct 12, 2023 at 07:19:25AM +1030, Qu Wenruo wrote:
> [BUG]
> When using "mkfs.btrfs" with "--rootdir" option, the top level inode
> (rootdir) will not get the same xattr from the source dir:
> 
>   mkdir -p source_dir/
>   touch source_dir/file
>   setfattr -n user.rootdir_xattr source_dir/
>   setfattr -n user.regular_xattr source_dir/file
>   mkfs.btrfs -f --rootdir source_dir $dev
>   mount $dev $mnt
>   getfattr $mnt
>   # Nothing <<<
>   getfattr $mnt/file
>   # file: $mnt/file
>   user.regular_xattr <<<
> 
> [CAUSE]
> In function traverse_directory(), we only call add_xattr_item() for all
> the child inodes, not really for the rootdir inode itself, leading to
> the missing xattr items.
> 
> Not only xattr, in fact we also miss the uid/gid/timestamps/mode for the
> rootdir inode.
> 
> [FIX]
> Extract a dedicated function, copy_rootdir_inode(), to handle every
> needed attributes for the rootdir inode, including:
> 
> - xattr
> - uid
> - gid
> - mode
> - timestamps
> 
> Issue: #688
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  mkfs/rootdir.c | 88 ++++++++++++++++++++++++++++++++++++++------------
>  1 file changed, 67 insertions(+), 21 deletions(-)
> 
> diff --git a/mkfs/rootdir.c b/mkfs/rootdir.c
> index a413a31eb2d6..24e26cdf50e0 100644
> --- a/mkfs/rootdir.c
> +++ b/mkfs/rootdir.c
> @@ -429,6 +429,69 @@ end:
>  	return ret;
>  }
>  
> +static int copy_rootdir_inode(struct btrfs_trans_handle *trans,
> +			      struct btrfs_root *root, const char *dir_name)
> +{
> +	u64 root_dir_inode_size;
> +	struct btrfs_inode_item *inode_item;
> +	struct btrfs_path path = { 0 };
> +	struct btrfs_key key;
> +	struct extent_buffer *leaf;
> +	struct stat st;
> +	int ret;
> +
> +	ret = stat(dir_name, &st);
> +	if (ret < 0) {
> +		ret = -errno;
> +		error("lstat failed for direcotry %s: $m", dir_name);
> +		return ret;
> +	}
> +
> +	ret = add_xattr_item(trans, root, btrfs_root_dirid(&root->root_item),
> +			     dir_name);
> +	if (ret < 0) {
> +		errno = -ret;
> +		error("failed to add xattr item for the top level inode: %m");
> +		return ret;
> +	}
> +
> +	key.objectid = btrfs_root_dirid(&root->root_item);
> +	key.offset = 0;
> +	key.type = BTRFS_INODE_ITEM_KEY;
> +	ret = btrfs_lookup_inode(trans, root, &path, &key, 1);
> +	if (ret > 0)
> +		ret = -ENOENT;
> +	if (ret) {
> +		error("failed to lookup root dir: %d", ret);
> +		goto error;
> +	}
> +
> +	leaf = path.nodes[0];
> +	inode_item = btrfs_item_ptr(leaf, path.slots[0],
> +				    struct btrfs_inode_item);
> +
> +	root_dir_inode_size = calculate_dir_inode_size(dir_name);
> +	btrfs_set_inode_size(leaf, inode_item, root_dir_inode_size);
> +
> +	/* Unlike fill_inode_item, we only need to copy part of the attributes. */
> +	btrfs_set_inode_uid(leaf, inode_item, st.st_uid);
> +	btrfs_set_inode_gid(leaf, inode_item, st.st_gid);
> +	btrfs_set_inode_mode(leaf, inode_item, st.st_mode);
> +	btrfs_set_timespec_sec(leaf, &inode_item->atime, st.st_atime);
> +	btrfs_set_timespec_nsec(leaf, &inode_item->atime, 0);
> +	btrfs_set_timespec_sec(leaf, &inode_item->ctime, st.st_ctime);
> +	btrfs_set_timespec_nsec(leaf, &inode_item->ctime, 0);
> +	btrfs_set_timespec_sec(leaf, &inode_item->mtime, st.st_mtime);
> +	btrfs_set_timespec_nsec(leaf, &inode_item->mtime, 0);
> +	btrfs_set_timespec_sec(leaf, &inode_item->otime, 0);
> +	btrfs_set_timespec_nsec(leaf, &inode_item->otime, 0);

We should put something sensible to the otime, either current time, real
otime or at least mtime/ctime as a fallback.

[PATCH v3 2/2] btrfs-progs: tests/mkfs: make sure rootdir inode got its attributes copied

[Qu Wenruo]

The new test case would:

- Prepare two loopback devices
  One is for storing the source directory (on a btrfs).
  This is to ensure we can set xattr for the directory, as filesystems
  like tmpfs (mostly utilized by mktemp) is not supporting xattr.

  The other one is the real target fs where we call "mkfs.btrfs
  --rootdir" on.

- Create the source directory with the following contents:
  * rootdir inode attributs:
    # mode (750)
    # uid (1000)
    # gid (1000)
    # xattr (user.rootdir)
  * one regular file, with attributes:
    # xattr (user.foorbar)

- Execute "mkfs.btrfs --rootdir" and mount the new fs

- Verify the above attributes
  The target fs should have the same attributes, especially for the
  rootdir inode.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 tests/mkfs-tests/027-rootdir-inode/test.sh | 60 ++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100755 tests/mkfs-tests/027-rootdir-inode/test.sh

diff --git a/tests/mkfs-tests/027-rootdir-inode/test.sh b/tests/mkfs-tests/027-rootdir-inode/test.sh
new file mode 100755
index 000000000000..e5de1485cc87
--- /dev/null
+++ b/tests/mkfs-tests/027-rootdir-inode/test.sh
@@ -0,0 +1,60 @@
+#!/bin/bash
+# Test if "mkfs.btrfs --rootdir" would properly copy all the attributes of the
+# source directory.
+
+source "$TEST_TOP/common" || exit
+
+setup_root_helper
+# Here we need two devices, one as a temporaray btrfs, storing the source
+# directory. As we want to setup xattr, which is not supported by tmpfs
+# (most modern distros go tmpfs for /tmp).
+# So we have to put the source directory on a fs that supports xattr.
+#
+# Then the second fs is the real one we mkfs on.
+setup_loopdevs 2
+prepare_loopdevs
+
+tmp_dev=${loopdevs[1]}
+real_dev=${loopdevs[2]}
+
+check_global_prereq setfattr
+check_global_prereq getfattr
+
+# Here we don't want to use /tmp, as it's pretty common /tmp is tmpfs, which
+# doesn't support xattr.
+# Instead we go $TEST_TOP/btrfs-progs-mkfs-tests-027.XXXXXX/ instead.
+run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$tmp_dev"
+run_check $SUDO_HELPER mount -t btrfs "$tmp_dev" "$TEST_MNT"
+
+run_check $SUDO_HELPER mkdir "$TEST_MNT/source_dir/"
+run_check $SUDO_HELPER chmod 750 "$TEST_MNT/source_dir/"
+run_check $SUDO_HELPER chown 1000:1000 "$TEST_MNT/source_dir/"
+run_check $SUDO_HELPER setfattr -n user.rootdir "$TEST_MNT/source_dir/"
+
+old_mode=$(run_check_stdout $SUDO_HELPER stat "$TEST_MNT/source_dir/" | grep "Uid:")
+run_check $SUDO_HELPER touch "$TEST_MNT/source_dir/foobar"
+run_check $SUDO_HELPER setfattr -n user.foobar "$TEST_MNT/source_dir/foobar"
+
+run_check $SUDO_HELPER "$TOP/mkfs.btrfs" --rootdir "$TEST_MNT/source_dir" -f "$real_dev"
+run_check $SUDO_HELPER umount "$TEST_MNT"
+
+run_check $SUDO_HELPER mount -t btrfs "$real_dev" "$TEST_MNT"
+
+new_mode=$(run_check_stdout $SUDO_HELPER stat "$TEST_MNT/" | grep "Uid:")
+new_rootdir_attr=$(run_check_stdout $SUDO_HELPER getfattr -n user.rootdir --absolute-names "$src_dir")
+new_foobar_attr=$(run_check_stdout getfattr -n user.foobar --absolute-names "$src_dir/foobar")
+
+run_check_umount_test_dev "$TEST_MNT"
+cleanup_loopdevs
+
+if ! echo "$new_rootdir_attr" | grep -q "user.rootdir" ; then
+	_fail "no rootdir xattr found"
+fi
+
+if ! echo "$new_foobar_attr"| grep -q "user.foobar" ; then
+	_fail "no regular file xattr found"
+fi
+
+if [ "$new_mode" != "$old_mode" ]; then
+	_fail "mode/uid/gid mismatch"
+fi
-- 
2.42.0

Re: [PATCH v3 0/2] btrfs-progs: make sure "mkfs --rootdir" copies all the attributes for the rootdir

[David Sterba]

On Thu, Oct 12, 2023 at 07:19:24AM +1030, Qu Wenruo wrote:
> [CHANGELOG]
> v3:
> - Use 'stat()' instead pf 'lstate()' for the rootdir
>   This would follow a softlink for the rootdir.
> 
> v2:
> - Add more attributes to be copied for rootdir, including:
>   * mode
>   * uid
>   * gid
>   * timestamps
> 
> - Update the test case
>   * Use two loopback devices
>     One to store the source directory, so that we're ensured to have
>     xattr support.
>   * Add checks for all the uid/gid/mode attributes
> 
> We got a bug report that "mkfs.btrfs --rootdir" copies all the xattr but
> the xattr of the source directory.
> 
> It turns out that we only do the regular xattr/gid/uid/mode/timestamps
> copy for all the child inodes, not the source directory itself.
> 
> Fix it and create a test case for it.
> 
> Qu Wenruo (2):
>   btrfs-progs: mkfs/rootdir: copy missing attributes for the rootdir
>     inode
>   btrfs-progs: tests/mkfs: make sure rootdir inode got its attributes
>     copied

Added to devel with some fixups, thanks.