Commit 159e0561 authored by Peng Tao's avatar Peng Tao Committed by Trond Myklebust
Browse files

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: default avatarPeng Tao <tao.peng@emc.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent f44106e2

fs/nfs/blocklayout/blocklayout.c

+36 −3
Original line number Diff line number Diff line
@@ -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,

};

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