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PROBLEM: Attempting to create subdirectory returns error after removing parent directory with child entries using rmdir()

DISCUSSION Bastian Arjun Shajit 2 participants 4 messages Jun 22, 2016 – Jun 23, 2016 7 messages not in the archive

Subsystems (2)
SMB client (CIFS) Kernel SMB3 server (ksmbd)
lore
Share & tools
lore

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Bastian Arjun Shajit

author
#2 lore raw

Hi,

We encountered the following error or unexpected behaviour when following the steps given below:

1. Mount the remote share exported by either windows or samba using the following command:
sudo mount -t cifs -o port=445,vers=2.1,username=<username>,password=password,noperm,actimeo=0 //<IP>/SH1 /mnt/test && cd /mnt/test

2. Run the attached program on the mounted share. You should see the following output:

**bastian@gutbark-UX32VD:/mnt/test$ /KVMstorage/cifs_dir_bug
** [4428] mkdir ./parentdir 0777
** [4428] mkdir ./parentdir/sub.0 0777
** [4428] chdir ./parentdir/sub.0
** [4428] rmdir /mnt/test/parentdir
!! [4428] stat() /mnt/test/parentdir Success
** [4428] mkdir /mnt/test/parentdir/sub.1
!! [4428] mkdir /mnt/test/parentdir/sub.1 failed(No such file or directory)

You can see from the above logs, stat of parentdir is successful but creating a new child directory under the parent fails.

The attached program does the following:
a. Create a parent directory
b. Create a sub-directory under the parent.
c. Change dir to sub-directory
d. Now delete the parent directory using absolute path from the cifs client using "rmdir".

The POSIX behaviour for rmdir() is that if there are entries other than "." and ".." it must return ENOTEMPTY error. But as per SMB2 protocol specification, we delete a directory by:
a. Open directory with "Delete on Close" Flag set in the "CreateOptions" field of the SMB2 CREATE request.
b. Close the open handle returned in the response for the previous request.

As per SMB2 specification, the SMB2 close will always return NT status STATUS_SUCCESS for removing the directory even if the directory has child entries, but the server does not delete the directory itself.

4. Manually running "tree" on the mounted share shows the following:

bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
1 directory, 0 files

We clearly see above that the parent directory does not show any child directories.

5.Now we unmount and mount the remote share again

bastian@gutbark-UX32VD:/mnt/test$ cd / && sudo umount /mnt/test
bastian@gutbark-UX32VD:/KVMstorage/$ sudo mount -t cifs -o
port=445,vers=2.1,username=<Username>,password=password,noperm,actimeo=0
//<IP>/SH1 /mnt/test && cd /mnt/test
bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
           |__ sub.0
2 directories, 0 files//

As you can see, remounting the remote share now displays a subdirectory which was not displayed in the earlier mount cycle.

We used the following test setup for reproducing the above said issue:
1. Cifs client: Version = 2.06, Linux versions: Ubuntu, 3.19.8-ckt5 & 3.16.0-49-generic
2. Server: Windows 8.1 pro, Windows 7, Samba 4.1.6-Ubuntu.
3. Reproducible only on SMB2 protocol version.

The issue was reproducible always on WIndows SMB server whereas on Samba server we were able to reproduce 1/2 times.

We ran the same tests on CIFS client version: 2.08, Linux versions 4.4 and 4.5 and we were unable to reproduce the issue.

Br,
Bastian

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>

static int dirbug();

int
main(int argc, char *argv[])

{
    return (dirbug());
}

#define MAX_TEST_PATH_LEN 1024

int dirbug()

{
    int         error;
    int         pid = getpid();
    struct stat st;
    long        len;
    char        *buf = NULL;
    char        *cwd = NULL;
    
    len = pathconf(".", _PC_PATH_MAX);
    if (((cwd = (char *)malloc((size_t)len)) == NULL) ||
        ((buf = (char *)malloc((size_t)len + MAX_TEST_PATH_LEN)) == NULL))
    {
        fprintf(stderr, "No memory to place current working dir (Err : %s)\n",
                        strerror(errno));
        goto err;
    }
    getcwd(cwd, len);

    sprintf(buf, "./parentdir");
    fprintf(stderr, "** [%d] mkdir %s 0777\n", pid, buf);
    error = mkdir(buf, 0777);
    if (error && (errno != EEXIST))
    {
        fprintf(stderr, "!! [%d] mkdir %s failed(%s)\n", pid, buf,
                                                         strerror(errno));
        goto err;
    }

    sprintf(buf, "./parentdir/sub.0");
    fprintf(stderr, "** [%d] mkdir %s 0777\n", pid, buf);
    error = mkdir(buf, 0777);
    if (error && (errno != EEXIST)) {
        fprintf(stderr, "!! [%d] mkdir %s failed(%s)\n", pid, buf,
                                                         strerror(errno));
        goto err;
    }
    fprintf(stderr, "** [%d] chdir %s\n", pid, buf);
    error = chdir(buf);
    if (error) {
        fprintf(stderr, "!! [%d] chdir %s failed(%s)\n", pid, buf,
                                                        strerror(errno));
        goto err;;
    }

    sprintf(buf, "%s/parentdir", cwd);
    fprintf(stderr, "** [%d] rmdir %s\n", pid, buf);
    if (rmdir(buf))
        fprintf(stderr, "!! [%d] rmdir %s failed(%s)\n", pid, buf,
                                                        strerror(errno));

    errno = 0;
    error = stat(buf, &st);
    fprintf(stderr, "!! [%d] stat() %s %s\n", pid, buf,
                                              strerror(errno));

    sprintf(buf, "%s/parentdir/sub.1", cwd);
    fprintf(stderr, "** [%d] mkdir %s\n", pid, buf);
    error = mkdir(buf, 0777);
    if (error && (errno != EEXIST)) {
        fprintf(stderr, "!! [%d] mkdir %s failed(%s)\n", pid, buf,
                                                        strerror(errno));
        goto err;
    }

    return 0;

err:

    if (cwd)
        free(cwd);
    if (buf)
        free(buf);
    return 1;
}

A message that is not in the archive (sent off-list or not yet received): [email protected]

#4 lore raw

Does this patch which is in recent kernels change the behavior:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/fs/cifs?id=897fba1172d637d344f009d700f7eb8a1fa262f1

Quoted 82 lines · Bastian Arjun Shajit

Hi,

We encountered the following error or unexpected behaviour when following the steps given below:

1. Mount the remote share exported by either windows or samba using the following command:
sudo mount -t cifs -o port=445,vers=2.1,username=<username>,password=password,noperm,actimeo=0 //<IP>/SH1 /mnt/test && cd /mnt/test

2. Run the attached program on the mounted share. You should see the following output:

**bastian@gutbark-UX32VD:/mnt/test$ /KVMstorage/cifs_dir_bug
** [4428] mkdir ./parentdir 0777
** [4428] mkdir ./parentdir/sub.0 0777
** [4428] chdir ./parentdir/sub.0
** [4428] rmdir /mnt/test/parentdir
!! [4428] stat() /mnt/test/parentdir Success
** [4428] mkdir /mnt/test/parentdir/sub.1
!! [4428] mkdir /mnt/test/parentdir/sub.1 failed(No such file or directory)

You can see from the above logs, stat of parentdir is successful but creating a new child directory under the parent fails.

The attached program does the following:
a. Create a parent directory
b. Create a sub-directory under the parent.
c. Change dir to sub-directory
d. Now delete the parent directory using absolute path from the cifs client using "rmdir".

The POSIX behaviour for rmdir() is that if there are entries other than "." and ".." it must return ENOTEMPTY error. But as per SMB2 protocol specification, we delete a directory by:
a. Open directory with "Delete on Close" Flag set in the "CreateOptions" field of the SMB2 CREATE request.
b. Close the open handle returned in the response for the previous request.

As per SMB2 specification, the SMB2 close will always return NT status STATUS_SUCCESS for removing the directory even if the directory has child entries, but the server does not delete the directory itself.

4. Manually running "tree" on the mounted share shows the following:

bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
1 directory, 0 files

We clearly see above that the parent directory does not show any child directories.

5.Now we unmount and mount the remote share again

bastian@gutbark-UX32VD:/mnt/test$ cd / && sudo umount /mnt/test
bastian@gutbark-UX32VD:/KVMstorage/$ sudo mount -t cifs -o
port=445,vers=2.1,username=<Username>,password=password,noperm,actimeo=0
//<IP>/SH1 /mnt/test && cd /mnt/test
bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
           |__ sub.0
2 directories, 0 files//

As you can see, remounting the remote share now displays a subdirectory which was not displayed in the earlier mount cycle.

We used the following test setup for reproducing the above said issue:
1. Cifs client: Version = 2.06, Linux versions: Ubuntu, 3.19.8-ckt5 & 3.16.0-49-generic
2. Server: Windows 8.1 pro, Windows 7, Samba 4.1.6-Ubuntu.
3. Reproducible only on SMB2 protocol version.

The issue was reproducible always on WIndows SMB server whereas on Samba server we were able to reproduce 1/2 times.

We ran the same tests on CIFS client version: 2.08, Linux versions 4.4 and 4.5 and we were unable to reproduce the issue.

Br,
Bastian

Signature · 3 lines
Thanks,

Steve

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): 6d5f3758e7b946a9a6d9e629cac722a5-SUpINa3nmyRMOBdrsOXnL7H8+uLQl0YSwzqs5ZKRSiY@public.gmane.org

author
#7 lore raw

Hi Steve,

Quoted 3 lines · Steve French

Does this patch which is in recent kernels change the behavior:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/fs/cifs?id=897fba1172d637d344f009d700f7eb8a1fa262f1

I think this patch might solve the problem. I will test and update asap.

Br,
Bastian

Quoted 87 lines
Quoted 82 lines · Bastian Arjun Shajit

Hi,

We encountered the following error or unexpected behaviour when following the steps given below:

1. Mount the remote share exported by either windows or samba using the following command:
sudo mount -t cifs -o port=445,vers=2.1,username=<username>,password=password,noperm,actimeo=0 //<IP>/SH1 /mnt/test && cd /mnt/test

2. Run the attached program on the mounted share. You should see the following output:

**bastian@gutbark-UX32VD:/mnt/test$ /KVMstorage/cifs_dir_bug
** [4428] mkdir ./parentdir 0777
** [4428] mkdir ./parentdir/sub.0 0777
** [4428] chdir ./parentdir/sub.0
** [4428] rmdir /mnt/test/parentdir
!! [4428] stat() /mnt/test/parentdir Success
** [4428] mkdir /mnt/test/parentdir/sub.1
!! [4428] mkdir /mnt/test/parentdir/sub.1 failed(No such file or directory)

You can see from the above logs, stat of parentdir is successful but creating a new child directory under the parent fails.

The attached program does the following:
a. Create a parent directory
b. Create a sub-directory under the parent.
c. Change dir to sub-directory
d. Now delete the parent directory using absolute path from the cifs client using "rmdir".

The POSIX behaviour for rmdir() is that if there are entries other than "." and ".." it must return ENOTEMPTY error. But as per SMB2 protocol specification, we delete a directory by:
a. Open directory with "Delete on Close" Flag set in the "CreateOptions" field of the SMB2 CREATE request.
b. Close the open handle returned in the response for the previous request.

As per SMB2 specification, the SMB2 close will always return NT status STATUS_SUCCESS for removing the directory even if the directory has child entries, but the server does not delete the directory itself.

4. Manually running "tree" on the mounted share shows the following:

bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
1 directory, 0 files

We clearly see above that the parent directory does not show any child directories.

5.Now we unmount and mount the remote share again

bastian@gutbark-UX32VD:/mnt/test$ cd / && sudo umount /mnt/test
bastian@gutbark-UX32VD:/KVMstorage/$ sudo mount -t cifs -o
port=445,vers=2.1,username=<Username>,password=password,noperm,actimeo=0
//<IP>/SH1 /mnt/test && cd /mnt/test
bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
            |__ sub.0
2 directories, 0 files//

As you can see, remounting the remote share now displays a subdirectory which was not displayed in the earlier mount cycle.

We used the following test setup for reproducing the above said issue:
1. Cifs client: Version = 2.06, Linux versions: Ubuntu, 3.19.8-ckt5 & 3.16.0-49-generic
2. Server: Windows 8.1 pro, Windows 7, Samba 4.1.6-Ubuntu.
3. Reproducible only on SMB2 protocol version.

The issue was reproducible always on WIndows SMB server whereas on Samba server we were able to reproduce 1/2 times.

We ran the same tests on CIFS client version: 2.08, Linux versions 4.4 and 4.5 and we were unable to reproduce the issue.

Br,
Bastian

A message that is not in the archive (sent off-list or not yet received): [email protected]

A message that is not in the archive (sent off-list or not yet received): f035ef339da04044b0034211ad937f8e-SUpINa3nmyS6oL0Ed9aWIrH8+uLQl0YSwzqs5ZKRSiY@public.gmane.org

author
#10 lore raw

Hi Steve,

Quoted 7 lines · Shajit Bastian

Hi Steve,

Quoted 3 lines · Steve French

Does this patch which is in recent kernels change the behavior:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/fs/cifs?id=897fba1172d637d344f009d700f7eb8a1fa262f1

I think this patch might solve the problem. I will test and update asap.

I applied the patch and tested again. This solves the problem. Thanks you.

Br,
Bastian

Quoted 92 lines

Br,
Bastian

Quoted 78 lines
Quoted 76 lines · Bastian Arjun Shajit

Hi,

We encountered the following error or unexpected behaviour when following the steps given below:

1. Mount the remote share exported by either windows or samba using the following command:
sudo mount -t cifs -o port=445,vers=2.1,username=<username>,password=password,noperm,actimeo=0 //<IP>/SH1 /mnt/test && cd /mnt/test

2. Run the attached program on the mounted share. You should see the following output:

**bastian@gutbark-UX32VD:/mnt/test$ /KVMstorage/cifs_dir_bug
** [4428] mkdir ./parentdir 0777
** [4428] mkdir ./parentdir/sub.0 0777
** [4428] chdir ./parentdir/sub.0
** [4428] rmdir /mnt/test/parentdir
!! [4428] stat() /mnt/test/parentdir Success
** [4428] mkdir /mnt/test/parentdir/sub.1
!! [4428] mkdir /mnt/test/parentdir/sub.1 failed(No such file or directory)

You can see from the above logs, stat of parentdir is successful but creating a new child directory under the parent fails.

The attached program does the following:
a. Create a parent directory
b. Create a sub-directory under the parent.
c. Change dir to sub-directory
d. Now delete the parent directory using absolute path from the cifs client using "rmdir".

The POSIX behaviour for rmdir() is that if there are entries other than "." and ".." it must return ENOTEMPTY error. But as per SMB2 protocol specification, we delete a directory by:
a. Open directory with "Delete on Close" Flag set in the "CreateOptions" field of the SMB2 CREATE request.
b. Close the open handle returned in the response for the previous request.

As per SMB2 specification, the SMB2 close will always return NT status STATUS_SUCCESS for removing the directory even if the directory has child entries, but the server does not delete the directory itself.

4. Manually running "tree" on the mounted share shows the following:

bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
1 directory, 0 files

We clearly see above that the parent directory does not show any child directories.

5.Now we unmount and mount the remote share again

bastian@gutbark-UX32VD:/mnt/test$ cd / && sudo umount /mnt/test
bastian@gutbark-UX32VD:/KVMstorage/$ sudo mount -t cifs -o
port=445,vers=2.1,username=<Username>,password=password,noperm,actimeo=0
//<IP>/SH1 /mnt/test && cd /mnt/test
bastian@gutbark-UX32VD:/mnt/test$ tree
.
|__parentdir
             |__ sub.0
2 directories, 0 files//

As you can see, remounting the remote share now displays a subdirectory which was not displayed in the earlier mount cycle.

We used the following test setup for reproducing the above said issue:
1. Cifs client: Version = 2.06, Linux versions: Ubuntu, 3.19.8-ckt5 & 3.16.0-49-generic
2. Server: Windows 8.1 pro, Windows 7, Samba 4.1.6-Ubuntu.
3. Reproducible only on SMB2 protocol version.

The issue was reproducible always on WIndows SMB server whereas on Samba server we were able to reproduce 1/2 times.

Quoted 7 lines
Quoted 6 lines

We ran the same tests on CIFS client version: 2.08, Linux versions 4.4 and 4.5 and we were unable to reproduce the issue.

Br,
Bastian

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