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NFSv4.1/flexfiles: Allow coalescing of new layout segments and existing ones 

In order to ensure atomicity of updates, we merge the old layout segments
into the new ones, and then invalidate the old ones.

Also ensure that we order the list of layout segments so that
RO segments are preferred over RW.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
hifive-unleashed-5.1
Trond Myklebust 2015-08-25 17:38:25 -04:00
parent 03772d2f00
commit 0762ed2ced
2 changed files with 76 additions and 0 deletions
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60
fs/nfs/flexfilelayout/flexfilelayout.c
View File

@ -265,6 +265,65 @@ static void _ff_layout_free_lseg(struct nfs4_ff_layout_segment *fls)
}
}
static bool
ff_lseg_range_is_after(const struct pnfs_layout_range *l1,
const struct pnfs_layout_range *l2)
{
u64 end1, end2;
if (l1->iomode != l2->iomode)
return l1->iomode != IOMODE_READ;
end1 = pnfs_calc_offset_end(l1->offset, l1->length);
end2 = pnfs_calc_offset_end(l2->offset, l2->length);
if (end1 < l2->offset)
return false;
if (end2 < l1->offset)
return true;
return l2->offset <= l1->offset;
}
static bool
ff_lseg_merge(struct pnfs_layout_segment *new,
struct pnfs_layout_segment *old)
{
u64 new_end, old_end;
if (new->pls_range.iomode != old->pls_range.iomode)
return false;
old_end = pnfs_calc_offset_end(old->pls_range.offset,
old->pls_range.length);
if (old_end < new->pls_range.offset)
return false;
new_end = pnfs_calc_offset_end(new->pls_range.offset,
new->pls_range.length);
if (new_end < old->pls_range.offset)
return false;
/* Mergeable: copy info from 'old' to 'new' */
if (new_end < old_end)
new_end = old_end;
if (new->pls_range.offset < old->pls_range.offset)
new->pls_range.offset = old->pls_range.offset;
new->pls_range.length = pnfs_calc_offset_length(new->pls_range.offset,
new_end);
if (test_bit(NFS_LSEG_ROC, &old->pls_flags))
set_bit(NFS_LSEG_ROC, &new->pls_flags);
if (test_bit(NFS_LSEG_LAYOUTRETURN, &old->pls_flags))
set_bit(NFS_LSEG_LAYOUTRETURN, &new->pls_flags);
return true;
}
static void
ff_layout_add_lseg(struct pnfs_layout_hdr *lo,
struct pnfs_layout_segment *lseg,
struct list_head *free_me)
{
pnfs_generic_layout_insert_lseg(lo, lseg,
ff_lseg_range_is_after,
ff_lseg_merge,
free_me);
}
static void ff_layout_sort_mirrors(struct nfs4_ff_layout_segment *fls)
{
int i, j;
@ -2046,6 +2105,7 @@ static struct pnfs_layoutdriver_type flexfilelayout_type = {
.free_layout_hdr = ff_layout_free_layout_hdr,
.alloc_lseg = ff_layout_alloc_lseg,
.free_lseg = ff_layout_free_lseg,
.add_lseg = ff_layout_add_lseg,
.pg_read_ops = &ff_layout_pg_read_ops,
.pg_write_ops = &ff_layout_pg_write_ops,
.get_ds_info = ff_layout_get_ds_info,

16
fs/nfs/pnfs.h
View File

@ -539,6 +539,22 @@ pnfs_use_threshold(struct nfs4_threshold **dst, struct nfs4_threshold *src,
nfss->pnfs_curr_ld->id == src->l_type);
}
static inline u64
pnfs_calc_offset_end(u64 offset, u64 len)
{
if (len == NFS4_MAX_UINT64 || len >= NFS4_MAX_UINT64 - offset)
return NFS4_MAX_UINT64;
return offset + len - 1;
}
static inline u64
pnfs_calc_offset_length(u64 offset, u64 end)
{
if (end == NFS4_MAX_UINT64 || end <= offset)
return NFS4_MAX_UINT64;
return 1 + end - offset;
}
extern unsigned int layoutstats_timer;
#ifdef NFS_DEBUG