• David Howells's avatar
    VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) · e36cb0b8
    David Howells authored
    Convert the following where appropriate:
    
     (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).
    
     (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).
    
     (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry).  This is actually more
         complicated than it appears as some calls should be converted to
         d_can_lookup() instead.  The difference is whether the directory in
         question is a real dir with a ->lookup op or whether it's a fake dir with
         a ->d_automount op.
    
    In some circumstances, we can subsume checks for dentry->d_inode not being
    NULL into this, provided we the code isn't in a filesystem that expects
    d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
    use d_inode() rather than d_backing_inode() to get the inode pointer).
    
    Note that the dentry type field may be set to something other than
    DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
    manages the fall-through from a negative dentry to a lower layer.  In such a
    case, the dentry type of the negative union dentry is set to the same as the
    type of the lower dentry.
    
    However, if you know d_inode is not NULL at the call site, then you can use
    the d_is_xxx() functions even in a filesystem.
    
    There is one further complication: a 0,0 chardev dentry may be labelled
    DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE.  Strictly, this was
    intended for special directory entry types that don't have attached inodes.
    
    The following perl+coccinelle script was used:
    
    use strict;
    
    my @callers;
    open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
        die "Can't grep for S_ISDIR and co. callers";
    @callers = <$fd>;
    close($fd);
    unless (@callers) {
        print "No matches\n";
        exit(0);
    }
    
    my @cocci = (
        '@@',
        'expression E;',
        '@@',
        '',
        '- S_ISLNK(E->d_inode->i_mode)',
        '+ d_is_symlink(E)',
        '',
        '@@',
        'expression E;',
        '@@',
        '',
        '- S_ISDIR(E->d_inode->i_mode)',
        '+ d_is_dir(E)',
        '',
        '@@',
        'expression E;',
        '@@',
        '',
        '- S_ISREG(E->d_inode->i_mode)',
        '+ d_is_reg(E)' );
    
    my $coccifile = "tmp.sp.cocci";
    open($fd, ">$coccifile") || die $coccifile;
    print($fd "$_\n") || die $coccifile foreach (@cocci);
    close($fd);
    
    foreach my $file (@callers) {
        chomp $file;
        print "Processing ", $file, "\n";
        system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
    	die "spatch failed";
    }
    
    [AV: overlayfs parts skipped]
    Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    e36cb0b8
namespace.c 78 KB