[patch 2/7] vfs: mountinfo: add seq_file_root()
Add a new function:
seq_file_root()
This is similar to seq_path(), but calculates the path relative to the
given root, instead of current->fs->root. If the path was unreachable
from root, then modify the root parameter to reflect this.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/dcache.c b/fs/dcache.c
index 635c2aa..3ee588d5 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1759,10 +1759,8 @@
/**
* d_path - return the path of a dentry
- * @dentry: dentry to report
- * @vfsmnt: vfsmnt to which the dentry belongs
- * @root: root dentry
- * @rootmnt: vfsmnt to which the root dentry belongs
+ * @path: the dentry/vfsmount to report
+ * @root: root vfsmnt/dentry (may be modified by this function)
* @buffer: buffer to return value in
* @buflen: buffer length
*
@@ -1772,10 +1770,15 @@
* Returns the buffer or an error code if the path was too long.
*
* "buflen" should be positive. Caller holds the dcache_lock.
+ *
+ * If path is not reachable from the supplied root, then the value of
+ * root is changed (without modifying refcounts).
*/
-static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
- struct path *root, char *buffer, int buflen)
+char *__d_path(const struct path *path, struct path *root,
+ char *buffer, int buflen)
{
+ struct dentry *dentry = path->dentry;
+ struct vfsmount *vfsmnt = path->mnt;
char * end = buffer+buflen;
char * retval;
@@ -1824,6 +1827,8 @@
if (prepend(&retval, &buflen, dentry->d_name.name,
dentry->d_name.len) != 0)
goto Elong;
+ root->mnt = vfsmnt;
+ root->dentry = dentry;
return retval;
Elong:
return ERR_PTR(-ENAMETOOLONG);
@@ -1846,6 +1851,7 @@
{
char *res;
struct path root;
+ struct path tmp;
/*
* We have various synthetic filesystems that never get mounted. On
@@ -1862,7 +1868,8 @@
path_get(&root);
read_unlock(¤t->fs->lock);
spin_lock(&dcache_lock);
- res = __d_path(path->dentry, path->mnt, &root, buf, buflen);
+ tmp = root;
+ res = __d_path(path, &tmp, buf, buflen);
spin_unlock(&dcache_lock);
path_put(&root);
return res;
@@ -1970,9 +1977,10 @@
spin_lock(&dcache_lock);
if (pwd.dentry->d_parent == pwd.dentry || !d_unhashed(pwd.dentry)) {
unsigned long len;
+ struct path tmp = root;
char * cwd;
- cwd = __d_path(pwd.dentry, pwd.mnt, &root, page, PAGE_SIZE);
+ cwd = __d_path(&pwd, &tmp, page, PAGE_SIZE);
spin_unlock(&dcache_lock);
error = PTR_ERR(cwd);
diff --git a/fs/seq_file.c b/fs/seq_file.c
index ae59f5a..3f54dbd 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -393,6 +393,36 @@
EXPORT_SYMBOL(seq_path);
/*
+ * Same as seq_path, but relative to supplied root.
+ *
+ * root may be changed, see __d_path().
+ */
+int seq_path_root(struct seq_file *m, struct path *path, struct path *root,
+ char *esc)
+{
+ int err = -ENAMETOOLONG;
+ if (m->count < m->size) {
+ char *s = m->buf + m->count;
+ char *p;
+
+ spin_lock(&dcache_lock);
+ p = __d_path(path, root, s, m->size - m->count);
+ spin_unlock(&dcache_lock);
+ err = PTR_ERR(p);
+ if (!IS_ERR(p)) {
+ s = mangle_path(s, p, esc);
+ if (s) {
+ p = m->buf + m->count;
+ m->count = s - m->buf;
+ return 0;
+ }
+ }
+ }
+ m->count = m->size;
+ return err;
+}
+
+/*
* returns the path of the 'dentry' from the root of its filesystem.
*/
int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 6396003..cfb1627 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -301,6 +301,7 @@
*/
extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);
+extern char *__d_path(const struct path *path, struct path *root, char *, int);
extern char *d_path(struct path *, char *, int);
extern char *dentry_path(struct dentry *, char *, int);
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 11676cc..5b5369c 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h
@@ -46,6 +46,8 @@
int seq_path(struct seq_file *, struct path *, char *);
int seq_dentry(struct seq_file *, struct dentry *, char *);
+int seq_path_root(struct seq_file *m, struct path *path, struct path *root,
+ char *esc);
int single_open(struct file *, int (*)(struct seq_file *, void *), void *);
int single_release(struct inode *, struct file *);