A helper for ovl_getattr() to map the values of st_dev and st_ino
according to constant st_ino rules.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/inode.c | 52 ++++++++++++++++++++++++++++++++++------------------
1 file changed, 34 insertions(+), 18 deletions(-)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index b772e5a2a730..6c54ecff56ee 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -58,6 +58,34 @@ int ovl_setattr(struct dentry *dentry, struct iattr *attr)
return err;
}
+static int ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat)
+{
+ bool samefs = ovl_same_sb(dentry->d_sb);
+
+ if (samefs) {
+ /*
+ * When all layers are on the same fs, all real inode
+ * number are unique, so we use the overlay st_dev,
+ * which is friendly to du -x.
+ */
+ stat->dev = dentry->d_sb->s_dev;
+ } else if (S_ISDIR(dentry->d_inode->i_mode)) {
+ /*
+ * Always use the overlay st_dev for directories, so 'find
+ * -xdev' will scan the entire overlay mount and won't cross the
+ * overlay mount boundaries.
+ *
+ * If not all layers are on the same fs the pair {real st_ino;
+ * overlay st_dev} is not unique, so use the non persistent
+ * overlay st_ino for directories.
+ */
+ stat->dev = dentry->d_sb->s_dev;
+ stat->ino = dentry->d_inode->i_ino;
+ }
+
+ return 0;
+}
+
int ovl_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int flags)
{
@@ -75,13 +103,10 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
goto out;
/*
- * When all layers are on the same fs, all real inode number are
- * unique, so we use the overlay st_dev, which is friendly to du -x.
- *
- * We also use st_ino of the copy up origin, if we know it.
+ * When all layers are on the same fs, we use st_ino of copy up origin.
* This guaranties constant st_dev/st_ino across copy up.
*
- * If filesystem supports NFS export ops, this also guaranties
+ * If lower filesystem supports NFS file handles, this also guaranties
* persistent st_ino across mount cycle.
*/
if (ovl_same_sb(dentry->d_sb)) {
@@ -108,21 +133,12 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
ovl_test_flag(OVL_INDEX, d_inode(dentry)))
stat->ino = lowerstat.ino;
}
- stat->dev = dentry->d_sb->s_dev;
- } else if (is_dir) {
- /*
- * If not all layers are on the same fs the pair {real st_ino;
- * overlay st_dev} is not unique, so use the non persistent
- * overlay st_ino.
- *
- * Always use the overlay st_dev for directories, so 'find
- * -xdev' will scan the entire overlay mount and won't cross the
- * overlay mount boundaries.
- */
- stat->dev = dentry->d_sb->s_dev;
- stat->ino = dentry->d_inode->i_ino;
}
+ err = ovl_map_dev_ino(dentry, stat);
+ if (err)
+ goto out;
+
/*
* It's probably not worth it to count subdirs to get the
* correct link count. nlink=1 seems to pacify 'find' and
--
2.7.4
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