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-rw-r--r--fs/overlayfs/inode.c58
1 files changed, 40 insertions, 18 deletions
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index fcd97b783fa1..3b1bd469accd 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -669,38 +669,59 @@ struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
return inode;
}
+/*
+ * Does overlay inode need to be hashed by lower inode?
+ */
+static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper,
+ struct dentry *lower, struct dentry *index)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ /* No, if pure upper */
+ if (!lower)
+ return false;
+
+ /* Yes, if already indexed */
+ if (index)
+ return true;
+
+ /* Yes, if won't be copied up */
+ if (!ofs->upper_mnt)
+ return true;
+
+ /* No, if lower hardlink is or will be broken on copy up */
+ if ((upper || !ovl_indexdir(sb)) &&
+ !d_is_dir(lower) && d_inode(lower)->i_nlink > 1)
+ return false;
+
+ /* No, if non-indexed upper with NFS export */
+ if (sb->s_export_op && upper)
+ return false;
+
+ /* Otherwise, hash by lower inode for fsnotify */
+ return true;
+}
+
struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
struct dentry *lowerdentry, struct dentry *index,
unsigned int numlower)
{
- struct ovl_fs *ofs = sb->s_fs_info;
struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL;
struct inode *inode;
- /* Already indexed or could be indexed on copy up? */
- bool indexed = (index || (ovl_indexdir(sb) && !upperdentry));
- struct dentry *origin = indexed ? lowerdentry : NULL;
+ bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, index);
bool is_dir;
- if (WARN_ON(upperdentry && indexed && !lowerdentry))
- return ERR_PTR(-EIO);
-
if (!realinode)
realinode = d_inode(lowerdentry);
/*
- * Copy up origin (lower) may exist for non-indexed non-dir upper, but
- * we must not use lower as hash key in that case.
- * Hash non-dir that is or could be indexed by origin inode.
- * Hash dir that is or could be merged by origin inode.
- * Hash pure upper and non-indexed non-dir by upper inode.
- * Hash non-indexed dir by upper inode for NFS export.
+ * Copy up origin (lower) may exist for non-indexed upper, but we must
+ * not use lower as hash key if this is a broken hardlink.
*/
is_dir = S_ISDIR(realinode->i_mode);
- if (is_dir && (indexed || !sb->s_export_op || !ofs->upper_mnt))
- origin = lowerdentry;
-
- if (upperdentry || origin) {
- struct inode *key = d_inode(origin ?: upperdentry);
+ if (upperdentry || bylower) {
+ struct inode *key = d_inode(bylower ? lowerdentry :
+ upperdentry);
unsigned int nlink = is_dir ? 1 : realinode->i_nlink;
inode = iget5_locked(sb, (unsigned long) key,
@@ -728,6 +749,7 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
nlink = ovl_get_nlink(lowerdentry, upperdentry, nlink);
set_nlink(inode, nlink);
} else {
+ /* Lower hardlink that will be broken on copy up */
inode = new_inode(sb);
if (!inode)
goto out_nomem;