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

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[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>
This commit is contained in:
Ram Pai
2008-03-27 13:06:20 +01:00
committed by Al Viro
parent 934b25c597
commit 6092d04818
4 changed files with 117 additions and 39 deletions
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88
fs/dcache.c
View File

@@ -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;