| Message ID | 20190326190301.32365-9-rgoldwyn@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/15] btrfs: create a mount option for dax | expand |
On Tue, Mar 26, 2019 at 02:02:54PM -0500, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > dax_iomap_cow copies a page before presenting for mmap. > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > --- > fs/dax.c | 33 ++++++++++++++++++++++++++++++++- > 1 file changed, 32 insertions(+), 1 deletion(-) > > diff --git a/fs/dax.c b/fs/dax.c > index e254535dd830..21ee3df6f02c 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1269,6 +1269,33 @@ static bool dax_fault_is_synchronous(unsigned long flags, > && (iomap->flags & IOMAP_F_DIRTY); > } > > +static int dax_iomap_cow(struct iomap *iomap, loff_t pos, pfn_t *pfn) > +{ > + void *daddr; > + pgoff_t pgoff; > + long rc; > + int id; > + sector_t sector; > + > + pos = round_down(pos, PAGE_SIZE); > + > + sector = round_down(iomap->addr + iomap->offset - pos, PAGE_SIZE) >> 9; > + rc = bdev_dax_pgoff(iomap->bdev, sector, PAGE_SIZE, &pgoff); > + if (rc) > + return rc; > + > + id = dax_read_lock(); > + rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &daddr, pfn); > + if (rc < 0) > + goto out; > + > + dax_to_dax_copy(iomap, pos, daddr, PAGE_SIZE); > + > +out: > + dax_read_unlock(id); > + return rc; > +} > + > static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > int *iomap_errp, const struct iomap_ops *ops) > { > @@ -1372,7 +1399,11 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, > count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); > major = VM_FAULT_MAJOR; > } > - error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); > + > + if (iomap.flags & IOMAP_F_COW) > + error = dax_iomap_cow(&iomap, pos, &pfn); Why wouldn't dax_iomap_cow also apply to dax_iomap_pmd_fault? --D > + else > + error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); > if (error < 0) > goto error_finish_iomap; > > -- > 2.16.4 >
diff --git a/fs/dax.c b/fs/dax.c index e254535dd830..21ee3df6f02c 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1269,6 +1269,33 @@ static bool dax_fault_is_synchronous(unsigned long flags, && (iomap->flags & IOMAP_F_DIRTY); } +static int dax_iomap_cow(struct iomap *iomap, loff_t pos, pfn_t *pfn) +{ + void *daddr; + pgoff_t pgoff; + long rc; + int id; + sector_t sector; + + pos = round_down(pos, PAGE_SIZE); + + sector = round_down(iomap->addr + iomap->offset - pos, PAGE_SIZE) >> 9; + rc = bdev_dax_pgoff(iomap->bdev, sector, PAGE_SIZE, &pgoff); + if (rc) + return rc; + + id = dax_read_lock(); + rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &daddr, pfn); + if (rc < 0) + goto out; + + dax_to_dax_copy(iomap, pos, daddr, PAGE_SIZE); + +out: + dax_read_unlock(id); + return rc; +} + static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops) { @@ -1372,7 +1399,11 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); major = VM_FAULT_MAJOR; } - error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); + + if (iomap.flags & IOMAP_F_COW) + error = dax_iomap_cow(&iomap, pos, &pfn); + else + error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); if (error < 0) goto error_finish_iomap;