Merge tag 'ovl-fixes-6.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs
Pull overlayfs fixes from Amir Goldstein:
- Various fixes for regressions due to conversion to new mount
api in v6.5
- Disable a new mount option syntax (append lowerdir) that was
added in v6.5 because we plan to add a different lowerdir
append syntax in v6.7
* tag 'ovl-fixes-6.6-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs:
ovl: temporarily disable appending lowedirs
ovl: fix regression in showing lowerdir mount option
ovl: fix regression in parsing of mount options with escaped comma
fs: factor out vfs_parse_monolithic_sep() helper
diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst
index cdefbe7..5b93268 100644
--- a/Documentation/filesystems/overlayfs.rst
+++ b/Documentation/filesystems/overlayfs.rst
@@ -339,6 +339,18 @@
rightmost one and going left. In the above example lower1 will be the
top, lower2 the middle and lower3 the bottom layer.
+Note: directory names containing colons can be provided as lower layer by
+escaping the colons with a single backslash. For example:
+
+ mount -t overlay overlay -olowerdir=/a\:lower\:\:dir /merged
+
+Since kernel version v6.5, directory names containing colons can also
+be provided as lower layer using the fsconfig syscall from new mount api:
+
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", "/a:lower::dir", 0);
+
+In the latter case, colons in lower layer directory names will be escaped
+as an octal characters (\072) when displayed in /proc/self/mountinfo.
Metadata only copy up
---------------------
diff --git a/fs/fs_context.c b/fs/fs_context.c
index a0ad7a0..98589aa 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -192,17 +192,19 @@ int vfs_parse_fs_string(struct fs_context *fc, const char *key,
EXPORT_SYMBOL(vfs_parse_fs_string);
/**
- * generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
+ * vfs_parse_monolithic_sep - Parse key[=val][,key[=val]]* mount data
* @fc: The superblock configuration to fill in.
* @data: The data to parse
+ * @sep: callback for separating next option
*
- * Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
- * called from the ->monolithic_mount_data() fs_context operation.
+ * Parse a blob of data that's in key[=val][,key[=val]]* form with a custom
+ * option separator callback.
*
* Returns 0 on success or the error returned by the ->parse_option() fs_context
* operation on failure.
*/
-int generic_parse_monolithic(struct fs_context *fc, void *data)
+int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
+ char *(*sep)(char **))
{
char *options = data, *key;
int ret = 0;
@@ -214,7 +216,7 @@ int generic_parse_monolithic(struct fs_context *fc, void *data)
if (ret)
return ret;
- while ((key = strsep(&options, ",")) != NULL) {
+ while ((key = sep(&options)) != NULL) {
if (*key) {
size_t v_len = 0;
char *value = strchr(key, '=');
@@ -233,6 +235,28 @@ int generic_parse_monolithic(struct fs_context *fc, void *data)
return ret;
}
+EXPORT_SYMBOL(vfs_parse_monolithic_sep);
+
+static char *vfs_parse_comma_sep(char **s)
+{
+ return strsep(s, ",");
+}
+
+/**
+ * generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
+ * @fc: The superblock configuration to fill in.
+ * @data: The data to parse
+ *
+ * Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
+ * called from the ->monolithic_mount_data() fs_context operation.
+ *
+ * Returns 0 on success or the error returned by the ->parse_option() fs_context
+ * operation on failure.
+ */
+int generic_parse_monolithic(struct fs_context *fc, void *data)
+{
+ return vfs_parse_monolithic_sep(fc, data, vfs_parse_comma_sep);
+}
EXPORT_SYMBOL(generic_parse_monolithic);
/**
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
index 95b7515..f6ff23f 100644
--- a/fs/overlayfs/params.c
+++ b/fs/overlayfs/params.c
@@ -157,6 +157,34 @@ const struct fs_parameter_spec ovl_parameter_spec[] = {
{}
};
+static char *ovl_next_opt(char **s)
+{
+ char *sbegin = *s;
+ char *p;
+
+ if (sbegin == NULL)
+ return NULL;
+
+ for (p = sbegin; *p; p++) {
+ if (*p == '\\') {
+ p++;
+ if (!*p)
+ break;
+ } else if (*p == ',') {
+ *p = '\0';
+ *s = p + 1;
+ return sbegin;
+ }
+ }
+ *s = NULL;
+ return sbegin;
+}
+
+static int ovl_parse_monolithic(struct fs_context *fc, void *data)
+{
+ return vfs_parse_monolithic_sep(fc, data, ovl_next_opt);
+}
+
static ssize_t ovl_parse_param_split_lowerdirs(char *str)
{
ssize_t nr_layers = 1, nr_colons = 0;
@@ -164,7 +192,8 @@ static ssize_t ovl_parse_param_split_lowerdirs(char *str)
for (s = d = str;; s++, d++) {
if (*s == '\\') {
- s++;
+ /* keep esc chars in split lowerdir */
+ *d++ = *s++;
} else if (*s == ':') {
bool next_colon = (*(s + 1) == ':');
@@ -239,7 +268,7 @@ static void ovl_unescape(char *s)
}
}
-static int ovl_mount_dir(const char *name, struct path *path)
+static int ovl_mount_dir(const char *name, struct path *path, bool upper)
{
int err = -ENOMEM;
char *tmp = kstrdup(name, GFP_KERNEL);
@@ -248,7 +277,7 @@ static int ovl_mount_dir(const char *name, struct path *path)
ovl_unescape(tmp);
err = ovl_mount_dir_noesc(tmp, path);
- if (!err && path->dentry->d_flags & DCACHE_OP_REAL) {
+ if (!err && upper && path->dentry->d_flags & DCACHE_OP_REAL) {
pr_err("filesystem on '%s' not supported as upperdir\n",
tmp);
path_put_init(path);
@@ -269,7 +298,7 @@ static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
struct path path;
char *dup;
- err = ovl_mount_dir(name, &path);
+ err = ovl_mount_dir(name, &path, true);
if (err)
return err;
@@ -321,12 +350,6 @@ static void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx)
* Set "/lower1", "/lower2", and "/lower3" as lower layers and
* "/data1" and "/data2" as data lower layers. Any existing lower
* layers are replaced.
- * (2) lowerdir=:/lower4
- * Append "/lower4" to current stack of lower layers. This requires
- * that there already is at least one lower layer configured.
- * (3) lowerdir=::/lower5
- * Append data "/lower5" as data lower layer. This requires that
- * there's at least one regular lower layer present.
*/
static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
{
@@ -348,49 +371,9 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
return 0;
}
- if (strncmp(name, "::", 2) == 0) {
- /*
- * This is a data layer.
- * There must be at least one regular lower layer
- * specified.
- */
- if (ctx->nr == 0) {
- pr_err("data lower layers without regular lower layers not allowed");
- return -EINVAL;
- }
-
- /* Skip the leading "::". */
- name += 2;
- data_layer = true;
- /*
- * A data layer is automatically an append as there
- * must've been at least one regular lower layer.
- */
- append = true;
- } else if (*name == ':') {
- /*
- * This is a regular lower layer.
- * If users want to append a layer enforce that they
- * have already specified a first layer before. It's
- * better to be strict.
- */
- if (ctx->nr == 0) {
- pr_err("cannot append layer if no previous layer has been specified");
- return -EINVAL;
- }
-
- /*
- * Once a sequence of data layers has started regular
- * lower layers are forbidden.
- */
- if (ctx->nr_data > 0) {
- pr_err("regular lower layers cannot follow data lower layers");
- return -EINVAL;
- }
-
- /* Skip the leading ":". */
- name++;
- append = true;
+ if (*name == ':') {
+ pr_err("cannot append lower layer");
+ return -EINVAL;
}
dup = kstrdup(name, GFP_KERNEL);
@@ -472,7 +455,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
l = &ctx->lower[nr];
memset(l, 0, sizeof(*l));
- err = ovl_mount_dir_noesc(dup_iter, &l->path);
+ err = ovl_mount_dir(dup_iter, &l->path, false);
if (err)
goto out_put;
@@ -682,6 +665,7 @@ static int ovl_reconfigure(struct fs_context *fc)
}
static const struct fs_context_operations ovl_context_ops = {
+ .parse_monolithic = ovl_parse_monolithic,
.parse_param = ovl_parse_param,
.get_tree = ovl_get_tree,
.reconfigure = ovl_reconfigure,
@@ -950,16 +934,23 @@ int ovl_show_options(struct seq_file *m, struct dentry *dentry)
struct super_block *sb = dentry->d_sb;
struct ovl_fs *ofs = OVL_FS(sb);
size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer;
- char **lowerdatadirs = &ofs->config.lowerdirs[nr_merged_lower];
- /* lowerdirs[] starts from offset 1 */
- seq_printf(m, ",lowerdir=%s", ofs->config.lowerdirs[1]);
- /* dump regular lower layers */
- for (nr = 2; nr < nr_merged_lower; nr++)
- seq_printf(m, ":%s", ofs->config.lowerdirs[nr]);
- /* dump data lower layers */
- for (nr = 0; nr < ofs->numdatalayer; nr++)
- seq_printf(m, "::%s", lowerdatadirs[nr]);
+ /*
+ * lowerdirs[] starts from offset 1, then
+ * >= 0 regular lower layers prefixed with : and
+ * >= 0 data-only lower layers prefixed with ::
+ *
+ * we need to escase comma and space like seq_show_option() does and
+ * we also need to escape the colon separator from lowerdir paths.
+ */
+ seq_puts(m, ",lowerdir=");
+ for (nr = 1; nr < ofs->numlayer; nr++) {
+ if (nr > 1)
+ seq_putc(m, ':');
+ if (nr >= nr_merged_lower)
+ seq_putc(m, ':');
+ seq_escape(m, ofs->config.lowerdirs[nr], ":, \t\n\\");
+ }
if (ofs->config.upperdir) {
seq_show_option(m, "upperdir", ofs->config.upperdir);
seq_show_option(m, "workdir", ofs->config.workdir);
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 96332db..c13e99c 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -136,6 +136,8 @@ extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc);
extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
const char *value, size_t v_size);
+int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
+ char *(*sep)(char **));
extern int generic_parse_monolithic(struct fs_context *fc, void *data);
extern int vfs_get_tree(struct fs_context *fc);
extern void put_fs_context(struct fs_context *fc);
