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 <hobin.woo@samsung.com>
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a63c7b0a10cfca3b3075f4dc14435add1bcec91b..df84bd256c9f5b2965c16e748189cc2a9f50f6f0 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -394,9 +394,13 @@ 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)                                       \
@@ -585,8 +589,12 @@ 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,

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8270fe9e3641eb52521ef288ee46047559835bfb..37023d0bdae49061ded0bf8f73fdb80cc3a2e55b 100644 (file)
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -2071,8 +2071,12 @@ 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 df07e78487d560f1e2d96b5e5249a57a080c4ed2..1abeb820a630b2bf57fe15a30bacbf28b47d18d3 100644 (file)
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1046,6 +1046,7 @@ 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