From 647d253fcd53fae185408b33ec5587a57cb3cc88 Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Fri, 11 May 2018 11:49:30 -0400 Subject: [PATCH] ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry Now we have the notion of data dentry and metacopy dentry. ovl_dentry_lower() will return uppermost lower dentry, but it could be either data or metacopy dentry. Now we support metacopy dentries in lower layers so it is possible that lowerstack[0] is metacopy dentry while lowerstack[1] is actual data dentry. So add an helper which returns lowest most dentry which is supposed to be data dentry. Signed-off-by: Vivek Goyal Reviewed-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/overlayfs/overlayfs.h | 1 + fs/overlayfs/util.c | 13 +++++++++++++ 2 files changed, 14 insertions(+) diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index a59c546c10cf..deda94381aac 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -221,6 +221,7 @@ void ovl_path_lowerdata(struct dentry *dentry, struct path *path); enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); struct dentry *ovl_dentry_upper(struct dentry *dentry); struct dentry *ovl_dentry_lower(struct dentry *dentry); +struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); struct ovl_layer *ovl_layer_lower(struct dentry *dentry); struct dentry *ovl_dentry_real(struct dentry *dentry); struct dentry *ovl_i_dentry_upper(struct inode *inode); diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 32ff67fa0bfb..7c7b95d5da1f 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -207,6 +207,19 @@ struct ovl_layer *ovl_layer_lower(struct dentry *dentry) return oe->numlower ? oe->lowerstack[0].layer : NULL; } +/* + * ovl_dentry_lower() could return either a data dentry or metacopy dentry + * dependig on what is stored in lowerstack[0]. At times we need to find + * lower dentry which has data (and not metacopy dentry). This helper + * returns the lower data dentry. + */ +struct dentry *ovl_dentry_lowerdata(struct dentry *dentry) +{ + struct ovl_entry *oe = dentry->d_fsdata; + + return oe->numlower ? oe->lowerstack[oe->numlower - 1].dentry : NULL; +} + struct dentry *ovl_dentry_real(struct dentry *dentry) { return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry);