Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:

 - Convert content from the ext4 wiki to Documentation rst files so it
   is more likely to be updated as we add new features to ext4.

 - Add 64-bit timestamp support to ext4's superblock fields.

 - ... and the usual bug fixes and cleanups, including a Spectre gadget
   fixup and some hardening against maliciously corrupted file systems.

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (34 commits)
  ext4: remove unneeded variable "err" in ext4_mb_release_inode_pa()
  ext4: improve code readability in ext4_iget()
  ext4: fix spectre gadget in ext4_mb_regular_allocator()
  ext4: check for NUL characters in extended attribute's name
  ext4: use ext4_warning() for sb_getblk failure
  ext4: fix race when setting the bitmap corrupted flag
  ext4: reset error code in ext4_find_entry in fallback
  ext4: handle layout changes to pinned DAX mappings
  dax: dax_layout_busy_page() warn on !exceptional
  docs: fix up the obviously obsolete bits in the new ext4 documentation
  docs: add new ext4 superblock time extension fields
  docs: create filesystem internal section
  ext4: use swap macro in mext_page_double_lock
  ext4: check allocation failure when duplicating "data" in ext4_remount()
  ext4: fix warning message in ext4_enable_quotas()
  ext4: super: extend timestamps to 40 bits
  jbd2: replace current_kernel_time64 with ktime equivalent
  ext4: use timespec64 for all inode times
  ext4: use ktime_get_real_seconds for i_dtime
  ext4: use 64-bit timestamps for mmp_time
  ...

1 files changed, 54 insertions, 11 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4efe77286ecd..8f6ad7667974 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -317,7 +317,7 @@ stop_handle:
 	 * (Well, we could do this if we need to, but heck - it works)
 	 */
 	ext4_orphan_del(handle, inode);
-	EXT4_I(inode)->i_dtime	= get_seconds();
+	EXT4_I(inode)->i_dtime	= (__u32)ktime_get_real_seconds();
 
 	/*
 	 * One subtle ordering requirement: if anything has gone wrong
@@ -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;
 
@@ -4944,17 +4982,14 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 		ret = -EFSCORRUPTED;
 		goto bad_inode;
 	} else if (!ext4_has_inline_data(inode)) {
-		if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
-			if ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-			    (S_ISLNK(inode->i_mode) &&
-			     !ext4_inode_is_fast_symlink(inode))))
-				/* Validate extent which is part of inode */
+		/* validate the block references in the inode */
+		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		   (S_ISLNK(inode->i_mode) &&
+		    !ext4_inode_is_fast_symlink(inode))) {
+			if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
 				ret = ext4_ext_check_inode(inode);
-		} else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-			   (S_ISLNK(inode->i_mode) &&
-			    !ext4_inode_is_fast_symlink(inode))) {
-			/* Validate block references which are part of inode */
-			ret = ext4_ind_check_inode(inode);
+			else
+				ret = ext4_ind_check_inode(inode);
 		}
 	}
 	if (ret)
@@ -5553,6 +5588,14 @@ 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.