From: Valerie Aurora <vaurora@xxxxxxxxxx>
Define the fallthru dcache flag and file system op. Mask out the
DCACHE_FALLTHRU flag on dentry creation.
Actual users and changes to lookup come in later patches.
Signed-off-by: Valerie Aurora <vaurora@xxxxxxxxxx>
---
Documentation/filesystems/vfs.txt | 6 ++++++
fs/dcache.c | 2 +-
include/linux/dcache.h | 6 ++++++
include/linux/fs.h | 2 ++
4 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index d9a43db..3335773 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -328,6 +328,7 @@ struct inode_operations {
int (*rmdir) (struct inode *,struct dentry *);
int (*mknod) (struct inode *,struct dentry *,int,dev_t);
int (*whiteout) (struct inode *, struct dentry *, struct dentry *);
+ int (*fallthru) (struct inode *, struct dentry *);
int (*rename) (struct inode *, struct dentry *,
struct inode *, struct dentry *);
int (*readlink) (struct dentry *, char __user *,int);
@@ -399,6 +400,11 @@ otherwise noted.
second is the dentry for the whiteout itself. This method
must unlink() or rmdir() the original entry if it exists.
+ fallthru: called by the readdir(2) system call on a layered file
+ system. Only required if you want to support fallthrus.
+ Fallthrus are place-holders for directory entries visible from
+ a lower level file system.
+
rename: called by the rename(2) system call to rename the object to
have the parent and name given by the second inode and dentry.
diff --git a/fs/dcache.c b/fs/dcache.c
index 1974031..41278d7 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1371,7 +1371,7 @@ static void __d_instantiate(struct dentry *dentry, struct inode *inode)
{
spin_lock(&dentry->d_lock);
if (inode) {
- dentry->d_flags &= ~DCACHE_WHITEOUT;
+ dentry->d_flags &= ~(DCACHE_WHITEOUT | DCACHE_FALLTHRU);
if (unlikely(IS_AUTOMOUNT(inode)))
dentry->d_flags |= DCACHE_NEED_AUTOMOUNT;
list_add(&dentry->d_alias, &inode->i_dentry);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 98187cf..1c4ad1b 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -208,6 +208,7 @@ struct dentry_operations {
#define DCACHE_CANT_MOUNT 0x0100
#define DCACHE_GENOCIDE 0x0200
#define DCACHE_WHITEOUT 0x0400 /* Stop lookup in a unioned file system */
+#define DCACHE_FALLTHRU 0x0800 /* Continue lookup below an opaque dir */
#define DCACHE_OP_HASH 0x1000
#define DCACHE_OP_COMPARE 0x2000
@@ -417,6 +418,11 @@ static inline int d_is_whiteout(struct dentry *dentry)
return dentry->d_flags & DCACHE_WHITEOUT;
}
+static inline int d_is_fallthru(struct dentry *dentry)
+{
+ return dentry->d_flags & DCACHE_FALLTHRU;
+}
+
static inline bool d_mountpoint(struct dentry *dentry)
{
return dentry->d_flags & DCACHE_MOUNTED;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 134b5d7..b21aed3 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -209,6 +209,7 @@ struct inodes_stat_t {
#define MS_I_VERSION (1<<23) /* Update inode I_version field */
#define MS_STRICTATIME (1<<24) /* Always perform atime updates */
#define MS_WHITEOUT (1<<25) /* FS supports whiteout filetype */
+#define MS_FALLTHRU (1<<26) /* FS supports fallthru filetype */
#define MS_NOSEC (1<<28)
#define MS_BORN (1<<29)
#define MS_ACTIVE (1<<30)
@@ -1603,6 +1604,7 @@ struct inode_operations {
int (*rmdir) (struct inode *,struct dentry *);
int (*mknod) (struct inode *,struct dentry *,int,dev_t);
int (*whiteout) (struct inode *, struct dentry *, struct dentry *);
+ int (*fallthru) (struct inode *, struct dentry *);
int (*rename) (struct inode *, struct dentry *,
struct inode *, struct dentry *);
void (*truncate) (struct inode *);
--
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