MODULE_PARM_DESC(metacopy,
"Default to on or off for the metadata only copy up feature");
-enum {
+enum ovl_opt {
Opt_lowerdir,
Opt_upperdir,
Opt_workdir,
{}
};
+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;
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) == ':');
pr_err("failed to resolve '%s': %i\n", name, err);
goto out;
}
- err = -EINVAL;
- if (ovl_dentry_weird(path->dentry)) {
- pr_err("filesystem on '%s' not supported\n", name);
- goto out_put;
- }
- if (!d_is_dir(path->dentry)) {
- pr_err("'%s' not a directory\n", name);
- goto out_put;
- }
return 0;
-out_put:
- path_put_init(path);
out:
return err;
}
if (tmp) {
ovl_unescape(tmp);
err = ovl_mount_dir_noesc(tmp, path);
-
- if (!err && path->dentry->d_flags & DCACHE_OP_REAL) {
- pr_err("filesystem on '%s' not supported as upperdir\n",
- tmp);
- path_put_init(path);
- err = -EINVAL;
- }
kfree(tmp);
}
return err;
}
-static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
- bool workdir)
+static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path,
+ enum ovl_opt layer, const char *name, bool upper)
{
- int err;
- struct ovl_fs *ofs = fc->s_fs_info;
- struct ovl_config *config = &ofs->config;
- struct ovl_fs_context *ctx = fc->fs_private;
- struct path path;
- char *dup;
+ if (ovl_dentry_weird(path->dentry))
+ return invalfc(fc, "filesystem on %s not supported", name);
- err = ovl_mount_dir(name, &path);
- if (err)
- return err;
+ 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
* as the mount attributes could change.
*/
- if (__mnt_is_readonly(path.mnt)) {
- path_put(&path);
- return -EINVAL;
+ if (upper) {
+ if (path->dentry->d_flags & DCACHE_OP_REAL)
+ 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);
}
+ return 0;
+}
- dup = kstrdup(name, GFP_KERNEL);
- if (!dup) {
- path_put(&path);
- return -ENOMEM;
- }
+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;
- if (workdir) {
- kfree(config->workdir);
- config->workdir = dup;
- path_put(&ctx->work);
- ctx->work = path;
- } else {
- kfree(config->upperdir);
- config->upperdir = dup;
- path_put(&ctx->upper);
- ctx->upper = path;
+ switch (layer) {
+ case Opt_workdir:
+ swap(config->workdir, *pname);
+ swap(ctx->work, *path);
+ break;
+ case Opt_upperdir:
+ swap(config->upperdir, *pname);
+ swap(ctx->upper, *path);
+ break;
+ default:
+ WARN_ON(1);
}
- return 0;
}
-static void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx)
+static int ovl_parse_layer(struct fs_context *fc, struct fs_parameter *param,
+ enum ovl_opt layer)
{
- for (size_t nr = 0; nr < ctx->nr; nr++) {
- path_put(&ctx->lower[nr].path);
- kfree(ctx->lower[nr].name);
- ctx->lower[nr].name = NULL;
+ char *name = kstrdup(param->string, GFP_KERNEL);
+ bool upper = (layer == Opt_upperdir || layer == Opt_workdir);
+ struct path path;
+ int err;
+
+ if (!name)
+ return -ENOMEM;
+
+ err = ovl_mount_dir(name, &path);
+ if (err)
+ goto out_free;
+
+ err = ovl_mount_dir_check(fc, &path, layer, name, upper);
+ if (err)
+ goto out_put;
+
+ /* Store the user provided path string in ctx to show in mountinfo */
+ ovl_add_layer(fc, layer, &path, &name);
+
+out_put:
+ path_put(&path);
+out_free:
+ kfree(name);
+ return err;
+}
+
+static void ovl_reset_lowerdirs(struct ovl_fs_context *ctx)
+{
+ struct ovl_fs_context_layer *l = ctx->lower;
+
+ // Reset old user provided lowerdir string
+ kfree(ctx->lowerdir_all);
+ ctx->lowerdir_all = NULL;
+
+ for (size_t nr = 0; nr < ctx->nr; nr++, l++) {
+ path_put(&l->path);
+ kfree(l->name);
+ l->name = NULL;
}
ctx->nr = 0;
ctx->nr_data = 0;
/*
* Parse lowerdir= mount option:
*
- * (1) lowerdir=/lower1:/lower2:/lower3::/data1::/data2
+ * e.g.: lowerdir=/lower1:/lower2:/lower3::/data1::/data2
* 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)
{
int err;
struct ovl_fs_context *ctx = fc->fs_private;
struct ovl_fs_context_layer *l;
- char *dup = NULL, *dup_iter;
+ char *dup = NULL, *iter;
ssize_t nr_lower = 0, nr = 0, nr_data = 0;
- bool append = false, data_layer = false;
+ bool data_layer = false;
/*
* Ensure we're backwards compatible with mount(2)
*/
/* drop all existing lower layers */
- if (!*name) {
- ovl_parse_param_drop_lowerdir(ctx);
- 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;
- }
+ ovl_reset_lowerdirs(ctx);
- /* 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;
- }
+ if (!*name)
+ return 0;
- /* Skip the leading ":". */
- name++;
- append = true;
+ if (*name == ':') {
+ pr_err("cannot append lower layer");
+ return -EINVAL;
}
+ // Store user provided lowerdir string to show in mount options
+ ctx->lowerdir_all = kstrdup(name, GFP_KERNEL);
+ if (!ctx->lowerdir_all)
+ return -ENOMEM;
+
dup = kstrdup(name, GFP_KERNEL);
if (!dup)
return -ENOMEM;
if (nr_lower < 0)
goto out_err;
- if ((nr_lower > OVL_MAX_STACK) ||
- (append && (size_add(ctx->nr, nr_lower) > OVL_MAX_STACK))) {
+ if (nr_lower > OVL_MAX_STACK) {
pr_err("too many lower directories, limit is %d\n", OVL_MAX_STACK);
goto out_err;
}
- if (!append)
- ovl_parse_param_drop_lowerdir(ctx);
-
- /*
- * (1) append
- *
- * We want nr <= nr_lower <= capacity We know nr > 0 and nr <=
- * capacity. If nr == 0 this wouldn't be append. If nr +
- * nr_lower is <= capacity then nr <= nr_lower <= capacity
- * already holds. If nr + nr_lower exceeds capacity, we realloc.
- *
- * (2) replace
- *
- * Ensure we're backwards compatible with mount(2) which allows
- * "lowerdir=/a:/b:/c,lowerdir=/d:/e:/f" causing the last
- * specified lowerdir mount option to win.
- *
- * We want nr <= nr_lower <= capacity We know either (i) nr == 0
- * or (ii) nr > 0. We also know nr_lower > 0. The capacity
- * could've been changed multiple times already so we only know
- * nr <= capacity. If nr + nr_lower > capacity we realloc,
- * otherwise nr <= nr_lower <= capacity holds already.
- */
- nr_lower += ctx->nr;
if (nr_lower > ctx->capacity) {
err = -ENOMEM;
l = krealloc_array(ctx->lower, nr_lower, sizeof(*ctx->lower),
ctx->capacity = nr_lower;
}
- /*
- * (3) By (1) and (2) we know nr <= nr_lower <= capacity.
- * (4) If ctx->nr == 0 => replace
- * We have verified above that the lowerdir mount option
- * isn't an append, i.e., the lowerdir mount option
- * doesn't start with ":" or "::".
- * (4.1) The lowerdir mount options only contains regular lower
- * layers ":".
- * => Nothing to verify.
- * (4.2) The lowerdir mount options contains regular ":" and
- * data "::" layers.
- * => We need to verify that data lower layers "::" aren't
- * followed by regular ":" lower layers
- * (5) If ctx->nr > 0 => append
- * We know that there's at least one regular layer
- * otherwise we would've failed when parsing the previous
- * lowerdir mount option.
- * (5.1) The lowerdir mount option is a regular layer ":" append
- * => We need to verify that no data layers have been
- * specified before.
- * (5.2) The lowerdir mount option is a data layer "::" append
- * We know that there's at least one regular layer or
- * other data layers. => There's nothing to verify.
- */
- dup_iter = dup;
- for (nr = ctx->nr; nr < nr_lower; nr++) {
- l = &ctx->lower[nr];
+ iter = dup;
+ l = ctx->lower;
+ for (nr = 0; nr < nr_lower; nr++, l++) {
memset(l, 0, sizeof(*l));
- err = ovl_mount_dir_noesc(dup_iter, &l->path);
+ err = ovl_mount_dir(iter, &l->path);
+ if (err)
+ goto out_put;
+
+ err = ovl_mount_dir_check(fc, &l->path, Opt_lowerdir, iter, false);
if (err)
goto out_put;
err = -ENOMEM;
- l->name = kstrdup(dup_iter, GFP_KERNEL_ACCOUNT);
+ l->name = kstrdup(iter, GFP_KERNEL_ACCOUNT);
if (!l->name)
goto out_put;
break;
err = -EINVAL;
- dup_iter = strchr(dup_iter, '\0') + 1;
- if (*dup_iter) {
+ iter = strchr(iter, '\0') + 1;
+ if (*iter) {
/*
* This is a regular layer so we require that
* there are no data layers.
/* This is a data lower layer. */
data_layer = true;
- dup_iter++;
+ iter++;
}
ctx->nr = nr_lower;
ctx->nr_data += nr_data;
return 0;
out_put:
- /*
- * We know nr >= ctx->nr < nr_lower. If we failed somewhere
- * we want to undo until nr == ctx->nr. This is correct for
- * both ctx->nr == 0 and ctx->nr > 0.
- */
- for (; nr >= ctx->nr; nr--) {
- l = &ctx->lower[nr];
- kfree(l->name);
- l->name = NULL;
- path_put(&l->path);
-
- /* don't overflow */
- if (nr == 0)
- break;
- }
+ ovl_reset_lowerdirs(ctx);
out_err:
kfree(dup);
err = ovl_parse_param_lowerdir(param->string, fc);
break;
case Opt_upperdir:
- fallthrough;
case Opt_workdir:
- err = ovl_parse_param_upperdir(param->string, fc,
- (Opt_workdir == opt));
+ err = ovl_parse_layer(fc, param, opt);
break;
case Opt_default_permissions:
config->default_permissions = true;
static inline void ovl_fs_context_free(struct ovl_fs_context *ctx)
{
- ovl_parse_param_drop_lowerdir(ctx);
+ ovl_reset_lowerdirs(ctx);
path_put(&ctx->upper);
path_put(&ctx->work);
kfree(ctx->lower);
}
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,
{
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]);
+ char **lowerdirs = ofs->config.lowerdirs;
+
+ /*
+ * lowerdirs[0] holds the colon separated list that user provided
+ * with lowerdir mount option.
+ */
+ seq_show_option(m, "lowerdir", lowerdirs[0]);
if (ofs->config.upperdir) {
seq_show_option(m, "upperdir", ofs->config.upperdir);
seq_show_option(m, "workdir", ofs->config.workdir);
projects / thirdparty / kernel / linux.git / blobdiff