[PATCH 2.6.35] NFSv4: Don't do idmapper upcalls during XDR decode

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From: Arnaud Giersch on 12 Aug 2010 06:40

---

From: Arnaud Giersch <arnaud.giersch(a)free.fr>

Move the name to id mapping out of the XDR decode functions.

Add two new fields to struct nfs_fattr: user_name and group_name, that
are defined iff a name to id mapping should be done.
A new function, nfs_fattr_name_to_id(), is defined to call the
idmapper if needed.

This also fixes the empty core dumps that may be produced on NFSv4
mounts since commit 80e52aced138bb41b045a8595a87510f27d8d8c5.

Signed-off-by: Arnaud Giersch <arnaud.giersch(a)free.fr>

---
Hi,

The purpose of this patch is to avoid empty core dumps on NFS4 mounts,
as reported in http://article.gmane.org/gmane.linux.kernel/998617, or
http://article.gmane.org/gmane.linux.nfs/33390.

This is my attempt to implement the suggestion made by Trond Myklebust
in http://article.gmane.org/gmane.linux.nfs/33391.

A previous submission (http://article.gmane.org/gmane.linux.nfs/33422)
did not get any feedback. The only difference with this first patch is
the test in nfs_free_fattr(), as the fattr parameter may be NULL.

I am currently running a patched kernel on my workstation, and did not
notice any problem.

Regards,
Arnaud Giersch

fs/nfs/inode.c | 35 ++++++++++++
fs/nfs/nfs4xdr.c | 109 ++++++++++++++-----------------------
include/linux/nfs_fs.h | 4 ++
include/linux/nfs_xdr.h | 7 +++
4 files changed, 88 insertions(+), 67 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 7d2d6c7..b1f7799 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -234,6 +234,35 @@ nfs_init_locked(struct inode *inode, void *opaque)
return 0;
}

+static void
+nfs_fattr_name_to_id(struct nfs_client *clp, struct nfs_fattr *fattr)
+{
+ if (fattr->user_name) {
+ struct nfs_name *name = fattr->user_name;
+ if (nfs_map_name_to_uid(clp, name->buf, name->len,
+ &fattr->uid) == 0)
+ fattr->valid |= NFS_ATTR_FATTR_OWNER;
+ else
+ dprintk("%s: nfs_map_name_to_uid failed!\n",
+ __func__);
+ kfree(fattr->user_name);
+ fattr->user_name = NULL;
+ dprintk("%s: uid=%d\n", __func__, (int)fattr->uid);
+ }
+ if (fattr->group_name) {
+ struct nfs_name *name = fattr->group_name;
+ if (nfs_map_group_to_gid(clp, name->buf, name->len,
+ &fattr->gid) == 0)
+ fattr->valid |= NFS_ATTR_FATTR_GROUP;
+ else
+ dprintk("%s: nfs_map_group_to_gid failed!\n",
+ __func__);
+ kfree(fattr->group_name);
+ fattr->group_name = NULL;
+ dprintk("%s: gid=%d\n", __func__, (int)fattr->gid);
+ }
+}
+
/* Don't use READDIRPLUS on directories that we believe are too large */
#define NFS_LIMIT_READDIRPLUS (8*PAGE_SIZE)

@@ -263,6 +292,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
inode = ERR_PTR(-ENOMEM);
goto out_no_inode;
}
+ nfs_fattr_name_to_id(NFS_SERVER(inode)->nfs_client, fattr);

if (inode->i_state & I_NEW) {
struct nfs_inode *nfsi = NFS_I(inode);
@@ -997,6 +1027,8 @@ unsigned long nfs_inc_attr_generation_counter(void)
void nfs_fattr_init(struct nfs_fattr *fattr)
{
fattr->valid = 0;
+ fattr->user_name = NULL;
+ fattr->group_name = NULL;
fattr->time_start = jiffies;
fattr->gencount = nfs_inc_attr_generation_counter();
}
@@ -1071,6 +1103,7 @@ int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
{
int status;

+ nfs_fattr_name_to_id(NFS_SERVER(inode)->nfs_client, fattr);
if ((fattr->valid & NFS_ATTR_FATTR) == 0)
return 0;
spin_lock(&inode->i_lock);
@@ -1110,6 +1143,7 @@ int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
{
int status;

+ nfs_fattr_name_to_id(NFS_SERVER(inode)->nfs_client, fattr);
spin_lock(&inode->i_lock);
status = nfs_post_op_update_inode_locked(inode, fattr);
spin_unlock(&inode->i_lock);
@@ -1131,6 +1165,7 @@ int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fa
{
int status;

+ nfs_fattr_name_to_id(NFS_SERVER(inode)->nfs_client, fattr);
spin_lock(&inode->i_lock);
/* Don't do a WCC update if these attributes are already stale */
if ((fattr->valid & NFS_ATTR_FATTR) == 0 ||
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 08ef912..c6e7197 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -3271,13 +3271,13 @@ out_overflow:
}

static int decode_attr_owner(struct xdr_stream *xdr, uint32_t *bitmap,
- struct nfs_client *clp, uint32_t *uid, int may_sleep)
+ struct nfs_client *clp, struct nfs_name **owner)
{
uint32_t len;
__be32 *p;
int ret = 0;

- *uid = -2;
+ BUG_ON(*owner);
if (unlikely(bitmap[1] & (FATTR4_WORD1_OWNER - 1U)))
return -EIO;
if (likely(bitmap[1] & FATTR4_WORD1_OWNER)) {
@@ -3288,20 +3288,18 @@ static int decode_attr_owner(struct xdr_stream *xdr, uint32_t *bitmap,
p = xdr_inline_decode(xdr, len);
if (unlikely(!p))
goto out_overflow;
- if (!may_sleep) {
- /* do nothing */
- } else if (len < XDR_MAX_NETOBJ) {
- if (nfs_map_name_to_uid(clp, (char *)p, len, uid) == 0)
- ret = NFS_ATTR_FATTR_OWNER;
- else
- dprintk("%s: nfs_map_name_to_uid failed!\n",
- __func__);
+ if (len < XDR_MAX_NETOBJ) {
+ *owner = kmalloc((sizeof **owner) + len, GFP_NOFS);
+ if (*owner) {
+ (*owner)->len = len;
+ memcpy((*owner)->buf, p, len);
+ } else
+ dprintk("%s: kmalloc failed!\n", __func__);
} else
dprintk("%s: name too long (%u)!\n",
__func__, len);
bitmap[1] &= ~FATTR4_WORD1_OWNER;
}
- dprintk("%s: uid=%d\n", __func__, (int)*uid);
return ret;
out_overflow:
print_overflow_msg(__func__, xdr);
@@ -3309,13 +3307,13 @@ out_overflow:
}

static int decode_attr_group(struct xdr_stream *xdr, uint32_t *bitmap,
- struct nfs_client *clp, uint32_t *gid, int may_sleep)
+ struct nfs_client *clp, struct nfs_name **group)
{
uint32_t len;
__be32 *p;
int ret = 0;

- *gid = -2;
+ BUG_ON(*group);
if (unlikely(bitmap[1] & (FATTR4_WORD1_OWNER_GROUP - 1U)))
return -EIO;
if (likely(bitmap[1] & FATTR4_WORD1_OWNER_GROUP)) {
@@ -3326,20 +3324,18 @@ static int decode_attr_group(struct xdr_stream *xdr, uint32_t *bitmap,
p = xdr_inline_decode(xdr, len);
if (unlikely(!p))
goto out_overflow;
- if (!may_sleep) {
- /* do nothing */
- } else if (len < XDR_MAX_NETOBJ) {
- if (nfs_map_group_to_gid(clp, (char *)p, len, gid) == 0)
- ret = NFS_ATTR_FATTR_GROUP;
- else
- dprintk("%s: nfs_map_group_to_gid failed!\n",
- __func__);
+ if (len < XDR_MAX_NETOBJ) {
+ *group = kmalloc((sizeof **group) + len, GFP_NOFS);
+ if (*group) {
+ (*group)->len = len;
+ memcpy((*group)->buf, p, len);
+ } else
+ dprintk("%s: kmalloc failed!\n", __func__);
} else
dprintk("%s: name too long (%u)!\n",
__func__, len);
bitmap[1] &= ~FATTR4_WORD1_OWNER_GROUP;
}
- dprintk("%s: gid=%d\n", __func__, (int)*gid);
return ret;
out_overflow:
print_overflow_msg(__func__, xdr);
@@ -3745,7 +3741,7 @@ xdr_error:
}

static int decode_getfattr(struct xdr_stream *xdr, struct nfs_fattr *fattr,
- const struct nfs_server *server, int may_sleep)
+ const struct nfs_server *server)
{
__be32 *savep;
uint32_t attrlen,
@@ -3818,13 +3814,13 @@ static int decode_getfattr(struct xdr_stream *xdr, struct nfs_fattr *fattr,
fattr->valid |= status;

status = decode_attr_owner(xdr, bitmap, server->nfs_client,
- &fattr->uid, may_sleep);
+ &fattr->user_name);
if (status < 0)
goto xdr_error;
fattr->valid |= status;

status = decode_attr_group(xdr, bitmap, server->nfs_client,
- &fattr->gid, may_sleep);
+ &fattr->group_name);
if (status < 0)
goto xdr_error;
fattr->valid |= status;
@@ -4757,8 +4753,7 @@ static int nfs4_xdr_dec_open_downgrade(struct rpc_rqst *rqstp, __be32 *p, struct
status = decode_open_downgrade(&xdr, res);
if (status != 0)
goto out;
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -4785,8 +4780,7 @@ static int nfs4_xdr_dec_access(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_ac
status = decode_access(&xdr, res);
if (status != 0)
goto out;
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -4813,8 +4807,7 @@ static int nfs4_xdr_dec_lookup(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_lo
goto out;
if ((status = decode_getfh(&xdr, res->fh)) != 0)
goto out;
- status = decode_getfattr(&xdr, res->fattr, res->server
- ,!RPC_IS_ASYNC(rqstp->rq_task));
+ status = decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -4838,8 +4831,7 @@ static int nfs4_xdr_dec_lookup_root(struct rpc_rqst *rqstp, __be32 *p, struct nf
if ((status = decode_putrootfh(&xdr)) != 0)
goto out;
if ((status = decode_getfh(&xdr, res->fh)) == 0)
- status = decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ status = decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -4864,8 +4856,7 @@ static int nfs4_xdr_dec_remove(struct rpc_rqst *rqstp, __be32 *p, struct nfs_rem
goto out;
if ((status = decode_remove(&xdr, &res->cinfo)) != 0)
goto out;
- decode_getfattr(&xdr, res->dir_attr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->dir_attr, res->server);
out:
return status;
}
@@ -4895,13 +4886,11 @@ static int nfs4_xdr_dec_rename(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_re
if ((status = decode_rename(&xdr, &res->old_cinfo, &res->new_cinfo)) != 0)
goto out;
/* Current FH is target directory */
- if (decode_getfattr(&xdr, res->new_fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task)) != 0)
+ if (decode_getfattr(&xdr, res->new_fattr, res->server) != 0)
goto out;
if ((status = decode_restorefh(&xdr)) != 0)
goto out;
- decode_getfattr(&xdr, res->old_fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->old_fattr, res->server);
out:
return status;
}
@@ -4934,13 +4923,11 @@ static int nfs4_xdr_dec_link(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_link
* Note order: OP_LINK leaves the directory as the current
* filehandle.
*/
- if (decode_getfattr(&xdr, res->dir_attr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task)) != 0)
+ if (decode_getfattr(&xdr, res->dir_attr, res->server) != 0)
goto out;
if ((status = decode_restorefh(&xdr)) != 0)
goto out;
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -4969,13 +4956,11 @@ static int nfs4_xdr_dec_create(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_cr
goto out;
if ((status = decode_getfh(&xdr, res->fh)) != 0)
goto out;
- if (decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task)) != 0)
+ if (decode_getfattr(&xdr, res->fattr, res->server) != 0)
goto out;
if ((status = decode_restorefh(&xdr)) != 0)
goto out;
- decode_getfattr(&xdr, res->dir_fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->dir_fattr, res->server);
out:
return status;
}
@@ -5007,8 +4992,7 @@ static int nfs4_xdr_dec_getattr(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_g
status = decode_putfh(&xdr);
if (status)
goto out;
- status = decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ status = decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -5115,8 +5099,7 @@ static int nfs4_xdr_dec_close(struct rpc_rqst *rqstp, __be32 *p, struct nfs_clos
* an ESTALE error. Shouldn't be a problem,
* though, since fattr->valid will remain unset.
*/
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -5148,13 +5131,11 @@ static int nfs4_xdr_dec_open(struct rpc_rqst *rqstp, __be32 *p, struct nfs_openr
goto out;
if (decode_getfh(&xdr, &res->fh) != 0)
goto out;
- if (decode_getfattr(&xdr, res->f_attr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task)) != 0)
+ if (decode_getfattr(&xdr, res->f_attr, res->server) != 0)
goto out;
if (decode_restorefh(&xdr) != 0)
goto out;
- decode_getfattr(&xdr, res->dir_attr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->dir_attr, res->server);
out:
return status;
}
@@ -5202,8 +5183,7 @@ static int nfs4_xdr_dec_open_noattr(struct rpc_rqst *rqstp, __be32 *p, struct nf
status = decode_open(&xdr, res);
if (status)
goto out;
- decode_getfattr(&xdr, res->f_attr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->f_attr, res->server);
out:
return status;
}
@@ -5230,8 +5210,7 @@ static int nfs4_xdr_dec_setattr(struct rpc_rqst *rqstp, __be32 *p, struct nfs_se
status = decode_setattr(&xdr);
if (status)
goto out;
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -5418,8 +5397,7 @@ static int nfs4_xdr_dec_write(struct rpc_rqst *rqstp, __be32 *p, struct nfs_writ
status = decode_write(&xdr, res);
if (status)
goto out;
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
if (!status)
status = res->count;
out:
@@ -5448,8 +5426,7 @@ static int nfs4_xdr_dec_commit(struct rpc_rqst *rqstp, __be32 *p, struct nfs_wri
status = decode_commit(&xdr, res);
if (status)
goto out;
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -5615,8 +5592,7 @@ static int nfs4_xdr_dec_delegreturn(struct rpc_rqst *rqstp, __be32 *p, struct nf
status = decode_delegreturn(&xdr);
if (status != 0)
goto out;
- decode_getfattr(&xdr, res->fattr, res->server,
- !RPC_IS_ASYNC(rqstp->rq_task));
+ decode_getfattr(&xdr, res->fattr, res->server);
out:
return status;
}
@@ -5644,8 +5620,7 @@ static int nfs4_xdr_dec_fs_locations(struct rpc_rqst *req, __be32 *p,
goto out;
xdr_enter_page(&xdr, PAGE_SIZE);
status = decode_getfattr(&xdr, &res->fs_locations->fattr,
- res->fs_locations->server,
- !RPC_IS_ASYNC(req->rq_task));
+ res->fs_locations->server);
out:
return status;
}
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 508f8cf..6ce7a08 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -369,6 +369,10 @@ extern struct nfs_fattr *nfs_alloc_fattr(void);

static inline void nfs_free_fattr(const struct nfs_fattr *fattr)
{
+ if (!fattr)
+ return;
+ kfree(fattr->user_name);
+ kfree(fattr->group_name);
kfree(fattr);
}

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index fc46192..fc58d5d 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -27,10 +27,17 @@ static inline int nfs_fsid_equal(const struct nfs_fsid *a, const struct nfs_fsid
return a->major == b->major && a->minor == b->minor;
}

+struct nfs_name {
+ size_t len;
+ char buf[];
+};
+
struct nfs_fattr {
unsigned int valid; /* which fields are valid */
umode_t mode;
__u32 nlink;
+ struct nfs_name *user_name;
+ struct nfs_name *group_name;
__u32 uid;
__u32 gid;
dev_t rdev;
--
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