page cache: use xa_lock

Remove the address_space ->tree_lock and use the xa_lock newly added to
the radix_tree_root.  Rename the address_space ->page_tree to ->i_pages,
since we don't really care that it's a tree.

[willy@infradead.org: fix nds32, fs/dax.c]
  Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

14 files changed, 134 insertions, 140 deletions

diff --git a/fs/afs/write.c b/fs/afs/write.c
index 9370e2feb999..dbc3c0b0142d 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -570,10 +570,11 @@ static int afs_writepages_region(struct address_space *mapping,
 
                 _debug("wback %lx", page->index);
 
-                /* at this point we hold neither mapping->tree_lock nor lock on
-                 * the page itself: the page may be truncated or invalidated
-                 * (changing page->mapping to NULL), or even swizzled back from
-                 * swapper_space to tmpfs file mapping
+                /*
+                 * at this point we hold neither the i_pages lock nor the
+                 * page lock: the page may be truncated or invalidated
+                 * (changing page->mapping to NULL), or even swizzled
+                 * back from swapper_space to tmpfs file mapping
                  */
                 ret = lock_page_killable(page);
                 if (ret < 0) {
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 562c3e633403..578181cd96b5 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -458,7 +458,7 @@ static noinline int add_ra_bio_pages(struct inode *inode,
                         break;
 
                 rcu_read_lock();
-                page = radix_tree_lookup(&mapping->page_tree, pg_index);
+                page = radix_tree_lookup(&mapping->i_pages, pg_index);
                 rcu_read_unlock();
                 if (page && !radix_tree_exceptional_entry(page)) {
                         misses++;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 47a8fe9d22e8..cf87976e389d 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3963,11 +3963,11 @@ retry:
 
                         done_index = page->index;
                         /*
-                         * At this point we hold neither mapping->tree_lock nor
-                         * lock on the page itself: the page may be truncated or
-                         * invalidated (changing page->mapping to NULL), or even
-                         * swizzled back from swapper_space to tmpfs file
-                         * mapping
+                         * At this point we hold neither the i_pages lock nor
+                         * the page lock: the page may be truncated or
+                         * invalidated (changing page->mapping to NULL),
+                         * or even swizzled back from swapper_space to
+                         * tmpfs file mapping
                          */
                         if (!trylock_page(page)) {
                                 flush_write_bio(epd);
@@ -5174,13 +5174,13 @@ void clear_extent_buffer_dirty(struct extent_buffer *eb)
                 WARN_ON(!PagePrivate(page));
 
                 clear_page_dirty_for_io(page);
-                spin_lock_irq(&page->mapping->tree_lock);
+                xa_lock_irq(&page->mapping->i_pages);
                 if (!PageDirty(page)) {
-                        radix_tree_tag_clear(&page->mapping->page_tree,
+                        radix_tree_tag_clear(&page->mapping->i_pages,
                                                 page_index(page),
                                                 PAGECACHE_TAG_DIRTY);
                 }
-                spin_unlock_irq(&page->mapping->tree_lock);
+                xa_unlock_irq(&page->mapping->i_pages);
                 ClearPageError(page);
                 unlock_page(page);
         }
diff --git a/fs/buffer.c b/fs/buffer.c
index 64b1e2065b6b..f3491074b035 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -185,10 +185,9 @@ EXPORT_SYMBOL(end_buffer_write_sync);
  * we get exclusion from try_to_free_buffers with the blockdev mapping's
  * private_lock.
  *
- * Hack idea: for the blockdev mapping, i_bufferlist_lock contention
+ * Hack idea: for the blockdev mapping, private_lock contention
  * may be quite high.  This code could TryLock the page, and if that
- * succeeds, there is no need to take private_lock. (But if
- * private_lock is contended then so is mapping->tree_lock).
+ * succeeds, there is no need to take private_lock.
  */
 static struct buffer_head *
 __find_get_block_slow(struct block_device *bdev, sector_t block)
@@ -599,14 +598,14 @@ void __set_page_dirty(struct page *page, struct address_space *mapping,
 {
         unsigned long flags;
 
-        spin_lock_irqsave(&mapping->tree_lock, flags);
+        xa_lock_irqsave(&mapping->i_pages, flags);
         if (page->mapping) {    /* Race with truncate? */
                 WARN_ON_ONCE(warn && !PageUptodate(page));
                 account_page_dirtied(page, mapping);
-                radix_tree_tag_set(&mapping->page_tree,
+                radix_tree_tag_set(&mapping->i_pages,
                                 page_index(page), PAGECACHE_TAG_DIRTY);
         }
-        spin_unlock_irqrestore(&mapping->tree_lock, flags);
+        xa_unlock_irqrestore(&mapping->i_pages, flags);
 }
 EXPORT_SYMBOL_GPL(__set_page_dirty);
 
@@ -1096,7 +1095,7 @@ __getblk_slow(struct block_device *bdev, sector_t block,
  * inode list.
  *
  * mark_buffer_dirty() is atomic.  It takes bh->b_page->mapping->private_lock,
- * mapping->tree_lock and mapping->host->i_lock.
+ * i_pages lock and mapping->host->i_lock.
  */
 void mark_buffer_dirty(struct buffer_head *bh)
 {
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 7cee97b93a61..4bcd4e838b47 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1987,11 +1987,10 @@ wdata_prepare_pages(struct cifs_writedata *wdata, unsigned int found_pages,
         for (i = 0; i < found_pages; i++) {
                 page = wdata->pages[i];
                 /*
-                 * At this point we hold neither mapping->tree_lock nor
-                 * lock on the page itself: the page may be truncated or
-                 * invalidated (changing page->mapping to NULL), or even
-                 * swizzled back from swapper_space to tmpfs file
-                 * mapping
+                 * At this point we hold neither the i_pages lock nor the
+                 * page lock: the page may be truncated or invalidated
+                 * (changing page->mapping to NULL), or even swizzled
+                 * back from swapper_space to tmpfs file mapping
                  */
 
                 if (nr_pages == 0)
diff --git a/fs/dax.c b/fs/dax.c
index a77394fe586e..aaec72ded1b6 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -158,11 +158,9 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo
 }
 
 /*
- * We do not necessarily hold the mapping->tree_lock when we call this
- * function so it is possible that 'entry' is no longer a valid item in the
- * radix tree.  This is okay because all we really need to do is to find the
- * correct waitqueue where tasks might be waiting for that old 'entry' and
- * wake them.
+ * @entry may no longer be the entry at the index in the mapping.
+ * The important information it's conveying is whether the entry at
+ * this index used to be a PMD entry.
  */
 static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
                 pgoff_t index, void *entry, bool wake_all)
@@ -174,7 +172,7 @@ static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
 
         /*
          * Checking for locked entry and prepare_to_wait_exclusive() happens
-         * under mapping->tree_lock, ditto for entry handling in our callers.
+         * under the i_pages lock, ditto for entry handling in our callers.
          * So at this point all tasks that could have seen our entry locked
          * must be in the waitqueue and the following check will see them.
          */
@@ -183,41 +181,39 @@ static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
 }
 
 /*
- * Check whether the given slot is locked. The function must be called with
- * mapping->tree_lock held
+ * Check whether the given slot is locked.  Must be called with the i_pages
+ * lock held.
  */
 static inline int slot_locked(struct address_space *mapping, void **slot)
 {
         unsigned long entry = (unsigned long)
-                radix_tree_deref_slot_protected(slot, &mapping->tree_lock);
+                radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock);
         return entry & RADIX_DAX_ENTRY_LOCK;
 }
 
 /*
- * Mark the given slot is locked. The function must be called with
- * mapping->tree_lock held
+ * Mark the given slot as locked.  Must be called with the i_pages lock held.
  */
 static inline void *lock_slot(struct address_space *mapping, void **slot)
 {
         unsigned long entry = (unsigned long)
-                radix_tree_deref_slot_protected(slot, &mapping->tree_lock);
+                radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock);
 
         entry |= RADIX_DAX_ENTRY_LOCK;
-        radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry);
+        radix_tree_replace_slot(&mapping->i_pages, slot, (void *)entry);
         return (void *)entry;
 }
 
 /*
- * Mark the given slot is unlocked. The function must be called with
- * mapping->tree_lock held
+ * Mark the given slot as unlocked.  Must be called with the i_pages lock held.
  */
 static inline void *unlock_slot(struct address_space *mapping, void **slot)
 {
         unsigned long entry = (unsigned long)
-                radix_tree_deref_slot_protected(slot, &mapping->tree_lock);
+                radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock);
 
         entry &= ~(unsigned long)RADIX_DAX_ENTRY_LOCK;
-        radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry);
+        radix_tree_replace_slot(&mapping->i_pages, slot, (void *)entry);
         return (void *)entry;
 }
 
@@ -228,7 +224,7 @@ static inline void *unlock_slot(struct address_space *mapping, void **slot)
  * put_locked_mapping_entry() when he locked the entry and now wants to
  * unlock it.
  *
- * The function must be called with mapping->tree_lock held.
+ * Must be called with the i_pages lock held.
  */
 static void *get_unlocked_mapping_entry(struct address_space *mapping,
                                         pgoff_t index, void ***slotp)
@@ -241,7 +237,7 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping,
         ewait.wait.func = wake_exceptional_entry_func;
 
         for (;;) {
-                entry = __radix_tree_lookup(&mapping->page_tree, index, NULL,
+                entry = __radix_tree_lookup(&mapping->i_pages, index, NULL,
                                           &slot);
                 if (!entry ||
                     WARN_ON_ONCE(!radix_tree_exceptional_entry(entry)) ||
@@ -254,10 +250,10 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping,
                 wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key);
                 prepare_to_wait_exclusive(wq, &ewait.wait,
                                           TASK_UNINTERRUPTIBLE);
-                spin_unlock_irq(&mapping->tree_lock);
+                xa_unlock_irq(&mapping->i_pages);
                 schedule();
                 finish_wait(wq, &ewait.wait);
-                spin_lock_irq(&mapping->tree_lock);
+                xa_lock_irq(&mapping->i_pages);
         }
 }
 
@@ -266,15 +262,15 @@ static void dax_unlock_mapping_entry(struct address_space *mapping,
 {
         void *entry, **slot;
 
-        spin_lock_irq(&mapping->tree_lock);
-        entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot);
+        xa_lock_irq(&mapping->i_pages);
+        entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, &slot);
         if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) ||
                          !slot_locked(mapping, slot))) {
-                spin_unlock_irq(&mapping->tree_lock);
+                xa_unlock_irq(&mapping->i_pages);
                 return;
         }
         unlock_slot(mapping, slot);
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(&mapping->i_pages);
         dax_wake_mapping_entry_waiter(mapping, index, entry, false);
 }
 
@@ -388,7 +384,7 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
         void *entry, **slot;
 
 restart:
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(&mapping->i_pages);
         entry = get_unlocked_mapping_entry(mapping, index, &slot);
 
         if (WARN_ON_ONCE(entry && !radix_tree_exceptional_entry(entry))) {
@@ -420,12 +416,12 @@ restart:
                 if (pmd_downgrade) {
                         /*
                          * Make sure 'entry' remains valid while we drop
-                         * mapping->tree_lock.
+                         * the i_pages lock.
                          */
                         entry = lock_slot(mapping, slot);
                 }
 
-                spin_unlock_irq(&mapping->tree_lock);
+                xa_unlock_irq(&mapping->i_pages);
                 /*
                  * Besides huge zero pages the only other thing that gets
                  * downgraded are empty entries which don't need to be
@@ -442,27 +438,27 @@ restart:
                                 put_locked_mapping_entry(mapping, index);
                         return ERR_PTR(err);
                 }
-                spin_lock_irq(&mapping->tree_lock);
+                xa_lock_irq(&mapping->i_pages);
 
                 if (!entry) {
                         /*
-                         * We needed to drop the page_tree lock while calling
+                         * We needed to drop the i_pages lock while calling
                          * radix_tree_preload() and we didn't have an entry to
                          * lock.  See if another thread inserted an entry at
                          * our index during this time.
                          */
-                        entry = __radix_tree_lookup(&mapping->page_tree, index,
+                        entry = __radix_tree_lookup(&mapping->i_pages, index,
                                         NULL, &slot);
                         if (entry) {
                                 radix_tree_preload_end();
-                                spin_unlock_irq(&mapping->tree_lock);
+                                xa_unlock_irq(&mapping->i_pages);
                                 goto restart;
                         }
                 }
 
                 if (pmd_downgrade) {
                         dax_disassociate_entry(entry, mapping, false);
-                        radix_tree_delete(&mapping->page_tree, index);
+                        radix_tree_delete(&mapping->i_pages, index);
                         mapping->nrexceptional--;
                         dax_wake_mapping_entry_waiter(mapping, index, entry,
                                         true);
@@ -470,11 +466,11 @@ restart:
 
                 entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY);
 
-                err = __radix_tree_insert(&mapping->page_tree, index,
+                err = __radix_tree_insert(&mapping->i_pages, index,
                                 dax_radix_order(entry), entry);
                 radix_tree_preload_end();
                 if (err) {
-                        spin_unlock_irq(&mapping->tree_lock);
+                        xa_unlock_irq(&mapping->i_pages);
                         /*
                          * Our insertion of a DAX entry failed, most likely
                          * because we were inserting a PMD entry and it
@@ -487,12 +483,12 @@ restart:
                 }
                 /* Good, we have inserted empty locked entry into the tree. */
                 mapping->nrexceptional++;
-                spin_unlock_irq(&mapping->tree_lock);
+                xa_unlock_irq(&mapping->i_pages);
                 return entry;
         }
         entry = lock_slot(mapping, slot);
  out_unlock:
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(&mapping->i_pages);
         return entry;
 }
 
@@ -501,23 +497,23 @@ static int __dax_invalidate_mapping_entry(struct address_space *mapping,
 {
         int ret = 0;
         void *entry;
-        struct radix_tree_root *page_tree = &mapping->page_tree;
+        struct radix_tree_root *pages = &mapping->i_pages;
 
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(pages);
         entry = get_unlocked_mapping_entry(mapping, index, NULL);
         if (!entry || WARN_ON_ONCE(!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)))
+            (radix_tree_tag_get(pages, index, PAGECACHE_TAG_DIRTY) ||
+             radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE)))
                 goto out;
         dax_disassociate_entry(entry, mapping, trunc);
-        radix_tree_delete(page_tree, index);
+        radix_tree_delete(pages, index);
         mapping->nrexceptional--;
         ret = 1;
 out:
         put_unlocked_mapping_entry(mapping, index, entry);
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(pages);
         return ret;
 }
 /*
@@ -587,7 +583,7 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
                                       void *entry, pfn_t pfn_t,
                                       unsigned long flags, bool dirty)
 {
-        struct radix_tree_root *page_tree = &mapping->page_tree;
+        struct radix_tree_root *pages = &mapping->i_pages;
         unsigned long pfn = pfn_t_to_pfn(pfn_t);
         pgoff_t index = vmf->pgoff;
         void *new_entry;
@@ -604,7 +600,7 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
                         unmap_mapping_pages(mapping, vmf->pgoff, 1, false);
         }
 
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(pages);
         new_entry = dax_radix_locked_entry(pfn, flags);
         if (dax_entry_size(entry) != dax_entry_size(new_entry)) {
                 dax_disassociate_entry(entry, mapping, false);
@@ -624,17 +620,17 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
                 void **slot;
                 void *ret;
 
-                ret = __radix_tree_lookup(page_tree, index, &node, &slot);
+                ret = __radix_tree_lookup(pages, index, &node, &slot);
                 WARN_ON_ONCE(ret != entry);
-                __radix_tree_replace(page_tree, node, slot,
+                __radix_tree_replace(pages, node, slot,
                                      new_entry, NULL);
                 entry = new_entry;
         }
 
         if (dirty)
-                radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY);
+                radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY);
 
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(pages);
         return entry;
 }
 
@@ -723,7 +719,7 @@ unlock_pte:
 static int dax_writeback_one(struct dax_device *dax_dev,
                 struct address_space *mapping, pgoff_t index, void *entry)
 {
-        struct radix_tree_root *page_tree = &mapping->page_tree;
+        struct radix_tree_root *pages = &mapping->i_pages;
         void *entry2, **slot;
         unsigned long pfn;
         long ret = 0;
@@ -736,7 +732,7 @@ static int dax_writeback_one(struct dax_device *dax_dev,
         if (WARN_ON(!radix_tree_exceptional_entry(entry)))
                 return -EIO;
 
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(pages);
         entry2 = get_unlocked_mapping_entry(mapping, index, &slot);
         /* Entry got punched out / reallocated? */
         if (!entry2 || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry2)))
@@ -755,7 +751,7 @@ static int dax_writeback_one(struct dax_device *dax_dev,
         }
 
         /* Another fsync thread may have already written back this entry */
-        if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))
+        if (!radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE))
                 goto put_unlocked;
         /* Lock the entry to serialize with page faults */
         entry = lock_slot(mapping, slot);
@@ -763,11 +759,11 @@ static int dax_writeback_one(struct dax_device *dax_dev,
          * We can clear the tag now but we have to be careful so that concurrent
          * dax_writeback_one() calls for the same index cannot finish before we
          * actually flush the caches. This is achieved as the calls will look
-         * at the entry only under tree_lock and once they do that they will
-         * see the entry locked and wait for it to unlock.
+         * at the entry only under the i_pages lock and once they do that
+         * they will see the entry locked and wait for it to unlock.
          */
-        radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE);
-        spin_unlock_irq(&mapping->tree_lock);
+        radix_tree_tag_clear(pages, index, PAGECACHE_TAG_TOWRITE);
+        xa_unlock_irq(pages);
 
         /*
          * Even if dax_writeback_mapping_range() was given a wbc->range_start
@@ -787,16 +783,16 @@ static int dax_writeback_one(struct dax_device *dax_dev,
          * the pfn mappings are writeprotected and fault waits for mapping
          * entry lock.
          */
-        spin_lock_irq(&mapping->tree_lock);
-        radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY);
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_lock_irq(pages);
+        radix_tree_tag_clear(pages, index, PAGECACHE_TAG_DIRTY);
+        xa_unlock_irq(pages);
         trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT);
         put_locked_mapping_entry(mapping, index);
         return ret;
 
  put_unlocked:
         put_unlocked_mapping_entry(mapping, index, entry2);
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(pages);
         return ret;
 }
 
@@ -1566,21 +1562,21 @@ static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
         pgoff_t index = vmf->pgoff;
         int vmf_ret, error;
 
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(&mapping->i_pages);
         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);
+                xa_unlock_irq(&mapping->i_pages);
                 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);
+        radix_tree_tag_set(&mapping->i_pages, index, PAGECACHE_TAG_DIRTY);
         entry = lock_slot(mapping, slot);
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(&mapping->i_pages);
         switch (pe_size) {
         case PE_SIZE_PTE:
                 error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index db50686f5096..02237d4d91f5 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2424,12 +2424,12 @@ void f2fs_set_page_dirty_nobuffers(struct page *page)
         SetPageDirty(page);
         spin_unlock(&mapping->private_lock);
 
-        spin_lock_irqsave(&mapping->tree_lock, flags);
+        xa_lock_irqsave(&mapping->i_pages, flags);
         WARN_ON_ONCE(!PageUptodate(page));
         account_page_dirtied(page, mapping);
-        radix_tree_tag_set(&mapping->page_tree,
+        radix_tree_tag_set(&mapping->i_pages,
                         page_index(page), PAGECACHE_TAG_DIRTY);
-        spin_unlock_irqrestore(&mapping->tree_lock, flags);
+        xa_unlock_irqrestore(&mapping->i_pages, flags);
         unlock_page_memcg(page);
 
         __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index fe661274ff10..8c9c2f31b253 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -732,10 +732,10 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
 
         if (bit_pos == NR_DENTRY_IN_BLOCK &&
                         !truncate_hole(dir, page->index, page->index + 1)) {
-                spin_lock_irqsave(&mapping->tree_lock, flags);
-                radix_tree_tag_clear(&mapping->page_tree, page_index(page),
+                xa_lock_irqsave(&mapping->i_pages, flags);
+                radix_tree_tag_clear(&mapping->i_pages, page_index(page),
                                      PAGECACHE_TAG_DIRTY);
-                spin_unlock_irqrestore(&mapping->tree_lock, flags);
+                xa_unlock_irqrestore(&mapping->i_pages, flags);
 
                 clear_page_dirty_for_io(page);
                 ClearPagePrivate(page);
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 3b77d6421218..265da200daa8 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -226,10 +226,10 @@ int f2fs_write_inline_data(struct inode *inode, struct page *page)
         kunmap_atomic(src_addr);
         set_page_dirty(dn.inode_page);
 
-        spin_lock_irqsave(&mapping->tree_lock, flags);
-        radix_tree_tag_clear(&mapping->page_tree, page_index(page),
+        xa_lock_irqsave(&mapping->i_pages, flags);
+        radix_tree_tag_clear(&mapping->i_pages, page_index(page),
                              PAGECACHE_TAG_DIRTY);
-        spin_unlock_irqrestore(&mapping->tree_lock, flags);
+        xa_unlock_irqrestore(&mapping->i_pages, flags);
 
         set_inode_flag(inode, FI_APPEND_WRITE);
         set_inode_flag(inode, FI_DATA_EXIST);
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 9a99243054ba..f202398e20ea 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -91,11 +91,11 @@ static void clear_node_page_dirty(struct page *page)
         unsigned int long flags;
 
         if (PageDirty(page)) {
-                spin_lock_irqsave(&mapping->tree_lock, flags);
-                radix_tree_tag_clear(&mapping->page_tree,
+                xa_lock_irqsave(&mapping->i_pages, flags);
+                radix_tree_tag_clear(&mapping->i_pages,
                                 page_index(page),
                                 PAGECACHE_TAG_DIRTY);
-                spin_unlock_irqrestore(&mapping->tree_lock, flags);
+                xa_unlock_irqrestore(&mapping->i_pages, flags);
 
                 clear_page_dirty_for_io(page);
                 dec_page_count(F2FS_M_SB(mapping), F2FS_DIRTY_NODES);
@@ -1161,7 +1161,7 @@ void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
         f2fs_bug_on(sbi, check_nid_range(sbi, nid));
 
         rcu_read_lock();
-        apage = radix_tree_lookup(&NODE_MAPPING(sbi)->page_tree, nid);
+        apage = radix_tree_lookup(&NODE_MAPPING(sbi)->i_pages, nid);
         rcu_read_unlock();
         if (apage)
                 return;
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 1280f915079b..4b12ba70a895 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -347,9 +347,9 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
          * By the time control reaches here, RCU grace period has passed
          * since I_WB_SWITCH assertion and all wb stat update transactions
          * between unlocked_inode_to_wb_begin/end() are guaranteed to be
-         * synchronizing against mapping->tree_lock.
+         * synchronizing against the i_pages lock.
          *
-         * Grabbing old_wb->list_lock, inode->i_lock and mapping->tree_lock
+         * Grabbing old_wb->list_lock, inode->i_lock and the i_pages lock
          * gives us exclusion against all wb related operations on @inode
          * including IO list manipulations and stat updates.
          */
@@ -361,7 +361,7 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
                 spin_lock_nested(&old_wb->list_lock, SINGLE_DEPTH_NESTING);
         }
         spin_lock(&inode->i_lock);
-        spin_lock_irq(&mapping->tree_lock);
+        xa_lock_irq(&mapping->i_pages);
 
         /*
          * Once I_FREEING is visible under i_lock, the eviction path owns
@@ -373,22 +373,22 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
         /*
          * Count and transfer stats.  Note that PAGECACHE_TAG_DIRTY points
          * to possibly dirty pages while PAGECACHE_TAG_WRITEBACK points to
-         * pages actually under underwriteback.
+         * pages actually under writeback.
          */
-        radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, 0,
+        radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter, 0,
                                    PAGECACHE_TAG_DIRTY) {
                 struct page *page = radix_tree_deref_slot_protected(slot,
-                                                        &mapping->tree_lock);
+                                                &mapping->i_pages.xa_lock);
                 if (likely(page) && PageDirty(page)) {
                         dec_wb_stat(old_wb, WB_RECLAIMABLE);
                         inc_wb_stat(new_wb, WB_RECLAIMABLE);
                 }
         }
 
-        radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, 0,
+        radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter, 0,
                                    PAGECACHE_TAG_WRITEBACK) {
                 struct page *page = radix_tree_deref_slot_protected(slot,
-                                                        &mapping->tree_lock);
+                                                &mapping->i_pages.xa_lock);
                 if (likely(page)) {
                         WARN_ON_ONCE(!PageWriteback(page));
                         dec_wb_stat(old_wb, WB_WRITEBACK);
@@ -430,7 +430,7 @@ skip_switch:
          */
         smp_store_release(&inode->i_state, inode->i_state & ~I_WB_SWITCH);
 
-        spin_unlock_irq(&mapping->tree_lock);
+        xa_unlock_irq(&mapping->i_pages);
         spin_unlock(&inode->i_lock);
         spin_unlock(&new_wb->list_lock);
         spin_unlock(&old_wb->list_lock);
@@ -506,8 +506,8 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id)
 
         /*
          * In addition to synchronizing among switchers, I_WB_SWITCH tells
-         * the RCU protected stat update paths to grab the mapping's
-         * tree_lock so that stat transfer can synchronize against them.
+         * the RCU protected stat update paths to grab the i_page
+         * lock so that stat transfer can synchronize against them.
          * Let's continue after I_WB_SWITCH is guaranteed to be visible.
          */
         call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn);
diff --git a/fs/inode.c b/fs/inode.c
index b153aeaa61ea..13ceb98c3bd3 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -348,8 +348,7 @@ EXPORT_SYMBOL(inc_nlink);
 
 static void __address_space_init_once(struct address_space *mapping)
 {
-        INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC | __GFP_ACCOUNT);
-        spin_lock_init(&mapping->tree_lock);
+        INIT_RADIX_TREE(&mapping->i_pages, GFP_ATOMIC | __GFP_ACCOUNT);
         init_rwsem(&mapping->i_mmap_rwsem);
         INIT_LIST_HEAD(&mapping->private_list);
         spin_lock_init(&mapping->private_lock);
@@ -504,14 +503,14 @@ EXPORT_SYMBOL(__remove_inode_hash);
 void clear_inode(struct inode *inode)
 {
         /*
-         * We have to cycle tree_lock here because reclaim can be still in the
+         * We have to cycle the i_pages lock here because reclaim can be in the
          * process of removing the last page (in __delete_from_page_cache())
-         * and we must not free mapping under it.
+         * and we must not free the mapping under it.
          */
-        spin_lock_irq(&inode->i_data.tree_lock);
+        xa_lock_irq(&inode->i_data.i_pages);
         BUG_ON(inode->i_data.nrpages);
         BUG_ON(inode->i_data.nrexceptional);
-        spin_unlock_irq(&inode->i_data.tree_lock);
+        xa_unlock_irq(&inode->i_data.i_pages);
         BUG_ON(!list_empty(&inode->i_data.private_list));
         BUG_ON(!(inode->i_state & I_FREEING));
         BUG_ON(inode->i_state & I_CLEAR);
diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c
index c21e0b4454a6..dec98cab729d 100644
--- a/fs/nilfs2/btnode.c
+++ b/fs/nilfs2/btnode.c
@@ -193,9 +193,9 @@ retry:
                                        (unsigned long long)oldkey,
                                        (unsigned long long)newkey);
 
-                spin_lock_irq(&btnc->tree_lock);
-                err = radix_tree_insert(&btnc->page_tree, newkey, obh->b_page);
-                spin_unlock_irq(&btnc->tree_lock);
+                xa_lock_irq(&btnc->i_pages);
+                err = radix_tree_insert(&btnc->i_pages, newkey, obh->b_page);
+                xa_unlock_irq(&btnc->i_pages);
                 /*
                  * Note: page->index will not change to newkey until
                  * nilfs_btnode_commit_change_key() will be called.
@@ -251,11 +251,11 @@ void nilfs_btnode_commit_change_key(struct address_space *btnc,
                                        (unsigned long long)newkey);
                 mark_buffer_dirty(obh);
 
-                spin_lock_irq(&btnc->tree_lock);
-                radix_tree_delete(&btnc->page_tree, oldkey);
-                radix_tree_tag_set(&btnc->page_tree, newkey,
+                xa_lock_irq(&btnc->i_pages);
+                radix_tree_delete(&btnc->i_pages, oldkey);
+                radix_tree_tag_set(&btnc->i_pages, newkey,
                                    PAGECACHE_TAG_DIRTY);
-                spin_unlock_irq(&btnc->tree_lock);
+                xa_unlock_irq(&btnc->i_pages);
 
                 opage->index = obh->b_blocknr = newkey;
                 unlock_page(opage);
@@ -283,9 +283,9 @@ void nilfs_btnode_abort_change_key(struct address_space *btnc,
                 return;
 
         if (nbh == NULL) {      /* blocksize == pagesize */
-                spin_lock_irq(&btnc->tree_lock);
-                radix_tree_delete(&btnc->page_tree, newkey);
-                spin_unlock_irq(&btnc->tree_lock);
+                xa_lock_irq(&btnc->i_pages);
+                radix_tree_delete(&btnc->i_pages, newkey);
+                xa_unlock_irq(&btnc->i_pages);
                 unlock_page(ctxt->bh->b_page);
         } else
                 brelse(nbh);
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c
index 68241512d7c1..4cb850a6f1c2 100644
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -331,15 +331,15 @@ repeat:
                         struct page *page2;
 
                         /* move the page to the destination cache */
-                        spin_lock_irq(&smap->tree_lock);
-                        page2 = radix_tree_delete(&smap->page_tree, offset);
+                        xa_lock_irq(&smap->i_pages);
+                        page2 = radix_tree_delete(&smap->i_pages, offset);
                         WARN_ON(page2 != page);
 
                         smap->nrpages--;
-                        spin_unlock_irq(&smap->tree_lock);
+                        xa_unlock_irq(&smap->i_pages);
 
-                        spin_lock_irq(&dmap->tree_lock);
-                        err = radix_tree_insert(&dmap->page_tree, offset, page);
+                        xa_lock_irq(&dmap->i_pages);
+                        err = radix_tree_insert(&dmap->i_pages, offset, page);
                         if (unlikely(err < 0)) {
                                 WARN_ON(err == -EEXIST);
                                 page->mapping = NULL;
@@ -348,11 +348,11 @@ repeat:
                                 page->mapping = dmap;
                                 dmap->nrpages++;
                                 if (PageDirty(page))
-                                        radix_tree_tag_set(&dmap->page_tree,
+                                        radix_tree_tag_set(&dmap->i_pages,
                                                            offset,
                                                            PAGECACHE_TAG_DIRTY);
                         }
-                        spin_unlock_irq(&dmap->tree_lock);
+                        xa_unlock_irq(&dmap->i_pages);
                 }
                 unlock_page(page);
         }
@@ -474,15 +474,15 @@ int __nilfs_clear_page_dirty(struct page *page)
         struct address_space *mapping = page->mapping;
 
         if (mapping) {
-                spin_lock_irq(&mapping->tree_lock);
+                xa_lock_irq(&mapping->i_pages);
                 if (test_bit(PG_dirty, &page->flags)) {
-                        radix_tree_tag_clear(&mapping->page_tree,
+                        radix_tree_tag_clear(&mapping->i_pages,
                                              page_index(page),
                                              PAGECACHE_TAG_DIRTY);
-                        spin_unlock_irq(&mapping->tree_lock);
+                        xa_unlock_irq(&mapping->i_pages);
                         return clear_page_dirty_for_io(page);
                 }
-                spin_unlock_irq(&mapping->tree_lock);
+                xa_unlock_irq(&mapping->i_pages);
                 return 0;
         }
         return TestClearPageDirty(page);