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[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: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
master
Ram Pai 14 years ago
committed by Al Viro
parent
commit
6092d04818
  1. 90
      fs/dcache.c
  2. 65
      fs/seq_file.c
  3. 1
      include/linux/dcache.h
  4. 2
      include/linux/seq_file.h

90
fs/dcache.c

@ -1746,6 +1746,17 @@ shouldnt_be_hashed:
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;

65
fs/seq_file.c

@ -350,28 +350,40 @@ int seq_printf(struct seq_file *m, const char *f, ...)
}
EXPORT_SYMBOL(seq_printf);
static char *mangle_path(char *s, char *p, char *esc)
{
while (s <= p) {
char c = *p++;
if (!c) {
return s;
} else if (!strchr(esc, c)) {
*s++ = c;
} else if (s + 4 > p) {
break;
} else {
*s++ = '\\';
*s++ = '0' + ((c & 0300) >> 6);
*s++ = '0' + ((c & 070) >> 3);
*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)) {
while (s <= p) {
char c = *p++;
if (!c) {
p = m->buf + m->count;
m->count = s - m->buf;
return s - p;
} else if (!strchr(esc, c)) {
*s++ = c;
} else if (s + 4 > p) {
break;
} else {
*s++ = '\\';
*s++ = '0' + ((c & 0300) >> 6);
*s++ = '0' + ((c & 070) >> 3);
*s++ = '0' + (c & 07);
}
s = mangle_path(s, p, esc);
if (s) {
p = m->buf + m->count;
m->count = s - m->buf;
return s - p;
}
}
}
@ -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);

1
include/linux/dcache.h

@ -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.. */

2
include/linux/seq_file.h

@ -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 *);

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