BKL: Remove BKL from ncpfs

Dozen of changes in ncpfs to provide some locking other than BKL.

In readdir cache unlock and mark complete first page as last operation,
so it can be used for synchronization, as code intended.

When updating dentry name on case insensitive filesystems do at least
some basic locking...

Hold i_mutex when updating inode fields.

Push some ncp_conn_is_valid down to ncp_request.  Connection can become
invalid at any moment, and fewer error code paths to test the better.

Use i_size_{read,write} to modify file size.

Set inode's backing_dev_info as ncpfs has its own special bdi.

In ioctl unbreak ioctls invoked on filesystem mounted 'ro' - tests are
for inode writeable or owner match, but were turned to filesystem
writeable and inode writeable or owner match.  Also collect all permission
checks in single place.

Add some locking, and remove comments saying that it would be cool to
add some locks to the code.

Constify some pointers.

Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 56 insertions, 45 deletions

diff --git a/fs/ncpfs/ncplib_kernel.c b/fs/ncpfs/ncplib_kernel.c
index 0ec6237a5970..a95615a0b6ac 100644
--- a/fs/ncpfs/ncplib_kernel.c
+++ b/fs/ncpfs/ncplib_kernel.c
@@ -107,17 +107,17 @@ ncp_reply_data(struct ncp_server *server, int offset)
         return &(server->packet[sizeof(struct ncp_reply_header) + offset]);
 }
 
-static inline u8 BVAL(void *data)
+static inline u8 BVAL(const void *data)
 {
-        return *(u8 *)data;
+        return *(const u8 *)data;
 }
 
 static u8 ncp_reply_byte(struct ncp_server *server, int offset)
 {
-        return *(u8 *)ncp_reply_data(server, offset);
+        return *(const u8 *)ncp_reply_data(server, offset);
 }
 
-static inline u16 WVAL_LH(void *data)
+static inline u16 WVAL_LH(const void *data)
 {
         return get_unaligned_le16(data);
 }
@@ -134,7 +134,7 @@ ncp_reply_be16(struct ncp_server *server, int offset)
         return get_unaligned_be16(ncp_reply_data(server, offset));
 }
 
-static inline u32 DVAL_LH(void *data)
+static inline u32 DVAL_LH(const void *data)
 {
         return get_unaligned_le32(data);
 }
@@ -349,9 +349,9 @@ int ncp_dirhandle_free(struct ncp_server* server, __u8 dirhandle) {
         return result;
 }
 
-void ncp_extract_file_info(void *structure, struct nw_info_struct *target)
+void ncp_extract_file_info(const void *structure, struct nw_info_struct *target)
 {
-        __u8 *name_len;
+        const __u8 *name_len;
         const int info_struct_size = offsetof(struct nw_info_struct, nameLen);
 
         memcpy(target, structure, info_struct_size);
@@ -364,7 +364,7 @@ void ncp_extract_file_info(void *structure, struct nw_info_struct *target)
 }
 
 #ifdef CONFIG_NCPFS_NFS_NS
-static inline void ncp_extract_nfs_info(unsigned char *structure,
+static inline void ncp_extract_nfs_info(const unsigned char *structure,
                                  struct nw_nfs_info *target)
 {
         target->mode = DVAL_LH(structure);
@@ -417,7 +417,7 @@ int ncp_obtain_nfs_info(struct ncp_server *server,
  * Returns information for a (one-component) name relative to
  * the specified directory.
  */
-int ncp_obtain_info(struct ncp_server *server, struct inode *dir, char *path,
+int ncp_obtain_info(struct ncp_server *server, struct inode *dir, const char *path,
                         struct nw_info_struct *target)
 {
         __u8  volnum = NCP_FINFO(dir)->volNumber;
@@ -452,16 +452,16 @@ out:
 #ifdef CONFIG_NCPFS_NFS_NS
 static int
 ncp_obtain_DOS_dir_base(struct ncp_server *server,
-                __u8 volnum, __le32 dirent,
-                char *path, /* At most 1 component */
+                __u8 ns, __u8 volnum, __le32 dirent,
+                const char *path, /* At most 1 component */
                 __le32 *DOS_dir_base)
 {
         int result;
 
         ncp_init_request(server);
         ncp_add_byte(server, 6); /* subfunction */
-        ncp_add_byte(server, server->name_space[volnum]);
-        ncp_add_byte(server, server->name_space[volnum]);
+        ncp_add_byte(server, ns);
+        ncp_add_byte(server, ns);
         ncp_add_word(server, cpu_to_le16(0x8006)); /* get all */
         ncp_add_dword(server, RIM_DIRECTORY);
         ncp_add_handle_path(server, volnum, dirent, 1, path);
@@ -523,10 +523,27 @@ ncp_get_known_namespace(struct ncp_server *server, __u8 volume)
 #endif  /* defined(CONFIG_NCPFS_OS2_NS) || defined(CONFIG_NCPFS_NFS_NS) */
 }
 
+int
+ncp_update_known_namespace(struct ncp_server *server, __u8 volume, int *ret_ns)
+{
+        int ns = ncp_get_known_namespace(server, volume);
+
+        if (ret_ns)
+                *ret_ns = ns;
+
+        DPRINTK("lookup_vol: namespace[%d] = %d\n",
+                volume, server->name_space[volume]);
+
+        if (server->name_space[volume] == ns)
+                return 0;
+        server->name_space[volume] = ns;
+        return 1;
+}
+
 static int
 ncp_ObtainSpecificDirBase(struct ncp_server *server,
                 __u8 nsSrc, __u8 nsDst, __u8 vol_num, __le32 dir_base,
-                char *path, /* At most 1 component */
+                const char *path, /* At most 1 component */
                 __le32 *dirEntNum, __le32 *DosDirNum)
 {
         int result;
@@ -560,14 +577,13 @@ ncp_mount_subdir(struct ncp_server *server,
 {
         int dstNS;
         int result;
-        
-        dstNS = ncp_get_known_namespace(server, volNumber);
+
+        ncp_update_known_namespace(server, volNumber, &dstNS);
         if ((result = ncp_ObtainSpecificDirBase(server, srcNS, dstNS, volNumber, 
                                       dirEntNum, NULL, newDirEnt, newDosEnt)) != 0)
         {
                 return result;
         }
-        server->name_space[volNumber] = dstNS;
         *volume = volNumber;
         server->m.mounted_vol[1] = 0;
         server->m.mounted_vol[0] = 'X';
@@ -575,11 +591,10 @@ ncp_mount_subdir(struct ncp_server *server,
 }
 
 int 
-ncp_get_volume_root(struct ncp_server *server, const char *volname,
-                    __u32* volume, __le32* dirent, __le32* dosdirent)
+ncp_get_volume_root(struct ncp_server *server,
+                    const char *volname, __u32* volume, __le32* dirent, __le32* dosdirent)
 {
         int result;
-        __u8 volnum;
 
         DPRINTK("ncp_get_volume_root: looking up vol %s\n", volname);
 
@@ -601,21 +616,14 @@ ncp_get_volume_root(struct ncp_server *server, const char *volname,
                 return result;
         }
         *dirent = *dosdirent = ncp_reply_dword(server, 4);
-        volnum = ncp_reply_byte(server, 8);
+        *volume = ncp_reply_byte(server, 8);
         ncp_unlock_server(server);
-        *volume = volnum;
-
-        server->name_space[volnum] = ncp_get_known_namespace(server, volnum);
-
-        DPRINTK("lookup_vol: namespace[%d] = %d\n",
-                volnum, server->name_space[volnum]);
-
         return 0;
 }
 
 int
-ncp_lookup_volume(struct ncp_server *server, const char *volname,
-                  struct nw_info_struct *target)
+ncp_lookup_volume(struct ncp_server *server,
+                  const char *volname, struct nw_info_struct *target)
 {
         int result;
 
@@ -625,6 +633,7 @@ ncp_lookup_volume(struct ncp_server *server, const char *volname,
         if (result) {
                 return result;
         }
+        ncp_update_known_namespace(server, target->volNumber, NULL);
         target->nameLen = strlen(volname);
         memcpy(target->entryName, volname, target->nameLen+1);
         target->attributes = aDIR;
@@ -676,8 +685,8 @@ int ncp_modify_nfs_info(struct ncp_server *server, __u8 volnum, __le32 dirent,
 {
         int result = 0;
 
+        ncp_init_request(server);
         if (server->name_space[volnum] == NW_NS_NFS) {
-                ncp_init_request(server);
                 ncp_add_byte(server, 25);       /* subfunction */
                 ncp_add_byte(server, server->name_space[volnum]);
                 ncp_add_byte(server, NW_NS_NFS);
@@ -690,8 +699,8 @@ int ncp_modify_nfs_info(struct ncp_server *server, __u8 volnum, __le32 dirent,
                 ncp_add_dword_lh(server, 1);    /* nlinks */
                 ncp_add_dword_lh(server, rdev);
                 result = ncp_request(server, 87);
-                ncp_unlock_server(server);
         }
+        ncp_unlock_server(server);
         return result;
 }
 #endif
@@ -700,7 +709,7 @@ int ncp_modify_nfs_info(struct ncp_server *server, __u8 volnum, __le32 dirent,
 static int
 ncp_DeleteNSEntry(struct ncp_server *server,
                   __u8 have_dir_base, __u8 volnum, __le32 dirent,
-                  char* name, __u8 ns, __le16 attr)
+                  const char* name, __u8 ns, __le16 attr)
 {
         int result;
 
@@ -734,23 +743,25 @@ ncp_del_file_or_subdir2(struct ncp_server *server,
 
 int
 ncp_del_file_or_subdir(struct ncp_server *server,
-                       struct inode *dir, char *name)
+                       struct inode *dir, const char *name)
 {
         __u8  volnum = NCP_FINFO(dir)->volNumber;
         __le32 dirent = NCP_FINFO(dir)->dirEntNum;
+        int name_space;
 
+        name_space = server->name_space[volnum];
 #ifdef CONFIG_NCPFS_NFS_NS
-        if (server->name_space[volnum]==NW_NS_NFS)
+        if (name_space == NW_NS_NFS)
         {
                 int result;
  
-                result=ncp_obtain_DOS_dir_base(server, volnum, dirent, name, &dirent);
+                result=ncp_obtain_DOS_dir_base(server, name_space, volnum, dirent, name, &dirent);
                 if (result) return result;
-                return ncp_DeleteNSEntry(server, 1, volnum, dirent, NULL, NW_NS_DOS, cpu_to_le16(0x8006));
+                name = NULL;
+                name_space = NW_NS_DOS;
         }
-        else
 #endif  /* CONFIG_NCPFS_NFS_NS */
-                return ncp_DeleteNSEntry(server, 1, volnum, dirent, name, server->name_space[volnum], cpu_to_le16(0x8006));
+        return ncp_DeleteNSEntry(server, 1, volnum, dirent, name, name_space, cpu_to_le16(0x8006));
 }
 
 static inline void ConvertToNWfromDWORD(__u16 v0, __u16 v1, __u8 ret[6])
@@ -765,7 +776,7 @@ static inline void ConvertToNWfromDWORD(__u16 v0, __u16 v1, __u8 ret[6])
 /* If both dir and name are NULL, then in target there's already a
    looked-up entry that wants to be opened. */
 int ncp_open_create_file_or_subdir(struct ncp_server *server,
-                                   struct inode *dir, char *name,
+                                   struct inode *dir, const char *name,
                                    int open_create_mode,
                                    __le32 create_attributes,
                                    __le16 desired_acc_rights,
@@ -890,8 +901,8 @@ int ncp_search_for_fileset(struct ncp_server *server,
 
 static int
 ncp_RenameNSEntry(struct ncp_server *server,
-                  struct inode *old_dir, char *old_name, __le16 old_type,
-                  struct inode *new_dir, char *new_name)
+                  struct inode *old_dir, const char *old_name, __le16 old_type,
+                  struct inode *new_dir, const char *new_name)
 {
         int result = -EINVAL;
 
@@ -929,8 +940,8 @@ out:
 }
 
 int ncp_ren_or_mov_file_or_subdir(struct ncp_server *server,
-                                struct inode *old_dir, char *old_name,
-                                struct inode *new_dir, char *new_name)
+                                struct inode *old_dir, const char *old_name,
+                                struct inode *new_dir, const char *new_name)
 {
         int result;
         __le16 old_type = cpu_to_le16(0x06);
@@ -958,7 +969,7 @@ int
 ncp_read_kernel(struct ncp_server *server, const char *file_id,
              __u32 offset, __u16 to_read, char *target, int *bytes_read)
 {
-        char *source;
+        const char *source;
         int result;
 
         ncp_init_request(server);