On 05/29/2012 08:57 AM, Peng Tao wrote: > 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. >
Please add the dprints > Cc: [email protected] > Signed-off-by: Peng Tao <[email protected]> > --- > Change from v2: > Add symptom in commit log. > > fs/nfs/blocklayout/blocklayout.c | 39 +++++++++++++++++++++++++++++++++++-- > 1 files 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, > }; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
