src/patches/suse-2.6.27.31/patches.suse/fs-knows-MAY_APPEND.diff

   1 From: Andreas Gruenbacher <agruen@suse.de>
   2 Subject: Allow filesystems to handle MAY_APPEND
   3
   4 The MS_WITHAPPEND super_block flag tells the vfs that the permission
   5 inode operation understands the MAY_APPEND flag. This is required for
   6 implementing permission models which go beyond the traditional UNIX
   7 semantics.
   8
   9 If a filesystem does not set the flag, the behavior is unchanged.
  10
  11 Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
  12
  13 ---
  14  fs/namei.c         |    6 +++++-
  15  include/linux/fs.h |    2 ++
  16  2 files changed, 7 insertions(+), 1 deletion(-)
  17
  18 --- a/fs/namei.c
  19 +++ b/fs/namei.c
  20 @@ -230,6 +230,7 @@ int generic_permission(struct inode *ino
  21  int inode_permission(struct inode *inode, int mask)
  22  {
  23         int retval;
  24 +       int submask = mask;
  25
  26         if (mask & MAY_WRITE) {
  27                 umode_t mode = inode->i_mode;
  28 @@ -248,9 +249,12 @@ int inode_permission(struct inode *inode
  29                         return -EACCES;
  30         }
  31
  32 +       if (!IS_WITHAPPEND(inode))
  33 +               submask &= ~MAY_APPEND;
  34 +
  35         /* Ordinary permission routines do not understand MAY_APPEND. */
  36         if (inode->i_op && inode->i_op->permission) {
  37 -               retval = inode->i_op->permission(inode, mask);
  38 +               retval = inode->i_op->permission(inode, submask);
  39                 if (!retval) {
  40                         /*
  41                          * Exec permission on a regular file is denied if none
  42 --- a/include/linux/fs.h
  43 +++ b/include/linux/fs.h
  44 @@ -133,6 +133,7 @@ extern int dir_notify_enable;
  45  #define MS_RELATIME    (1<<21) /* Update atime relative to mtime/ctime. */
  46  #define MS_KERNMOUNT   (1<<22) /* this is a kern_mount call */
  47  #define MS_I_VERSION   (1<<23) /* Update inode I_version field */
  48 +#define MS_WITHAPPEND  (1<<24) /* iop->permission() understands MAY_APPEND */
  49  #define MS_ACTIVE      (1<<30)
  50  #define MS_NOUSER      (1<<31)
  51
  52 @@ -183,6 +184,7 @@ extern int dir_notify_enable;
  53  #define IS_MANDLOCK(inode)     __IS_FLG(inode, MS_MANDLOCK)
  54  #define IS_NOATIME(inode)   __IS_FLG(inode, MS_RDONLY|MS_NOATIME)
  55  #define IS_I_VERSION(inode)   __IS_FLG(inode, MS_I_VERSION)
  56 +#define IS_WITHAPPEND(inode)   __IS_FLG(inode, MS_WITHAPPEND)
  57
  58  #define IS_NOQUOTA(inode)      ((inode)->i_flags & S_NOQUOTA)
  59  #define IS_APPEND(inode)       ((inode)->i_flags & S_APPEND)