From 159e0561e322dd8008fff59e36efff8d2bdd0b0e Mon Sep 17 00:00:00 2001 From: Peng Tao Date: Tue, 29 May 2012 13:57:58 +0800 Subject: [PATCH] pnfsblock: bail out partial page IO Current block layout driver read/write code assumes page aligned IO in many places. Add a checker to validate the assumption. Otherwise there would be data corruption like when application does open(O_WRONLY) and page unaliged write. Signed-off-by: Peng Tao Signed-off-by: Trond Myklebust --- fs/nfs/blocklayout/blocklayout.c | 39 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 3 deletions(-) diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c index 7ae8a60..dd392ed 100644 --- a/fs/nfs/blocklayout/blocklayout.c +++ b/fs/nfs/blocklayout/blocklayout.c @@ -228,6 +228,14 @@ bl_end_par_io_read(void *data, int unused) schedule_work(&rdata->task.u.tk_work); } +static bool +bl_check_alignment(u64 offset, u32 len, unsigned long blkmask) +{ + if ((offset & blkmask) || (len & blkmask)) + return false; + return true; +} + static enum pnfs_try_status bl_read_pagelist(struct nfs_read_data *rdata) { @@ -244,6 +252,9 @@ bl_read_pagelist(struct nfs_read_data *rdata) dprintk("%s enter nr_pages %u offset %lld count %u\n", __func__, rdata->pages.npages, f_offset, (unsigned int)rdata->args.count); + if (!bl_check_alignment(f_offset, rdata->args.count, PAGE_CACHE_MASK)) + goto use_mds; + par = alloc_parallel(rdata); if (!par) goto use_mds; @@ -552,7 +563,7 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync) struct bio *bio = NULL; struct pnfs_block_extent *be = NULL, *cow_read = NULL; sector_t isect, last_isect = 0, extent_length = 0; - struct parallel_io *par; + struct parallel_io *par = NULL; loff_t offset = wdata->args.offset; size_t count = wdata->args.count; struct page **pages = wdata->args.pages; @@ -563,6 +574,10 @@ bl_write_pagelist(struct nfs_write_data *wdata, int sync) NFS_SERVER(header->inode)->pnfs_blksize >> PAGE_CACHE_SHIFT; dprintk("%s enter, %Zu@%lld\n", __func__, count, offset); + /* Check for alignment first */ + if (!bl_check_alignment(offset, count, PAGE_CACHE_MASK)) + goto out_mds; + /* At this point, wdata->pages is a (sequential) list of nfs_pages. * We want to write each, and if there is an error set pnfs_error * to have it redone using nfs. @@ -996,14 +1011,32 @@ bl_clear_layoutdriver(struct nfs_server *server) return 0; } +static void +bl_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) +{ + if (!bl_check_alignment(req->wb_offset, req->wb_bytes, PAGE_CACHE_MASK)) + nfs_pageio_reset_read_mds(pgio); + else + pnfs_generic_pg_init_read(pgio, req); +} + +static void +bl_pg_init_write(struct nfs_pageio_descriptor *pgio, struct nfs_page *req) +{ + if (!bl_check_alignment(req->wb_offset, req->wb_bytes, PAGE_CACHE_MASK)) + nfs_pageio_reset_write_mds(pgio); + else + pnfs_generic_pg_init_write(pgio, req); +} + static const struct nfs_pageio_ops bl_pg_read_ops = { - .pg_init = pnfs_generic_pg_init_read, + .pg_init = bl_pg_init_read, .pg_test = pnfs_generic_pg_test, .pg_doio = pnfs_generic_pg_readpages, }; static const struct nfs_pageio_ops bl_pg_write_ops = { - .pg_init = pnfs_generic_pg_init_write, + .pg_init = bl_pg_init_write, .pg_test = pnfs_generic_pg_test, .pg_doio = pnfs_generic_pg_writepages, }; -- 2.7.4