From: Weston Andros Adamson <dros@xxxxxxxxxx>
This patch has been added to the 4.1 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 5e3a98883e7ebdd1440f829a9e9dd5c3d2c5903b ]
pnfs_generic_commit_cancel_empty_pagelist calls nfs_commitdata_release,
but that is wrong: nfs_commitdata_release puts the open context, something
that isn't valid until nfs_init_commit is called, which is never the case
when pnfs_generic_commit_cancel_empty_pagelist is called.
This was introduced in "nfs: avoid race that crashes nfs_init_commit".
Signed-off-by: Weston Andros Adamson <dros@xxxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
fs/nfs/pnfs_nfs.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 8bd645a..19c1bcf 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -247,7 +247,11 @@ void pnfs_fetch_commit_bucket_list(struct list_head *pages,
}
/* Helper function for pnfs_generic_commit_pagelist to catch an empty
- * page list. This can happen when two commits race. */
+ * page list. This can happen when two commits race.
+ *
+ * This must be called instead of nfs_init_commit - call one or the other, but
+ * not both!
+ */
static bool
pnfs_generic_commit_cancel_empty_pagelist(struct list_head *pages,
struct nfs_commit_data *data,
@@ -256,7 +260,11 @@ pnfs_generic_commit_cancel_empty_pagelist(struct list_head *pages,
if (list_empty(pages)) {
if (atomic_dec_and_test(&cinfo->mds->rpcs_out))
wake_up_atomic_t(&cinfo->mds->rpcs_out);
- nfs_commitdata_release(data);
+ /* don't call nfs_commitdata_release - it tries to put
+ * the open_context which is not acquired until nfs_init_commit
+ * which has not been called on @data */
+ WARN_ON_ONCE(data->context);
+ nfs_commit_free(data);
return true;
}
--
2.5.0
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