diff options
| -rw-r--r-- | fs/overlayfs/export.c | 40 |
1 files changed, 35 insertions, 5 deletions
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c index 09fbfa83eeff..862c368883c9 100644 --- a/fs/overlayfs/export.c +++ b/fs/overlayfs/export.c @@ -19,6 +19,40 @@ #include <linux/ratelimit.h> #include "overlayfs.h" +/* + * We only need to encode origin if there is a chance that the same object was + * encoded pre copy up and then we need to stay consistent with the same + * encoding also after copy up. If non-pure upper is not indexed, then it was + * copied up before NFS export was enabled. In that case we don't need to worry + * about staying consistent with pre copy up encoding and we encode an upper + * file handle. Overlay root dentry is a private case of non-indexed upper. + * + * The following table summarizes the different file handle encodings used for + * different overlay object types: + * + * Object type | Encoding + * -------------------------------- + * Pure upper | U + * Non-indexed upper | U + * Indexed upper | L + * Non-upper | L + * + * U = upper file handle + * L = lower file handle + */ +static bool ovl_should_encode_origin(struct dentry *dentry) +{ + if (!ovl_dentry_lower(dentry)) + return false; + + /* Decoding a non-indexed upper from origin is not implemented */ + if (ovl_dentry_upper(dentry) && + !ovl_test_flag(OVL_INDEX, d_inode(dentry))) + return false; + + return true; +} + static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen) { struct dentry *upper = ovl_dentry_upper(dentry); @@ -26,11 +60,7 @@ static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen) struct ovl_fh *fh = NULL; int err; - /* - * On overlay with an upper layer, overlay root inode is encoded as - * an upper file handle, because upper root dir is not indexed. - */ - if (dentry == dentry->d_sb->s_root && upper) + if (!ovl_should_encode_origin(dentry)) origin = NULL; err = -EACCES; |