From: Peng Tao Date: Thu, 3 Jul 2014 05:07:45 +0000 (+0800) Subject: pnfs/filelayout: fix race between mark_request_commit and scan_commit_lists X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=c8a3292d246f3ed326698ed6acf3286c62b7bf11;p=linux-beck.git pnfs/filelayout: fix race between mark_request_commit and scan_commit_lists We need to hold cinfo lock while setting bucket->wlseg and adding req to nwritten list at the same time. Otherwise there might be a window where nwritten list is empty yet we set bucket->wlseg, in which case ff_layout_scan_ds_commit_list() may end up clearing bucket->wlseg incorrectly, casuing client to oops later on. This was found when testing flexfile layout but filelayout has the same problem. Signed-off-by: Peng Tao Signed-off-by: Tom Haynes Signed-off-by: Trond Myklebust --- diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c index 504d58a51d35..a928f92bcb10 100644 --- a/fs/nfs/filelayout/filelayout.c +++ b/fs/nfs/filelayout/filelayout.c @@ -1035,18 +1035,22 @@ out: pnfs_put_lseg(freeme); } -static struct list_head * -filelayout_choose_commit_list(struct nfs_page *req, - struct pnfs_layout_segment *lseg, - struct nfs_commit_info *cinfo) +static void +filelayout_mark_request_commit(struct nfs_page *req, + struct pnfs_layout_segment *lseg, + struct nfs_commit_info *cinfo) + { struct nfs4_filelayout_segment *fl = FILELAYOUT_LSEG(lseg); u32 i, j; struct list_head *list; struct pnfs_commit_bucket *buckets; - if (fl->commit_through_mds) - return &cinfo->mds->list; + if (fl->commit_through_mds) { + list = &cinfo->mds->list; + spin_lock(cinfo->lock); + goto mds_commit; + } /* Note that we are calling nfs4_fl_calc_j_index on each page * that ends up being committed to a data server. An attractive @@ -1070,19 +1074,22 @@ filelayout_choose_commit_list(struct nfs_page *req, } set_bit(PG_COMMIT_TO_DS, &req->wb_flags); cinfo->ds->nwritten++; - spin_unlock(cinfo->lock); - return list; -} -static void -filelayout_mark_request_commit(struct nfs_page *req, - struct pnfs_layout_segment *lseg, - struct nfs_commit_info *cinfo) -{ - struct list_head *list; - - list = filelayout_choose_commit_list(req, lseg, cinfo); - nfs_request_add_commit_list(req, list, cinfo); +mds_commit: + /* nfs_request_add_commit_list(). We need to add req to list without + * dropping cinfo lock. + */ + set_bit(PG_CLEAN, &(req)->wb_flags); + nfs_list_add_request(req, list); + cinfo->mds->ncommit++; + spin_unlock(cinfo->lock); + if (!cinfo->dreq) { + inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); + inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info, + BDI_RECLAIMABLE); + __mark_inode_dirty(req->wb_context->dentry->d_inode, + I_DIRTY_DATASYNC); + } } static u32 calc_ds_index_from_commit(struct pnfs_layout_segment *lseg, u32 i)