pnfs/blocklayout: refactor extent processing

Factor out a helper for all per-extent work, and merge the now trivial
functions for lseg allocation and parsing.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 105 insertions, 102 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 61a858cd54fe..76ec017a6f0a 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -513,144 +513,147 @@ static int decode_sector_number(__be32 **rp, sector_t *sp)
         return 0;
 }
 
-/* XDR decode pnfs_block_layout4 structure */
 static int
-nfs4_blk_process_layoutget(struct pnfs_layout_hdr *lo,
-                           struct nfs4_layoutget_res *lgr, gfp_t gfp_flags)
+bl_alloc_extent(struct xdr_stream *xdr, struct pnfs_layout_hdr *lo,
+                struct layout_verification *lv, struct list_head *extents,
+                gfp_t gfp_mask)
 {
-        struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
-        int i, status = -EIO;
-        uint32_t count;
-        struct pnfs_block_extent *be = NULL, *save;
-        struct xdr_stream stream;
-        struct xdr_buf buf;
-        struct page *scratch;
+        struct pnfs_block_extent *be;
+        struct nfs4_deviceid id;
+        int error;
         __be32 *p;
+
+        p = xdr_inline_decode(xdr, 28 + NFS4_DEVICEID4_SIZE);
+        if (!p)
+                return -EIO;
+
+        be = kzalloc(sizeof(*be), GFP_NOFS);
+        if (!be)
+                return -ENOMEM;
+
+        memcpy(&id, p, NFS4_DEVICEID4_SIZE);
+        p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
+
+        error = -EIO;
+        be->be_device = nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &id,
+                                                lo->plh_lc_cred, gfp_mask);
+        if (!be->be_device)
+                goto out_free_be;
+
+        /*
+         * The next three values are read in as bytes, but stored in the
+         * extent structure in 512-byte granularity.
+         */
+        if (decode_sector_number(&p, &be->be_f_offset) < 0)
+                goto out_put_deviceid;
+        if (decode_sector_number(&p, &be->be_length) < 0)
+                goto out_put_deviceid;
+        if (decode_sector_number(&p, &be->be_v_offset) < 0)
+                goto out_put_deviceid;
+        be->be_state = be32_to_cpup(p++);
+
+        error = verify_extent(be, lv);
+        if (error) {
+                dprintk("%s: extent verification failed\n", __func__);
+                goto out_put_deviceid;
+        }
+
+        list_add_tail(&be->be_list, extents);
+        return 0;
+
+out_put_deviceid:
+        nfs4_put_deviceid_node(be->be_device);
+out_free_be:
+        kfree(be);
+        return error;
+}
+
+static struct pnfs_layout_segment *
+bl_alloc_lseg(struct pnfs_layout_hdr *lo, struct nfs4_layoutget_res *lgr,
+                gfp_t gfp_mask)
+{
         struct layout_verification lv = {
                 .mode = lgr->range.iomode,
                 .start = lgr->range.offset >> SECTOR_SHIFT,
                 .inval = lgr->range.offset >> SECTOR_SHIFT,
                 .cowread = lgr->range.offset >> SECTOR_SHIFT,
         };
+        struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
+        struct pnfs_layout_segment *lseg;
+        struct xdr_buf buf;
+        struct xdr_stream xdr;
+        struct page *scratch;
+        int status, i;
+        uint32_t count;
+        __be32 *p;
         LIST_HEAD(extents);
 
         dprintk("---> %s\n", __func__);
 
-        scratch = alloc_page(gfp_flags);
+        lseg = kzalloc(sizeof(*lseg), gfp_mask);
+        if (!lseg)
+                return ERR_PTR(-ENOMEM);
+
+        status = -ENOMEM;
+        scratch = alloc_page(gfp_mask);
         if (!scratch)
-                return -ENOMEM;
+                goto out;
 
-        xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
-        xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
+        xdr_init_decode_pages(&xdr, &buf,
+                        lgr->layoutp->pages, lgr->layoutp->len);
+        xdr_set_scratch_buffer(&xdr, page_address(scratch), PAGE_SIZE);
 
-        p = xdr_inline_decode(&stream, 4);
+        status = -EIO;
+        p = xdr_inline_decode(&xdr, 4);
         if (unlikely(!p))
-                goto out_err;
+                goto out_free_scratch;
 
         count = be32_to_cpup(p++);
+        dprintk("%s: number of extents %d\n", __func__, count);
 
-        dprintk("%s enter, number of extents %i\n", __func__, count);
-        p = xdr_inline_decode(&stream, (28 + NFS4_DEVICEID4_SIZE) * count);
-        if (unlikely(!p))
-                goto out_err;
-
-        /* Decode individual extents, putting them in temporary
-         * staging area until whole layout is decoded to make error
-         * recovery easier.
+        /*
+         * Decode individual extents, putting them in temporary staging area
+         * until whole layout is decoded to make error recovery easier.
          */
         for (i = 0; i < count; i++) {
-                struct nfs4_deviceid id;
-
-                be = kzalloc(sizeof(struct pnfs_block_extent), GFP_NOFS);
-                if (!be) {
-                        status = -ENOMEM;
-                        goto out_err;
-                }
-                memcpy(&id, p, NFS4_DEVICEID4_SIZE);
-                p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
-
-                be->be_device =
-                        nfs4_find_get_deviceid(NFS_SERVER(lo->plh_inode), &id,
-                                                lo->plh_lc_cred, gfp_flags);
-                if (!be->be_device)
-                        goto out_err;
-
-                /* The next three values are read in as bytes,
-                 * but stored as 512-byte sector lengths
-                 */
-                if (decode_sector_number(&p, &be->be_f_offset) < 0)
-                        goto out_err;
-                if (decode_sector_number(&p, &be->be_length) < 0)
-                        goto out_err;
-                if (decode_sector_number(&p, &be->be_v_offset) < 0)
-                        goto out_err;
-                be->be_state = be32_to_cpup(p++);
-                if (verify_extent(be, &lv)) {
-                        dprintk("%s verify failed\n", __func__);
-                        goto out_err;
-                }
-                list_add_tail(&be->be_list, &extents);
+                status = bl_alloc_extent(&xdr, lo, &lv, &extents, gfp_mask);
+                if (status)
+                        goto process_extents;
         }
+
         if (lgr->range.offset + lgr->range.length !=
                         lv.start << SECTOR_SHIFT) {
                 dprintk("%s Final length mismatch\n", __func__);
-                be = NULL;
-                goto out_err;
+                status = -EIO;
+                goto process_extents;
         }
+
         if (lv.start < lv.cowread) {
                 dprintk("%s Final uncovered COW extent\n", __func__);
-                be = NULL;
-                goto out_err;
-        }
-        /* Extents decoded properly, now try to merge them in to
-         * existing layout extents.
-         */
-        list_for_each_entry_safe(be, save, &extents, be_list) {
-                list_del(&be->be_list);
-
-                status = ext_tree_insert(bl, be);
-                if (status)
-                        goto out_free_list;
+                status = -EIO;
         }
-        status = 0;
- out:
-        __free_page(scratch);
-        dprintk("%s returns %i\n", __func__, status);
-        return status;
 
- out_err:
-        nfs4_put_deviceid_node(be->be_device);
-        kfree(be);
- out_free_list:
+process_extents:
         while (!list_empty(&extents)) {
-                be = list_first_entry(&extents, struct pnfs_block_extent,
-                                      be_list);
+                struct pnfs_block_extent *be =
+                        list_first_entry(&extents, struct pnfs_block_extent,
+                                         be_list);
                 list_del(&be->be_list);
-                nfs4_put_deviceid_node(be->be_device);
-                kfree(be);
-        }
-        goto out;
-}
 
-/* We pretty much ignore lseg, and store all data layout wide, so we
- * can correctly merge.
- */
-static struct pnfs_layout_segment *bl_alloc_lseg(struct pnfs_layout_hdr *lo,
-                                                 struct nfs4_layoutget_res *lgr,
-                                                 gfp_t gfp_flags)
-{
-        struct pnfs_layout_segment *lseg;
-        int status;
+                if (!status)
+                        status = ext_tree_insert(bl, be);
 
-        dprintk("%s enter\n", __func__);
-        lseg = kzalloc(sizeof(*lseg), gfp_flags);
-        if (!lseg)
-                return ERR_PTR(-ENOMEM);
-        status = nfs4_blk_process_layoutget(lo, lgr, gfp_flags);
+                if (status) {
+                        nfs4_put_deviceid_node(be->be_device);
+                        kfree(be);
+                }
+        }
+
+out_free_scratch:
+        __free_page(scratch);
+out:
+        dprintk("%s returns %d\n", __func__, status);
         if (status) {
-                /* We don't want to call the full-blown bl_free_lseg,
-                 * since on error extents were not touched.
-                 */
                 kfree(lseg);
                 return ERR_PTR(status);
         }