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Subject[PATCH 5.0 184/238] NFS: Fix I/O request leakages
Date
5.0-stable review patch.  If anyone has any objections, please let me know.

------------------

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

commit f57dcf4c72113c745d83f1c65f7291299f65c14f upstream.

When we fail to add the request to the I/O queue, we currently leave it
to the caller to free the failed request. However since some of the
requests that fail are actually created by nfs_pageio_add_request()
itself, and are not passed back the caller, this leads to a leakage
issue, which can again cause page locks to leak.

This commit addresses the leakage by freeing the created requests on
error, using desc->pg_completion_ops->error_cleanup()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Fixes: a7d42ddb30997 ("nfs: add mirroring support to pgio layer")
Cc: stable@vger.kernel.org # v4.0: c18b96a1b862: nfs: clean up rest of reqs
Cc: stable@vger.kernel.org # v4.0: d600ad1f2bdb: NFS41: pop some layoutget
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/pagelist.c | 26 +++++++++++++++++++++-----
1 file changed, 21 insertions(+), 5 deletions(-)

--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -988,6 +988,17 @@ static void nfs_pageio_doio(struct nfs_p
}
}

+static void
+nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
+ struct nfs_page *req)
+{
+ LIST_HEAD(head);
+
+ nfs_list_remove_request(req);
+ nfs_list_add_request(req, &head);
+ desc->pg_completion_ops->error_cleanup(&head);
+}
+
/**
* nfs_pageio_add_request - Attempt to coalesce a request into a page list.
* @desc: destination io descriptor
@@ -1025,10 +1036,8 @@ static int __nfs_pageio_add_request(stru
nfs_page_group_unlock(req);
desc->pg_moreio = 1;
nfs_pageio_doio(desc);
- if (desc->pg_error < 0)
- return 0;
- if (mirror->pg_recoalesce)
- return 0;
+ if (desc->pg_error < 0 || mirror->pg_recoalesce)
+ goto out_cleanup_subreq;
/* retry add_request for this subreq */
nfs_page_group_lock(req);
continue;
@@ -1061,6 +1070,10 @@ err_ptr:
desc->pg_error = PTR_ERR(subreq);
nfs_page_group_unlock(req);
return 0;
+out_cleanup_subreq:
+ if (req != subreq)
+ nfs_pageio_cleanup_request(desc, subreq);
+ return 0;
}

static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
@@ -1168,11 +1181,14 @@ int nfs_pageio_add_request(struct nfs_pa
if (nfs_pgio_has_mirroring(desc))
desc->pg_mirror_idx = midx;
if (!nfs_pageio_add_request_mirror(desc, dupreq))
- goto out_failed;
+ goto out_cleanup_subreq;
}

return 1;

+out_cleanup_subreq:
+ if (req != dupreq)
+ nfs_pageio_cleanup_request(desc, dupreq);
out_failed:
nfs_pageio_error_cleanup(desc);
return 0;

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