{
unsigned i;
+ iput(ofs->workbasedir_trap);
iput(ofs->indexdir_trap);
iput(ofs->workdir_trap);
iput(ofs->upperdir_trap);
return 0;
}
+/*
+ * Determine how we treat concurrent use of upperdir/workdir based on the
+ * index feature. This is papering over mount leaks of container runtimes,
+ * for example, an old overlay mount is leaked and now its upperdir is
+ * attempted to be used as a lower layer in a new overlay mount.
+ */
+static int ovl_report_in_use(struct ovl_fs *ofs, const char *name)
+{
+ if (ofs->config.index) {
+ pr_err("overlayfs: %s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n",
+ name);
+ return -EBUSY;
+ } else {
+ pr_warn("overlayfs: %s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n",
+ name);
+ return 0;
+ }
+}
+
static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs,
struct path *upperpath)
{
upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);
ofs->upper_mnt = upper_mnt;
- err = -EBUSY;
if (ovl_inuse_trylock(ofs->upper_mnt->mnt_root)) {
ofs->upperdir_locked = true;
- } else if (ofs->config.index) {
- pr_err("overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection.\n");
- goto out;
} else {
- pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
+ err = ovl_report_in_use(ofs, "upperdir");
+ if (err)
+ goto out;
}
err = 0;
ofs->workbasedir = dget(workpath.dentry);
- err = -EBUSY;
if (ovl_inuse_trylock(ofs->workbasedir)) {
ofs->workdir_locked = true;
- } else if (ofs->config.index) {
- pr_err("overlayfs: workdir is in-use by another mount, mount with '-o index=off' to override exclusive workdir protection.\n");
- goto out;
} else {
- pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n");
+ err = ovl_report_in_use(ofs, "workdir");
+ if (err)
+ goto out;
}
+ err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap,
+ "workdir");
+ if (err)
+ goto out;
+
err = ovl_make_workdir(sb, ofs, &workpath);
out:
if (err < 0)
goto out;
- err = -EBUSY;
- if (ovl_is_inuse(stack[i].dentry)) {
- pr_err("overlayfs: lowerdir is in-use as upperdir/workdir\n");
- goto out;
- }
-
err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir");
if (err)
goto out;
+ if (ovl_is_inuse(stack[i].dentry)) {
+ err = ovl_report_in_use(ofs, "lowerdir");
+ if (err)
+ goto out;
+ }
+
mnt = clone_private_mount(&stack[i]);
err = PTR_ERR(mnt);
if (IS_ERR(mnt)) {
* - another layer of this overlayfs instance
* - upper/work dir of any overlayfs instance
*/
-static int ovl_check_layer(struct super_block *sb, struct dentry *dentry,
- const char *name)
+static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs,
+ struct dentry *dentry, const char *name)
{
struct dentry *next = dentry, *parent;
int err = 0;
/* Walk back ancestors to root (inclusive) looking for traps */
while (!err && parent != next) {
- if (ovl_is_inuse(parent)) {
- err = -EBUSY;
- pr_err("overlayfs: %s path overlapping in-use upperdir/workdir\n",
- name);
- } else if (ovl_lookup_trap_inode(sb, parent)) {
+ if (ovl_lookup_trap_inode(sb, parent)) {
err = -ELOOP;
pr_err("overlayfs: overlapping %s path\n", name);
+ } else if (ovl_is_inuse(parent)) {
+ err = ovl_report_in_use(ofs, name);
}
next = parent;
parent = dget_parent(next);
int i, err;
if (ofs->upper_mnt) {
- err = ovl_check_layer(sb, ofs->upper_mnt->mnt_root, "upperdir");
+ err = ovl_check_layer(sb, ofs, ofs->upper_mnt->mnt_root,
+ "upperdir");
if (err)
return err;
* workbasedir. In that case, we already have their traps in
* inode cache and we will catch that case on lookup.
*/
- err = ovl_check_layer(sb, ofs->workbasedir, "workdir");
+ err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir");
if (err)
return err;
}
for (i = 0; i < ofs->numlower; i++) {
- err = ovl_check_layer(sb, ofs->lower_layers[i].mnt->mnt_root,
+ err = ovl_check_layer(sb, ofs,
+ ofs->lower_layers[i].mnt->mnt_root,
"lowerdir");
if (err)
return err;