#include <linux/memcontrol.h>
#include <linux/mm.h>
#include <linux/mutex.h>
+#include <linux/pagevec.h>
#include <linux/pmem.h>
#include <linux/sched.h>
#include <linux/uio.h>
blk_queue_exit(bdev->bd_queue);
}
+struct page *read_dax_sector(struct block_device *bdev, sector_t n)
+{
+ struct page *page = alloc_pages(GFP_KERNEL, 0);
+ struct blk_dax_ctl dax = {
+ .size = PAGE_SIZE,
+ .sector = n & ~((((int) PAGE_SIZE) / 512) - 1),
+ };
+ long rc;
+
+ if (!page)
+ return ERR_PTR(-ENOMEM);
+
+ rc = dax_map_atomic(bdev, &dax);
+ if (rc < 0)
+ return ERR_PTR(rc);
+ memcpy_from_pmem(page_address(page), dax.addr, PAGE_SIZE);
+ dax_unmap_atomic(bdev, &dax);
+ return page;
+}
+
/*
* dax_clear_blocks() is called from within transaction context from XFS,
* and hence this means the stack from this point must follow GFP_NOFS
loff_t end = pos + iov_iter_count(iter);
memset(&bh, 0, sizeof(bh));
+ bh.b_bdev = inode->i_sb->s_bdev;
if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ) {
struct address_space *mapping = inode->i_mapping;
- mutex_lock(&inode->i_mutex);
+ inode_lock(inode);
retval = filemap_write_and_wait_range(mapping, pos, end - 1);
if (retval) {
- mutex_unlock(&inode->i_mutex);
+ inode_unlock(inode);
goto out;
}
}
retval = dax_io(inode, iter, pos, end, get_block, &bh);
if ((flags & DIO_LOCKING) && iov_iter_rw(iter) == READ)
- mutex_unlock(&inode->i_mutex);
+ inode_unlock(inode);
if ((retval > 0) && end_io)
end_io(iocb, pos, retval, bh.b_private);
return 0;
}
+#define NO_SECTOR -1
+#define DAX_PMD_INDEX(page_index) (page_index & (PMD_MASK >> PAGE_CACHE_SHIFT))
+
+static int dax_radix_entry(struct address_space *mapping, pgoff_t index,
+ sector_t sector, bool pmd_entry, bool dirty)
+{
+ struct radix_tree_root *page_tree = &mapping->page_tree;
+ pgoff_t pmd_index = DAX_PMD_INDEX(index);
+ int type, error = 0;
+ void *entry;
+
+ WARN_ON_ONCE(pmd_entry && !dirty);
+ if (dirty)
+ __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+
+ spin_lock_irq(&mapping->tree_lock);
+
+ entry = radix_tree_lookup(page_tree, pmd_index);
+ if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD) {
+ index = pmd_index;
+ goto dirty;
+ }
+
+ entry = radix_tree_lookup(page_tree, index);
+ if (entry) {
+ type = RADIX_DAX_TYPE(entry);
+ if (WARN_ON_ONCE(type != RADIX_DAX_PTE &&
+ type != RADIX_DAX_PMD)) {
+ error = -EIO;
+ goto unlock;
+ }
+
+ if (!pmd_entry || type == RADIX_DAX_PMD)
+ goto dirty;
+
+ /*
+ * We only insert dirty PMD entries into the radix tree. This
+ * means we don't need to worry about removing a dirty PTE
+ * entry and inserting a clean PMD entry, thus reducing the
+ * range we would flush with a follow-up fsync/msync call.
+ */
+ radix_tree_delete(&mapping->page_tree, index);
+ mapping->nrexceptional--;
+ }
+
+ if (sector == NO_SECTOR) {
+ /*
+ * This can happen during correct operation if our pfn_mkwrite
+ * fault raced against a hole punch operation. If this
+ * happens the pte that was hole punched will have been
+ * unmapped and the radix tree entry will have been removed by
+ * the time we are called, but the call will still happen. We
+ * will return all the way up to wp_pfn_shared(), where the
+ * pte_same() check will fail, eventually causing page fault
+ * to be retried by the CPU.
+ */
+ goto unlock;
+ }
+
+ error = radix_tree_insert(page_tree, index,
+ RADIX_DAX_ENTRY(sector, pmd_entry));
+ if (error)
+ goto unlock;
+
+ mapping->nrexceptional++;
+ dirty:
+ if (dirty)
+ radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY);
+ unlock:
+ spin_unlock_irq(&mapping->tree_lock);
+ return error;
+}
+
+static int dax_writeback_one(struct block_device *bdev,
+ struct address_space *mapping, pgoff_t index, void *entry)
+{
+ struct radix_tree_root *page_tree = &mapping->page_tree;
+ int type = RADIX_DAX_TYPE(entry);
+ struct radix_tree_node *node;
+ struct blk_dax_ctl dax;
+ void **slot;
+ int ret = 0;
+
+ spin_lock_irq(&mapping->tree_lock);
+ /*
+ * Regular page slots are stabilized by the page lock even
+ * without the tree itself locked. These unlocked entries
+ * need verification under the tree lock.
+ */
+ if (!__radix_tree_lookup(page_tree, index, &node, &slot))
+ goto unlock;
+ if (*slot != entry)
+ goto unlock;
+
+ /* another fsync thread may have already written back this entry */
+ if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))
+ goto unlock;
+
+ if (WARN_ON_ONCE(type != RADIX_DAX_PTE && type != RADIX_DAX_PMD)) {
+ ret = -EIO;
+ goto unlock;
+ }
+
+ dax.sector = RADIX_DAX_SECTOR(entry);
+ dax.size = (type == RADIX_DAX_PMD ? PMD_SIZE : PAGE_SIZE);
+ spin_unlock_irq(&mapping->tree_lock);
+
+ /*
+ * We cannot hold tree_lock while calling dax_map_atomic() because it
+ * eventually calls cond_resched().
+ */
+ ret = dax_map_atomic(bdev, &dax);
+ if (ret < 0)
+ return ret;
+
+ if (WARN_ON_ONCE(ret < dax.size)) {
+ ret = -EIO;
+ goto unmap;
+ }
+
+ wb_cache_pmem(dax.addr, dax.size);
+
+ spin_lock_irq(&mapping->tree_lock);
+ radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE);
+ spin_unlock_irq(&mapping->tree_lock);
+ unmap:
+ dax_unmap_atomic(bdev, &dax);
+ return ret;
+
+ unlock:
+ spin_unlock_irq(&mapping->tree_lock);
+ return ret;
+}
+
+/*
+ * Flush the mapping to the persistent domain within the byte range of [start,
+ * end]. This is required by data integrity operations to ensure file data is
+ * on persistent storage prior to completion of the operation.
+ */
+int dax_writeback_mapping_range(struct address_space *mapping, loff_t start,
+ loff_t end)
+{
+ struct inode *inode = mapping->host;
+ struct block_device *bdev = inode->i_sb->s_bdev;
+ pgoff_t start_index, end_index, pmd_index;
+ pgoff_t indices[PAGEVEC_SIZE];
+ struct pagevec pvec;
+ bool done = false;
+ int i, ret = 0;
+ void *entry;
+
+ if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))
+ return -EIO;
+
+ start_index = start >> PAGE_CACHE_SHIFT;
+ end_index = end >> PAGE_CACHE_SHIFT;
+ pmd_index = DAX_PMD_INDEX(start_index);
+
+ rcu_read_lock();
+ entry = radix_tree_lookup(&mapping->page_tree, pmd_index);
+ rcu_read_unlock();
+
+ /* see if the start of our range is covered by a PMD entry */
+ if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD)
+ start_index = pmd_index;
+
+ tag_pages_for_writeback(mapping, start_index, end_index);
+
+ pagevec_init(&pvec, 0);
+ while (!done) {
+ pvec.nr = find_get_entries_tag(mapping, start_index,
+ PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE,
+ pvec.pages, indices);
+
+ if (pvec.nr == 0)
+ break;
+
+ for (i = 0; i < pvec.nr; i++) {
+ if (indices[i] > end_index) {
+ done = true;
+ break;
+ }
+
+ ret = dax_writeback_one(bdev, mapping, indices[i],
+ pvec.pages[i]);
+ if (ret < 0)
+ return ret;
+ }
+ }
+ wmb_pmem();
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
+
static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
struct vm_area_struct *vma, struct vm_fault *vmf)
{
}
dax_unmap_atomic(bdev, &dax);
+ error = dax_radix_entry(mapping, vmf->pgoff, dax.sector, false,
+ vmf->flags & FAULT_FLAG_WRITE);
+ if (error)
+ goto out;
+
error = vm_insert_mixed(vma, vaddr, dax.pfn);
out:
memset(&bh, 0, sizeof(bh));
block = (sector_t)vmf->pgoff << (PAGE_SHIFT - blkbits);
+ bh.b_bdev = inode->i_sb->s_bdev;
bh.b_size = PAGE_SIZE;
repeat:
delete_from_page_cache(page);
unlock_page(page);
page_cache_release(page);
+ page = NULL;
}
/*
struct block_device *bdev;
pgoff_t size, pgoff;
sector_t block;
- int result = 0;
+ int error, result = 0;
+ bool alloc = false;
/* dax pmd mappings require pfn_t_devmap() */
if (!IS_ENABLED(CONFIG_FS_DAX_PMD))
}
memset(&bh, 0, sizeof(bh));
+ bh.b_bdev = inode->i_sb->s_bdev;
block = (sector_t)pgoff << (PAGE_SHIFT - blkbits);
bh.b_size = PMD_SIZE;
- if (get_block(inode, block, &bh, write) != 0)
+
+ if (get_block(inode, block, &bh, 0) != 0)
return VM_FAULT_SIGBUS;
+
+ if (!buffer_mapped(&bh) && write) {
+ if (get_block(inode, block, &bh, 1) != 0)
+ return VM_FAULT_SIGBUS;
+ alloc = true;
+ }
+
bdev = bh.b_bdev;
- i_mmap_lock_read(mapping);
/*
* If the filesystem isn't willing to tell us the length of a hole,
*/
if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) {
dax_pmd_dbg(&bh, address, "allocated block too small");
- goto fallback;
+ return VM_FAULT_FALLBACK;
}
/*
* If we allocated new storage, make sure no process has any
* zero pages covering this hole
*/
- if (buffer_new(&bh)) {
- i_mmap_unlock_read(mapping);
- unmap_mapping_range(mapping, pgoff << PAGE_SHIFT, PMD_SIZE, 0);
- i_mmap_lock_read(mapping);
+ if (alloc) {
+ loff_t lstart = pgoff << PAGE_SHIFT;
+ loff_t lend = lstart + PMD_SIZE - 1; /* inclusive */
+
+ truncate_pagecache_range(inode, lstart, lend);
}
+ i_mmap_lock_read(mapping);
+
/*
* If a truncate happened while we were allocating blocks, we may
* leave blocks allocated to the file that are beyond EOF. We can't
goto out;
}
if ((pgoff | PG_PMD_COLOUR) >= size) {
- dax_pmd_dbg(&bh, address, "pgoff unaligned");
+ dax_pmd_dbg(&bh, address,
+ "offset + huge page size > file size");
goto fallback;
}
}
dax_unmap_atomic(bdev, &dax);
+ /*
+ * For PTE faults we insert a radix tree entry for reads, and
+ * leave it clean. Then on the first write we dirty the radix
+ * tree entry via the dax_pfn_mkwrite() path. This sequence
+ * allows the dax_pfn_mkwrite() call to be simpler and avoid a
+ * call into get_block() to translate the pgoff to a sector in
+ * order to be able to create a new radix tree entry.
+ *
+ * The PMD path doesn't have an equivalent to
+ * dax_pfn_mkwrite(), though, so for a read followed by a
+ * write we traverse all the way through __dax_pmd_fault()
+ * twice. This means we can just skip inserting a radix tree
+ * entry completely on the initial read and just wait until
+ * the write to insert a dirty entry.
+ */
+ if (write) {
+ error = dax_radix_entry(mapping, pgoff, dax.sector,
+ true, true);
+ if (error) {
+ dax_pmd_dbg(&bh, address,
+ "PMD radix insertion failed");
+ goto fallback;
+ }
+ }
+
dev_dbg(part_to_dev(bdev->bd_part),
"%s: %s addr: %lx pfn: %lx sect: %llx\n",
__func__, current->comm, address,
* dax_pfn_mkwrite - handle first write to DAX page
* @vma: The virtual memory area where the fault occurred
* @vmf: The description of the fault
- *
*/
int dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
- struct super_block *sb = file_inode(vma->vm_file)->i_sb;
+ struct file *file = vma->vm_file;
- sb_start_pagefault(sb);
- file_update_time(vma->vm_file);
- sb_end_pagefault(sb);
+ /*
+ * We pass NO_SECTOR to dax_radix_entry() because we expect that a
+ * RADIX_DAX_PTE entry already exists in the radix tree from a
+ * previous call to __dax_fault(). We just want to look up that PTE
+ * entry using vmf->pgoff and make sure the dirty tag is set. This
+ * saves us from having to make a call to get_block() here to look
+ * up the sector.
+ */
+ dax_radix_entry(file->f_mapping, vmf->pgoff, NO_SECTOR, false, true);
return VM_FAULT_NOPAGE;
}
EXPORT_SYMBOL_GPL(dax_pfn_mkwrite);
BUG_ON((offset + length) > PAGE_CACHE_SIZE);
memset(&bh, 0, sizeof(bh));
+ bh.b_bdev = inode->i_sb->s_bdev;
bh.b_size = PAGE_CACHE_SIZE;
err = get_block(inode, index, &bh, 0);
if (err < 0)
projects / cascardo / linux.git / blobdiff