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pnfs/blocklayout: refactor extent processing
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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>
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Christoph Hellwig authored and Trond Myklebust committed Sep 12, 2014
1 parent 9cc4754 commit ca0fe1d
Showing 1 changed file with 105 additions and 102 deletions.
207 changes: 105 additions & 102 deletions fs/nfs/blocklayout/blocklayout.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
}
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