From 9678e630305724487f1fc101d6b83c383ff9cc90 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Wed, 3 Jan 2018 19:34:45 +0200 Subject: ovl: fix inconsistent d_ino for legacy merge dir For a merge dir that was copied up before v4.12 or that was hand crafted offline (e.g. mkdir {upper/lower}/dir), upper dir does not contain the 'trusted.overlay.origin' xattr. In that case, stat(2) on the merge dir returns the lower dir st_ino, but getdents(2) returns the upper dir d_ino. After this change, on merge dir lookup, missing origin xattr on upper dir will be fixed and 'impure' xattr will be fixed on parent of the legacy merge dir. Suggested-by: zhangyi (F) Reviewed-by: zhangyi (F) Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/overlayfs/copy_up.c | 4 ++-- fs/overlayfs/namei.c | 33 +++++++++++++++++++++++++++++++++ fs/overlayfs/overlayfs.h | 2 ++ 3 files changed, 37 insertions(+), 2 deletions(-) (limited to 'fs/overlayfs') diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index eb3b8d3..206ecec 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -288,8 +288,8 @@ out: return fh; } -static int ovl_set_origin(struct dentry *dentry, struct dentry *lower, - struct dentry *upper) +int ovl_set_origin(struct dentry *dentry, struct dentry *lower, + struct dentry *upper) { const struct ovl_fh *fh = NULL; int err; diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 69a43ed..69f4f19 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -584,6 +584,27 @@ static int ovl_find_layer(struct ovl_fs *ofs, struct ovl_path *path) return i; } +/* Fix missing 'origin' xattr */ +static int ovl_fix_origin(struct dentry *dentry, struct dentry *lower, + struct dentry *upper) +{ + int err; + + if (ovl_check_origin_xattr(upper)) + return 0; + + err = ovl_want_write(dentry); + if (err) + return err; + + err = ovl_set_origin(dentry, lower, upper); + if (!err) + err = ovl_set_impure(dentry->d_parent, upper->d_parent); + + ovl_drop_write(dentry); + return err; +} + struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { @@ -674,6 +695,18 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, if (!this) continue; + /* + * If no origin fh is stored in upper of a merge dir, store fh + * of lower dir and set upper parent "impure". + */ + if (upperdentry && !ctr && !ofs->noxattr) { + err = ovl_fix_origin(dentry, this, upperdentry); + if (err) { + dput(this); + goto out_put; + } + } + stack[ctr].dentry = this; stack[ctr].layer = lower.layer; ctr++; diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index b489099..d1cfa69 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -322,3 +322,5 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags); int ovl_copy_xattr(struct dentry *old, struct dentry *new); int ovl_set_attr(struct dentry *upper, struct kstat *stat); struct ovl_fh *ovl_encode_fh(struct dentry *lower, bool is_upper); +int ovl_set_origin(struct dentry *dentry, struct dentry *lower, + struct dentry *upper); -- cgit v1.1