NFS: nfs_find_open_context() may only select open files

[ Upstream commit e97bc66377bca097e1f3349ca18ca17f202ff659 ]

If a file has already been closed, then it should not be selected to
support further I/O.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
[Trond: Fix an invalid pointer deref reported by Colin Ian King]
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 8c0f916380c4e205d261160cf7f1e69b138315f3..209263c0c537757ded40b5a1bc76a3c6ad8cd459 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1048,6 +1048,7 @@ EXPORT_SYMBOL_GPL(nfs_inode_attach_open_context);
 void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx)
 {
        filp->private_data = get_nfs_open_context(ctx);
+       set_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
        if (list_empty(&ctx->list))
                nfs_inode_attach_open_context(ctx);
 }
@@ -1067,6 +1068,8 @@ struct nfs_open_context *nfs_find_open_context(struct inode *inode, const struct
                        continue;
                if ((pos->mode & (FMODE_READ|FMODE_WRITE)) != mode)
                        continue;
+               if (!test_bit(NFS_CONTEXT_FILE_OPEN, &pos->flags))
+                       continue;
                ctx = get_nfs_open_context(pos);
                if (ctx)
                        break;
@@ -1082,6 +1085,7 @@ void nfs_file_clear_open_context(struct file *filp)
        if (ctx) {
                struct inode *inode = d_inode(ctx->dentry);
 
+               clear_bit(NFS_CONTEXT_FILE_OPEN, &ctx->flags);
                /*
                 * We fatal error on write before. Try to writeback
                 * every page again.

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index ad09c0cc54645d5b772b223c5c11a6b26209f580..978ef674f03883627dd03e49003c8a146ae0b61d 100644 (file)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -79,6 +79,7 @@ struct nfs_open_context {
 #define NFS_CONTEXT_RESEND_WRITES      (1)
 #define NFS_CONTEXT_BAD                        (2)
 #define NFS_CONTEXT_UNLOCK     (3)
+#define NFS_CONTEXT_FILE_OPEN          (4)
        int error;
 
        struct list_head list;