#include <linux/slab.h>
#include <linux/cred.h>
#include <linux/xattr.h>
+#include <linux/exportfs.h>
+#include <linux/uuid.h>
+#include <linux/namei.h>
+#include <linux/ratelimit.h>
#include "overlayfs.h"
#include "ovl_entry.h"
return ofs->same_sb;
}
+bool ovl_can_decode_fh(struct super_block *sb)
+{
+ return (sb->s_export_op && sb->s_export_op->fh_to_dentry &&
+ !uuid_is_null(&sb->s_uuid));
+}
+
+struct dentry *ovl_indexdir(struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ return ofs->indexdir;
+}
+
struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
{
size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
struct ovl_entry *oe = dentry->d_fsdata;
enum ovl_path_type type = 0;
- if (oe->__upperdentry) {
+ if (ovl_dentry_upper(dentry)) {
type = __OVL_PATH_UPPER;
/*
void ovl_path_upper(struct dentry *dentry, struct path *path)
{
struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct ovl_entry *oe = dentry->d_fsdata;
path->mnt = ofs->upper_mnt;
- path->dentry = ovl_upperdentry_dereference(oe);
+ path->dentry = ovl_dentry_upper(dentry);
}
void ovl_path_lower(struct dentry *dentry, struct path *path)
struct dentry *ovl_dentry_upper(struct dentry *dentry)
{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return ovl_upperdentry_dereference(oe);
+ return ovl_upperdentry_dereference(OVL_I(d_inode(dentry)));
}
-static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
+struct dentry *ovl_dentry_lower(struct dentry *dentry)
{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
return oe->numlower ? oe->lowerstack[0].dentry : NULL;
}
-struct dentry *ovl_dentry_lower(struct dentry *dentry)
+struct dentry *ovl_dentry_real(struct dentry *dentry)
{
- struct ovl_entry *oe = dentry->d_fsdata;
+ return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);
+}
- return __ovl_dentry_lower(oe);
+struct dentry *ovl_i_dentry_upper(struct inode *inode)
+{
+ return ovl_upperdentry_dereference(OVL_I(inode));
}
-struct dentry *ovl_dentry_real(struct dentry *dentry)
+struct inode *ovl_inode_upper(struct inode *inode)
{
- struct ovl_entry *oe = dentry->d_fsdata;
- struct dentry *realdentry;
+ struct dentry *upperdentry = ovl_i_dentry_upper(inode);
- realdentry = ovl_upperdentry_dereference(oe);
- if (!realdentry)
- realdentry = __ovl_dentry_lower(oe);
+ return upperdentry ? d_inode(upperdentry) : NULL;
+}
- return realdentry;
+struct inode *ovl_inode_lower(struct inode *inode)
+{
+ return OVL_I(inode)->lower;
}
-struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
+struct inode *ovl_inode_real(struct inode *inode)
{
- struct ovl_entry *oe = dentry->d_fsdata;
+ return ovl_inode_upper(inode) ?: ovl_inode_lower(inode);
+}
- return oe->cache;
+
+struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
+{
+ return OVL_I(d_inode(dentry))->cache;
}
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- oe->cache = cache;
+ OVL_I(d_inode(dentry))->cache = cache;
}
bool ovl_dentry_is_opaque(struct dentry *dentry)
return oe->opaque;
}
-bool ovl_dentry_is_impure(struct dentry *dentry)
+bool ovl_dentry_is_whiteout(struct dentry *dentry)
+{
+ return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
+}
+
+void ovl_dentry_set_opaque(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
- return oe->impure;
+ oe->opaque = true;
}
-bool ovl_dentry_is_whiteout(struct dentry *dentry)
+/*
+ * For hard links it's possible for ovl_dentry_upper() to return positive, while
+ * there's no actual upper alias for the inode. Copy up code needs to know
+ * about the existence of the upper alias, so it can't use ovl_dentry_upper().
+ */
+bool ovl_dentry_has_upper_alias(struct dentry *dentry)
{
- return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return oe->has_upper;
}
-void ovl_dentry_set_opaque(struct dentry *dentry)
+void ovl_dentry_set_upper_alias(struct dentry *dentry)
{
struct ovl_entry *oe = dentry->d_fsdata;
- oe->opaque = true;
+ oe->has_upper = true;
}
bool ovl_redirect_dir(struct super_block *sb)
const char *ovl_dentry_get_redirect(struct dentry *dentry)
{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return oe->redirect;
+ return OVL_I(d_inode(dentry))->redirect;
}
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
{
- struct ovl_entry *oe = dentry->d_fsdata;
+ struct ovl_inode *oi = OVL_I(d_inode(dentry));
- kfree(oe->redirect);
- oe->redirect = redirect;
+ kfree(oi->redirect);
+ oi->redirect = redirect;
}
-void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
+void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
+ struct dentry *lowerdentry)
{
- struct ovl_entry *oe = dentry->d_fsdata;
+ if (upperdentry)
+ OVL_I(inode)->__upperdentry = upperdentry;
+ if (lowerdentry)
+ OVL_I(inode)->lower = d_inode(lowerdentry);
- WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
- WARN_ON(oe->__upperdentry);
- /*
- * Make sure upperdentry is consistent before making it visible to
- * ovl_upperdentry_dereference().
- */
- smp_wmb();
- oe->__upperdentry = upperdentry;
+ ovl_copyattr(d_inode(upperdentry ?: lowerdentry), inode);
}
-void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
+void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
{
- WRITE_ONCE(inode->i_private, (unsigned long) realinode |
- (is_upper ? OVL_ISUPPER_MASK : 0));
-}
+ struct inode *upperinode = d_inode(upperdentry);
-void ovl_inode_update(struct inode *inode, struct inode *upperinode)
-{
- WARN_ON(!upperinode);
- WARN_ON(!inode_unhashed(inode));
- WRITE_ONCE(inode->i_private,
- (unsigned long) upperinode | OVL_ISUPPER_MASK);
- if (!S_ISDIR(upperinode->i_mode))
+ WARN_ON(OVL_I(inode)->__upperdentry);
+
+ /*
+ * Make sure upperdentry is consistent before making it visible
+ */
+ smp_wmb();
+ OVL_I(inode)->__upperdentry = upperdentry;
+ if (!S_ISDIR(upperinode->i_mode) && inode_unhashed(inode)) {
+ inode->i_private = upperinode;
__insert_inode_hash(inode, (unsigned long) upperinode);
+ }
}
void ovl_dentry_version_inc(struct dentry *dentry)
{
- struct ovl_entry *oe = dentry->d_fsdata;
+ struct inode *inode = d_inode(dentry);
- WARN_ON(!inode_is_locked(dentry->d_inode));
- oe->version++;
+ WARN_ON(!inode_is_locked(inode));
+ OVL_I(inode)->version++;
}
u64 ovl_dentry_version_get(struct dentry *dentry)
{
- struct ovl_entry *oe = dentry->d_fsdata;
+ struct inode *inode = d_inode(dentry);
- WARN_ON(!inode_is_locked(dentry->d_inode));
- return oe->version;
+ WARN_ON(!inode_is_locked(inode));
+ return OVL_I(inode)->version;
}
bool ovl_is_whiteout(struct dentry *dentry)
int ovl_copy_up_start(struct dentry *dentry)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct ovl_entry *oe = dentry->d_fsdata;
+ struct ovl_inode *oi = OVL_I(d_inode(dentry));
int err;
- spin_lock(&ofs->copyup_wq.lock);
- err = wait_event_interruptible_locked(ofs->copyup_wq, !oe->copying);
- if (!err) {
- if (oe->__upperdentry)
- err = 1; /* Already copied up */
- else
- oe->copying = true;
+ err = mutex_lock_interruptible(&oi->lock);
+ if (!err && ovl_dentry_has_upper_alias(dentry)) {
+ err = 1; /* Already copied up */
+ mutex_unlock(&oi->lock);
}
- spin_unlock(&ofs->copyup_wq.lock);
return err;
}
void ovl_copy_up_end(struct dentry *dentry)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct ovl_entry *oe = dentry->d_fsdata;
-
- spin_lock(&ofs->copyup_wq.lock);
- oe->copying = false;
- wake_up_locked(&ofs->copyup_wq);
- spin_unlock(&ofs->copyup_wq.lock);
+ mutex_unlock(&OVL_I(d_inode(dentry))->lock);
}
bool ovl_check_dir_xattr(struct dentry *dentry, const char *name)
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry)
{
int err;
- struct ovl_entry *oe = dentry->d_fsdata;
- if (oe->impure)
+ if (ovl_test_flag(OVL_IMPURE, d_inode(dentry)))
return 0;
/*
err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE,
"y", 1, 0);
if (!err)
- oe->impure = true;
+ ovl_set_flag(OVL_IMPURE, d_inode(dentry));
return err;
}
+
+void ovl_set_flag(unsigned long flag, struct inode *inode)
+{
+ set_bit(flag, &OVL_I(inode)->flags);
+}
+
+bool ovl_test_flag(unsigned long flag, struct inode *inode)
+{
+ return test_bit(flag, &OVL_I(inode)->flags);
+}
+
+/**
+ * Caller must hold a reference to inode to prevent it from being freed while
+ * it is marked inuse.
+ */
+bool ovl_inuse_trylock(struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ bool locked = false;
+
+ spin_lock(&inode->i_lock);
+ if (!(inode->i_state & I_OVL_INUSE)) {
+ inode->i_state |= I_OVL_INUSE;
+ locked = true;
+ }
+ spin_unlock(&inode->i_lock);
+
+ return locked;
+}
+
+void ovl_inuse_unlock(struct dentry *dentry)
+{
+ if (dentry) {
+ struct inode *inode = d_inode(dentry);
+
+ spin_lock(&inode->i_lock);
+ WARN_ON(!(inode->i_state & I_OVL_INUSE));
+ inode->i_state &= ~I_OVL_INUSE;
+ spin_unlock(&inode->i_lock);
+ }
+}
+
+/* Called must hold OVL_I(inode)->oi_lock */
+static void ovl_cleanup_index(struct dentry *dentry)
+{
+ struct inode *dir = ovl_indexdir(dentry->d_sb)->d_inode;
+ struct dentry *lowerdentry = ovl_dentry_lower(dentry);
+ struct dentry *upperdentry = ovl_dentry_upper(dentry);
+ struct dentry *index = NULL;
+ struct inode *inode;
+ struct qstr name;
+ int err;
+
+ err = ovl_get_index_name(lowerdentry, &name);
+ if (err)
+ goto fail;
+
+ inode = d_inode(upperdentry);
+ if (inode->i_nlink != 1) {
+ pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n",
+ upperdentry, inode->i_ino, inode->i_nlink);
+ /*
+ * We either have a bug with persistent union nlink or a lower
+ * hardlink was added while overlay is mounted. Adding a lower
+ * hardlink and then unlinking all overlay hardlinks would drop
+ * overlay nlink to zero before all upper inodes are unlinked.
+ * As a safety measure, when that situation is detected, set
+ * the overlay nlink to the index inode nlink minus one for the
+ * index entry itself.
+ */
+ set_nlink(d_inode(dentry), inode->i_nlink - 1);
+ ovl_set_nlink_upper(dentry);
+ goto out;
+ }
+
+ inode_lock_nested(dir, I_MUTEX_PARENT);
+ /* TODO: whiteout instead of cleanup to block future open by handle */
+ index = lookup_one_len(name.name, ovl_indexdir(dentry->d_sb), name.len);
+ err = PTR_ERR(index);
+ if (!IS_ERR(index))
+ err = ovl_cleanup(dir, index);
+ inode_unlock(dir);
+ if (err)
+ goto fail;
+
+out:
+ dput(index);
+ return;
+
+fail:
+ pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err);
+ goto out;
+}
+
+/*
+ * Operations that change overlay inode and upper inode nlink need to be
+ * synchronized with copy up for persistent nlink accounting.
+ */
+int ovl_nlink_start(struct dentry *dentry, bool *locked)
+{
+ struct ovl_inode *oi = OVL_I(d_inode(dentry));
+ const struct cred *old_cred;
+ int err;
+
+ if (!d_inode(dentry) || d_is_dir(dentry))
+ return 0;
+
+ /*
+ * With inodes index is enabled, we store the union overlay nlink
+ * in an xattr on the index inode. When whiting out lower hardlinks
+ * we need to decrement the overlay persistent nlink, but before the
+ * first copy up, we have no upper index inode to store the xattr.
+ *
+ * As a workaround, before whiteout/rename over of a lower hardlink,
+ * copy up to create the upper index. Creating the upper index will
+ * initialize the overlay nlink, so it could be dropped if unlink
+ * or rename succeeds.
+ *
+ * TODO: implement metadata only index copy up when called with
+ * ovl_copy_up_flags(dentry, O_PATH).
+ */
+ if (ovl_indexdir(dentry->d_sb) && !ovl_dentry_has_upper_alias(dentry) &&
+ d_inode(ovl_dentry_lower(dentry))->i_nlink > 1) {
+ err = ovl_copy_up(dentry);
+ if (err)
+ return err;
+ }
+
+ err = mutex_lock_interruptible(&oi->lock);
+ if (err)
+ return err;
+
+ if (!ovl_test_flag(OVL_INDEX, d_inode(dentry)))
+ goto out;
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+ /*
+ * The overlay inode nlink should be incremented/decremented IFF the
+ * upper operation succeeds, along with nlink change of upper inode.
+ * Therefore, before link/unlink/rename, we store the union nlink
+ * value relative to the upper inode nlink in an upper inode xattr.
+ */
+ err = ovl_set_nlink_upper(dentry);
+ revert_creds(old_cred);
+
+out:
+ if (err)
+ mutex_unlock(&oi->lock);
+ else
+ *locked = true;
+
+ return err;
+}
+
+void ovl_nlink_end(struct dentry *dentry, bool locked)
+{
+ if (locked) {
+ if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) &&
+ d_inode(dentry)->i_nlink == 0) {
+ const struct cred *old_cred;
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+ ovl_cleanup_index(dentry);
+ revert_creds(old_cred);
+ }
+
+ mutex_unlock(&OVL_I(d_inode(dentry))->lock);
+ }
+}
projects / linux.git / blobdiff