[PATCH 5.13 182/351] NFS: nfs_find_open_context() may only select open files

Greg Kroah-Hartman
2021-07-19T17:36:47Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ 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>
---
fs/nfs/inode.c | 4 ++++
include/linux/nfs_fs.h | 1 +
2 files changed, 5 insertions(+)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 327f9ae4dd3f..1acae1716df1 100644
--- 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 ffba254d2098..ce6474594872 100644
--- 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;
--
2.30.2