Merge tag 'ovl-update-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs

be3c2131 · Linus Torvalds <[email protected]> · 2023-06-29 13:01:27 -07:00

Pull overlayfs update from Amir Goldstein:

 - fix two NULL pointer deref bugs (Zhihao Cheng)

 - add support for "data-only" lower layers destined to be used by
   composefs

 - port overlayfs to the new mount api (Christian Brauner)

* tag 'ovl-update-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/overlayfs/vfs: (26 commits)
  ovl: add Amir as co-maintainer
  ovl: reserve ability to reconfigure mount options with new mount api
  ovl: modify layer parameter parsing
  ovl: port to new mount api
  ovl: factor out ovl_parse_options() helper
  ovl: store enum redirect_mode in config instead of a string
  ovl: pass ovl_fs to xino helpers
  ovl: clarify ovl_get_root() semantics
  ovl: negate the ofs->share_whiteout boolean
  ovl: check type and offset of struct vfsmount in ovl_entry
  ovl: implement lazy lookup of lowerdata in data-only layers
  ovl: prepare for lazy lookup of lowerdata inode
  ovl: prepare to store lowerdata redirect for lazy lowerdata lookup
  ovl: implement lookup in data-only layers
  ovl: introduce data-only lower layers
  ovl: remove unneeded goto instructions
  ovl: deduplicate lowerdata and lowerstack[]
  ovl: deduplicate lowerpath and lowerstack[]
  ovl: move ovl_entry into ovl_inode
  ovl: factor out ovl_free_entry() and ovl_stack_*() helpers
  ...

Commit: be3c213150dc4370ef211a78d78457ff166eba4e
Parents: eee9c708 · 62149a74

Merge commit. Changes below are compared with the first parent: eee9c708.

Changes

15 files changed · +1390 −704

File	Status	Add	Del	Content
Documentation/filesystems/overlayfs.rst	modified	+39	−5	View file
MAINTAINERS	modified	+1	−0	View file
fs/overlayfs/Makefile	modified	+1	−1	View file
fs/overlayfs/copy_up.c	modified	+11	−0	View file
fs/overlayfs/dir.c	modified	+4	−5	View file
fs/overlayfs/export.c	modified	+21	−20	View file
fs/overlayfs/file.c	modified	+19	−2	View file
fs/overlayfs/inode.c	modified	+40	−33	View file
fs/overlayfs/namei.c	modified	+157	−44	View file
fs/overlayfs/overlayfs.h	modified	+81	−25	View file
fs/overlayfs/ovl_entry.h	modified	+69	−22	View file
fs/overlayfs/params.c	added	+389	−0	View file
fs/overlayfs/readdir.c	modified	+11	−8	View file
fs/overlayfs/super.c	modified	+415	−492	View file
fs/overlayfs/util.c	modified	+132	−47	View file

Only the first 600 diff lines are shown. Download the complete patch.

Documentation/filesystems/overlayfs.rst

View file

diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst
index 4c76fda..eb7d2c8 100644
--- a/Documentation/filesystems/overlayfs.rst
+++ b/Documentation/filesystems/overlayfs.rst
@@ -231,12 +231,11 @@ Mount options:
     Redirects are enabled.
 - "redirect_dir=follow":
     Redirects are not created, but followed.
-- "redirect_dir=off":
-    Redirects are not created and only followed if "redirect_always_follow"
-    feature is enabled in the kernel/module config.
 - "redirect_dir=nofollow":
-    Redirects are not created and not followed (equivalent to "redirect_dir=off"
-    if "redirect_always_follow" feature is not enabled).
+    Redirects are not created and not followed.
+- "redirect_dir=off":
+    If "redirect_always_follow" is enabled in the kernel/module config,
+    this "off" traslates to "follow", otherwise it translates to "nofollow".
 
 When the NFS export feature is enabled, every copied up directory is
 indexed by the file handle of the lower inode and a file handle of the
@@ -371,6 +370,41 @@ conflict with metacopy=on, and will result in an error.
 [*] redirect_dir=follow only conflicts with metacopy=on if upperdir=... is
 given.
 
+
+Data-only lower layers
+----------------------
+
+With "metacopy" feature enabled, an overlayfs regular file may be a composition
+of information from up to three different layers:
+
+ 1) metadata from a file in the upper layer
+
+ 2) st_ino and st_dev object identifier from a file in a lower layer
+
+ 3) data from a file in another lower layer (further below)
+
+The "lower data" file can be on any lower layer, except from the top most
+lower layer.
+
+Below the top most lower layer, any number of lower most layers may be defined
+as "data-only" lower layers, using double colon ("::") separators.
+A normal lower layer is not allowed to be below a data-only layer, so single
+colon separators are not allowed to the right of double colon ("::") separators.
+
+
+For example:
+
+  mount -t overlay overlay -olowerdir=/l1:/l2:/l3::/do1::/do2 /merged
+
+The paths of files in the "data-only" lower layers are not visible in the
+merged overlayfs directories and the metadata and st_ino/st_dev of files
+in the "data-only" lower layers are not visible in overlayfs inodes.
+
+Only the data of the files in the "data-only" lower layers may be visible
+when a "metacopy" file in one of the lower layers above it, has a "redirect"
+to the absolute path of the "lower data" file in the "data-only" lower layer.
+
+
 Sharing and copying layers
 --------------------------
 

MAINTAINERS

View file

diff --git a/MAINTAINERS b/MAINTAINERS
index efdcc8f..0628557 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15937,6 +15937,7 @@ F:	include/media/i2c/ov2659.h
 
 OVERLAY FILESYSTEM
 M:	Miklos Szeredi <[email protected]>
+M:	Amir Goldstein <[email protected]>
 L:	[email protected]
 S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git

fs/overlayfs/Makefile

View file

diff --git a/fs/overlayfs/Makefile b/fs/overlayfs/Makefile
index 9164c58..4e173d5 100644
--- a/fs/overlayfs/Makefile
+++ b/fs/overlayfs/Makefile
@@ -6,4 +6,4 @@
 obj-$(CONFIG_OVERLAY_FS) += overlay.o
 
 overlay-objs := super.o namei.o util.o inode.o file.o dir.o readdir.o \
-		copy_up.o export.o
+		copy_up.o export.o params.o

fs/overlayfs/copy_up.c

View file

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index f658cc8..568f743 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -575,6 +575,7 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c)
 			/* Restore timestamps on parent (best effort) */
 			ovl_set_timestamps(ofs, upperdir, &c->pstat);
 			ovl_dentry_set_upper_alias(c->dentry);
+			ovl_dentry_update_reval(c->dentry, upper);
 		}
 	}
 	inode_unlock(udir);
@@ -894,6 +895,7 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
 		inode_unlock(udir);
 
 		ovl_dentry_set_upper_alias(c->dentry);
+		ovl_dentry_update_reval(c->dentry, ovl_dentry_upper(c->dentry));
 	}
 
 out:
@@ -1071,6 +1073,15 @@ static int ovl_copy_up_flags(struct dentry *dentry, int flags)
 	if (WARN_ON(disconnected && d_is_dir(dentry)))
 		return -EIO;
 
+	/*
+	 * We may not need lowerdata if we are only doing metacopy up, but it is
+	 * not very important to optimize this case, so do lazy lowerdata lookup
+	 * before any copy up, so we can do it before taking ovl_inode_lock().
+	 */
+	err = ovl_maybe_lookup_lowerdata(dentry);
+	if (err)
+		return err;
+
 	old_cred = ovl_override_creds(dentry->d_sb);
 	while (!err) {
 		struct dentry *next;

fs/overlayfs/dir.c

View file

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index fc25fb9..033fc04 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -83,7 +83,7 @@ static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
 		ofs->whiteout = whiteout;
 	}
 
-	if (ofs->share_whiteout) {
+	if (!ofs->no_shared_whiteout) {
 		whiteout = ovl_lookup_temp(ofs, workdir);
 		if (IS_ERR(whiteout))
 			goto out;
@@ -95,7 +95,7 @@ static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
 		if (err != -EMLINK) {
 			pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%i)\n",
 				ofs->whiteout->d_inode->i_nlink, err);
-			ofs->share_whiteout = false;
+			ofs->no_shared_whiteout = true;
 		}
 		dput(whiteout);
 	}
@@ -269,8 +269,7 @@ static int ovl_instantiate(struct dentry *dentry, struct inode *inode,
 
 	ovl_dir_modified(dentry->d_parent, false);
 	ovl_dentry_set_upper_alias(dentry);
-	ovl_dentry_update_reval(dentry, newdentry,
-			DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
+	ovl_dentry_init_reval(dentry, newdentry, NULL);
 
 	if (!hardlink) {
 		/*
@@ -953,7 +952,7 @@ static bool ovl_type_merge_or_lower(struct dentry *dentry)
 
 static bool ovl_can_move(struct dentry *dentry)
 {
-	return ovl_redirect_dir(dentry->d_sb) ||
+	return ovl_redirect_dir(OVL_FS(dentry->d_sb)) ||
 		!d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
 }
 

fs/overlayfs/export.c

View file

diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index defd4e2..35680b6 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -80,7 +80,7 @@ static int ovl_connectable_layer(struct dentry *dentry)
 
 	/* We can get overlay root from root of any layer */
 	if (dentry == dentry->d_sb->s_root)
-		return oe->numlower;
+		return ovl_numlower(oe);
 
 	/*
 	 * If it's an unindexed merge dir, then it's not connectable with any
@@ -91,7 +91,7 @@ static int ovl_connectable_layer(struct dentry *dentry)
 		return 0;
 
 	/* We can get upper/overlay path from indexed/lower dentry */
-	return oe->lowerstack[0].layer->idx;
+	return ovl_lowerstack(oe)->layer->idx;
 }
 
 /*
@@ -105,6 +105,7 @@ static int ovl_connectable_layer(struct dentry *dentry)
 static int ovl_connect_layer(struct dentry *dentry)
 {
 	struct dentry *next, *parent = NULL;
+	struct ovl_entry *oe = OVL_E(dentry);
 	int origin_layer;
 	int err = 0;
 
@@ -112,7 +113,7 @@ static int ovl_connect_layer(struct dentry *dentry)
 	    WARN_ON(!ovl_dentry_lower(dentry)))
 		return -EIO;
 
-	origin_layer = OVL_E(dentry)->lowerstack[0].layer->idx;
+	origin_layer = ovl_lowerstack(oe)->layer->idx;
 	if (ovl_dentry_test_flag(OVL_E_CONNECTED, dentry))
 		return origin_layer;
 
@@ -285,21 +286,29 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
 	struct dentry *lower = lowerpath ? lowerpath->dentry : NULL;
 	struct dentry *upper = upper_alias ?: index;
 	struct dentry *dentry;
-	struct inode *inode;
+	struct inode *inode = NULL;
 	struct ovl_entry *oe;
 	struct ovl_inode_params oip = {
-		.lowerpath = lowerpath,
 		.index = index,
-		.numlower = !!lower
 	};
 
 	/* We get overlay directory dentries with ovl_lookup_real() */
 	if (d_is_dir(upper ?: lower))
 		return ERR_PTR(-EIO);
 
+	oe = ovl_alloc_entry(!!lower);
+	if (!oe)
+		return ERR_PTR(-ENOMEM);
+
 	oip.upperdentry = dget(upper);
+	if (lower) {
+		ovl_lowerstack(oe)->dentry = dget(lower);
+		ovl_lowerstack(oe)->layer = lowerpath->layer;
+	}
+	oip.oe = oe;
 	inode = ovl_get_inode(sb, &oip);
 	if (IS_ERR(inode)) {
+		ovl_free_entry(oe);
 		dput(upper);
 		return ERR_CAST(inode);
 	}
@@ -314,20 +323,11 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
 	dentry = d_alloc_anon(inode->i_sb);
 	if (unlikely(!dentry))
 		goto nomem;
-	oe = ovl_alloc_entry(lower ? 1 : 0);
-	if (!oe)
-		goto nomem;
 
-	if (lower) {
-		oe->lowerstack->dentry = dget(lower);
-		oe->lowerstack->layer = lowerpath->layer;
-	}
-	dentry->d_fsdata = oe;
 	if (upper_alias)
 		ovl_dentry_set_upper_alias(dentry);
 
-	ovl_dentry_update_reval(dentry, upper,
-			DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
+	ovl_dentry_init_reval(dentry, upper, OVL_I_E(inode));
 
 	return d_instantiate_anon(dentry, inode);
 
@@ -342,15 +342,16 @@ out_iput:
 /* Get the upper or lower dentry in stack whose on layer @idx */
 static struct dentry *ovl_dentry_real_at(struct dentry *dentry, int idx)
 {
-	struct ovl_entry *oe = dentry->d_fsdata;
+	struct ovl_entry *oe = OVL_E(dentry);
+	struct ovl_path *lowerstack = ovl_lowerstack(oe);
 	int i;
 
 	if (!idx)
 		return ovl_dentry_upper(dentry);
 
-	for (i = 0; i < oe->numlower; i++) {
-		if (oe->lowerstack[i].layer->idx == idx)
-			return oe->lowerstack[i].dentry;
+	for (i = 0; i < ovl_numlower(oe); i++) {
+		if (lowerstack[i].layer->idx == idx)
+			return lowerstack[i].dentry;
 	}
 
 	return NULL;

fs/overlayfs/file.c

View file

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 1f93a3a..21245b0 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -107,14 +107,23 @@ static int ovl_real_fdget_meta(const struct file *file, struct fd *real,
 {
 	struct dentry *dentry = file_dentry(file);
 	struct path realpath;
+	int err;
 
 	real->flags = 0;
 	real->file = file->private_data;
 
-	if (allow_meta)
+	if (allow_meta) {
 		ovl_path_real(dentry, &realpath);
-	else
+	} else {
+		/* lazy lookup of lowerdata */
+		err = ovl_maybe_lookup_lowerdata(dentry);
+		if (err)
+			return err;
+
 		ovl_path_realdata(dentry, &realpath);
+	}
+	if (!realpath.dentry)
+		return -EIO;
 
 	/* Has it been copied up since we'd opened it? */
 	if (unlikely(file_inode(real->file) != d_inode(realpath.dentry))) {
@@ -150,6 +159,11 @@ static int ovl_open(struct inode *inode, struct file *file)
 	struct path realpath;
 	int err;
 
+	/* lazy lookup of lowerdata */
+	err = ovl_maybe_lookup_lowerdata(dentry);
+	if (err)
+		return err;
+
 	err = ovl_maybe_copy_up(dentry, file->f_flags);
 	if (err)
 		return err;
@@ -158,6 +172,9 @@ static int ovl_open(struct inode *inode, struct file *file)
 	file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
 
 	ovl_path_realdata(dentry, &realpath);
+	if (!realpath.dentry)
+		return -EIO;
+
 	realfile = ovl_open_realfile(file, &realpath);
 	if (IS_ERR(realfile))
 		return PTR_ERR(realfile);

fs/overlayfs/inode.c

View file

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 541cf37..a63e574 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -97,8 +97,9 @@ out:
 
 static void ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, int fsid)
 {
-	bool samefs = ovl_same_fs(dentry->d_sb);
-	unsigned int xinobits = ovl_xino_bits(dentry->d_sb);
+	struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
+	bool samefs = ovl_same_fs(ofs);
+	unsigned int xinobits = ovl_xino_bits(ofs);
 	unsigned int xinoshift = 64 - xinobits;
 
 	if (samefs) {
@@ -123,7 +124,7 @@ static void ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, int fsid)
 			stat->ino |= ((u64)fsid) << (xinoshift + 1);
 			stat->dev = dentry->d_sb->s_dev;
 			return;
-		} else if (ovl_xino_warn(dentry->d_sb)) {
+		} else if (ovl_xino_warn(ofs)) {
 			pr_warn_ratelimited("inode number too big (%pd2, ino=%llu, xinobits=%d)\n",
 					    dentry, stat->ino, xinobits);
 		}
@@ -149,7 +150,7 @@ static void ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, int fsid)
 		 * is unique per underlying fs, so we use the unique anonymous
 		 * bdev assigned to the underlying fs.
 		 */
-		stat->dev = OVL_FS(dentry->d_sb)->fs[fsid].pseudo_dev;
+		stat->dev = ofs->fs[fsid].pseudo_dev;
 	}
 }
 
@@ -186,7 +187,7 @@ int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
 	 * If lower filesystem supports NFS file handles, this also guaranties
 	 * persistent st_ino across mount cycle.
 	 */
-	if (!is_dir || ovl_same_dev(dentry->d_sb)) {
+	if (!is_dir || ovl_same_dev(OVL_FS(dentry->d_sb))) {
 		if (!OVL_TYPE_UPPER(type)) {
 			fsid = ovl_layer_lower(dentry)->fsid;
 		} else if (OVL_TYPE_ORIGIN(type)) {
@@ -240,15 +241,22 @@ int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
 			/*
 			 * If lower is not same as lowerdata or if there was
 			 * no origin on upper, we can end up here.
+			 * With lazy lowerdata lookup, guess lowerdata blocks
+			 * from size to avoid lowerdata lookup on stat(2).
 			 */
 			struct kstat lowerdatastat;
 			u32 lowermask = STATX_BLOCKS;
 
 			ovl_path_lowerdata(dentry, &realpath);
-			err = vfs_getattr(&realpath, &lowerdatastat,
-					  lowermask, flags);
-			if (err)
-				goto out;
+			if (realpath.dentry) {
+				err = vfs_getattr(&realpath, &lowerdatastat,
+						  lowermask, flags);
+				if (err)
+					goto out;
+			} else {
+				lowerdatastat.blocks =
+					round_up(stat->size, stat->blksize) >> 9;
+			}
 			stat->blocks = lowerdatastat.blocks;
 		}
 	}
@@ -288,8 +296,8 @@ int ovl_permission(struct mnt_idmap *idmap,
 	int err;
 
 	/* Careful in RCU walk mode */
-	ovl_i_path_real(inode, &realpath);
-	if (!realpath.dentry) {
+	realinode = ovl_i_path_real(inode, &realpath);
+	if (!realinode) {
 		WARN_ON(!(mask & MAY_NOT_BLOCK));
 		return -ECHILD;
 	}
@@ -302,7 +310,6 @@ int ovl_permission(struct mnt_idmap *idmap,
 	if (err)
 		return err;
 
-	realinode = d_inode(realpath.dentry);
 	old_cred = ovl_override_creds(inode->i_sb);
 	if (!upperinode &&
 	    !special_file(realinode->i_mode) && mask & MAY_WRITE) {
@@ -559,20 +566,20 @@ struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
 				 struct inode *inode, int type,
 				 bool rcu, bool noperm)
 {
-	struct inode *realinode = ovl_inode_real(inode);
+	struct inode *realinode;
 	struct posix_acl *acl;
 	struct path realpath;
 
-	if (!IS_POSIXACL(realinode))
-		return NULL;
-
 	/* Careful in RCU walk mode */
-	ovl_i_path_real(inode, &realpath);
-	if (!realpath.dentry) {
+	realinode = ovl_i_path_real(inode, &realpath);
+	if (!realinode) {
 		WARN_ON(!rcu);
 		return ERR_PTR(-ECHILD);
 	}
 
+	if (!IS_POSIXACL(realinode))
+		return NULL;
+
 	if (rcu) {
 		/*
 		 * If the layer is idmapped drop out of RCU path walk
@@ -710,6 +717,9 @@ static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 	struct inode *realinode = ovl_inode_realdata(inode);
 	const struct cred *old_cred;
 
+	if (!realinode)
+		return -EIO;
+
 	if (!realinode->i_op->fiemap)
 		return -EOPNOTSUPP;
 
@@ -952,7 +962,7 @@ static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode)
 
 static void ovl_next_ino(struct inode *inode)
 {
-	struct ovl_fs *ofs = inode->i_sb->s_fs_info;
+	struct ovl_fs *ofs = OVL_FS(inode->i_sb);
 
 	inode->i_ino = atomic_long_inc_return(&ofs->last_ino);
 	if (unlikely(!inode->i_ino))
@@ -961,7 +971,8 @@ static void ovl_next_ino(struct inode *inode)
 
 static void ovl_map_ino(struct inode *inode, unsigned long ino, int fsid)
 {
-	int xinobits = ovl_xino_bits(inode->i_sb);
+	struct ovl_fs *ofs = OVL_FS(inode->i_sb);
+	int xinobits = ovl_xino_bits(ofs);
 	unsigned int xinoshift = 64 - xinobits;
 
 	/*
@@ -972,7 +983,7 @@ static void ovl_map_ino(struct inode *inode, unsigned long ino, int fsid)
 	 * with d_ino also causes nfsd readdirplus to fail.
 	 */
 	inode->i_ino = ino;
-	if (ovl_same_fs(inode->i_sb)) {
+	if (ovl_same_fs(ofs)) {
 		return;
 	} else if (xinobits && likely(!(ino >> xinoshift))) {
 		inode->i_ino |= (unsigned long)fsid << (xinoshift + 1);
@@ -1003,14 +1014,10 @@ void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
 	struct inode *realinode;
 	struct ovl_inode *oi = OVL_I(inode);
 
-	if (oip->upperdentry)
-		oi->__upperdentry = oip->upperdentry;
-	if (oip->lowerpath && oip->lowerpath->dentry) {
-		oi->lowerpath.dentry = dget(oip->lowerpath->dentry);
-		oi->lowerpath.layer = oip->lowerpath->layer;
-	}
-	if (oip->lowerdata)
-		oi->lowerdata = igrab(d_inode(oip->lowerdata));
+	oi->__upperdentry = oip->upperdentry;
+	oi->oe = oip->oe;
+	oi->redirect = oip->redirect;
+	oi->lowerdata_redirect = oip->lowerdata_redirect;
 
 	realinode = ovl_inode_real(inode);
 	ovl_copyattr(inode);
@@ -1325,7 +1332,7 @@ struct inode *ovl_get_inode(struct super_block *sb,
 {
 	struct ovl_fs *ofs = OVL_FS(sb);
 	struct dentry *upperdentry = oip->upperdentry;
-	struct ovl_path *lowerpath = oip->lowerpath;
+	struct ovl_path *lowerpath = ovl_lowerpath(oip->oe);
 	struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL;
 	struct inode *inode;
 	struct dentry *lowerdentry = lowerpath ? lowerpath->dentry : NULL;
@@ -1369,7 +1376,9 @@ struct inode *ovl_get_inode(struct super_block *sb,
 			}
 
 			dput(upperdentry);
+			ovl_free_entry(oip->oe);
 			kfree(oip->redirect);
+			kfree(oip->lowerdata_redirect);
 			goto out;
 		}
 
@@ -1398,14 +1407,12 @@ struct inode *ovl_get_inode(struct super_block *sb,
 	if (oip->index)
 		ovl_set_flag(OVL_INDEX, inode);
 
-	OVL_I(inode)->redirect = oip->redirect;
-
 	if (bylower)
 		ovl_set_flag(OVL_CONST_INO, inode);
 
 	/* Check for non-merge dir that may have whiteouts */
 	if (is_dir) {
-		if (((upperdentry && lowerdentry) || oip->numlower > 1) ||
+		if (((upperdentry && lowerdentry) || ovl_numlower(oip->oe) > 1) ||
 		    ovl_path_check_origin_xattr(ofs, &realpath)) {
 			ovl_set_flag(OVL_WHITEOUTS, inode);
 		}

fs/overlayfs/namei.c

View file

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index cfb3420..57adf91 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -14,6 +14,8 @@
 #include <linux/exportfs.h>
 #include "overlayfs.h"
 
+#include "../internal.h"	/* for vfs_path_lookup */
+
 struct ovl_lookup_data {
 	struct super_block *sb;
 	struct vfsmount *mnt;
@@ -24,6 +26,8 @@ struct ovl_lookup_data {
 	bool last;
 	char *redirect;
 	bool metacopy;
+	/* Referring to last redirect xattr */
+	bool absolute_redirect;
 };
 
 static int ovl_check_redirect(const struct path *path, struct ovl_lookup_data *d,
@@ -33,11 +37,13 @@ static int ovl_check_redirect(const struct path *path, struct ovl_lookup_data *d
 	char *buf;
 	struct ovl_fs *ofs = OVL_FS(d->sb);
 
+	d->absolute_redirect = false;
 	buf = ovl_get_redirect_xattr(ofs, path, prelen + strlen(post));
 	if (IS_ERR_OR_NULL(buf))
 		return PTR_ERR(buf);
 
 	if (buf[0] == '/') {
+		d->absolute_redirect = true;
 		/*
 		 * One of the ancestor path elements in an absolute path
 		 * lookup in ovl_lookup_layer() could have been opaque and
@@ -349,6 +355,61 @@ static int ovl_lookup_layer(struct dentry *base, struct ovl_lookup_data *d,
 	return 0;
 }
 
+static int ovl_lookup_data_layer(struct dentry *dentry, const char *redirect,
+				 const struct ovl_layer *layer,
+				 struct path *datapath)
+{
+	int err;
+
+	err = vfs_path_lookup(layer->mnt->mnt_root, layer->mnt, redirect,
+			LOOKUP_BENEATH | LOOKUP_NO_SYMLINKS | LOOKUP_NO_XDEV,
+			datapath);
+	pr_debug("lookup lowerdata (%pd2, redirect=\"%s\", layer=%d, err=%i)\n",
+		 dentry, redirect, layer->idx, err);
+
+	if (err)
+		return err;
+
+	err = -EREMOTE;
+	if (ovl_dentry_weird(datapath->dentry))
+		goto out_path_put;
+
+	err = -ENOENT;
+	/* Only regular file is acceptable as lower data */
+	if (!d_is_reg(datapath->dentry))
+		goto out_path_put;

This diff is incomplete. Download the complete patch.

fs/overlayfs/overlayfs.h

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fs/overlayfs/ovl_entry.h

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fs/overlayfs/params.c

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fs/overlayfs/readdir.c

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fs/overlayfs/super.c

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fs/overlayfs/util.c

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