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dax: store pfns in the radix

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In preparation for examining the busy state of dax pages in the truncate
path, switch from sectors to pfns in the radix.

Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2017-10-14 17:13:45 -07:00
parent 6b2bb7265f
commit 3fe0791c29
2 changed files with 43 additions and 55 deletions
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15
drivers/dax/super.c
View file

@ -124,10 +124,19 @@ int __bdev_dax_supported(struct super_block *sb, int blocksize)
return len < 0 ? len : -EIO; return len < 0 ? len : -EIO;
} }
if ((IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) if (IS_ENABLED(CONFIG_FS_DAX_LIMITED) && pfn_t_special(pfn)) {
|| pfn_t_devmap(pfn)) /*
* An arch that has enabled the pmem api should also
* have its drivers support pfn_t_devmap()
*
* This is a developer warning and should not trigger in
* production. dax_flush() will crash since it depends
* on being able to do (page_address(pfn_to_page())).
*/
WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API));
} else if (pfn_t_devmap(pfn)) {
/* pass */; /* pass */;
else { } else {
pr_debug("VFS (%s): error: dax support not enabled\n", pr_debug("VFS (%s): error: dax support not enabled\n",
sb->s_id); sb->s_id);
return -EOPNOTSUPP; return -EOPNOTSUPP;

83
fs/dax.c
View file

@ -73,16 +73,15 @@ fs_initcall(init_dax_wait_table);
#define RADIX_DAX_ZERO_PAGE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) #define RADIX_DAX_ZERO_PAGE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2))
#define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3))
static unsigned long dax_radix_sector(void *entry) static unsigned long dax_radix_pfn(void *entry)
{ {
return (unsigned long)entry >> RADIX_DAX_SHIFT; return (unsigned long)entry >> RADIX_DAX_SHIFT;
} }
static void *dax_radix_locked_entry(sector_t sector, unsigned long flags) static void *dax_radix_locked_entry(unsigned long pfn, unsigned long flags)
{ {
return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags |
((unsigned long)sector << RADIX_DAX_SHIFT) | (pfn << RADIX_DAX_SHIFT) | RADIX_DAX_ENTRY_LOCK);
RADIX_DAX_ENTRY_LOCK);
} }
static unsigned int dax_radix_order(void *entry) static unsigned int dax_radix_order(void *entry)
@ -526,12 +525,13 @@ static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev,
*/ */
static void *dax_insert_mapping_entry(struct address_space *mapping, static void *dax_insert_mapping_entry(struct address_space *mapping,
struct vm_fault *vmf, struct vm_fault *vmf,
void *entry, sector_t sector, void *entry, pfn_t pfn_t,
unsigned long flags, bool dirty) unsigned long flags, bool dirty)
{ {
struct radix_tree_root *page_tree = &mapping->page_tree; struct radix_tree_root *page_tree = &mapping->page_tree;
void *new_entry; unsigned long pfn = pfn_t_to_pfn(pfn_t);
pgoff_t index = vmf->pgoff; pgoff_t index = vmf->pgoff;
void *new_entry;
if (dirty) if (dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES); __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@ -546,7 +546,7 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
} }
spin_lock_irq(&mapping->tree_lock); spin_lock_irq(&mapping->tree_lock);
new_entry = dax_radix_locked_entry(sector, flags); new_entry = dax_radix_locked_entry(pfn, flags);
if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
/* /*
@ -657,17 +657,14 @@ unlock_pte:
i_mmap_unlock_read(mapping); i_mmap_unlock_read(mapping);
} }
static int dax_writeback_one(struct block_device *bdev, static int dax_writeback_one(struct dax_device *dax_dev,
struct dax_device *dax_dev, struct address_space *mapping, struct address_space *mapping, pgoff_t index, void *entry)
pgoff_t index, void *entry)
{ {
struct radix_tree_root *page_tree = &mapping->page_tree; struct radix_tree_root *page_tree = &mapping->page_tree;
void *entry2, **slot, *kaddr; void *entry2, **slot;
long ret = 0, id; unsigned long pfn;
sector_t sector; long ret = 0;
pgoff_t pgoff;
size_t size; size_t size;
pfn_t pfn;
/* /*
* A page got tagged dirty in DAX mapping? Something is seriously * A page got tagged dirty in DAX mapping? Something is seriously
@ -683,10 +680,10 @@ static int dax_writeback_one(struct block_device *bdev,
goto put_unlocked; goto put_unlocked;
/* /*
* Entry got reallocated elsewhere? No need to writeback. We have to * Entry got reallocated elsewhere? No need to writeback. We have to
* compare sectors as we must not bail out due to difference in lockbit * compare pfns as we must not bail out due to difference in lockbit
* or entry type. * or entry type.
*/ */
if (dax_radix_sector(entry2) != dax_radix_sector(entry)) if (dax_radix_pfn(entry2) != dax_radix_pfn(entry))
goto put_unlocked; goto put_unlocked;
if (WARN_ON_ONCE(dax_is_empty_entry(entry) || if (WARN_ON_ONCE(dax_is_empty_entry(entry) ||
dax_is_zero_entry(entry))) { dax_is_zero_entry(entry))) {
@ -712,33 +709,15 @@ static int dax_writeback_one(struct block_device *bdev,
/* /*
* Even if dax_writeback_mapping_range() was given a wbc->range_start * Even if dax_writeback_mapping_range() was given a wbc->range_start
* in the middle of a PMD, the 'index' we are given will be aligned to * in the middle of a PMD, the 'index' we are given will be aligned to
* the start index of the PMD, as will the sector we pull from * the start index of the PMD, as will the pfn we pull from 'entry'.
* 'entry'. This allows us to flush for PMD_SIZE and not have to * This allows us to flush for PMD_SIZE and not have to worry about
* worry about partial PMD writebacks. * partial PMD writebacks.
*/ */
sector = dax_radix_sector(entry); pfn = dax_radix_pfn(entry);
size = PAGE_SIZE << dax_radix_order(entry); size = PAGE_SIZE << dax_radix_order(entry);
id = dax_read_lock(); dax_mapping_entry_mkclean(mapping, index, pfn);
ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); dax_flush(dax_dev, page_address(pfn_to_page(pfn)), size);
if (ret)
goto dax_unlock;
/*
* dax_direct_access() may sleep, so cannot hold tree_lock over
* its invocation.
*/
ret = dax_direct_access(dax_dev, pgoff, size / PAGE_SIZE, &kaddr, &pfn);
if (ret < 0)
goto dax_unlock;
if (WARN_ON_ONCE(ret < size / PAGE_SIZE)) {
ret = -EIO;
goto dax_unlock;
}
dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn));
dax_flush(dax_dev, kaddr, size);
/* /*
* After we have flushed the cache, we can clear the dirty tag. There * After we have flushed the cache, we can clear the dirty tag. There
* cannot be new dirty data in the pfn after the flush has completed as * cannot be new dirty data in the pfn after the flush has completed as
@ -749,8 +728,6 @@ static int dax_writeback_one(struct block_device *bdev,
radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY); radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY);
spin_unlock_irq(&mapping->tree_lock); spin_unlock_irq(&mapping->tree_lock);
trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT); trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT);
dax_unlock:
dax_read_unlock(id);
put_locked_mapping_entry(mapping, index); put_locked_mapping_entry(mapping, index);
return ret; return ret;
@ -808,8 +785,8 @@ int dax_writeback_mapping_range(struct address_space *mapping,
break; break;
} }
ret = dax_writeback_one(bdev, dax_dev, mapping, ret = dax_writeback_one(dax_dev, mapping, indices[i],
indices[i], pvec.pages[i]); pvec.pages[i]);
if (ret < 0) { if (ret < 0) {
mapping_set_error(mapping, ret); mapping_set_error(mapping, ret);
goto out; goto out;
@ -877,6 +854,7 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
int ret = VM_FAULT_NOPAGE; int ret = VM_FAULT_NOPAGE;
struct page *zero_page; struct page *zero_page;
void *entry2; void *entry2;
pfn_t pfn;
zero_page = ZERO_PAGE(0); zero_page = ZERO_PAGE(0);
if (unlikely(!zero_page)) { if (unlikely(!zero_page)) {
@ -884,14 +862,15 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
goto out; goto out;
} }
entry2 = dax_insert_mapping_entry(mapping, vmf, entry, 0, pfn = page_to_pfn_t(zero_page);
entry2 = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
RADIX_DAX_ZERO_PAGE, false); RADIX_DAX_ZERO_PAGE, false);
if (IS_ERR(entry2)) { if (IS_ERR(entry2)) {
ret = VM_FAULT_SIGBUS; ret = VM_FAULT_SIGBUS;
goto out; goto out;
} }
vm_insert_mixed(vmf->vma, vaddr, page_to_pfn_t(zero_page)); vm_insert_mixed(vmf->vma, vaddr, pfn);
out: out:
trace_dax_load_hole(inode, vmf, ret); trace_dax_load_hole(inode, vmf, ret);
return ret; return ret;
@ -1200,8 +1179,7 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (error < 0) if (error < 0)
goto error_finish_iomap; goto error_finish_iomap;
entry = dax_insert_mapping_entry(mapping, vmf, entry, entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
dax_iomap_sector(&iomap, pos),
0, write && !sync); 0, write && !sync);
if (IS_ERR(entry)) { if (IS_ERR(entry)) {
error = PTR_ERR(entry); error = PTR_ERR(entry);
@ -1280,13 +1258,15 @@ static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
void *ret = NULL; void *ret = NULL;
spinlock_t *ptl; spinlock_t *ptl;
pmd_t pmd_entry; pmd_t pmd_entry;
pfn_t pfn;
zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm);
if (unlikely(!zero_page)) if (unlikely(!zero_page))
goto fallback; goto fallback;
ret = dax_insert_mapping_entry(mapping, vmf, entry, 0, pfn = page_to_pfn_t(zero_page);
ret = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false); RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false);
if (IS_ERR(ret)) if (IS_ERR(ret))
goto fallback; goto fallback;
@ -1409,8 +1389,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (error < 0) if (error < 0)
goto finish_iomap; goto finish_iomap;
entry = dax_insert_mapping_entry(mapping, vmf, entry, entry = dax_insert_mapping_entry(mapping, vmf, entry, pfn,
dax_iomap_sector(&iomap, pos),
RADIX_DAX_PMD, write && !sync); RADIX_DAX_PMD, write && !sync);
if (IS_ERR(entry)) if (IS_ERR(entry))
goto finish_iomap; goto finish_iomap;