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>

3 files changed, 10 insertions, 10 deletions

diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index cc6a760..1c307f0 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -583,7 +583,7 @@ nfs4_reset_recoverydir(char *recdir)
 	if (status)
 		return status;
 	status = -ENOTDIR;
-	if (S_ISDIR(path.dentry->d_inode->i_mode)) {
+	if (d_is_dir(path.dentry)) {
 		strcpy(user_recovery_dirname, recdir);
 		status = 0;
 	}
@@ -1426,7 +1426,7 @@ nfsd4_client_tracking_init(struct net *net)
 	nn->client_tracking_ops = &nfsd4_legacy_tracking_ops;
 	status = kern_path(nfs4_recoverydir(), LOOKUP_FOLLOW, &path);
 	if (!status) {
-		status = S_ISDIR(path.dentry->d_inode->i_mode);
+		status = d_is_dir(path.dentry);
 		path_put(&path);
 		if (status)
 			goto do_init;
diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c
index 965b478..e9fa966 100644
--- a/fs/nfsd/nfsfh.c
+++ b/fs/nfsd/nfsfh.c
@@ -114,8 +114,8 @@ static inline __be32 check_pseudo_root(struct svc_rqst *rqstp,
 	 * We're exposing only the directories and symlinks that have to be
 	 * traversed on the way to real exports:
 	 */
-	if (unlikely(!S_ISDIR(dentry->d_inode->i_mode) &&
-		     !S_ISLNK(dentry->d_inode->i_mode)))
+	if (unlikely(!d_is_dir(dentry) &&
+		     !d_is_symlink(dentry)))
 		return nfserr_stale;
 	/*
 	 * A pseudoroot export gives permission to access only one
@@ -259,7 +259,7 @@ static __be32 nfsd_set_fh_dentry(struct svc_rqst *rqstp, struct svc_fh *fhp)
 		goto out;
 	}
 
-	if (S_ISDIR(dentry->d_inode->i_mode) &&
+	if (d_is_dir(dentry) &&
 			(dentry->d_flags & DCACHE_DISCONNECTED)) {
 		printk("nfsd: find_fh_dentry returned a DISCONNECTED directory: %pd2\n",
 				dentry);
@@ -414,7 +414,7 @@ static inline void _fh_update_old(struct dentry *dentry,
 {
 	fh->ofh_ino = ino_t_to_u32(dentry->d_inode->i_ino);
 	fh->ofh_generation = dentry->d_inode->i_generation;
-	if (S_ISDIR(dentry->d_inode->i_mode) ||
+	if (d_is_dir(dentry) ||
 	    (exp->ex_flags & NFSEXP_NOSUBTREECHECK))
 		fh->ofh_dirino = 0;
 }
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 5685c67..3685265 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -615,9 +615,9 @@ nfsd_access(struct svc_rqst *rqstp, struct svc_fh *fhp, u32 *access, u32 *suppor
 	export = fhp->fh_export;
 	dentry = fhp->fh_dentry;
 
-	if (S_ISREG(dentry->d_inode->i_mode))
+	if (d_is_reg(dentry))
 		map = nfs3_regaccess;
-	else if (S_ISDIR(dentry->d_inode->i_mode))
+	else if (d_is_dir(dentry))
 		map = nfs3_diraccess;
 	else
 		map = nfs3_anyaccess;
@@ -1402,7 +1402,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 
 		switch (createmode) {
 		case NFS3_CREATE_UNCHECKED:
-			if (! S_ISREG(dchild->d_inode->i_mode))
+			if (! d_is_reg(dchild))
 				goto out;
 			else if (truncp) {
 				/* in nfsv4, we need to treat this case a little
@@ -1615,7 +1615,7 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 	if (err)
 		goto out;
 	err = nfserr_isdir;
-	if (S_ISDIR(tfhp->fh_dentry->d_inode->i_mode))
+	if (d_is_dir(tfhp->fh_dentry))
 		goto out;
 	err = nfserr_perm;
 	if (!len)