ovl: consistent i_ino for non-samefs with xino

When overlay layers are not all on the same fs, but all inode numbers
of underlying fs do not use the high 'xino' bits, overlay st_ino values
are constant and persistent.

In that case, set i_ino value to the same value as st_ino for nfsd
readdirplus validator.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index bb290cd1e727c6edfe1ba366b2aa85ecdd05bbdd..425a94672300c78fc69393851f35795305c81d48 100644 (file)
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -305,7 +305,7 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
        if (d_is_dir(upper ?: lower))
                return ERR_PTR(-EIO);
 
-       inode = ovl_get_inode(sb, dget(upper), lower, index, !!lower);
+       inode = ovl_get_inode(sb, dget(upper), lowerpath, index, !!lower);
        if (IS_ERR(inode)) {
                dput(upper);
                return ERR_CAST(inode);

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 51d780898d891137384e4fc5b23a551fb759bfe6..6e3815fb006b8237a313e2b26069f6232c3d4609 100644 (file)
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -489,19 +489,26 @@ static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode)
 }
 
 static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev,
-                          unsigned long ino)
+                          unsigned long ino, int fsid)
 {
+       int xinobits = ovl_xino_bits(inode->i_sb);
+
        /*
         * When NFS export is enabled and d_ino is consistent with st_ino
-        * (samefs), set the same value to i_ino, because nfsd readdirplus
-        * compares d_ino values to i_ino values of child entries. When called
-        * from ovl_new_inode(), ino arg is 0, so i_ino will be updated to real
+        * (samefs or i_ino has enough bits to encode layer), set the same
+        * value used for d_ino to i_ino, because nfsd readdirplus compares
+        * d_ino values to i_ino values of child entries. When called from
+        * ovl_new_inode(), ino arg is 0, so i_ino will be updated to real
         * upper inode i_ino on ovl_inode_init() or ovl_inode_update().
         */
-       if (inode->i_sb->s_export_op && ovl_same_sb(inode->i_sb))
+       if (inode->i_sb->s_export_op &&
+           (ovl_same_sb(inode->i_sb) || xinobits)) {
                inode->i_ino = ino;
-       else
+               if (xinobits && fsid && !(ino >> (64 - xinobits)))
+                       inode->i_ino |= (unsigned long)fsid << (64 - xinobits);
+       } else {
                inode->i_ino = get_next_ino();
+       }
        inode->i_mode = mode;
        inode->i_flags |= S_NOCMTIME;
 #ifdef CONFIG_FS_POSIX_ACL
@@ -637,7 +644,7 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev)
 
        inode = new_inode(sb);
        if (inode)
-               ovl_fill_inode(inode, mode, rdev, 0);
+               ovl_fill_inode(inode, mode, rdev, 0, 0);
 
        return inode;
 }
@@ -743,12 +750,14 @@ static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper,
 }
 
 struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
-                           struct dentry *lowerdentry, struct dentry *index,
+                           struct ovl_path *lowerpath, struct dentry *index,
                            unsigned int numlower)
 {
        struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL;
        struct inode *inode;
+       struct dentry *lowerdentry = lowerpath ? lowerpath->dentry : NULL;
        bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, index);
+       int fsid = bylower ? lowerpath->layer->fsid : 0;
        bool is_dir;
        unsigned long ino = 0;
 
@@ -796,7 +805,7 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
                if (!inode)
                        goto out_nomem;
        }
-       ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino);
+       ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino, fsid);
        ovl_inode_init(inode, upperdentry, lowerdentry);
 
        if (upperdentry && ovl_is_impuredir(upperdentry))

diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index 52f0b13be6337c90c45bdea0073e40500859442a..2dba29eadde6b11d1d9211e921691b7d144d8a41 100644 (file)
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -1004,9 +1004,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
                upperdentry = dget(index);
 
        if (upperdentry || ctr) {
-               if (ctr)
-                       origin = stack[0].dentry;
-               inode = ovl_get_inode(dentry->d_sb, upperdentry, origin, index,
+               inode = ovl_get_inode(dentry->d_sb, upperdentry, stack, index,
                                      ctr);
                err = PTR_ERR(inode);
                if (IS_ERR(inode))

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 8eefc309aeb689df6421105623982dcd498dac20..e0b7de799f6b887a22cfe6a99faeec1430e50208 100644 (file)
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -338,7 +338,7 @@ struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
                               bool is_upper);
 struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
-                           struct dentry *lowerdentry, struct dentry *index,
+                           struct ovl_path *lowerpath, struct dentry *index,
                            unsigned int numlower);
 static inline void ovl_copyattr(struct inode *from, struct inode *to)
 {