From 2c0544b23568674efba22532e1f25fb62ce10163 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 30 May 2012 22:56:46 -0400 Subject: [PATCH] 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//trigger_fs_error. Signed-off-by: "Theodore Ts'o" Cc: ksumrall@google.com --- fs/ext4/ext4.h | 1 + fs/ext4/super.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 511011a1e85d..decc15d1b4b6 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -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; diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 628cfcdc0823..9f1ae6b36502 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -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;