Commit 9d1bc601 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Al Viro

[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: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6092d048
......@@ -1759,10 +1759,8 @@ static int prepend(char **buffer, int *buflen, const char *str,
/**
* 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 @@ static int prepend(char **buffer, int *buflen, const char *str,
* 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 @@ static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
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 *d_path(struct path *path, char *buf, int buflen)
{
char *res;
struct path root;
struct path tmp;
/*
* We have various synthetic filesystems that never get mounted. On
......@@ -1862,7 +1868,8 @@ char *d_path(struct path *path, char *buf, int buflen)
path_get(&root);
read_unlock(&current->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 @@ asmlinkage long sys_getcwd(char __user *buf, unsigned long size)
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);
......
......@@ -392,6 +392,36 @@ int seq_path(struct seq_file *m, struct path *path, char *esc)
}
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.
*/
......
......@@ -301,6 +301,7 @@ extern int d_validate(struct dentry *, struct dentry *);
*/
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);
......
......@@ -46,6 +46,8 @@ int seq_printf(struct seq_file *, const char *, ...)
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 *);
......
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