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authorRam Pai <linuxram@us.ibm.com>2008-03-27 13:06:20 +0100
committerAl Viro <viro@zeniv.linux.org.uk>2008-04-23 00:04:32 -0400
commit6092d048183b76bfa3f84b32f8158dd8d10bd811 (patch)
tree2d38af32961eb52b36daca2f29ce69e80f6e7283 /fs/dcache.c
parent934b25c597c0e98304a7eaec198a87e4633a42bb (diff)
downloadlwn-6092d048183b76bfa3f84b32f8158dd8d10bd811.tar.gz
lwn-6092d048183b76bfa3f84b32f8158dd8d10bd811.zip
[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>
Diffstat (limited to 'fs/dcache.c')
-rw-r--r--fs/dcache.c90
1 files changed, 66 insertions, 24 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 43455776711e..635c2aa427ed 100644
--- a/fs/dcache.c
+++ b/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);
@@ -1890,6 +1890,48 @@ char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
}
/*
+ * 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
* returns the length of the buffer filled (which
@@ -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;