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Commit 34d08260 authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Linus Torvalds
Browse files

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: default avatarArnd Bergmann <arnd@arndb.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f168d9fd

fs/reiserfs/journal.c

+11 −11
Original line number Diff line number Diff line
@@ -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 @@ static int journal_read(struct super_block *sb) 
	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 @@ static int do_journal_begin_r(struct reiserfs_transaction_handle *th, 
		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 @@ static int do_journal_begin_r(struct reiserfs_transaction_handle *th, 
	}

	/* 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;

fs/reiserfs/procfs.c

+9 −2
Original line number Diff line number Diff line
@@ -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),

fs/reiserfs/reiserfs.h

+1 −1
Original line number Diff line number Diff line
@@ -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;