VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)

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: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 8 insertions, 8 deletions

diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index 9385560..f21b6fb 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -252,7 +252,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de
 	if (!f->inocache)
 		return -EIO;
 
-	if (S_ISDIR(old_dentry->d_inode->i_mode))
+	if (d_is_dir(old_dentry))
 		return -EPERM;
 
 	/* XXX: This is ugly */
@@ -772,7 +772,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
 	 */
 	if (new_dentry->d_inode) {
 		victim_f = JFFS2_INODE_INFO(new_dentry->d_inode);
-		if (S_ISDIR(new_dentry->d_inode->i_mode)) {
+		if (d_is_dir(new_dentry)) {
 			struct jffs2_full_dirent *fd;
 
 			mutex_lock(&victim_f->sem);
@@ -807,7 +807,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
 
 	if (victim_f) {
 		/* There was a victim. Kill it off nicely */
-		if (S_ISDIR(new_dentry->d_inode->i_mode))
+		if (d_is_dir(new_dentry))
 			clear_nlink(new_dentry->d_inode);
 		else
 			drop_nlink(new_dentry->d_inode);
@@ -815,7 +815,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
 		   inode which didn't exist. */
 		if (victim_f->inocache) {
 			mutex_lock(&victim_f->sem);
-			if (S_ISDIR(new_dentry->d_inode->i_mode))
+			if (d_is_dir(new_dentry))
 				victim_f->inocache->pino_nlink = 0;
 			else
 				victim_f->inocache->pino_nlink--;
@@ -825,7 +825,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
 
 	/* If it was a directory we moved, and there was no victim,
 	   increase i_nlink on its new parent */
-	if (S_ISDIR(old_dentry->d_inode->i_mode) && !victim_f)
+	if (d_is_dir(old_dentry) && !victim_f)
 		inc_nlink(new_dir_i);
 
 	/* Unlink the original */
@@ -839,7 +839,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
 		struct jffs2_inode_info *f = JFFS2_INODE_INFO(old_dentry->d_inode);
 		mutex_lock(&f->sem);
 		inc_nlink(old_dentry->d_inode);
-		if (f->inocache && !S_ISDIR(old_dentry->d_inode->i_mode))
+		if (f->inocache && !d_is_dir(old_dentry))
 			f->inocache->pino_nlink++;
 		mutex_unlock(&f->sem);
 
@@ -852,7 +852,7 @@ static int jffs2_rename (struct inode *old_dir_i, struct dentry *old_dentry,
 		return ret;
 	}
 
-	if (S_ISDIR(old_dentry->d_inode->i_mode))
+	if (d_is_dir(old_dentry))
 		drop_nlink(old_dir_i);
 
 	new_dir_i->i_mtime = new_dir_i->i_ctime = old_dir_i->i_mtime = old_dir_i->i_ctime = ITIME(now);
diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index 0918f0e..3d76f28 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -138,7 +138,7 @@ static struct dentry *jffs2_get_parent(struct dentry *child)
 	struct jffs2_inode_info *f;
 	uint32_t pino;
 
-	BUG_ON(!S_ISDIR(child->d_inode->i_mode));
+	BUG_ON(!d_is_dir(child));
 
 	f = JFFS2_INODE_INFO(child->d_inode);