6.15-stable review patch. If anyone has any objections, please let me know.
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From: Steve French stfrench@microsoft.com
commit 8767cb3fbd514c4cf85b4f516ca30388e846f540 upstream.
Some servers (including Samba), support the SMB3.1.1 POSIX Extensions (which use reparse points for handling special files) but do not properly advertise file system attribute FILE_SUPPORTS_REPARSE_POINTS. Although we don't check for this attribute flag when querying special file information, we do check it when creating special files which causes them to fail unnecessarily. If we have negotiated SMB3.1.1 POSIX Extensions with the server we can expect the server to support creating special files via reparse points, and even if the server fails the operation due to really forbidding creating special files, then it should be no problem and is more likely to return a more accurate rc in any case (e.g. EACCES instead of EOPNOTSUPP).
Allow creating special files as long as the server supports either reparse points or the SMB3.1.1 POSIX Extensions (note that if the "sfu" mount option is specified it uses a different way of storing special files that does not rely on reparse points).
Cc: stable@vger.kernel.org Fixes: 6c06be908ca19 ("cifs: Check if server supports reparse points before using them") Acked-by: Ralph Boehme slow@samba.org Acked-by: Paulo Alcantara (Red Hat) pc@manguebit.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/client/smb2inode.c | 3 ++- fs/smb/client/smb2ops.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-)
--- a/fs/smb/client/smb2inode.c +++ b/fs/smb/client/smb2inode.c @@ -1346,7 +1346,8 @@ struct inode *smb2_get_reparse_inode(str * empty object on the server. */ if (!(le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS)) - return ERR_PTR(-EOPNOTSUPP); + if (!tcon->posix_extensions) + return ERR_PTR(-EOPNOTSUPP);
oparms = CIFS_OPARMS(cifs_sb, tcon, full_path, SYNCHRONIZE | DELETE | --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -5246,7 +5246,8 @@ static int smb2_make_node(unsigned int x if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) { rc = cifs_sfu_make_node(xid, inode, dentry, tcon, full_path, mode, dev); - } else if (le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS) { + } else if ((le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS) + || (tcon->posix_extensions)) { rc = smb2_mknod_reparse(xid, inode, dentry, tcon, full_path, mode, dev); }