| From | Greg Kroah-Hartman <> | Subject | [ 053/123] NFS: Ensure that we free the rpc_task after read and write cleanups are done | Date | Wed, 9 Jan 2013 12:34:52 -0800 |
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3.7-stable review patch. If anyone has any objections, please let me know.
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From: Trond Myklebust <Trond.Myklebust@netapp.com>
commit 6db6dd7d3fd8f7c765dabc376493d6791ab28bd6 upstream.
This patch ensures that we free the rpc_task after the cleanup callbacks are done in order to avoid a deadlock problem that can be triggered if the callback needs to wait for another workqueue item to complete.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Weston Andros Adamson <dros@netapp.com> Cc: Tejun Heo <tj@kernel.org> Cc: Bruce Fields <bfields@fieldses.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/nfs/read.c | 10 +++++++--- fs/nfs/write.c | 10 +++++++--- 2 files changed, 14 insertions(+), 6 deletions(-)
--- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -91,12 +91,16 @@ void nfs_readdata_release(struct nfs_rea put_nfs_open_context(rdata->args.context); if (rdata->pages.pagevec != rdata->pages.page_array) kfree(rdata->pages.pagevec); - if (rdata != &read_header->rpc_data) - kfree(rdata); - else + if (rdata == &read_header->rpc_data) { rdata->header = NULL; + rdata = NULL; + } if (atomic_dec_and_test(&hdr->refcnt)) hdr->completion_ops->completion(hdr); + /* Note: we only free the rpc_task after callbacks are done. + * See the comment in rpc_free_task() for why + */ + kfree(rdata); } EXPORT_SYMBOL_GPL(nfs_readdata_release); --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -126,12 +126,16 @@ void nfs_writedata_release(struct nfs_wr put_nfs_open_context(wdata->args.context); if (wdata->pages.pagevec != wdata->pages.page_array) kfree(wdata->pages.pagevec); - if (wdata != &write_header->rpc_data) - kfree(wdata); - else + if (wdata == &write_header->rpc_data) { wdata->header = NULL; + wdata = NULL; + } if (atomic_dec_and_test(&hdr->refcnt)) hdr->completion_ops->completion(hdr); + /* Note: we only free the rpc_task after callbacks are done. + * See the comment in rpc_free_task() for why + */ + kfree(wdata); } EXPORT_SYMBOL_GPL(nfs_writedata_release);
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