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authorMiklos Szeredi <mszeredi@redhat.com>2017-07-04 22:03:18 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2017-07-04 22:03:18 +0200
commit55acc6618259c8ff0a400a131f0f4b613e96010a (patch)
tree82f73eccca8d417ec8c77ad1b02dd28748c5c456
parent23f0ab13eaa69b4a351184cbec448be2aad3a3a9 (diff)
ovl: add flag for upper in ovl_entry
For rename, we need to ensure that an upper alias exists for hard links before attempting the operation. Introduce a flag in ovl_entry to track the state of the upper alias. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
-rw-r--r--fs/overlayfs/copy_up.c1
-rw-r--r--fs/overlayfs/dir.c1
-rw-r--r--fs/overlayfs/namei.c4
-rw-r--r--fs/overlayfs/overlayfs.h2
-rw-r--r--fs/overlayfs/ovl_entry.h5
-rw-r--r--fs/overlayfs/super.c1
-rw-r--r--fs/overlayfs/util.c19
7 files changed, 31 insertions, 2 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 8f9e26e91386..58c06bd58a96 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -472,6 +472,7 @@ static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
if (err)
goto out_cleanup;
+ ovl_dentry_set_upper_alias(c->dentry);
ovl_inode_update(d_inode(c->dentry), newdentry);
out:
dput(temp);
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index a072c27e03bc..8b2b23181b19 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -156,6 +156,7 @@ static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry, bool hardlink)
{
ovl_dentry_version_inc(dentry->d_parent);
+ ovl_dentry_set_upper_alias(dentry);
if (!hardlink) {
ovl_inode_update(inode, newdentry);
ovl_copyattr(newdentry->d_inode, inode);
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index f7fb0c919419..2d8b6292fe21 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -674,7 +674,9 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
dentry->d_fsdata = oe;
- if (index && !upperdentry)
+ if (upperdentry)
+ ovl_dentry_set_upper_alias(dentry);
+ else if (index)
upperdentry = dget(index);
if (upperdentry || ctr) {
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index f3e49cf34517..751b36a5c22f 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -206,6 +206,8 @@ void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
+bool ovl_dentry_has_upper_alias(struct dentry *dentry);
+void ovl_dentry_set_upper_alias(struct dentry *dentry);
bool ovl_redirect_dir(struct super_block *sb);
const char *ovl_dentry_get_redirect(struct dentry *dentry);
void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index 9642ec64467b..878a750986dd 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -42,7 +42,10 @@ struct ovl_fs {
/* private information held for every overlayfs dentry */
struct ovl_entry {
union {
- bool opaque;
+ struct {
+ unsigned long has_upper;
+ bool opaque;
+ };
struct rcu_head rcu;
};
unsigned numlower;
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 791581c370f5..f29ee08cf99f 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1119,6 +1119,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
kfree(lowertmp);
if (upperpath.dentry) {
+ oe->has_upper = true;
if (ovl_is_impuredir(upperpath.dentry))
ovl_set_flag(OVL_IMPURE, d_inode(root_dentry));
}
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index c80b4bf1e64f..38fa75228c66 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -201,6 +201,25 @@ void ovl_dentry_set_opaque(struct dentry *dentry)
oe->opaque = true;
}
+/*
+ * 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)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return oe->has_upper;
+}
+
+void ovl_dentry_set_upper_alias(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ oe->has_upper = true;
+}
+
bool ovl_redirect_dir(struct super_block *sb)
{
struct ovl_fs *ofs = sb->s_fs_info;