VFS: Split DCACHE_FILE_TYPE into regular and special types

Split DCACHE_FILE_TYPE into DCACHE_REGULAR_TYPE (dentries representing regular
files) and DCACHE_SPECIAL_TYPE (representing blockdev, chardev, FIFO and
socket files).

d_is_reg() and d_is_special() are added to detect these subtypes and
d_is_file() is left as the union of the two.

This allows a number of places that use S_ISREG(dentry->d_inode->i_mode) to
use d_is_reg(dentry) instead.

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

2 files changed, 27 insertions, 8 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index e33a0934efd7..c71e3732e53b 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1677,7 +1677,7 @@ EXPORT_SYMBOL(d_set_fallthru);
 
 static unsigned d_flags_for_inode(struct inode *inode)
 {
-        unsigned add_flags = DCACHE_FILE_TYPE;
+        unsigned add_flags = DCACHE_REGULAR_TYPE;
 
         if (!inode)
                 return DCACHE_MISS_TYPE;
@@ -1690,13 +1690,21 @@ static unsigned d_flags_for_inode(struct inode *inode)
                         else
                                 inode->i_opflags |= IOP_LOOKUP;
                 }
-        } else if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
-                if (unlikely(inode->i_op->follow_link))
+                goto type_determined;
+        }
+
+        if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
+                if (unlikely(inode->i_op->follow_link)) {
                         add_flags = DCACHE_SYMLINK_TYPE;
-                else
-                        inode->i_opflags |= IOP_NOFOLLOW;
+                        goto type_determined;
+                }
+                inode->i_opflags |= IOP_NOFOLLOW;
         }
 
+        if (unlikely(!S_ISREG(inode->i_mode)))
+                add_flags = DCACHE_SPECIAL_TYPE;
+
+type_determined:
         if (unlikely(IS_AUTOMOUNT(inode)))
                 add_flags |= DCACHE_NEED_AUTOMOUNT;
         return add_flags;
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 728f5d31b5e6..d8358799c594 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -219,8 +219,9 @@ struct dentry_operations {
 #define DCACHE_WHITEOUT_TYPE            0x00100000 /* Whiteout dentry (stop pathwalk) */
 #define DCACHE_DIRECTORY_TYPE           0x00200000 /* Normal directory */
 #define DCACHE_AUTODIR_TYPE             0x00300000 /* Lookupless directory (presumed automount) */
-#define DCACHE_SYMLINK_TYPE             0x00400000 /* Symlink (or fallthru to such) */
-#define DCACHE_FILE_TYPE                0x00500000 /* Other file type (or fallthru to such) */
+#define DCACHE_REGULAR_TYPE             0x00400000 /* Regular file type (or fallthru to such) */
+#define DCACHE_SPECIAL_TYPE             0x00500000 /* Other file type (or fallthru to such) */
+#define DCACHE_SYMLINK_TYPE             0x00600000 /* Symlink (or fallthru to such) */
 
 #define DCACHE_MAY_FREE                 0x00800000
 #define DCACHE_FALLTHRU                 0x01000000 /* Fall through to lower layer */
@@ -455,9 +456,19 @@ static inline bool d_is_symlink(const struct dentry *dentry)
         return __d_entry_type(dentry) == DCACHE_SYMLINK_TYPE;
 }
 
+static inline bool d_is_reg(const struct dentry *dentry)
+{
+        return __d_entry_type(dentry) == DCACHE_REGULAR_TYPE;
+}
+
+static inline bool d_is_special(const struct dentry *dentry)
+{
+        return __d_entry_type(dentry) == DCACHE_SPECIAL_TYPE;
+}
+
 static inline bool d_is_file(const struct dentry *dentry)
 {
-        return __d_entry_type(dentry) == DCACHE_FILE_TYPE;
+        return d_is_reg(dentry) || d_is_special(dentry);
 }
 
 static inline bool d_is_negative(const struct dentry *dentry)