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dax: Implement dax_finish_sync_fault()

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Implement a function that filesystems can call to finish handling of
synchronous page faults. It takes care of syncing appropriare file range
and insertion of page table entry.

Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Jan Kara 2017-11-01 16:36:43 +01:00 committed by Dan Williams
parent caa51d26f8
commit 71eab6dfd9
3 changed files with 87 additions and 0 deletions
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83
fs/dax.c
View file

@ -1492,3 +1492,86 @@ int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
}
}
EXPORT_SYMBOL_GPL(dax_iomap_fault);
/**
* dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables
* @vmf: The description of the fault
* @pe_size: Size of entry to be inserted
* @pfn: PFN to insert
*
* This function inserts writeable PTE or PMD entry into page tables for mmaped
* DAX file. It takes care of marking corresponding radix tree entry as dirty
* as well.
*/
static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
enum page_entry_size pe_size,
pfn_t pfn)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
void *entry, **slot;
pgoff_t index = vmf->pgoff;
int vmf_ret, error;
spin_lock_irq(&mapping->tree_lock);
entry = get_unlocked_mapping_entry(mapping, index, &slot);
/* Did we race with someone splitting entry or so? */
if (!entry ||
(pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) ||
(pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) {
put_unlocked_mapping_entry(mapping, index, entry);
spin_unlock_irq(&mapping->tree_lock);
trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf,
VM_FAULT_NOPAGE);
return VM_FAULT_NOPAGE;
}
radix_tree_tag_set(&mapping->page_tree, index, PAGECACHE_TAG_DIRTY);
entry = lock_slot(mapping, slot);
spin_unlock_irq(&mapping->tree_lock);
switch (pe_size) {
case PE_SIZE_PTE:
error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
vmf_ret = dax_fault_return(error);
break;
#ifdef CONFIG_FS_DAX_PMD
case PE_SIZE_PMD:
vmf_ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd,
pfn, true);
break;
#endif
default:
vmf_ret = VM_FAULT_FALLBACK;
}
put_locked_mapping_entry(mapping, index);
trace_dax_insert_pfn_mkwrite(mapping->host, vmf, vmf_ret);
return vmf_ret;
}
/**
* dax_finish_sync_fault - finish synchronous page fault
* @vmf: The description of the fault
* @pe_size: Size of entry to be inserted
* @pfn: PFN to insert
*
* This function ensures that the file range touched by the page fault is
* stored persistently on the media and handles inserting of appropriate page
* table entry.
*/
int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
pfn_t pfn)
{
int err;
loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT;
size_t len = 0;
if (pe_size == PE_SIZE_PTE)
len = PAGE_SIZE;
else if (pe_size == PE_SIZE_PMD)
len = PMD_SIZE;
else
WARN_ON_ONCE(1);
err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1);
if (err)
return VM_FAULT_SIGBUS;
return dax_insert_pfn_mkwrite(vmf, pe_size, pfn);
}
EXPORT_SYMBOL_GPL(dax_finish_sync_fault);

2
include/linux/dax.h
View file

@ -96,6 +96,8 @@ ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops);
int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
pfn_t *pfnp, const struct iomap_ops *ops);
int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
pfn_t pfn);
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
pgoff_t index);

2
include/trace/events/fs_dax.h
View file

@ -190,6 +190,8 @@ DEFINE_EVENT(dax_pte_fault_class, name, \
DEFINE_PTE_FAULT_EVENT(dax_pte_fault);
DEFINE_PTE_FAULT_EVENT(dax_pte_fault_done);
DEFINE_PTE_FAULT_EVENT(dax_load_hole);
DEFINE_PTE_FAULT_EVENT(dax_insert_pfn_mkwrite_no_entry);
DEFINE_PTE_FAULT_EVENT(dax_insert_pfn_mkwrite);
TRACE_EVENT(dax_insert_mapping,
TP_PROTO(struct inode *inode, struct vm_fault *vmf, void *radix_entry),