| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.6 052/203] pnfs_nfs: fix _cancel_empty_pagelist | Date | Mon, 25 Jul 2016 13:54:27 -0700 |
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4.6-stable review patch. If anyone has any objections, please let me know.
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From: Weston Andros Adamson <dros@monkey.org>
commit 5e3a98883e7ebdd1440f829a9e9dd5c3d2c5903b upstream.
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@primarydata.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/nfs/pnfs_nfs.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
--- a/fs/nfs/pnfs_nfs.c +++ b/fs/nfs/pnfs_nfs.c @@ -247,7 +247,11 @@ void pnfs_fetch_commit_bucket_list(struc } /* 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_pagelis 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; }
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