ext4, jbd2: ensure entering into panic after recording an error in superblock (4327ba52) · Commits · 戴 / test

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 <hobin.woo@samsung.com> Signed-off-by:

Daeho Jeong <daeho.jeong@samsung.com> Signed-off-by:

Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org

fs/ext4/super.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -388,10 +388,14 @@ static void ext4_handle_error(struct super_block *sb)
		smp_wmb();
		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);
		}
		}

		#define ext4_error_ratelimit(sb) \
		___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state), \
		@@ -585,9 +589,13 @@ 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, ...)

fs/jbd2/journal.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -2072,8 +2072,12 @@ 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);
		}
		}

		/**

include/linux/jbd2.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1112,6 +1112,7 @@ JBD2_FEATURE_INCOMPAT_FUNCS(csum3, CSUM_V3)
		#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

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