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

fs/dcache.c

+16 −8
Original line number Diff line number Diff line
@@ -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);

fs/seq_file.c

+30 −0
Original line number Diff line number Diff line
@@ -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.

 */

include/linux/dcache.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/seq_file.h

+2 −0
Original line number Diff line number Diff line
@@ -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 *);