On Wed, 18 Apr 2012, Dan Carpenter wrote:
> Hello Sage Weil,
>
> This is a semi-automatic email about new static checker warnings.
>
> The patch f59919a07e03: "ceph: move encode_fh to new API" from Apr 5,
> 2012, leads to the following Smatch complaint:
>
> fs/ceph/export.c:85 ceph_encode_fh()
> error: we previously assumed 'dentry' could be null (see line 67)
Thanks, Dan! This caught a minor bug.
Al, can you update f59919a07e0335358d9470289cf46ffb83b7d2f9 in your
for-next with the following?
diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 869c554..8e1b60e 100644
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -82,7 +82,7 @@ static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
type = 255;
} else {
dout("encode_fh %p\n", dentry);
- fh->ino = ceph_ino(dentry->d_inode);
+ fh->ino = ceph_ino(inode);
*max_len = handle_length;
type = 1;
}
...or the complete patch is below.
Thanks!
sage
>From 21d32da4f1731a583a471b24308b5f8c4e065ab6 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@xxxxxxxxxxxx>
Date: Wed, 18 Apr 2012 10:39:14 -0700
Subject: [PATCH] ceph: move encode_fh to new API
Use parent_inode has a flag for whether nfsd wants a connectable fh, but
generate one opportunistically so that we can take advantage of the
additional info in there.
Signed-off-by: Sage Weil <sage@xxxxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/ceph/export.c | 34 +++++++++++++++++++++-------------
1 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 4f9234c..8e1b60e 100644
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -40,38 +40,49 @@ struct ceph_nfs_confh {
u32 parent_name_hash;
} __attribute__ ((packed));
-static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len,
- int connectable)
+/*
+ * The presence of @parent_inode here tells us whether NFS wants a
+ * connectable file handle. However, we want to make a connectionable
+ * file handle unconditionally so that the MDS gets as much of a hint
+ * as possible. That means we only use @parent_dentry to indicate
+ * whether nfsd wants a connectable fh, and whether we should indicate
+ * failure from a too-small @max_len.
+ */
+static int ceph_encode_fh(struct inode *inode, u32 *rawfh, int *max_len,
+ struct inode *parent_inode)
{
int type;
struct ceph_nfs_fh *fh = (void *)rawfh;
struct ceph_nfs_confh *cfh = (void *)rawfh;
- struct dentry *parent;
- struct inode *inode = dentry->d_inode;
int connected_handle_length = sizeof(*cfh)/4;
int handle_length = sizeof(*fh)/4;
+ struct dentry *dentry = d_find_alias(inode);
+ struct dentry *parent;
/* don't re-export snaps */
if (ceph_snap(inode) != CEPH_NOSNAP)
return -EINVAL;
- spin_lock(&dentry->d_lock);
- parent = dentry->d_parent;
- if (*max_len >= connected_handle_length) {
+ /* if we found an alias, generate a connectable fh */
+ if (*max_len >= connected_handle_length && dentry) {
dout("encode_fh %p connectable\n", dentry);
- cfh->ino = ceph_ino(dentry->d_inode);
+ spin_lock(&dentry->d_lock);
+ parent = dentry->d_parent;
+ cfh->ino = ceph_ino(inode);
cfh->parent_ino = ceph_ino(parent->d_inode);
cfh->parent_name_hash = ceph_dentry_hash(parent->d_inode,
dentry);
*max_len = connected_handle_length;
type = 2;
+ spin_unlock(&dentry->d_lock);
} else if (*max_len >= handle_length) {
- if (connectable) {
+ if (parent_inode) {
+ /* nfsd wants connectable */
*max_len = connected_handle_length;
type = 255;
} else {
dout("encode_fh %p\n", dentry);
- fh->ino = ceph_ino(dentry->d_inode);
+ fh->ino = ceph_ino(inode);
*max_len = handle_length;
type = 1;
}
@@ -79,7 +90,6 @@ static int ceph_encode_fh(struct dentry *dentry, u32 *rawfh, int *max_len,
*max_len = handle_length;
type = 255;
}
- spin_unlock(&dentry->d_lock);
return type;
}
@@ -247,9 +257,7 @@ static struct dentry *ceph_fh_to_parent(struct super_block *sb,
}
const struct export_operations ceph_export_ops = {
-#ifdef CEPH_BREAKAGE_FIXED
.encode_fh = ceph_encode_fh,
-#endif
.fh_to_dentry = ceph_fh_to_dentry,
.fh_to_parent = ceph_fh_to_parent,
};
--
1.7.9
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