4 files changed, 68 insertions, 0 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 6d7dec48372b..1fc013f3d944 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2459,6 +2459,7 @@ extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *);
 extern int ext4_inode_attach_jinode(struct inode *inode);
 extern int ext4_can_truncate(struct inode *inode);
 extern int ext4_truncate(struct inode *);
+extern int ext4_break_layouts(struct inode *);
 extern int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length);
 extern int ext4_truncate_restart_trans(handle_t *, struct inode *, int nblocks);
 extern void ext4_set_inode_flags(struct inode *);
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 8ce6fd5b10dd..72a361d5ef74 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4826,6 +4826,13 @@ static long ext4_zero_range(struct file *file, loff_t offset,
                  * released from page cache.
                  */
                 down_write(&EXT4_I(inode)->i_mmap_sem);
+
+                ret = ext4_break_layouts(inode);
+                if (ret) {
+                        up_write(&EXT4_I(inode)->i_mmap_sem);
+                        goto out_mutex;
+                }
+
                 ret = ext4_update_disksize_before_punch(inode, offset, len);
                 if (ret) {
                         up_write(&EXT4_I(inode)->i_mmap_sem);
@@ -5499,6 +5506,11 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
          * page cache.
          */
         down_write(&EXT4_I(inode)->i_mmap_sem);
+
+        ret = ext4_break_layouts(inode);
+        if (ret)
+                goto out_mmap;
+
         /*
          * Need to round down offset to be aligned with page size boundary
          * for page size > block size.
@@ -5647,6 +5659,11 @@ int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len)
          * page cache.
          */
         down_write(&EXT4_I(inode)->i_mmap_sem);
+
+        ret = ext4_break_layouts(inode);
+        if (ret)
+                goto out_mmap;
+
         /*
          * Need to round down to align start offset to page size boundary
          * for page size > block size.
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ba0de19fb1ad..60432498acfb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4191,6 +4191,39 @@ int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
         return 0;
 }
 
+static void ext4_wait_dax_page(struct ext4_inode_info *ei, bool *did_unlock)
+{
+        *did_unlock = true;
+        up_write(&ei->i_mmap_sem);
+        schedule();
+        down_write(&ei->i_mmap_sem);
+}
+
+int ext4_break_layouts(struct inode *inode)
+{
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        struct page *page;
+        bool retry;
+        int error;
+
+        if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem)))
+                return -EINVAL;
+
+        do {
+                retry = false;
+                page = dax_layout_busy_page(inode->i_mapping);
+                if (!page)
+                        return 0;
+
+                error = ___wait_var_event(&page->_refcount,
+                                atomic_read(&page->_refcount) == 1,
+                                TASK_INTERRUPTIBLE, 0, 0,
+                                ext4_wait_dax_page(ei, &retry));
+        } while (error == 0 && retry);
+
+        return error;
+}
+
 /*
  * ext4_punch_hole: punches a hole in a file by releasing the blocks
  * associated with the given offset and length
@@ -4264,6 +4297,11 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
          * page cache.
          */
         down_write(&EXT4_I(inode)->i_mmap_sem);
+
+        ret = ext4_break_layouts(inode);
+        if (ret)
+                goto out_dio;
+
         first_block_offset = round_up(offset, sb->s_blocksize);
         last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
 
@@ -5553,6 +5591,14 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                                 ext4_wait_for_tail_page_commit(inode);
                 }
                 down_write(&EXT4_I(inode)->i_mmap_sem);
+
+                rc = ext4_break_layouts(inode);
+                if (rc) {
+                        up_write(&EXT4_I(inode)->i_mmap_sem);
+                        error = rc;
+                        goto err_out;
+                }
+
                 /*
                  * Truncate pagecache after we've waited for commit
                  * in data=journal mode to make pages freeable.
diff --git a/fs/ext4/truncate.h b/fs/ext4/truncate.h
index 0cb13badf473..bcbe3668c1d4 100644
--- a/fs/ext4/truncate.h
+++ b/fs/ext4/truncate.h
@@ -11,6 +11,10 @@
  */
 static inline void ext4_truncate_failed_write(struct inode *inode)
 {
+        /*
+         * We don't need to call ext4_break_layouts() because the blocks we
+         * are truncating were never visible to userspace.
+         */
         down_write(&EXT4_I(inode)->i_mmap_sem);
         truncate_inode_pages(inode->i_mapping, inode->i_size);
         ext4_truncate(inode);