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From: Amir Goldstein <amir73il@gmail.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-unionfs@vger.kernel.org
Subject: [PATCH v4 11/25] ovl: cleanup bad and stale index entries on mount
Date: Wed, 21 Jun 2017 15:28:42 +0300	[thread overview]
Message-ID: <1498048136-28218-12-git-send-email-amir73il@gmail.com> (raw)
In-Reply-To: <1498048136-28218-1-git-send-email-amir73il@gmail.com>

Bad index entries are entries whose name does not match the
origin file handle stored in trusted.overlay.origin xattr.
Bad index entries could be a result of a system power off in
the middle of copy up.

Stale index entries are entries whose origin file handle is
stale. Stale index entries could be a result of copying layers
or removing lower entries while the overlay is not mounted.
The case of copying layers should be detected earlier by the
verification of upper root dir origin and index dir origin.

Both bad and stale index entries are detected and removed
on mount.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/overlayfs/dir.c       |  4 ++-
 fs/overlayfs/namei.c     | 74 ++++++++++++++++++++++++++++++++++++++++++------
 fs/overlayfs/overlayfs.h |  6 +++-
 fs/overlayfs/readdir.c   | 50 ++++++++++++++++++++++++++++++++
 fs/overlayfs/super.c     |  6 ++++
 5 files changed, 130 insertions(+), 10 deletions(-)

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index a63a71656e9b..822be8647d88 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -24,7 +24,7 @@ module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
 MODULE_PARM_DESC(ovl_redirect_max,
 		 "Maximum length of absolute redirect xattr value");
 
-void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
+int ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
 {
 	int err;
 
@@ -39,6 +39,8 @@ void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
 		pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
 		       wdentry, err);
 	}
+
+	return err;
 }
 
 struct dentry *ovl_lookup_temp(struct dentry *workdir)
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index debe489fbb47..261ea51199c6 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -285,17 +285,17 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,
 }
 
 
-static int ovl_check_origin(struct dentry *dentry, struct dentry *upperdentry,
+static int ovl_check_origin(struct dentry *upperdentry,
+			    struct path *lowerstack, unsigned int numlower,
 			    struct path **stackp, unsigned int *ctrp)
 {
-	struct ovl_entry *roe = dentry->d_sb->s_root->d_fsdata;
 	struct vfsmount *mnt;
 	struct dentry *origin = NULL;
 	int i;
 
 
-	for (i = 0; i < roe->numlower; i++) {
-		mnt = roe->lowerstack[i].mnt;
+	for (i = 0; i < numlower; i++) {
+		mnt = lowerstack[i].mnt;
 		origin = ovl_get_origin(upperdentry, mnt);
 		if (IS_ERR(origin))
 			return PTR_ERR(origin);
@@ -307,8 +307,9 @@ static int ovl_check_origin(struct dentry *dentry, struct dentry *upperdentry,
 	if (!origin)
 		return 0;
 
-	BUG_ON(*stackp || *ctrp);
-	*stackp = kmalloc(sizeof(struct path), GFP_TEMPORARY);
+	BUG_ON(*ctrp);
+	if (!*stackp)
+		*stackp = kmalloc(sizeof(struct path), GFP_TEMPORARY);
 	if (!*stackp) {
 		dput(origin);
 		return -ENOMEM;
@@ -380,6 +381,63 @@ int ovl_verify_origin(struct dentry *dentry, struct vfsmount *mnt,
 }
 
 /*
+ * Verify that an index entry name matches the origin file handle stored in
+ * OVL_XATTR_ORIGIN and that origin file handle can be decoded to lower path.
+ * Return 0 on match, -ESTALE on mismatch or stale origin, < 0 on error.
+ */
+int ovl_verify_index(struct dentry *index, struct path *lowerstack,
+		     unsigned int numlower)
+{
+	struct ovl_fh *fh = NULL;
+	size_t len;
+	struct path origin = { };
+	struct path *stack = &origin;
+	unsigned int ctr = 0;
+	int err;
+
+	if (!d_inode(index))
+		return 0;
+
+	err = -EISDIR;
+	if (d_is_dir(index))
+		goto fail;
+
+	err = -EINVAL;
+	if (index->d_name.len < sizeof(struct ovl_fh)*2)
+		goto fail;
+
+	err = -ENOMEM;
+	len = index->d_name.len / 2;
+	fh = kzalloc(len, GFP_TEMPORARY);
+	if (!fh)
+		goto fail;
+
+	err = -EINVAL;
+	if (hex2bin((u8 *)fh, index->d_name.name, len) || len != fh->len)
+		goto fail;
+
+	err = ovl_verify_origin_fh(index, fh);
+	if (err)
+		goto fail;
+
+	err = ovl_check_origin(index, lowerstack, numlower, &stack, &ctr);
+	if (!err && !ctr)
+		err = -ESTALE;
+	if (err)
+		goto fail;
+
+	dput(origin.dentry);
+out:
+	kfree(fh);
+	return err;
+
+fail:
+	pr_warn_ratelimited("overlayfs: failed to verify index (%pd2, err=%i)\n",
+			    index, err);
+	goto out;
+}
+
+/*
  * Lookup in indexdir for the index entry of a lower real inode or a copy up
  * origin inode. The index entry name is the hex representation of the lower
  * inode file handle.
@@ -535,8 +593,8 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 			 * number - it's the same as if we held a reference
 			 * to a dentry in lower layer that was moved under us.
 			 */
-			err = ovl_check_origin(dentry, upperdentry,
-					       &stack, &ctr);
+			err = ovl_check_origin(upperdentry, roe->lowerstack,
+					       roe->numlower, &stack, &ctr);
 			if (err)
 				goto out;
 		}
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 596b728f394c..a92af10fd369 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -246,6 +246,8 @@ static inline bool ovl_is_impuredir(struct dentry *dentry)
 /* namei.c */
 int ovl_verify_origin(struct dentry *dentry, struct vfsmount *mnt,
 		      struct dentry *origin, bool is_upper, bool set);
+int ovl_verify_index(struct dentry *index, struct path *lowerstack,
+		     unsigned int numlower);
 int ovl_lookup_index(struct dentry *dentry, struct dentry *upper,
 		     struct dentry *lower, struct dentry **indexp);
 int ovl_path_next(int idx, struct dentry *dentry, struct path *path, int *idxp);
@@ -260,6 +262,8 @@ void ovl_cache_free(struct list_head *list);
 int ovl_check_d_type_supported(struct path *realpath);
 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 			 struct dentry *dentry, int level);
+int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
+			 struct path *lowerstack, unsigned int numlower);
 
 /* inode.c */
 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
@@ -299,7 +303,7 @@ struct cattr {
 int ovl_create_real(struct inode *dir, struct dentry *newdentry,
 		    struct cattr *attr,
 		    struct dentry *hardlink, bool debug);
-void ovl_cleanup(struct inode *dir, struct dentry *dentry);
+int ovl_cleanup(struct inode *dir, struct dentry *dentry);
 
 /* copy_up.c */
 int ovl_copy_up(struct dentry *dentry);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 3de5ebe7e7b9..e59d3e1c9173 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -786,3 +786,53 @@ void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
 		ovl_cleanup(dir, dentry);
 	}
 }
+
+int ovl_indexdir_cleanup(struct dentry *dentry, struct vfsmount *mnt,
+			 struct path *lowerstack, unsigned int numlower)
+{
+	int err;
+	struct inode *dir = dentry->d_inode;
+	struct path path = { .mnt = mnt, .dentry = dentry };
+	LIST_HEAD(list);
+	struct ovl_cache_entry *p;
+	struct ovl_readdir_data rdd = {
+		.ctx.actor = ovl_fill_merge,
+		.dentry = NULL,
+		.list = &list,
+		.root = RB_ROOT,
+		.is_lowest = false,
+	};
+
+	err = ovl_dir_read(&path, &rdd);
+	if (err)
+		goto out;
+
+	inode_lock_nested(dir, I_MUTEX_PARENT);
+	list_for_each_entry(p, &list, l_node) {
+		struct dentry *index;
+
+		if (p->name[0] == '.') {
+			if (p->len == 1)
+				continue;
+			if (p->len == 2 && p->name[1] == '.')
+				continue;
+		}
+		index = lookup_one_len(p->name, dentry, p->len);
+		if (IS_ERR(index)) {
+			err = PTR_ERR(index);
+			break;
+		}
+		if (ovl_verify_index(index, lowerstack, numlower)) {
+			err = ovl_cleanup(dir, index);
+			if (err)
+				break;
+		}
+		dput(index);
+	}
+	inode_unlock(dir);
+out:
+	ovl_cache_free(&list);
+	if (err)
+		pr_err("overlayfs: failed index dir cleanup (%i)\n", err);
+	return err;
+}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 2e6062a073d4..b3ac406654bd 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1050,6 +1050,12 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
 						upperpath.dentry, true, true);
 			if (err)
 				pr_err("overlayfs: failed to verify index dir origin\n");
+
+			/* Cleanup bad/stale index entries */
+			if (!err)
+				err = ovl_indexdir_cleanup(ufs->indexdir,
+							   ufs->upper_mnt,
+							   stack, numlower);
 		}
 		if (err || !ufs->indexdir)
 			pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n");
-- 
2.7.4

  parent reply	other threads:[~2017-06-21 12:29 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-21 12:28 [PATCH v4 00/25] Overlayfs inodes index Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 01/25] vfs: introduce inode 'inuse' lock Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 02/25] ovl: get exclusive ownership on upper/work dirs Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 03/25] ovl: relax same fs constrain for ovl_check_origin() Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 04/25] ovl: generalize ovl_create_workdir() Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 05/25] ovl: introduce the inodes index dir feature Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 06/25] ovl: verify upper root dir matches lower root dir Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 07/25] ovl: verify index dir matches upper dir Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 08/25] ovl: store path type in dentry Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 09/25] ovl: cram dentry state booleans into type flags Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 10/25] ovl: lookup index entry for copy up origin Amir Goldstein
2017-06-21 12:28 ` Amir Goldstein [this message]
2017-06-21 12:28 ` [PATCH v4 12/25] ovl: allocate an ovl_inode struct Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 13/25] ovl: store upper/lower real inode in ovl_inode_info Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 14/25] ovl: use ovl_inode_init() for initializing new inode Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 15/25] ovl: hash overlay non-dir inodes by copy up origin inode Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 16/25] ovl: defer upper dir lock to tempfile link Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 17/25] ovl: factor out ovl_copy_up_inode() helper Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 18/25] ovl: generalize ovl_copy_up_locked() using actors Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 19/25] ovl: generalize ovl_copy_up_one() " Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 20/25] ovl: use ovl_inode mutex to synchronize concurrent copy up Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 21/25] ovl: implement index dir copy up method Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 22/25] ovl: link up indexed lower hardlink on lookup Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 23/25] ovl: fix nlink leak in ovl_rename() Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 24/25] ovl: persistent overlay inode nlink for indexed inodes Amir Goldstein
2017-06-23 11:34   ` Amir Goldstein
2017-06-21 12:28 ` [PATCH v4 25/25] ovl: cleanup orphan index entries Amir Goldstein
2017-06-21 16:45   ` Amir Goldstein
2017-06-21 17:02 ` [PATCH v4 00/25] Overlayfs inodes index Amir Goldstein
2017-06-21 20:03   ` Amir Goldstein
2017-06-22 10:18 ` [PATCH v4 26/25] ovl: document copying layers restrictions with " Amir Goldstein

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