Commit 991e72eb authored by Al Viro's avatar Al Viro Committed by Steve French
Browse files

cifs: switch build_path_from_dentry() to using dentry_path_raw() 



The cost is that we might need to flip '/' to '\\' in more than
just the prefix.  Needs profiling, but I suspect that we won't
get slowdown on that.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent f6a9bc33

fs/cifs/dir.c

+23 −62
Original line number Diff line number Diff line
@@ -93,20 +93,16 @@ char * 
build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,

				       bool prefix)

{

	struct dentry *temp;

	int namelen;

	int dfsplen;

	int pplen = 0;

	char *full_path = page;

	char dirsep;

	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);

	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);

	unsigned seq;

	char dirsep = CIFS_DIR_SEP(cifs_sb);

	char *s;



	if (unlikely(!page))

		return ERR_PTR(-ENOMEM);



	dirsep = CIFS_DIR_SEP(cifs_sb);

	if (prefix)

		dfsplen = strnlen(tcon->treeName, MAX_TREE_SIZE + 1);

	else
@@ -115,74 +111,39 @@ build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page, 
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)

		pplen = cifs_sb->prepath ? strlen(cifs_sb->prepath) + 1 : 0;



cifs_bp_rename_retry:

	namelen = dfsplen + pplen;

	seq = read_seqbegin(&rename_lock);

	rcu_read_lock();

	for (temp = direntry; !IS_ROOT(temp);) {

		namelen += (1 + temp->d_name.len);

		temp = temp->d_parent;

	}

	rcu_read_unlock();



	if (namelen >= PAGE_SIZE)

	s = dentry_path_raw(direntry, page, PAGE_SIZE);

	if (IS_ERR(s))

		return s;

	if (!s[1])	// for root we want "", not "/"

		s++;

	if (s < (char *)page + pplen + dfsplen)

		return ERR_PTR(-ENAMETOOLONG);



	full_path[namelen] = 0;	/* trailing null */

	rcu_read_lock();

	for (temp = direntry; !IS_ROOT(temp);) {

		spin_lock(&temp->d_lock);

		namelen -= 1 + temp->d_name.len;

		if (namelen < 0) {

			spin_unlock(&temp->d_lock);

			break;

		} else {

			full_path[namelen] = dirsep;

			strncpy(full_path + namelen + 1, temp->d_name.name,

				temp->d_name.len);

			cifs_dbg(FYI, "name: %s\n", full_path + namelen);

		}

		spin_unlock(&temp->d_lock);

		temp = temp->d_parent;

	}

	rcu_read_unlock();

	if (namelen != dfsplen + pplen || read_seqretry(&rename_lock, seq)) {

		cifs_dbg(FYI, "did not end path lookup where expected. namelen=%ddfsplen=%d\n",

			 namelen, dfsplen);

		/* presumably this is only possible if racing with a rename

		of one of the parent directories  (we can not lock the dentries

		above us to prevent this, but retrying should be harmless) */

		goto cifs_bp_rename_retry;

	}

	/* DIR_SEP already set for byte  0 / vs \ but not for

	   subsequent slashes in prepath which currently must

	   be entered the right way - not sure if there is an alternative

	   since the '\' is a valid posix character so we can not switch

	   those safely to '/' if any are found in the middle of the prepath */

	/* BB test paths to Windows with '/' in the midst of prepath */



	if (pplen) {

		int i;



		cifs_dbg(FYI, "using cifs_sb prepath <%s>\n", cifs_sb->prepath);

		memcpy(full_path+dfsplen+1, cifs_sb->prepath, pplen-1);

		full_path[dfsplen] = dirsep;

		for (i = 0; i < pplen-1; i++)

			if (full_path[dfsplen+1+i] == '/')

				full_path[dfsplen+1+i] = CIFS_DIR_SEP(cifs_sb);

		s -= pplen;

		memcpy(s + 1, cifs_sb->prepath, pplen - 1);

		*s = '/';

	}

	if (dirsep != '/') {

		/* BB test paths to Windows with '/' in the midst of prepath */

		char *p;



		for (p = s; *p; p++)

			if (*p == '/')

				*p = dirsep;

	}

	if (dfsplen) {

		strncpy(full_path, tcon->treeName, dfsplen);

		s -= dfsplen;

		memcpy(s, tcon->treeName, dfsplen);

		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {

			int i;

			for (i = 0; i < dfsplen; i++) {

				if (full_path[i] == '\\')

					full_path[i] = '/';

				if (s[i] == '\\')

					s[i] = '/';

			}

		}

	}

	return full_path;

	return s;

}



/*