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Diffstat (limited to 'fs/dax.c')
-rw-r--r--fs/dax.c301
1 files changed, 195 insertions, 106 deletions
diff --git a/fs/dax.c b/fs/dax.c
index a8732fbed381..c45598b912e1 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -451,16 +451,37 @@ void dax_wake_mapping_entry_waiter(struct address_space *mapping,
__wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
}
+static int __dax_invalidate_mapping_entry(struct address_space *mapping,
+ pgoff_t index, bool trunc)
+{
+ int ret = 0;
+ void *entry;
+ struct radix_tree_root *page_tree = &mapping->page_tree;
+
+ spin_lock_irq(&mapping->tree_lock);
+ entry = get_unlocked_mapping_entry(mapping, index, NULL);
+ if (!entry || !radix_tree_exceptional_entry(entry))
+ goto out;
+ if (!trunc &&
+ (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) ||
+ radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)))
+ goto out;
+ radix_tree_delete(page_tree, index);
+ mapping->nrexceptional--;
+ ret = 1;
+out:
+ put_unlocked_mapping_entry(mapping, index, entry);
+ spin_unlock_irq(&mapping->tree_lock);
+ return ret;
+}
/*
* Delete exceptional DAX entry at @index from @mapping. Wait for radix tree
* entry to get unlocked before deleting it.
*/
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
{
- void *entry;
+ int ret = __dax_invalidate_mapping_entry(mapping, index, true);
- spin_lock_irq(&mapping->tree_lock);
- entry = get_unlocked_mapping_entry(mapping, index, NULL);
/*
* This gets called from truncate / punch_hole path. As such, the caller
* must hold locks protecting against concurrent modifications of the
@@ -468,16 +489,46 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
* caller has seen exceptional entry for this index, we better find it
* at that index as well...
*/
- if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry))) {
- spin_unlock_irq(&mapping->tree_lock);
- return 0;
- }
- radix_tree_delete(&mapping->page_tree, index);
+ WARN_ON_ONCE(!ret);
+ return ret;
+}
+
+/*
+ * Invalidate exceptional DAX entry if easily possible. This handles DAX
+ * entries for invalidate_inode_pages() so we evict the entry only if we can
+ * do so without blocking.
+ */
+int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index)
+{
+ int ret = 0;
+ void *entry, **slot;
+ struct radix_tree_root *page_tree = &mapping->page_tree;
+
+ spin_lock_irq(&mapping->tree_lock);
+ entry = __radix_tree_lookup(page_tree, index, NULL, &slot);
+ if (!entry || !radix_tree_exceptional_entry(entry) ||
+ slot_locked(mapping, slot))
+ goto out;
+ if (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) ||
+ radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))
+ goto out;
+ radix_tree_delete(page_tree, index);
mapping->nrexceptional--;
+ ret = 1;
+out:
spin_unlock_irq(&mapping->tree_lock);
- dax_wake_mapping_entry_waiter(mapping, index, entry, true);
+ if (ret)
+ dax_wake_mapping_entry_waiter(mapping, index, entry, true);
+ return ret;
+}
- return 1;
+/*
+ * Invalidate exceptional DAX entry if it is clean.
+ */
+int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
+ pgoff_t index)
+{
+ return __dax_invalidate_mapping_entry(mapping, index, false);
}
/*
@@ -488,15 +539,16 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
* otherwise it will simply fall out of the page cache under memory
* pressure without ever having been dirtied.
*/
-static int dax_load_hole(struct address_space *mapping, void *entry,
+static int dax_load_hole(struct address_space *mapping, void **entry,
struct vm_fault *vmf)
{
struct page *page;
+ int ret;
/* Hole page already exists? Return it... */
- if (!radix_tree_exceptional_entry(entry)) {
- vmf->page = entry;
- return VM_FAULT_LOCKED;
+ if (!radix_tree_exceptional_entry(*entry)) {
+ page = *entry;
+ goto out;
}
/* This will replace locked radix tree entry with a hole page */
@@ -504,8 +556,17 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
vmf->gfp_mask | __GFP_ZERO);
if (!page)
return VM_FAULT_OOM;
+ out:
vmf->page = page;
- return VM_FAULT_LOCKED;
+ ret = finish_fault(vmf);
+ vmf->page = NULL;
+ *entry = page;
+ if (!ret) {
+ /* Grab reference for PTE that is now referencing the page */
+ get_page(page);
+ return VM_FAULT_NOPAGE;
+ }
+ return ret;
}
static int copy_user_dax(struct block_device *bdev, sector_t sector, size_t size,
@@ -630,8 +691,8 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping,
pgoff_t index, unsigned long pfn)
{
struct vm_area_struct *vma;
- pte_t *ptep;
- pte_t pte;
+ pte_t pte, *ptep = NULL;
+ pmd_t *pmdp = NULL;
spinlock_t *ptl;
bool changed;
@@ -646,21 +707,42 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping,
address = pgoff_address(index, vma);
changed = false;
- if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
+ if (follow_pte_pmd(vma->vm_mm, address, &ptep, &pmdp, &ptl))
continue;
- if (pfn != pte_pfn(*ptep))
- goto unlock;
- if (!pte_dirty(*ptep) && !pte_write(*ptep))
- goto unlock;
- flush_cache_page(vma, address, pfn);
- pte = ptep_clear_flush(vma, address, ptep);
- pte = pte_wrprotect(pte);
- pte = pte_mkclean(pte);
- set_pte_at(vma->vm_mm, address, ptep, pte);
- changed = true;
-unlock:
- pte_unmap_unlock(ptep, ptl);
+ if (pmdp) {
+#ifdef CONFIG_FS_DAX_PMD
+ pmd_t pmd;
+
+ if (pfn != pmd_pfn(*pmdp))
+ goto unlock_pmd;
+ if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp))
+ goto unlock_pmd;
+
+ flush_cache_page(vma, address, pfn);
+ pmd = pmdp_huge_clear_flush(vma, address, pmdp);
+ pmd = pmd_wrprotect(pmd);
+ pmd = pmd_mkclean(pmd);
+ set_pmd_at(vma->vm_mm, address, pmdp, pmd);
+ changed = true;
+unlock_pmd:
+ spin_unlock(ptl);
+#endif
+ } else {
+ if (pfn != pte_pfn(*ptep))
+ goto unlock_pte;
+ if (!pte_dirty(*ptep) && !pte_write(*ptep))
+ goto unlock_pte;
+
+ flush_cache_page(vma, address, pfn);
+ pte = ptep_clear_flush(vma, address, ptep);
+ pte = pte_wrprotect(pte);
+ pte = pte_mkclean(pte);
+ set_pte_at(vma->vm_mm, address, ptep, pte);
+ changed = true;
+unlock_pte:
+ pte_unmap_unlock(ptep, ptl);
+ }
if (changed)
mmu_notifier_invalidate_page(vma->vm_mm, address);
@@ -908,7 +990,6 @@ int __dax_zero_page_range(struct block_device *bdev, sector_t sector,
}
EXPORT_SYMBOL_GPL(__dax_zero_page_range);
-#ifdef CONFIG_FS_IOMAP
static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos)
{
return iomap->blkno + (((pos & PAGE_MASK) - iomap->offset) >> 9);
@@ -934,11 +1015,27 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED))
return -EIO;
+ /*
+ * Write can allocate block for an area which has a hole page mapped
+ * into page tables. We have to tear down these mappings so that data
+ * written by write(2) is visible in mmap.
+ */
+ if ((iomap->flags & IOMAP_F_NEW) && inode->i_mapping->nrpages) {
+ invalidate_inode_pages2_range(inode->i_mapping,
+ pos >> PAGE_SHIFT,
+ (end - 1) >> PAGE_SHIFT);
+ }
+
while (pos < end) {
unsigned offset = pos & (PAGE_SIZE - 1);
struct blk_dax_ctl dax = { 0 };
ssize_t map_len;
+ if (fatal_signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+
dax.sector = dax_iomap_sector(iomap, pos);
dax.size = (length + offset + PAGE_SIZE - 1) & PAGE_MASK;
map_len = dax_map_atomic(iomap->bdev, &dax);
@@ -992,23 +1089,6 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
if (iov_iter_rw(iter) == WRITE)
flags |= IOMAP_WRITE;
- /*
- * Yes, even DAX files can have page cache attached to them: A zeroed
- * page is inserted into the pagecache when we have to serve a write
- * fault on a hole. It should never be dirtied and can simply be
- * dropped from the pagecache once we get real data for the page.
- *
- * XXX: This is racy against mmap, and there's nothing we can do about
- * it. We'll eventually need to shift this down even further so that
- * we can check if we allocated blocks over a hole first.
- */
- if (mapping->nrpages) {
- ret = invalidate_inode_pages2_range(mapping,
- pos >> PAGE_SHIFT,
- (pos + iov_iter_count(iter) - 1) >> PAGE_SHIFT);
- WARN_ON_ONCE(ret);
- }
-
while (iov_iter_count(iter)) {
ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops,
iter, dax_iomap_actor);
@@ -1023,6 +1103,15 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
}
EXPORT_SYMBOL_GPL(dax_iomap_rw);
+static int dax_fault_return(int error)
+{
+ if (error == 0)
+ return VM_FAULT_NOPAGE;
+ if (error == -ENOMEM)
+ return VM_FAULT_OOM;
+ return VM_FAULT_SIGBUS;
+}
+
/**
* dax_iomap_fault - handle a page fault on a DAX file
* @vma: The virtual memory area where the fault occurred
@@ -1055,12 +1144,6 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
if (pos >= i_size_read(inode))
return VM_FAULT_SIGBUS;
- entry = grab_mapping_entry(mapping, vmf->pgoff, 0);
- if (IS_ERR(entry)) {
- error = PTR_ERR(entry);
- goto out;
- }
-
if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page)
flags |= IOMAP_WRITE;
@@ -1071,9 +1154,15 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
*/
error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap);
if (error)
- goto unlock_entry;
+ return dax_fault_return(error);
if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) {
- error = -EIO; /* fs corruption? */
+ vmf_ret = dax_fault_return(-EIO); /* fs corruption? */
+ goto finish_iomap;
+ }
+
+ entry = grab_mapping_entry(mapping, vmf->pgoff, 0);
+ if (IS_ERR(entry)) {
+ vmf_ret = dax_fault_return(PTR_ERR(entry));
goto finish_iomap;
}
@@ -1096,13 +1185,13 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
}
if (error)
- goto finish_iomap;
+ goto error_unlock_entry;
__SetPageUptodate(vmf->cow_page);
vmf_ret = finish_fault(vmf);
if (!vmf_ret)
vmf_ret = VM_FAULT_DONE_COW;
- goto finish_iomap;
+ goto unlock_entry;
}
switch (iomap.type) {
@@ -1114,12 +1203,15 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
}
error = dax_insert_mapping(mapping, iomap.bdev, sector,
PAGE_SIZE, &entry, vma, vmf);
+ /* -EBUSY is fine, somebody else faulted on the same PTE */
+ if (error == -EBUSY)
+ error = 0;
break;
case IOMAP_UNWRITTEN:
case IOMAP_HOLE:
if (!(vmf->flags & FAULT_FLAG_WRITE)) {
- vmf_ret = dax_load_hole(mapping, entry, vmf);
- break;
+ vmf_ret = dax_load_hole(mapping, &entry, vmf);
+ goto unlock_entry;
}
/*FALLTHRU*/
default:
@@ -1128,31 +1220,25 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
break;
}
+ error_unlock_entry:
+ vmf_ret = dax_fault_return(error) | major;
+ unlock_entry:
+ put_locked_mapping_entry(mapping, vmf->pgoff, entry);
finish_iomap:
if (ops->iomap_end) {
- if (error || (vmf_ret & VM_FAULT_ERROR)) {
- /* keep previous error */
- ops->iomap_end(inode, pos, PAGE_SIZE, 0, flags,
- &iomap);
- } else {
- error = ops->iomap_end(inode, pos, PAGE_SIZE,
- PAGE_SIZE, flags, &iomap);
- }
- }
- unlock_entry:
- if (vmf_ret != VM_FAULT_LOCKED || error)
- put_locked_mapping_entry(mapping, vmf->pgoff, entry);
- out:
- if (error == -ENOMEM)
- return VM_FAULT_OOM | major;
- /* -EBUSY is fine, somebody else faulted on the same PTE */
- if (error < 0 && error != -EBUSY)
- return VM_FAULT_SIGBUS | major;
- if (vmf_ret) {
- WARN_ON_ONCE(error); /* -EBUSY from ops->iomap_end? */
- return vmf_ret;
+ int copied = PAGE_SIZE;
+
+ if (vmf_ret & VM_FAULT_ERROR)
+ copied = 0;
+ /*
+ * The fault is done by now and there's no way back (other
+ * thread may be already happily using PTE we have installed).
+ * Just ignore error from ->iomap_end since we cannot do much
+ * with it.
+ */
+ ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap);
}
- return VM_FAULT_NOPAGE | major;
+ return vmf_ret;
}
EXPORT_SYMBOL_GPL(dax_iomap_fault);
@@ -1277,16 +1363,6 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
goto fallback;
/*
- * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX
- * PMD or a HZP entry. If it can't (because a 4k page is already in
- * the tree, for instance), it will return -EEXIST and we just fall
- * back to 4k entries.
- */
- entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD);
- if (IS_ERR(entry))
- goto fallback;
-
- /*
* Note that we don't use iomap_apply here. We aren't doing I/O, only
* setting up a mapping, so really we're using iomap_begin() as a way
* to look up our filesystem block.
@@ -1294,10 +1370,21 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
pos = (loff_t)pgoff << PAGE_SHIFT;
error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap);
if (error)
- goto unlock_entry;
+ goto fallback;
+
if (iomap.offset + iomap.length < pos + PMD_SIZE)
goto finish_iomap;
+ /*
+ * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX
+ * PMD or a HZP entry. If it can't (because a 4k page is already in
+ * the tree, for instance), it will return -EEXIST and we just fall
+ * back to 4k entries.
+ */
+ entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD);
+ if (IS_ERR(entry))
+ goto finish_iomap;
+
vmf.pgoff = pgoff;
vmf.flags = flags;
vmf.gfp_mask = mapping_gfp_mask(mapping) | __GFP_IO;
@@ -1310,7 +1397,7 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
case IOMAP_UNWRITTEN:
case IOMAP_HOLE:
if (WARN_ON_ONCE(write))
- goto finish_iomap;
+ goto unlock_entry;
result = dax_pmd_load_hole(vma, pmd, &vmf, address, &iomap,
&entry);
break;
@@ -1319,20 +1406,23 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
break;
}
+ unlock_entry:
+ put_locked_mapping_entry(mapping, pgoff, entry);
finish_iomap:
if (ops->iomap_end) {
- if (result == VM_FAULT_FALLBACK) {
- ops->iomap_end(inode, pos, PMD_SIZE, 0, iomap_flags,
- &iomap);
- } else {
- error = ops->iomap_end(inode, pos, PMD_SIZE, PMD_SIZE,
- iomap_flags, &iomap);
- if (error)
- result = VM_FAULT_FALLBACK;
- }
+ int copied = PMD_SIZE;
+
+ if (result == VM_FAULT_FALLBACK)
+ copied = 0;
+ /*
+ * The fault is done by now and there's no way back (other
+ * thread may be already happily using PMD we have installed).
+ * Just ignore error from ->iomap_end since we cannot do much
+ * with it.
+ */
+ ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags,
+ &iomap);
}
- unlock_entry:
- put_locked_mapping_entry(mapping, pgoff, entry);
fallback:
if (result == VM_FAULT_FALLBACK) {
split_huge_pmd(vma, pmd, address);
@@ -1342,4 +1432,3 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address,
}
EXPORT_SYMBOL_GPL(dax_iomap_pmd_fault);
#endif /* CONFIG_FS_DAX_PMD */
-#endif /* CONFIG_FS_IOMAP */
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-02 07:50:07 +0000