summaryrefslogtreecommitdiff
path: root/fs/overlayfs/params.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/overlayfs/params.c')
-rw-r--r--fs/overlayfs/params.c126
1 files changed, 59 insertions, 67 deletions
diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
index b9355bb6d75a..f6ff23fd101c 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,
@@ -752,12 +736,12 @@ void ovl_free_fs(struct ovl_fs *ofs)
if (ofs->upperdir_locked)
ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root);
- /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */
- mounts = (struct vfsmount **) ofs->layers;
+ /* Reuse ofs->config.lowerdirs as a vfsmount array before freeing it */
+ mounts = (struct vfsmount **) ofs->config.lowerdirs;
for (i = 0; i < ofs->numlayer; i++) {
iput(ofs->layers[i].trap);
+ kfree(ofs->config.lowerdirs[i]);
mounts[i] = ofs->layers[i].mnt;
- kfree(ofs->layers[i].name);
}
kern_unmount_array(mounts, ofs->numlayer);
kfree(ofs->layers);
@@ -765,6 +749,7 @@ void ovl_free_fs(struct ovl_fs *ofs)
free_anon_bdev(ofs->fs[i].pseudo_dev);
kfree(ofs->fs);
+ kfree(ofs->config.lowerdirs);
kfree(ofs->config.upperdir);
kfree(ofs->config.workdir);
if (ofs->creator_cred)
@@ -949,16 +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;
- const struct ovl_layer *data_layers = &ofs->layers[nr_merged_lower];
-
- /* ofs->layers[0] is the upper layer */
- seq_printf(m, ",lowerdir=%s", ofs->layers[1].name);
- /* dump regular lower layers */
- for (nr = 2; nr < nr_merged_lower; nr++)
- seq_printf(m, ":%s", ofs->layers[nr].name);
- /* dump data lower layers */
- for (nr = 0; nr < ofs->numdatalayer; nr++)
- seq_printf(m, "::%s", data_layers[nr].name);
+
+ /*
+ * 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);
generated by cgit (git 2.34.1) at 2024-05-31 00:46:41 +0000