On Thu, Mar 15, 2018 at 8:40 PM, Amir Goldstein <amir73il@xxxxxxxxx> wrote:
> On Thu, Mar 15, 2018 at 4:30 PM, Eddie Horng <eddiehorng.tw@xxxxxxxxx> wrote:
[...]
> The problem *is* with nfsd+overlayfs, because nfsd verifies
> in compose_entry_fh() that (dchild->d_inode->i_ino == ino), but it is not.
> In that case, encode_entryplus_baggage() falls back to encoding xdr_zero.
> In overlayfs stat.st_ino is consistent with readdir d_ino since kernel version
> v4.15 and only for all layers on the same fs.
>
> However, there is no guaranty that inode->i_ino is the same as stat.st_ino.
> Overlayfs exposes only stat.st_ino to user (as well as readdir d_ino), but
> never (to my knowledge) does it expose inode->i_ino.
>
> There was a nfsd fix for a somewhat similar problem that went into v4.16-rc1:
> 76c479480b9a nfsd: encode stat->mtime for getattr instead of inode->i_mtime
>
> The solution to the problem is to either convert all references of
> nfsd to i_inode
> with references to st_ino, or make sure to set inode->i_ino correctly for
> overlayfs inodes.
>
> From first glimps, the change in nfsd looks non trivial.
> The change to overlayfs seems doable, but didn't look closely yet.
> Will try to come up with test patch for you.
>
Eddie,
Please try this patch. It worked for me.
Thanks,
Amir.
From 5dfe75eaf1aec080d110df343aa339ad7b816670 Mon Sep 17 00:00:00 2001
From: Amir Goldstein <amir73il@xxxxxxxxx>
Date: Thu, 15 Mar 2018 23:39:01 +0200
Subject: [PATCH] ovl: set i_ino to the value of st_ino for NFS export
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
upper inode i_ino on ovl_inode_init() or ovl_inode_update().
Reported-by: Eddie Horng <eddiehorng.tw@xxxxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/inode.c | 21 +++++++++++++++++----
fs/overlayfs/util.c | 8 +++++++-
2 files changed, 24 insertions(+), 5 deletions(-)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 3b1bd469accd..4689716f23d8 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -459,9 +459,20 @@ static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode)
#endif
}
-static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev)
+static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev,
+ unsigned long ino)
{
- inode->i_ino = get_next_ino();
+ /*
+ * 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
+ * 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))
+ inode->i_ino = ino;
+ else
+ inode->i_ino = get_next_ino();
inode->i_mode = mode;
inode->i_flags |= S_NOCMTIME;
#ifdef CONFIG_FS_POSIX_ACL
@@ -597,7 +608,7 @@ 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);
+ ovl_fill_inode(inode, mode, rdev, 0);
return inode;
}
@@ -710,6 +721,7 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
struct inode *inode;
bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, index);
bool is_dir;
+ unsigned long ino = 0;
if (!realinode)
realinode = d_inode(lowerdentry);
@@ -748,13 +760,14 @@ struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry,
if (!is_dir)
nlink = ovl_get_nlink(lowerdentry, upperdentry, nlink);
set_nlink(inode, nlink);
+ ino = key->i_ino;
} else {
/* Lower hardlink that will be broken on copy up */
inode = new_inode(sb);
if (!inode)
goto out_nomem;
}
- ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev);
+ ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino);
ovl_inode_init(inode, upperdentry, lowerdentry);
if (upperdentry && ovl_is_impuredir(upperdentry))
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 930784a26623..493f9b76fbf6 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -279,12 +279,16 @@ void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect)
void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
struct dentry *lowerdentry)
{
+ struct inode *realinode = d_inode(upperdentry ?: lowerdentry);
+
if (upperdentry)
OVL_I(inode)->__upperdentry = upperdentry;
if (lowerdentry)
OVL_I(inode)->lower = igrab(d_inode(lowerdentry));
- ovl_copyattr(d_inode(upperdentry ?: lowerdentry), inode);
+ ovl_copyattr(realinode, inode);
+ if (!inode->i_ino)
+ inode->i_ino = realinode->i_ino;
}
void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
@@ -299,6 +303,8 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry)
smp_wmb();
OVL_I(inode)->__upperdentry = upperdentry;
if (inode_unhashed(inode)) {
+ if (!inode->i_ino)
+ inode->i_ino = upperinode->i_ino;
inode->i_private = upperinode;
__insert_inode_hash(inode, (unsigned long) upperinode);
}
--
2.7.4
