From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Add a new vm_operations struct btrfs_dax_vm_ops
specifically for dax files.
Since we will be removing(nulling) readpages/writepages for dax
return ENOEXEC only for non-dax files.
dax_insert_entry() looks ugly. Do you think we should break it
into dax_insert_cow_entry() and dax_insert_entry()?
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
fs/btrfs/ctree.h | 1 +
fs/btrfs/dax.c | 11 +++++++++++
fs/btrfs/file.c | 18 ++++++++++++++++--
fs/dax.c | 17 ++++++++++-------
4 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3bcd2a4959c1..0e5060933bde 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3802,6 +3802,7 @@ int btree_readahead_hook(struct extent_buffer *eb, int err);
/* dax.c */
ssize_t btrfs_file_dax_read(struct kiocb *iocb, struct iov_iter *to);
ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from);
+vm_fault_t btrfs_dax_fault(struct vm_fault *vmf);
#else
static inline ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from)
{
diff --git a/fs/btrfs/dax.c b/fs/btrfs/dax.c
index 49619fe3f94f..927f962d1e88 100644
--- a/fs/btrfs/dax.c
+++ b/fs/btrfs/dax.c
@@ -157,4 +157,15 @@ ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *iter)
}
return ret;
}
+
+vm_fault_t btrfs_dax_fault(struct vm_fault *vmf)
+{
+ vm_fault_t ret;
+ pfn_t pfn;
+ ret = dax_iomap_fault(vmf, PE_SIZE_PTE, &pfn, NULL, &btrfs_iomap_ops);
+ if (ret & VM_FAULT_NEEDDSYNC)
+ ret = dax_finish_sync_fault(vmf, PE_SIZE_PTE, pfn);
+
+ return ret;
+}
#endif /* CONFIG_FS_DAX */
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 3b320d0ab495..196c8f37ff9d 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2214,15 +2214,29 @@ static const struct vm_operations_struct btrfs_file_vm_ops = {
.page_mkwrite = btrfs_page_mkwrite,
};
+#ifdef CONFIG_FS_DAX
+static const struct vm_operations_struct btrfs_dax_vm_ops = {
+ .fault = btrfs_dax_fault,
+ .page_mkwrite = btrfs_dax_fault,
+ .pfn_mkwrite = btrfs_dax_fault,
+};
+#else
+#define btrfs_dax_vm_ops btrfs_file_vm_ops
+#endif
+
static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct address_space *mapping = filp->f_mapping;
+ struct inode *inode = file_inode(filp);
- if (!mapping->a_ops->readpage)
+ if (!IS_DAX(inode) && !mapping->a_ops->readpage)
return -ENOEXEC;
file_accessed(filp);
- vma->vm_ops = &btrfs_file_vm_ops;
+ if (IS_DAX(inode))
+ vma->vm_ops = &btrfs_dax_vm_ops;
+ else
+ vma->vm_ops = &btrfs_file_vm_ops;
return 0;
}
diff --git a/fs/dax.c b/fs/dax.c
index 21ee3df6f02c..41061da42771 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -708,14 +708,15 @@ static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev,
*/
static void *dax_insert_entry(struct xa_state *xas,
struct address_space *mapping, struct vm_fault *vmf,
- void *entry, pfn_t pfn, unsigned long flags, bool dirty)
+ void *entry, pfn_t pfn, unsigned long flags, bool dirty,
+ bool cow)
{
void *new_entry = dax_make_entry(pfn, flags);
if (dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
- if (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE)) {
+ if (cow || (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE))) {
unsigned long index = xas->xa_index;
/* we are replacing a zero page with block mapping */
if (dax_is_pmd_entry(entry))
@@ -732,7 +733,7 @@ static void *dax_insert_entry(struct xa_state *xas,
dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address);
}
- if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
+ if (cow || dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
/*
* Only swap our new entry into the page cache if the current
* entry is a zero page or an empty entry. If a normal PTE or
@@ -1031,7 +1032,7 @@ static vm_fault_t dax_load_hole(struct xa_state *xas,
vm_fault_t ret;
*entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
- DAX_ZERO_PAGE, false);
+ DAX_ZERO_PAGE, false, false);
ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
trace_dax_load_hole(inode, vmf, ret);
@@ -1408,7 +1409,8 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
goto error_finish_iomap;
entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn,
- 0, write && !sync);
+ 0, write && !sync,
+ (iomap.flags & IOMAP_F_COW) != 0);
/*
* If we are doing synchronous page fault and inode needs fsync,
@@ -1487,7 +1489,7 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
pfn = page_to_pfn_t(zero_page);
*entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
- DAX_PMD | DAX_ZERO_PAGE, false);
+ DAX_PMD | DAX_ZERO_PAGE, false, false);
ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
if (!pmd_none(*(vmf->pmd))) {
@@ -1610,7 +1612,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
goto finish_iomap;
entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn,
- DAX_PMD, write && !sync);
+ DAX_PMD, write && !sync,
+ false);
/*
* If we are doing synchronous page fault and inode needs fsync,
--
2.16.4
