diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst
index ae1f72b462e33cf004242eb289ca713ed044a6f2..0407f361f32a236b28dc0284d01ae2ef3f2aa1c7 100644
--- a/Documentation/filesystems/overlayfs.rst
+++ b/Documentation/filesystems/overlayfs.rst
@@ -344,10 +344,11 @@ 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:
+Since kernel version v6.8, directory names containing colons can also
+be configured as lower layer using the "lowerdir+" mount options and the
+fsconfig syscall from new mount api. For example:
- fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", "/a:lower::dir", 0);
+ 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.
@@ -416,6 +417,16 @@ Only the data of the files in the "data-only" lower layers may be visible
when a "metacopy" file in one of the lower layers above it, has a "redirect"
to the absolute path of the "lower data" file in the "data-only" lower layer.
+Since kernel version v6.8, "data-only" lower layers can also be added using
+the "datadir+" mount options and the fsconfig syscall from new mount api.
+For example:
+
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l1", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l2", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l3", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "datadir+", "/do1", 0);
+ fsconfig(fs_fd, FSCONFIG_SET_STRING, "datadir+", "/do2", 0);
+
fs-verity support
----------------------
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
index 88725982b6dd3f1e3232c578dd28e38328473ae4..ddab9ea267d1283b73f8245aa1adb81232f2a202 100644
--- a/fs/overlayfs/params.c
+++ b/fs/overlayfs/params.c
@@ -45,6 +45,8 @@ MODULE_PARM_DESC(metacopy,
enum ovl_opt {
Opt_lowerdir,
+ Opt_lowerdir_add,
+ Opt_datadir_add,
Opt_upperdir,
Opt_workdir,
Opt_default_permissions,
@@ -140,8 +142,11 @@ static int ovl_verity_mode_def(void)
#define fsparam_string_empty(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL)
+
const struct fs_parameter_spec ovl_parameter_spec[] = {
fsparam_string_empty("lowerdir", Opt_lowerdir),
+ fsparam_string("lowerdir+", Opt_lowerdir_add),
+ fsparam_string("datadir+", Opt_datadir_add),
fsparam_string("upperdir", Opt_upperdir),
fsparam_string("workdir", Opt_workdir),
fsparam_flag("default_permissions", Opt_default_permissions),
@@ -273,12 +278,15 @@ static int ovl_mount_dir(const char *name, struct path *path)
static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path,
enum ovl_opt layer, const char *name, bool upper)
{
+ struct ovl_fs_context *ctx = fc->fs_private;
+
if (ovl_dentry_weird(path->dentry))
return invalfc(fc, "filesystem on %s not supported", name);
if (!d_is_dir(path->dentry))
return invalfc(fc, "%s is not a directory", name);
+
/*
* Check whether upper path is read-only here to report failures
* early. Don't forget to recheck when the superblock is created
@@ -289,16 +297,45 @@ static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path,
return invalfc(fc, "filesystem on %s not supported as upperdir", name);
if (__mnt_is_readonly(path->mnt))
return invalfc(fc, "filesystem on %s is read-only", name);
+ } else {
+ if (ctx->lowerdir_all && layer != Opt_lowerdir)
+ return invalfc(fc, "lowerdir+ and datadir+ cannot follow lowerdir");
+ if (ctx->nr_data && layer == Opt_lowerdir_add)
+ return invalfc(fc, "regular lower layers cannot follow data layers");
+ if (ctx->nr == OVL_MAX_STACK)
+ return invalfc(fc, "too many lower directories, limit is %d",
+ OVL_MAX_STACK);
}
return 0;
}
+static int ovl_ctx_realloc_lower(struct fs_context *fc)
+{
+ struct ovl_fs_context *ctx = fc->fs_private;
+ struct ovl_fs_context_layer *l;
+ size_t nr;
+
+ if (ctx->nr < ctx->capacity)
+ return 0;
+
+ nr = min_t(size_t, max(4096 / sizeof(*l), ctx->capacity * 2),
+ OVL_MAX_STACK);
+ l = krealloc_array(ctx->lower, nr, sizeof(*l), GFP_KERNEL_ACCOUNT);
+ if (!l)
+ return -ENOMEM;
+
+ ctx->lower = l;
+ ctx->capacity = nr;
+ return 0;
+}
+
static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer,
struct path *path, char **pname)
{
struct ovl_fs *ofs = fc->s_fs_info;
struct ovl_config *config = &ofs->config;
struct ovl_fs_context *ctx = fc->fs_private;
+ struct ovl_fs_context_layer *l;
switch (layer) {
case Opt_workdir:
@@ -309,6 +346,16 @@ static void ovl_add_layer(struct fs_context *fc, enum ovl_opt layer,
swap(config->upperdir, *pname);
swap(ctx->upper, *path);
break;
+ case Opt_datadir_add:
+ ctx->nr_data++;
+ fallthrough;
+ case Opt_lowerdir_add:
+ WARN_ON(ctx->nr >= ctx->capacity);
+ l = &ctx->lower[ctx->nr++];
+ memset(l, 0, sizeof(*l));
+ swap(l->name, *pname);
+ swap(l->path, *path);
+ break;
default:
WARN_ON(1);
}
@@ -325,7 +372,10 @@ static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param,
if (!name)
return -ENOMEM;
- err = ovl_mount_dir(name, &path);
+ if (upper)
+ err = ovl_mount_dir(name, &path);
+ else
+ err = ovl_mount_dir_noesc(name, &path);
if (err)
goto out_free;
@@ -333,6 +383,12 @@ static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param,
if (err)
goto out_put;
+ if (!upper) {
+ err = ovl_ctx_realloc_lower(fc);
+ if (err)
+ goto out_put;
+ }
+
/* Store the user provided path string in ctx to show in mountinfo */
ovl_add_layer(fc, layer, &path, &name);
@@ -519,6 +575,8 @@ static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param)
case Opt_lowerdir:
err = ovl_parse_param_lowerdir(param->string, fc);
break;
+ case Opt_lowerdir_add:
+ case Opt_datadir_add:
case Opt_upperdir:
case Opt_workdir:
err = ovl_parse_layer(fc, param, opt);
@@ -894,13 +952,29 @@ 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, nr_lower = 0;
char **lowerdirs = ofs->config.lowerdirs;
/*
* lowerdirs[0] holds the colon separated list that user provided
* with lowerdir mount option.
+ * lowerdirs[1..numlayer] hold the lowerdir paths that were added
+ * using the lowerdir+ and datadir+ mount options.
+ * For now, we do not allow mixing the legacy lowerdir mount option
+ * with the new lowerdir+ and datadir+ mount options.
*/
- seq_show_option(m, "lowerdir", lowerdirs[0]);
+ if (lowerdirs[0]) {
+ seq_show_option(m, "lowerdir", lowerdirs[0]);
+ } else {
+ nr_lower = ofs->numlayer;
+ nr_merged_lower = nr_lower - ofs->numdatalayer;
+ }
+ for (nr = 1; nr < nr_lower; nr++) {
+ if (nr < nr_merged_lower)
+ seq_show_option(m, "lowerdir+", lowerdirs[nr]);
+ else
+ seq_show_option(m, "datadir+", lowerdirs[nr]);
+ }
if (ofs->config.upperdir) {
seq_show_option(m, "upperdir", ofs->config.upperdir);
seq_show_option(m, "workdir", ofs->config.workdir);