• David Howells's avatar
    vfs: Introduce fs_context, switch vfs_kern_mount() to it. · 9bc61ab1
    David Howells authored
    Introduce a filesystem context concept to be used during superblock
    creation for mount and superblock reconfiguration for remount.  This is
    allocated at the beginning of the mount procedure and into it is placed:
    
     (1) Filesystem type.
    
     (2) Namespaces.
    
     (3) Source/Device names (there may be multiple).
    
     (4) Superblock flags (SB_*).
    
     (5) Security details.
    
     (6) Filesystem-specific data, as set by the mount options.
    
    Accessor functions are then provided to set up a context, parameterise it
    from monolithic mount data (the data page passed to mount(2)) and tear it
    down again.
    
    A legacy wrapper is provided that implements what will be the basic
    operations, wrapping access to filesystems that aren't yet aware of the
    fs_context.
    
    Finally, vfs_kern_mount() is changed to make use of the fs_context and
    mount_fs() is replaced by vfs_get_tree(), called from vfs_kern_mount().
    [AV -- add missing kstrdup()]
    [AV -- put_cred() can be unconditional - fc->cred can't be NULL]
    [AV -- take legacy_validate() contents into legacy_parse_monolithic()]
    [AV -- merge KERNEL_MOUNT and USER_MOUNT]
    [AV -- don't unlock superblock on success return from vfs_get_tree()]
    [AV -- kill 'reference' argument of init_fs_context()]
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    Co-developed-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    9bc61ab1
namespace.c 86.3 KB