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Commit 6092d048 authored by Ram Pai's avatar Ram Pai Committed by Al Viro
Browse files

[patch 1/7] vfs: mountinfo: add dentry_path() 



[mszeredi@suse.cz] split big patch into managable chunks

Add the following functions:

  dentry_path()
  seq_dentry()

These are similar to d_path() and seq_path().  But instead of
calculating the path within a mount namespace, they calculate the path
from the root of the filesystem to a given dentry, ignoring mounts
completely.

Signed-off-by: default avatarRam Pai <linuxram@us.ibm.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 934b25c5

fs/dcache.c

+66 −24
Original line number Diff line number Diff line
@@ -1746,6 +1746,17 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) 
	goto shouldnt_be_hashed;

}



static int prepend(char **buffer, int *buflen, const char *str,

			  int namelen)

{

	*buflen -= namelen;

	if (*buflen < 0)

		return -ENAMETOOLONG;

	*buffer -= namelen;

	memcpy(*buffer, str, namelen);

	return 0;

}



/**

 * d_path - return the path of a dentry

 * @dentry: dentry to report
@@ -1767,17 +1778,11 @@ static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt, 
{

	char * end = buffer+buflen;

	char * retval;

	int namelen;



	*--end = '\0';

	buflen--;

	if (!IS_ROOT(dentry) && d_unhashed(dentry)) {

		buflen -= 10;

		end -= 10;

		if (buflen < 0)



	prepend(&end, &buflen, "\0", 1);

	if (!IS_ROOT(dentry) && d_unhashed(dentry) &&

		(prepend(&end, &buflen, " (deleted)", 10) != 0))

			goto Elong;

		memcpy(end, " (deleted)", 10);

	}



	if (buflen < 1)

		goto Elong;
@@ -1804,13 +1809,10 @@ static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt, 
		}

		parent = dentry->d_parent;

		prefetch(parent);

		namelen = dentry->d_name.len;

		buflen -= namelen + 1;

		if (buflen < 0)

		if ((prepend(&end, &buflen, dentry->d_name.name,

				dentry->d_name.len) != 0) ||

		    (prepend(&end, &buflen, "/", 1) != 0))

			goto Elong;

		end -= namelen;

		memcpy(end, dentry->d_name.name, namelen);

		*--end = '/';

		retval = end;

		dentry = parent;

	}
@@ -1818,12 +1820,10 @@ static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt, 
	return retval;



global_root:

	namelen = dentry->d_name.len;

	buflen -= namelen;

	if (buflen < 0)

	retval += 1;	/* hit the slash */

	if (prepend(&retval, &buflen, dentry->d_name.name,

		    dentry->d_name.len) != 0)

		goto Elong;

	retval -= namelen-1;	/* hit the slash */

	memcpy(retval, dentry->d_name.name, namelen);

	return retval;

Elong:

	return ERR_PTR(-ENAMETOOLONG);
@@ -1859,7 +1859,7 @@ char *d_path(struct path *path, char *buf, int buflen) 


	read_lock(&current->fs->lock);

	root = current->fs->root;

	path_get(&current->fs->root);

	path_get(&root);

	read_unlock(&current->fs->lock);

	spin_lock(&dcache_lock);

	res = __d_path(path->dentry, path->mnt, &root, buf, buflen);
@@ -1889,6 +1889,48 @@ char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen, 
	return memcpy(buffer, temp, sz);

}



/*

 * Write full pathname from the root of the filesystem into the buffer.

 */

char *dentry_path(struct dentry *dentry, char *buf, int buflen)

{

	char *end = buf + buflen;

	char *retval;



	spin_lock(&dcache_lock);

	prepend(&end, &buflen, "\0", 1);

	if (!IS_ROOT(dentry) && d_unhashed(dentry) &&

		(prepend(&end, &buflen, "//deleted", 9) != 0))

			goto Elong;

	if (buflen < 1)

		goto Elong;

	/* Get '/' right */

	retval = end-1;

	*retval = '/';



	for (;;) {

		struct dentry *parent;

		if (IS_ROOT(dentry))

			break;



		parent = dentry->d_parent;

		prefetch(parent);



		if ((prepend(&end, &buflen, dentry->d_name.name,

				dentry->d_name.len) != 0) ||

		    (prepend(&end, &buflen, "/", 1) != 0))

			goto Elong;



		retval = end;

		dentry = parent;

	}

	spin_unlock(&dcache_lock);

	return retval;

Elong:

	spin_unlock(&dcache_lock);

	return ERR_PTR(-ENAMETOOLONG);

}



/*

 * NOTE! The user-level library version returns a

 * character pointer. The kernel system call just
@@ -1918,9 +1960,9 @@ asmlinkage long sys_getcwd(char __user *buf, unsigned long size) 


	read_lock(&current->fs->lock);

	pwd = current->fs->pwd;

	path_get(&current->fs->pwd);

	path_get(&pwd);

	root = current->fs->root;

	path_get(&current->fs->root);

	path_get(&root);

	read_unlock(&current->fs->lock);



	error = -ENOENT;

fs/seq_file.c

+49 −16
Original line number Diff line number Diff line
@@ -350,18 +350,12 @@ int seq_printf(struct seq_file *m, const char *f, ...) 
}

EXPORT_SYMBOL(seq_printf);



int seq_path(struct seq_file *m, struct path *path, char *esc)

static char *mangle_path(char *s, char *p, char *esc)

{

	if (m->count < m->size) {

		char *s = m->buf + m->count;

		char *p = d_path(path, s, m->size - m->count);

		if (!IS_ERR(p)) {

	while (s <= p) {

		char c = *p++;

		if (!c) {

					p = m->buf + m->count;

					m->count = s - m->buf;

					return s - p;

			return s;

		} else if (!strchr(esc, c)) {

			*s++ = c;

		} else if (s + 4 > p) {
@@ -373,6 +367,24 @@ int seq_path(struct seq_file *m, struct path *path, char *esc) 
			*s++ = '0' + (c & 07);

		}

	}

	return NULL;

}



/*

 * return the absolute path of 'dentry' residing in mount 'mnt'.

 */

int seq_path(struct seq_file *m, struct path *path, char *esc)

{

	if (m->count < m->size) {

		char *s = m->buf + m->count;

		char *p = d_path(path, s, m->size - m->count);

		if (!IS_ERR(p)) {

			s = mangle_path(s, p, esc);

			if (s) {

				p = m->buf + m->count;

				m->count = s - m->buf;

				return s - p;

			}

		}

	}

	m->count = m->size;
@@ -380,6 +392,27 @@ int seq_path(struct seq_file *m, struct path *path, char *esc) 
}

EXPORT_SYMBOL(seq_path);



/*

 * returns the path of the 'dentry' from the root of its filesystem.

 */

int seq_dentry(struct seq_file *m, struct dentry *dentry, char *esc)

{

	if (m->count < m->size) {

		char *s = m->buf + m->count;

		char *p = dentry_path(dentry, s, m->size - m->count);

		if (!IS_ERR(p)) {

			s = mangle_path(s, p, esc);

			if (s) {

				p = m->buf + m->count;

				m->count = s - m->buf;

				return s - p;

			}

		}

	}

	m->count = m->size;

	return -1;

}



static void *single_start(struct seq_file *p, loff_t *pos)

{

	return NULL + (*pos == 0);

include/linux/dcache.h

+1 −0
Original line number Diff line number Diff line
@@ -302,6 +302,7 @@ extern int d_validate(struct dentry *, struct dentry *); 
extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...);



extern char *d_path(struct path *, char *, int);

extern char *dentry_path(struct dentry *, char *, int);



/* Allocation counts.. */

include/linux/seq_file.h

+2 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ struct seq_operations; 
struct file;

struct path;

struct inode;

struct dentry;



struct seq_file {

	char *buf;
@@ -44,6 +45,7 @@ int seq_printf(struct seq_file *, const char *, ...) 
	__attribute__ ((format (printf,2,3)));



int seq_path(struct seq_file *, struct path *, char *);

int seq_dentry(struct seq_file *, struct dentry *, char *);



int single_open(struct file *, int (*)(struct seq_file *, void *), void *);

int single_release(struct inode *, struct file *);