reiserfs: use monotonic time for j_trans_start_time

Using CLOCK_REALTIME time_t timestamps breaks on 32-bit systems in 2038,
and gives surprising results with a concurrent settimeofday().

This changes the reiserfs journal timestamps to use ktime_get_seconds()
instead, which makes it use a 64-bit CLOCK_MONOTONIC stamp.

In the procfs output, the monotonic timestamp needs to be converted back
to CLOCK_REALTIME to keep the existing ABI.

Link: http://lkml.kernel.org/r/20180620142522.27639-2-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 52eb5d2..8a76f9d 100644 (file)
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -2381,7 +2381,7 @@ static int journal_read(struct super_block *sb)
        struct reiserfs_journal_desc *desc;
        unsigned int oldest_trans_id = 0;
        unsigned int oldest_invalid_trans_id = 0;
-       time_t start;
+       time64_t start;
        unsigned long oldest_start = 0;
        unsigned long cur_dblock = 0;
        unsigned long newest_mount_id = 9;
@@ -2395,7 +2395,7 @@ static int journal_read(struct super_block *sb)
        cur_dblock = SB_ONDISK_JOURNAL_1st_BLOCK(sb);
        reiserfs_info(sb, "checking transaction log (%pg)\n",
                      journal->j_dev_bd);
-       start = get_seconds();
+       start = ktime_get_seconds();
 
        /*
         * step 1, read in the journal header block.  Check the transaction
@@ -2556,7 +2556,7 @@ start_log_replay:
        if (replay_count > 0) {
                reiserfs_info(sb,
                              "replayed %d transactions in %lu seconds\n",
-                             replay_count, get_seconds() - start);
+                             replay_count, ktime_get_seconds() - start);
        }
        /* needed to satisfy the locking in _update_journal_header_block */
        reiserfs_write_lock(sb);
@@ -2914,7 +2914,7 @@ int journal_transaction_should_end(struct reiserfs_transaction_handle *th,
                                   int new_alloc)
 {
        struct reiserfs_journal *journal = SB_JOURNAL(th->t_super);
-       time_t now = get_seconds();
+       time64_t now = ktime_get_seconds();
        /* cannot restart while nested */
        BUG_ON(!th->t_trans_id);
        if (th->t_refcount > 1)
@@ -3023,7 +3023,7 @@ static int do_journal_begin_r(struct reiserfs_transaction_handle *th,
                              struct super_block *sb, unsigned long nblocks,
                              int join)
 {
-       time_t now = get_seconds();
+       time64_t now = ktime_get_seconds();
        unsigned int old_trans_id;
        struct reiserfs_journal *journal = SB_JOURNAL(sb);
        struct reiserfs_transaction_handle myth;
@@ -3056,7 +3056,7 @@ relock:
                PROC_INFO_INC(sb, journal.journal_relock_writers);
                goto relock;
        }
-       now = get_seconds();
+       now = ktime_get_seconds();
 
        /*
         * if there is no room in the journal OR
@@ -3119,7 +3119,7 @@ relock:
        }
        /* we are the first writer, set trans_id */
        if (journal->j_trans_start_time == 0) {
-               journal->j_trans_start_time = get_seconds();
+               journal->j_trans_start_time = ktime_get_seconds();
        }
        atomic_inc(&journal->j_wcount);
        journal->j_len_alloc += nblocks;
@@ -3559,11 +3559,11 @@ static void flush_async_commits(struct work_struct *work)
  */
 void reiserfs_flush_old_commits(struct super_block *sb)
 {
-       time_t now;
+       time64_t now;
        struct reiserfs_transaction_handle th;
        struct reiserfs_journal *journal = SB_JOURNAL(sb);
 
-       now = get_seconds();
+       now = ktime_get_seconds();
        /*
         * safety check so we don't flush while we are replaying the log during
         * mount
@@ -3613,7 +3613,7 @@ void reiserfs_flush_old_commits(struct super_block *sb)
 static int check_journal_end(struct reiserfs_transaction_handle *th, int flags)
 {
 
-       time_t now;
+       time64_t now;
        int flush = flags & FLUSH_ALL;
        int commit_now = flags & COMMIT_NOW;
        int wait_on_commit = flags & WAIT;
@@ -3694,7 +3694,7 @@ static int check_journal_end(struct reiserfs_transaction_handle *th, int flags)
        }
 
        /* deal with old transactions where we are the last writers */
-       now = get_seconds();
+       now = ktime_get_seconds();
        if ((now - journal->j_trans_start_time) > journal->j_max_trans_age) {
                commit_now = 1;
                journal->j_next_async_flush = 1;

diff --git a/fs/reiserfs/procfs.c b/fs/reiserfs/procfs.c
index e39b391..f2cf344 100644 (file)
--- a/fs/reiserfs/procfs.c
+++ b/fs/reiserfs/procfs.c
@@ -297,6 +297,13 @@ static int show_oidmap(struct seq_file *m, void *unused)
        return 0;
 }
 
+static time64_t ktime_mono_to_real_seconds(time64_t mono)
+{
+       ktime_t kt = ktime_set(mono, NSEC_PER_SEC/2);
+
+       return ktime_divns(ktime_mono_to_real(kt), NSEC_PER_SEC);
+}
+
 static int show_journal(struct seq_file *m, void *unused)
 {
        struct super_block *sb = m->private;
@@ -325,7 +332,7 @@ static int show_journal(struct seq_file *m, void *unused)
                   "j_bcount: \t%lu\n"
                   "j_first_unflushed_offset: \t%lu\n"
                   "j_last_flush_trans_id: \t%u\n"
-                  "j_trans_start_time: \t%li\n"
+                  "j_trans_start_time: \t%lli\n"
                   "j_list_bitmap_index: \t%i\n"
                   "j_must_wait: \t%i\n"
                   "j_next_full_flush: \t%i\n"
@@ -366,7 +373,7 @@ static int show_journal(struct seq_file *m, void *unused)
                   JF(j_bcount),
                   JF(j_first_unflushed_offset),
                   JF(j_last_flush_trans_id),
-                  JF(j_trans_start_time),
+                  ktime_mono_to_real_seconds(JF(j_trans_start_time)),
                   JF(j_list_bitmap_index),
                   JF(j_must_wait),
                   JF(j_next_full_flush),

diff --git a/fs/reiserfs/reiserfs.h b/fs/reiserfs/reiserfs.h
index ae4811f..621b9a0 100644 (file)
--- a/fs/reiserfs/reiserfs.h
+++ b/fs/reiserfs/reiserfs.h
@@ -331,7 +331,7 @@ struct reiserfs_journal {
 
        struct buffer_head *j_header_bh;
 
-       time_t j_trans_start_time;      /* time this transaction started */
+       time64_t j_trans_start_time;    /* time this transaction started */
        struct mutex j_mutex;
        struct mutex j_flush_mutex;