From fe4b6c2682109967c21ff28a47adfb5cb7d361aa Mon Sep 17 00:00:00 2001 From: Daeho Jeong Date: Sun, 18 Oct 2015 17:02:56 -0400 Subject: [PATCH] ext4, jbd2: ensure entering into panic after recording an error in superblock commit 4327ba52afd03fc4b5afa0ee1d774c9c5b0e85c5 upstream. If a EXT4 filesystem utilizes JBD2 journaling and an error occurs, the journaling will be aborted first and the error number will be recorded into JBD2 superblock and, finally, the system will enter into the panic state in "errors=panic" option. But, in the rare case, this sequence is little twisted like the below figure and it will happen that the system enters into panic state, which means the system reset in mobile environment, before completion of recording an error in the journal superblock. In this case, e2fsck cannot recognize that the filesystem failure occurred in the previous run and the corruption wouldn't be fixed. Task A Task B ext4_handle_error() -> jbd2_journal_abort() -> __journal_abort_soft() -> __jbd2_journal_abort_hard() | -> journal->j_flags |= JBD2_ABORT; | | __ext4_abort() | -> jbd2_journal_abort() | | -> __journal_abort_soft() | | -> if (journal->j_flags & JBD2_ABORT) | | return; | -> panic() | -> jbd2_journal_update_sb_errno() Tested-by: Hobin Woo Signed-off-by: Daeho Jeong Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/super.c | 12 ++++++++++-- fs/jbd2/journal.c | 6 +++++- include/linux/jbd2.h | 1 + 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index af1eaed96a9..a7e07974942 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -400,9 +400,13 @@ static void ext4_handle_error(struct super_block *sb) ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only"); sb->s_flags |= MS_RDONLY; } - if (test_opt(sb, ERRORS_PANIC)) + if (test_opt(sb, ERRORS_PANIC)) { + if (EXT4_SB(sb)->s_journal && + !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR)) + return; panic("EXT4-fs (device %s): panic forced after error\n", sb->s_id); + } } void __ext4_error(struct super_block *sb, const char *function, @@ -576,8 +580,12 @@ void __ext4_abort(struct super_block *sb, const char *function, jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO); save_error_info(sb, function, line); } - if (test_opt(sb, ERRORS_PANIC)) + if (test_opt(sb, ERRORS_PANIC)) { + if (EXT4_SB(sb)->s_journal && + !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR)) + return; panic("EXT4-fs panic from previous error\n"); + } } void ext4_msg(struct super_block *sb, const char *prefix, const char *fmt, ...) diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 3e7ef8874ff..644f95e7208 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -2049,8 +2049,12 @@ static void __journal_abort_soft (journal_t *journal, int errno) __jbd2_journal_abort_hard(journal); - if (errno) + if (errno) { jbd2_journal_update_sb_errno(journal); + write_lock(&journal->j_state_lock); + journal->j_flags |= JBD2_REC_ERR; + write_unlock(&journal->j_state_lock); + } } /** diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 0c67c1f2a89..7d4a932305b 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -977,6 +977,7 @@ struct journal_s #define JBD2_ABORT_ON_SYNCDATA_ERR 0x040 /* Abort the journal on file * data write error in ordered * mode */ +#define JBD2_REC_ERR 0x080 /* The errno in the sb has been recorded */ /* * Function declarations for the journaling transaction and buffer