6.4-stable review patch. If anyone has any objections, please let me know.
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From: Trond Myklebust trond.myklebust@hammerspace.com
commit be2fd1560eb57b7298aa3c258ddcca0d53ecdea3 upstream.
Be more careful when tearing down the subrequests of an O_DIRECT write as part of a retransmission.
Reported-by: Chris Mason clm@fb.com Fixes: ed5d588fe47f ("NFS: Try to join page groups before an O_DIRECT retransmission") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfs/direct.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
--- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -472,20 +472,26 @@ out: return result; }
-static void -nfs_direct_join_group(struct list_head *list, struct inode *inode) +static void nfs_direct_join_group(struct list_head *list, struct inode *inode) { - struct nfs_page *req, *next; + struct nfs_page *req, *subreq;
list_for_each_entry(req, list, wb_list) { - if (req->wb_head != req || req->wb_this_page == req) + if (req->wb_head != req) continue; - for (next = req->wb_this_page; - next != req->wb_head; - next = next->wb_this_page) { - nfs_list_remove_request(next); - nfs_release_request(next); - } + subreq = req->wb_this_page; + if (subreq == req) + continue; + do { + /* + * Remove subrequests from this list before freeing + * them in the call to nfs_join_page_group(). + */ + if (!list_empty(&subreq->wb_list)) { + nfs_list_remove_request(subreq); + nfs_release_request(subreq); + } + } while ((subreq = subreq->wb_this_page) != req); nfs_join_page_group(req, inode); } }