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

Pull ext4 updates from Ted Ts'o:
 "A large number of bug fixes and cleanups.

  One new feature to allow users to more easily find the jbd2 journal
  thread for a particular ext4 file system"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (25 commits)
  jbd2: jbd2_get_transaction does not need to return a value
  jbd2: fix invalid descriptor block checksum
  ext4: fix bigalloc cluster freeing when hole punching under load
  ext4: add sysfs attr /sys/fs/ext4/<disk>/journal_task
  ext4: Change debugging support help prefix from EXT4 to Ext4
  ext4: fix compile error when using BUFFER_TRACE
  jbd2: fix compile warning when using JBUFFER_TRACE
  ext4: fix some error pointer dereferences
  ext4: annotate more implicit fall throughs
  ext4: annotate implicit fall throughs
  ext4: don't update s_rev_level if not required
  jbd2: fold jbd2_superblock_csum_{verify,set} into their callers
  jbd2: fix race when writing superblock
  ext4: fix crash during online resizing
  ext4: disallow files with EXT4_JOURNAL_DATA_FL from EXT4_IOC_SWAP_BOOT
  ext4: add mask of ext4 flags to swap
  ext4: update quota information while swapping boot loader inode
  ext4: cleanup pagecache before swap i_data
  ext4: fix check of inode in swap_inode_boot_loader
  ext4: unlock unused_pages timely when doing writeback
  ...

1 files changed, 13 insertions, 0 deletions

diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 5e4e78fc0b3a2..616c075da062a 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -30,6 +30,7 @@ typedef enum {
 	attr_feature,
 	attr_pointer_ui,
 	attr_pointer_atomic,
+	attr_journal_task,
 } attr_id_t;
 
 typedef enum {
@@ -125,6 +126,14 @@ static ssize_t trigger_test_error(struct ext4_sb_info *sbi,
 	return count;
 }
 
+static ssize_t journal_task_show(struct ext4_sb_info *sbi, char *buf)
+{
+	if (!sbi->s_journal)
+		return snprintf(buf, PAGE_SIZE, "<none>\n");
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+			task_pid_vnr(sbi->s_journal->j_task));
+}
+
 #define EXT4_ATTR(_name,_mode,_id)					\
 static struct ext4_attr ext4_attr_##_name = {				\
 	.attr = {.name = __stringify(_name), .mode = _mode },		\
@@ -188,6 +197,7 @@ EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
 EXT4_RO_ATTR_ES_UI(errors_count, s_error_count);
 EXT4_ATTR(first_error_time, 0444, first_error_time);
 EXT4_ATTR(last_error_time, 0444, last_error_time);
+EXT4_ATTR(journal_task, 0444, journal_task);
 
 static unsigned int old_bump_val = 128;
 EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val);
@@ -217,6 +227,7 @@ static struct attribute *ext4_attrs[] = {
 	ATTR_LIST(errors_count),
 	ATTR_LIST(first_error_time),
 	ATTR_LIST(last_error_time),
+	ATTR_LIST(journal_task),
 	NULL,
 };
 
@@ -304,6 +315,8 @@ static ssize_t ext4_attr_show(struct kobject *kobj,
 		return print_tstamp(buf, sbi->s_es, s_first_error_time);
 	case attr_last_error_time:
 		return print_tstamp(buf, sbi->s_es, s_last_error_time);
+	case attr_journal_task:
+		return journal_task_show(sbi, buf);
 	}
 
 	return 0;