NFSv4: Ensure that we track the NFSv4 lock state in read/write requests.

This patch fixes bugzilla entry 14501:
  https://bugzilla.kernel.org/show_bug.cgi?id=14501

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

6 files changed, 104 insertions, 17 deletions

diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index ad4cd31d6050..064a80961677 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -69,6 +69,7 @@ struct nfs_direct_req {
 
         /* I/O parameters */
         struct nfs_open_context *ctx;           /* file open context info */
+        struct nfs_lock_context *l_ctx;         /* Lock context info */
         struct kiocb *          iocb;           /* controlling i/o request */
         struct inode *          inode;          /* target file of i/o */
 
@@ -160,6 +161,7 @@ static inline struct nfs_direct_req *nfs_direct_req_alloc(void)
         INIT_LIST_HEAD(&dreq->rewrite_list);
         dreq->iocb = NULL;
         dreq->ctx = NULL;
+        dreq->l_ctx = NULL;
         spin_lock_init(&dreq->lock);
         atomic_set(&dreq->io_count, 0);
         dreq->count = 0;
@@ -173,6 +175,8 @@ static void nfs_direct_req_free(struct kref *kref)
 {
         struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref);
 
+        if (dreq->l_ctx != NULL)
+                nfs_put_lock_context(dreq->l_ctx);
         if (dreq->ctx != NULL)
                 put_nfs_open_context(dreq->ctx);
         kmem_cache_free(nfs_direct_cachep, dreq);
@@ -336,6 +340,7 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_direct_req *dreq,
                 data->cred = msg.rpc_cred;
                 data->args.fh = NFS_FH(inode);
                 data->args.context = ctx;
+                data->args.lock_context = dreq->l_ctx;
                 data->args.offset = pos;
                 data->args.pgbase = pgbase;
                 data->args.pages = data->pagevec;
@@ -416,24 +421,28 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
 static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
                                unsigned long nr_segs, loff_t pos)
 {
-        ssize_t result = 0;
+        ssize_t result = -ENOMEM;
         struct inode *inode = iocb->ki_filp->f_mapping->host;
         struct nfs_direct_req *dreq;
 
         dreq = nfs_direct_req_alloc();
-        if (!dreq)
-                return -ENOMEM;
+        if (dreq == NULL)
+                goto out;
 
         dreq->inode = inode;
         dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
+        dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
+        if (dreq->l_ctx == NULL)
+                goto out_release;
         if (!is_sync_kiocb(iocb))
                 dreq->iocb = iocb;
 
         result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos);
         if (!result)
                 result = nfs_direct_wait(dreq);
+out_release:
         nfs_direct_req_release(dreq);
-
+out:
         return result;
 }
 
@@ -574,6 +583,7 @@ static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq)
         data->args.offset = 0;
         data->args.count = 0;
         data->args.context = dreq->ctx;
+        data->args.lock_context = dreq->l_ctx;
         data->res.count = 0;
         data->res.fattr = &data->fattr;
         data->res.verf = &data->verf;
@@ -761,6 +771,7 @@ static ssize_t nfs_direct_write_schedule_segment(struct nfs_direct_req *dreq,
                 data->cred = msg.rpc_cred;
                 data->args.fh = NFS_FH(inode);
                 data->args.context = ctx;
+                data->args.lock_context = dreq->l_ctx;
                 data->args.offset = pos;
                 data->args.pgbase = pgbase;
                 data->args.pages = data->pagevec;
@@ -845,7 +856,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
                                 unsigned long nr_segs, loff_t pos,
                                 size_t count)
 {
-        ssize_t result = 0;
+        ssize_t result = -ENOMEM;
         struct inode *inode = iocb->ki_filp->f_mapping->host;
         struct nfs_direct_req *dreq;
         size_t wsize = NFS_SERVER(inode)->wsize;
@@ -853,7 +864,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
 
         dreq = nfs_direct_req_alloc();
         if (!dreq)
-                return -ENOMEM;
+                goto out;
         nfs_alloc_commit_data(dreq);
 
         if (dreq->commit_data == NULL || count < wsize)
@@ -861,14 +872,18 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov,
 
         dreq->inode = inode;
         dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp));
+        dreq->l_ctx = nfs_get_lock_context(dreq->ctx);
+        if (dreq->l_ctx != NULL)
+                goto out_release;
         if (!is_sync_kiocb(iocb))
                 dreq->iocb = iocb;
 
         result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, sync);
         if (!result)
                 result = nfs_direct_wait(dreq);
+out_release:
         nfs_direct_req_release(dreq);
-
+out:
         return result;
 }
 
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 099b3518feea..ec7a8f96a2c2 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -530,6 +530,68 @@ out:
         return err;
 }
 
+static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
+{
+        atomic_set(&l_ctx->count, 1);
+        l_ctx->lockowner = current->files;
+        l_ctx->pid = current->tgid;
+        INIT_LIST_HEAD(&l_ctx->list);
+}
+
+static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)
+{
+        struct nfs_lock_context *pos;
+
+        list_for_each_entry(pos, &ctx->lock_context.list, list) {
+                if (pos->lockowner != current->files)
+                        continue;
+                if (pos->pid != current->tgid)
+                        continue;
+                atomic_inc(&pos->count);
+                return pos;
+        }
+        return NULL;
+}
+
+struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
+{
+        struct nfs_lock_context *res, *new = NULL;
+        struct inode *inode = ctx->path.dentry->d_inode;
+
+        spin_lock(&inode->i_lock);
+        res = __nfs_find_lock_context(ctx);
+        if (res == NULL) {
+                spin_unlock(&inode->i_lock);
+                new = kmalloc(sizeof(*new), GFP_KERNEL);
+                if (new == NULL)
+                        return NULL;
+                nfs_init_lock_context(new);
+                spin_lock(&inode->i_lock);
+                res = __nfs_find_lock_context(ctx);
+                if (res == NULL) {
+                        list_add_tail(&new->list, &ctx->lock_context.list);
+                        new->open_context = ctx;
+                        res = new;
+                        new = NULL;
+                }
+        }
+        spin_unlock(&inode->i_lock);
+        kfree(new);
+        return res;
+}
+
+void nfs_put_lock_context(struct nfs_lock_context *l_ctx)
+{
+        struct nfs_open_context *ctx = l_ctx->open_context;
+        struct inode *inode = ctx->path.dentry->d_inode;
+
+        if (!atomic_dec_and_lock(&l_ctx->count, &inode->i_lock))
+                return;
+        list_del(&l_ctx->list);
+        spin_unlock(&inode->i_lock);
+        kfree(l_ctx);
+}
+
 /**
  * nfs_close_context - Common close_context() routine NFSv2/v3
  * @ctx: pointer to context
@@ -566,11 +628,11 @@ static struct nfs_open_context *alloc_nfs_open_context(struct path *path, struct
                 path_get(&ctx->path);
                 ctx->cred = get_rpccred(cred);
                 ctx->state = NULL;
-                ctx->lockowner = current->files;
                 ctx->flags = 0;
                 ctx->error = 0;
                 ctx->dir_cookie = 0;
-                atomic_set(&ctx->count, 1);
+                nfs_init_lock_context(&ctx->lock_context);
+                ctx->lock_context.open_context = ctx;
         }
         return ctx;
 }
@@ -578,7 +640,7 @@ static struct nfs_open_context *alloc_nfs_open_context(struct path *path, struct
 struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx)
 {
         if (ctx != NULL)
-                atomic_inc(&ctx->count);
+                atomic_inc(&ctx->lock_context.count);
         return ctx;
 }
 
@@ -586,7 +648,7 @@ static void __put_nfs_open_context(struct nfs_open_context *ctx, int is_sync)
 {
         struct inode *inode = ctx->path.dentry->d_inode;
 
-        if (!atomic_dec_and_lock(&ctx->count, &inode->i_lock))
+        if (!atomic_dec_and_lock(&ctx->lock_context.count, &inode->i_lock))
                 return;
         list_del(&ctx->list);
         spin_unlock(&inode->i_lock);
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 1f7781d636ae..873b62f209ea 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1324,14 +1324,14 @@ static void encode_putrootfh(struct xdr_stream *xdr, struct compound_hdr *hdr)
         hdr->replen += decode_putrootfh_maxsz;
 }
 
-static void encode_stateid(struct xdr_stream *xdr, const struct nfs_open_context *ctx)
+static void encode_stateid(struct xdr_stream *xdr, const struct nfs_open_context *ctx, const struct nfs_lock_context *l_ctx)
 {
         nfs4_stateid stateid;
         __be32 *p;
 
         p = reserve_space(xdr, NFS4_STATEID_SIZE);
         if (ctx->state != NULL) {
-                nfs4_copy_stateid(&stateid, ctx->state, ctx->lockowner);
+                nfs4_copy_stateid(&stateid, ctx->state, l_ctx->lockowner);
                 xdr_encode_opaque_fixed(p, stateid.data, NFS4_STATEID_SIZE);
         } else
                 xdr_encode_opaque_fixed(p, zero_stateid.data, NFS4_STATEID_SIZE);
@@ -1344,7 +1344,7 @@ static void encode_read(struct xdr_stream *xdr, const struct nfs_readargs *args,
         p = reserve_space(xdr, 4);
         *p = cpu_to_be32(OP_READ);
 
-        encode_stateid(xdr, args->context);
+        encode_stateid(xdr, args->context, args->lock_context);
 
         p = reserve_space(xdr, 12);
         p = xdr_encode_hyper(p, args->offset);
@@ -1523,7 +1523,7 @@ static void encode_write(struct xdr_stream *xdr, const struct nfs_writeargs *arg
         p = reserve_space(xdr, 4);
         *p = cpu_to_be32(OP_WRITE);
 
-        encode_stateid(xdr, args->context);
+        encode_stateid(xdr, args->context, args->lock_context);
 
         p = reserve_space(xdr, 16);
         p = xdr_encode_hyper(p, args->offset);
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index a3654e57b589..919490232e17 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -79,6 +79,7 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
         req->wb_pgbase  = offset;
         req->wb_bytes   = count;
         req->wb_context = get_nfs_open_context(ctx);
+        req->wb_lock_context = nfs_get_lock_context(ctx);
         kref_init(&req->wb_kref);
         return req;
 }
@@ -141,11 +142,16 @@ void nfs_clear_request(struct nfs_page *req)
 {
         struct page *page = req->wb_page;
         struct nfs_open_context *ctx = req->wb_context;
+        struct nfs_lock_context *l_ctx = req->wb_lock_context;
 
         if (page != NULL) {
                 page_cache_release(page);
                 req->wb_page = NULL;
         }
+        if (l_ctx != NULL) {
+                nfs_put_lock_context(l_ctx);
+                req->wb_lock_context = NULL;
+        }
         if (ctx != NULL) {
                 put_nfs_open_context(ctx);
                 req->wb_context = NULL;
@@ -235,7 +241,7 @@ static int nfs_can_coalesce_requests(struct nfs_page *prev,
 {
         if (req->wb_context->cred != prev->wb_context->cred)
                 return 0;
-        if (req->wb_context->lockowner != prev->wb_context->lockowner)
+        if (req->wb_lock_context->lockowner != prev->wb_lock_context->lockowner)
                 return 0;
         if (req->wb_context->state != prev->wb_context->state)
                 return 0;
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 5a33a92e8168..87adc2744246 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -190,6 +190,7 @@ static int nfs_read_rpcsetup(struct nfs_page *req, struct nfs_read_data *data,
         data->args.pages  = data->pagevec;
         data->args.count  = count;
         data->args.context = get_nfs_open_context(req->wb_context);
+        data->args.lock_context = req->wb_lock_context;
 
         data->res.fattr   = &data->fattr;
         data->res.count   = count;
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 03df22822c4c..5eccea127cac 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -689,7 +689,9 @@ int nfs_flush_incompatible(struct file *file, struct page *page)
                 req = nfs_page_find_request(page);
                 if (req == NULL)
                         return 0;
-                do_flush = req->wb_page != page || req->wb_context != ctx;
+                do_flush = req->wb_page != page || req->wb_context != ctx ||
+                        req->wb_lock_context->lockowner != current->files ||
+                        req->wb_lock_context->pid != current->tgid;
                 nfs_release_request(req);
                 if (!do_flush)
                         return 0;
@@ -813,6 +815,7 @@ static int nfs_write_rpcsetup(struct nfs_page *req,
         data->args.pages  = data->pagevec;
         data->args.count  = count;
         data->args.context = get_nfs_open_context(req->wb_context);
+        data->args.lock_context = req->wb_lock_context;
         data->args.stable  = NFS_UNSTABLE;
         if (how & FLUSH_STABLE) {
                 data->args.stable = NFS_DATA_SYNC;