[PATCH] dcache: extrace and use d_unlinked()

From: Alexey Dobriyan
Date: Sun May 03 2009 - 19:31:27 EST


d_unlinked() will be used in middle-term to ban checkpointing when opened
but unlinked file is detected, and in long term, to detect such situation
and special case on it.

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---
fs/dcache.c | 7 +++----
fs/namespace.c | 8 ++++----
include/linux/dcache.h | 5 +++++
3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 1fcffeb..86cb34f 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1910,7 +1910,7 @@ char *__d_path(const struct path *path, struct path *root,

spin_lock(&vfsmount_lock);
prepend(&end, &buflen, "\0", 1);
- if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+ if (d_unlinked(dentry) &&
(prepend(&end, &buflen, " (deleted)", 10) != 0))
goto Elong;

@@ -2035,7 +2035,7 @@ char *dentry_path(struct dentry *dentry, char *buf, int buflen)

spin_lock(&dcache_lock);
prepend(&end, &buflen, "\0", 1);
- if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+ if (d_unlinked(dentry) &&
(prepend(&end, &buflen, "//deleted", 9) != 0))
goto Elong;
if (buflen < 1)
@@ -2097,9 +2097,8 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
read_unlock(&current->fs->lock);

error = -ENOENT;
- /* Has the current directory has been unlinked? */
spin_lock(&dcache_lock);
- if (IS_ROOT(pwd.dentry) || !d_unhashed(pwd.dentry)) {
+ if (!d_unlinked(pwd.dentry)) {
unsigned long len;
struct path tmp = root;
char * cwd;
diff --git a/fs/namespace.c b/fs/namespace.c
index 4119620..b2bd687 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1417,7 +1417,7 @@ static int graft_tree(struct vfsmount *mnt, struct path *path)
goto out_unlock;

err = -ENOENT;
- if (IS_ROOT(path->dentry) || !d_unhashed(path->dentry))
+ if (!d_unlinked(path->dentry))
err = attach_recursive_mnt(mnt, path, NULL);
out_unlock:
mutex_unlock(&path->dentry->d_inode->i_mutex);
@@ -1599,7 +1599,7 @@ static int do_move_mount(struct path *path, char *old_name)
if (IS_DEADDIR(path->dentry->d_inode))
goto out1;

- if (!IS_ROOT(path->dentry) && d_unhashed(path->dentry))
+ if (d_unlinked(path->dentry))
goto out1;

err = -EINVAL;
@@ -2162,9 +2162,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
error = -ENOENT;
if (IS_DEADDIR(new.dentry->d_inode))
goto out2;
- if (d_unhashed(new.dentry) && !IS_ROOT(new.dentry))
+ if (d_unlinked(new.dentry))
goto out2;
- if (d_unhashed(old.dentry) && !IS_ROOT(old.dentry))
+ if (d_unlinked(old.dentry))
goto out2;
error = -EBUSY;
if (new.mnt == root.mnt ||
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 1515636..f8488bd 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -351,6 +351,11 @@ static inline int d_unhashed(struct dentry *dentry)
return (dentry->d_flags & DCACHE_UNHASHED);
}

+static inline int d_unlinked(struct dentry *dentry)
+{
+ return d_unhashed(dentry) && !IS_ROOT(dentry);
+}
+
static inline struct dentry *dget_parent(struct dentry *dentry)
{
struct dentry *ret;
--
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