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Commit 2c0544b2 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: add debugging trigger for ext4_error() 



Make it easy to test whether or not the error handling subsystem in
ext4 is working correctly.  This allows us to simulate an ext4_error()
by echoing a string to /sys/fs/ext4/<dev>/trigger_fs_error.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: ksumrall@google.com
parent 6f2e9f0e

fs/ext4/ext4.h

+1 −0
Original line number Diff line number Diff line
@@ -1197,6 +1197,7 @@ struct ext4_sb_info { 
	struct proc_dir_entry *s_proc;

	struct kobject s_kobj;

	struct completion s_kobj_unregister;

	struct super_block *s_sb;



	/* Journaling */

	struct journal_s *s_journal;

fs/ext4/super.c

+20 −0
Original line number Diff line number Diff line
@@ -2473,6 +2473,23 @@ static ssize_t sbi_ui_store(struct ext4_attr *a, 
	return count;

}



static ssize_t trigger_test_error(struct ext4_attr *a,

				  struct ext4_sb_info *sbi,

				  const char *buf, size_t count)

{

	int len = count;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	if (len && buf[len-1] == '\n')

		len--;



	if (len)

		ext4_error(sbi->s_sb, "%.*s", len, buf);

	return count;

}



#define EXT4_ATTR_OFFSET(_name,_mode,_show,_store,_elname) \

static struct ext4_attr ext4_attr_##_name = {			\

	.attr = {.name = __stringify(_name), .mode = _mode },	\
@@ -2503,6 +2520,7 @@ EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs); 
EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);

EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);

EXT4_RW_ATTR_SBI_UI(max_writeback_mb_bump, s_max_writeback_mb_bump);

EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);



static struct attribute *ext4_attrs[] = {

	ATTR_LIST(delayed_allocation_blocks),
@@ -2517,6 +2535,7 @@ static struct attribute *ext4_attrs[] = { 
	ATTR_LIST(mb_stream_req),

	ATTR_LIST(mb_group_prealloc),

	ATTR_LIST(max_writeback_mb_bump),

	ATTR_LIST(trigger_fs_error),

	NULL,

};
@@ -3087,6 +3106,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
		goto out_free_orig;

	}

	sb->s_fs_info = sbi;

	sbi->s_sb = sb;

	sbi->s_mount_opt = 0;

	sbi->s_resuid = EXT4_DEF_RESUID;

	sbi->s_resgid = EXT4_DEF_RESGID;