NFS: nfs_find_open_context() may only select open files

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]

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 529c409..d5d022f 100644 (file)
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1101,6 +1101,7 @@ 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);
 }
@@ -1120,6 +1121,8 @@ 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;
@@ -1135,6 +1138,7 @@ 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 ffba254..ce64745 100644 (file)
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -84,6 +84,7 @@ 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;