#include <linux/fs.h>
#include <linux/namei.h>
+#include <linux/pagemap.h>
#include <linux/xattr.h>
#include <linux/security.h>
#include <linux/mount.h>
if (oe->__upperdentry) {
type = __OVL_PATH_UPPER;
- if (oe->numlower) {
- if (S_ISDIR(dentry->d_inode->i_mode))
- type |= __OVL_PATH_MERGE;
- } else if (!oe->opaque) {
+ /*
+ * Non-dir dentry can hold lower dentry from previous
+ * location. Its purity depends only on opaque flag.
+ */
+ if (oe->numlower && S_ISDIR(dentry->d_inode->i_mode))
+ type |= __OVL_PATH_MERGE;
+ else if (!oe->opaque)
type |= __OVL_PATH_PURE;
- }
} else {
if (oe->numlower > 1)
type |= __OVL_PATH_MERGE;
}
}
+static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ unsigned int i;
+ int ret = 1;
+
+ for (i = 0; i < oe->numlower; i++) {
+ struct dentry *d = oe->lowerstack[i].dentry;
+
+ if (d->d_flags & DCACHE_OP_REVALIDATE) {
+ ret = d->d_op->d_revalidate(d, flags);
+ if (ret < 0)
+ return ret;
+ if (!ret) {
+ if (!(flags & LOOKUP_RCU))
+ d_invalidate(d);
+ return -ESTALE;
+ }
+ }
+ }
+ return 1;
+}
+
+static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ unsigned int i;
+ int ret = 1;
+
+ for (i = 0; i < oe->numlower; i++) {
+ struct dentry *d = oe->lowerstack[i].dentry;
+
+ if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) {
+ ret = d->d_op->d_weak_revalidate(d, flags);
+ if (ret <= 0)
+ break;
+ }
+ }
+ return ret;
+}
+
static const struct dentry_operations ovl_dentry_operations = {
.d_release = ovl_dentry_release,
+ .d_select_inode = ovl_d_select_inode,
+};
+
+static const struct dentry_operations ovl_reval_dentry_operations = {
+ .d_release = ovl_dentry_release,
+ .d_select_inode = ovl_d_select_inode,
+ .d_revalidate = ovl_dentry_revalidate,
+ .d_weak_revalidate = ovl_dentry_weak_revalidate,
};
static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
return oe;
}
+static bool ovl_dentry_remote(struct dentry *dentry)
+{
+ return dentry->d_flags &
+ (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
+}
+
+static bool ovl_dentry_weird(struct dentry *dentry)
+{
+ return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
+ DCACHE_MANAGE_TRANSIT |
+ DCACHE_OP_HASH |
+ DCACHE_OP_COMPARE);
+}
+
static inline struct dentry *ovl_lookup_real(struct dentry *dir,
struct qstr *name)
{
} else if (!dentry->d_inode) {
dput(dentry);
dentry = NULL;
+ } else if (ovl_dentry_weird(dentry)) {
+ dput(dentry);
+ /* Don't support traversing automounts and other weirdness */
+ dentry = ERR_PTR(-EREMOTE);
}
return dentry;
}
goto out;
if (this) {
+ if (unlikely(ovl_dentry_remote(this))) {
+ dput(this);
+ err = -EREMOTE;
+ goto out;
+ }
if (ovl_is_whiteout(this)) {
dput(this);
this = NULL;
mntput(ufs->upper_mnt);
for (i = 0; i < ufs->numlower; i++)
mntput(ufs->lower_mnt[i]);
+ kfree(ufs->lower_mnt);
kfree(ufs->config.lowerdir);
kfree(ufs->config.upperdir);
}
}
-static bool ovl_is_allowed_fs_type(struct dentry *root)
-{
- const struct dentry_operations *dop = root->d_op;
-
- /*
- * We don't support:
- * - automount filesystems
- * - filesystems with revalidate (FIXME for lower layer)
- * - filesystems with case insensitive names
- */
- if (dop &&
- (dop->d_manage || dop->d_automount ||
- dop->d_revalidate || dop->d_weak_revalidate ||
- dop->d_compare || dop->d_hash)) {
- return false;
- }
- return true;
-}
-
static int ovl_mount_dir_noesc(const char *name, struct path *path)
{
int err = -EINVAL;
goto out;
}
err = -EINVAL;
- if (!ovl_is_allowed_fs_type(path->dentry)) {
+ if (ovl_dentry_weird(path->dentry)) {
pr_err("overlayfs: filesystem on '%s' not supported\n", name);
goto out_put;
}
if (tmp) {
ovl_unescape(tmp);
err = ovl_mount_dir_noesc(tmp, path);
+
+ if (!err)
+ if (ovl_dentry_remote(path->dentry)) {
+ pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n",
+ tmp);
+ path_put(path);
+ err = -EINVAL;
+ }
kfree(tmp);
}
return err;
}
static int ovl_lower_dir(const char *name, struct path *path, long *namelen,
- int *stack_depth)
+ int *stack_depth, bool *remote)
{
int err;
struct kstatfs statfs;
*namelen = max(*namelen, statfs.f_namelen);
*stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
+ if (ovl_dentry_remote(path->dentry))
+ *remote = true;
+
return 0;
out_put:
unsigned int numlower;
unsigned int stacklen = 0;
unsigned int i;
+ bool remote = false;
int err;
err = -ENOMEM;
}
sb->s_stack_depth = 0;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
if (ufs->config.upperdir) {
if (!ufs->config.workdir) {
pr_err("overlayfs: missing 'workdir'\n");
lower = lowertmp;
for (numlower = 0; numlower < stacklen; numlower++) {
err = ovl_lower_dir(lower, &stack[numlower],
- &ufs->lower_namelen, &sb->s_stack_depth);
+ &ufs->lower_namelen, &sb->s_stack_depth,
+ &remote);
if (err)
goto out_put_lowerpath;
if (!ufs->upper_mnt)
sb->s_flags |= MS_RDONLY;
- sb->s_d_op = &ovl_dentry_operations;
+ if (remote)
+ sb->s_d_op = &ovl_reval_dentry_operations;
+ else
+ sb->s_d_op = &ovl_dentry_operations;
err = -ENOMEM;
oe = ovl_alloc_entry(numlower);
oe->lowerstack[i].dentry = stack[i].dentry;
oe->lowerstack[i].mnt = ufs->lower_mnt[i];
}
+ kfree(stack);
root_dentry->d_fsdata = oe;
+ ovl_copyattr(ovl_dentry_real(root_dentry)->d_inode,
+ root_dentry->d_inode);
+
sb->s_magic = OVERLAYFS_SUPER_MAGIC;
sb->s_op = &ovl_super_operations;
sb->s_root = root_dentry;
Code Review / kvmfornfv.git / blobdiff