From 278f6679f454bf185a07d9a4ca355b153482d17a Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Thu, 8 Aug 2013 17:34:46 -0400 Subject: reiserfs: locking, handle nested locks properly The reiserfs write lock replaced the BKL and uses similar semantics. Frederic's locking code makes a distinction between when the lock is nested and when it's being acquired/released, but I don't think that's the right distinction to make. The right distinction is between the lock being released at end-of-use and the lock being released for a schedule. The unlock should return the depth and the lock should restore it, rather than the other way around as it is now. This patch implements that and adds a number of places where the lock should be dropped. Signed-off-by: Jeff Mahoney --- fs/reiserfs/journal.c | 104 +++++++++++++++++++++++++++----------------------- 1 file changed, 56 insertions(+), 48 deletions(-) (limited to 'fs/reiserfs/journal.c') diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c index 742fdd4c209a..73feacc49b2e 100644 --- a/fs/reiserfs/journal.c +++ b/fs/reiserfs/journal.c @@ -947,9 +947,11 @@ static int reiserfs_async_progress_wait(struct super_block *s) struct reiserfs_journal *j = SB_JOURNAL(s); if (atomic_read(&j->j_async_throttle)) { - reiserfs_write_unlock(s); + int depth; + + depth = reiserfs_write_unlock_nested(s); congestion_wait(BLK_RW_ASYNC, HZ / 10); - reiserfs_write_lock(s); + reiserfs_write_lock_nested(s, depth); } return 0; @@ -972,6 +974,7 @@ static int flush_commit_list(struct super_block *s, struct reiserfs_journal *journal = SB_JOURNAL(s); int retval = 0; int write_len; + int depth; reiserfs_check_lock_depth(s, "flush_commit_list"); @@ -1018,12 +1021,12 @@ static int flush_commit_list(struct super_block *s, * We might sleep in numerous places inside * write_ordered_buffers. Relax the write lock. */ - reiserfs_write_unlock(s); + depth = reiserfs_write_unlock_nested(s); ret = write_ordered_buffers(&journal->j_dirty_buffers_lock, journal, jl, &jl->j_bh_list); if (ret < 0 && retval == 0) retval = ret; - reiserfs_write_lock(s); + reiserfs_write_lock_nested(s, depth); } BUG_ON(!list_empty(&jl->j_bh_list)); /* @@ -1043,9 +1046,9 @@ static int flush_commit_list(struct super_block *s, tbh = journal_find_get_block(s, bn); if (tbh) { if (buffer_dirty(tbh)) { - reiserfs_write_unlock(s); + depth = reiserfs_write_unlock_nested(s); ll_rw_block(WRITE, 1, &tbh); - reiserfs_write_lock(s); + reiserfs_write_lock_nested(s, depth); } put_bh(tbh) ; } @@ -1057,17 +1060,17 @@ static int flush_commit_list(struct super_block *s, (jl->j_start + i) % SB_ONDISK_JOURNAL_SIZE(s); tbh = journal_find_get_block(s, bn); - reiserfs_write_unlock(s); - wait_on_buffer(tbh); - reiserfs_write_lock(s); + depth = reiserfs_write_unlock_nested(s); + __wait_on_buffer(tbh); + reiserfs_write_lock_nested(s, depth); // since we're using ll_rw_blk above, it might have skipped over // a locked buffer. Double check here // /* redundant, sync_dirty_buffer() checks */ if (buffer_dirty(tbh)) { - reiserfs_write_unlock(s); + depth = reiserfs_write_unlock_nested(s); sync_dirty_buffer(tbh); - reiserfs_write_lock(s); + reiserfs_write_lock_nested(s, depth); } if (unlikely(!buffer_uptodate(tbh))) { #ifdef CONFIG_REISERFS_CHECK @@ -1091,12 +1094,12 @@ static int flush_commit_list(struct super_block *s, if (buffer_dirty(jl->j_commit_bh)) BUG(); mark_buffer_dirty(jl->j_commit_bh) ; - reiserfs_write_unlock(s); + depth = reiserfs_write_unlock_nested(s); if (reiserfs_barrier_flush(s)) __sync_dirty_buffer(jl->j_commit_bh, WRITE_FLUSH_FUA); else sync_dirty_buffer(jl->j_commit_bh); - reiserfs_write_lock(s); + reiserfs_write_lock_nested(s, depth); } /* If there was a write error in the journal - we can't commit this @@ -1228,15 +1231,16 @@ static int _update_journal_header_block(struct super_block *sb, { struct reiserfs_journal_header *jh; struct reiserfs_journal *journal = SB_JOURNAL(sb); + int depth; if (reiserfs_is_journal_aborted(journal)) return -EIO; if (trans_id >= journal->j_last_flush_trans_id) { if (buffer_locked((journal->j_header_bh))) { - reiserfs_write_unlock(sb); - wait_on_buffer((journal->j_header_bh)); - reiserfs_write_lock(sb); + depth = reiserfs_write_unlock_nested(sb); + __wait_on_buffer(journal->j_header_bh); + reiserfs_write_lock_nested(sb, depth); if (unlikely(!buffer_uptodate(journal->j_header_bh))) { #ifdef CONFIG_REISERFS_CHECK reiserfs_warning(sb, "journal-699", @@ -1254,14 +1258,14 @@ static int _update_journal_header_block(struct super_block *sb, jh->j_mount_id = cpu_to_le32(journal->j_mount_id); set_buffer_dirty(journal->j_header_bh); - reiserfs_write_unlock(sb); + depth = reiserfs_write_unlock_nested(sb); if (reiserfs_barrier_flush(sb)) __sync_dirty_buffer(journal->j_header_bh, WRITE_FLUSH_FUA); else sync_dirty_buffer(journal->j_header_bh); - reiserfs_write_lock(sb); + reiserfs_write_lock_nested(sb, depth); if (!buffer_uptodate(journal->j_header_bh)) { reiserfs_warning(sb, "journal-837", "IO error during journal replay"); @@ -1341,6 +1345,7 @@ static int flush_journal_list(struct super_block *s, unsigned long j_len_saved = jl->j_len; struct reiserfs_journal *journal = SB_JOURNAL(s); int err = 0; + int depth; BUG_ON(j_len_saved <= 0); @@ -1495,9 +1500,9 @@ static int flush_journal_list(struct super_block *s, "cn->bh is NULL"); } - reiserfs_write_unlock(s); - wait_on_buffer(cn->bh); - reiserfs_write_lock(s); + depth = reiserfs_write_unlock_nested(s); + __wait_on_buffer(cn->bh); + reiserfs_write_lock_nested(s, depth); if (!cn->bh) { reiserfs_panic(s, "journal-1012", @@ -1974,6 +1979,7 @@ static int journal_compare_desc_commit(struct super_block *sb, /* returns 0 if it did not find a description block ** returns -1 if it found a corrupt commit block ** returns 1 if both desc and commit were valid +** NOTE: only called during fs mount */ static int journal_transaction_is_valid(struct super_block *sb, struct buffer_head *d_bh, @@ -2073,8 +2079,9 @@ static void brelse_array(struct buffer_head **heads, int num) /* ** given the start, and values for the oldest acceptable transactions, -** this either reads in a replays a transaction, or returns because the transaction -** is invalid, or too old. +** this either reads in a replays a transaction, or returns because the +** transaction is invalid, or too old. +** NOTE: only called during fs mount */ static int journal_read_transaction(struct super_block *sb, unsigned long cur_dblock, @@ -2208,10 +2215,7 @@ static int journal_read_transaction(struct super_block *sb, ll_rw_block(READ, get_desc_trans_len(desc), log_blocks); for (i = 0; i < get_desc_trans_len(desc); i++) { - reiserfs_write_unlock(sb); wait_on_buffer(log_blocks[i]); - reiserfs_write_lock(sb); - if (!buffer_uptodate(log_blocks[i])) { reiserfs_warning(sb, "journal-1212", "REPLAY FAILURE fsck required! " @@ -2318,12 +2322,13 @@ static struct buffer_head *reiserfs_breada(struct block_device *dev, /* ** read and replay the log -** on a clean unmount, the journal header's next unflushed pointer will be to an invalid -** transaction. This tests that before finding all the transactions in the log, which makes normal mount times fast. -** -** After a crash, this starts with the next unflushed transaction, and replays until it finds one too old, or invalid. -** +** on a clean unmount, the journal header's next unflushed pointer will +** be to an invalid transaction. This tests that before finding all the +** transactions in the log, which makes normal mount times fast. +** After a crash, this starts with the next unflushed transaction, and +** replays until it finds one too old, or invalid. ** On exit, it sets things up so the first transaction will work correctly. +** NOTE: only called during fs mount */ static int journal_read(struct super_block *sb) { @@ -2501,14 +2506,18 @@ static int journal_read(struct super_block *sb) "replayed %d transactions in %lu seconds\n", replay_count, get_seconds() - start); } + /* needed to satisfy the locking in _update_journal_header_block */ + reiserfs_write_lock(sb); if (!bdev_read_only(sb->s_bdev) && _update_journal_header_block(sb, journal->j_start, journal->j_last_flush_trans_id)) { + reiserfs_write_unlock(sb); /* replay failed, caller must call free_journal_ram and abort ** the mount */ return -1; } + reiserfs_write_unlock(sb); return 0; } @@ -2828,13 +2837,7 @@ int journal_init(struct super_block *sb, const char *j_dev_name, goto free_and_return; } - /* - * Journal_read needs to be inspected in order to push down - * the lock further inside (or even remove it). - */ - reiserfs_write_lock(sb); ret = journal_read(sb); - reiserfs_write_unlock(sb); if (ret < 0) { reiserfs_warning(sb, "reiserfs-2006", "Replay Failure, unable to mount"); @@ -2923,9 +2926,9 @@ static void queue_log_writer(struct super_block *s) add_wait_queue(&journal->j_join_wait, &wait); set_current_state(TASK_UNINTERRUPTIBLE); if (test_bit(J_WRITERS_QUEUED, &journal->j_state)) { - reiserfs_write_unlock(s); + int depth = reiserfs_write_unlock_nested(s); schedule(); - reiserfs_write_lock(s); + reiserfs_write_lock_nested(s, depth); } __set_current_state(TASK_RUNNING); remove_wait_queue(&journal->j_join_wait, &wait); @@ -2943,9 +2946,12 @@ static void let_transaction_grow(struct super_block *sb, unsigned int trans_id) struct reiserfs_journal *journal = SB_JOURNAL(sb); unsigned long bcount = journal->j_bcount; while (1) { - reiserfs_write_unlock(sb); + int depth; + + depth = reiserfs_write_unlock_nested(sb); schedule_timeout_uninterruptible(1); - reiserfs_write_lock(sb); + reiserfs_write_lock_nested(sb, depth); + journal->j_current_jl->j_state |= LIST_COMMIT_PENDING; while ((atomic_read(&journal->j_wcount) > 0 || atomic_read(&journal->j_jlock)) && @@ -2976,6 +2982,7 @@ static int do_journal_begin_r(struct reiserfs_transaction_handle *th, struct reiserfs_transaction_handle myth; int sched_count = 0; int retval; + int depth; reiserfs_check_lock_depth(sb, "journal_begin"); BUG_ON(nblocks > journal->j_trans_max); @@ -2996,9 +3003,9 @@ static int do_journal_begin_r(struct reiserfs_transaction_handle *th, if (test_bit(J_WRITERS_BLOCKED, &journal->j_state)) { unlock_journal(sb); - reiserfs_write_unlock(sb); + depth = reiserfs_write_unlock_nested(sb); reiserfs_wait_on_write_block(sb); - reiserfs_write_lock(sb); + reiserfs_write_lock_nested(sb, depth); PROC_INFO_INC(sb, journal.journal_relock_writers); goto relock; } @@ -3821,6 +3828,7 @@ void reiserfs_restore_prepared_buffer(struct super_block *sb, if (test_clear_buffer_journal_restore_dirty(bh) && buffer_journal_dirty(bh)) { struct reiserfs_journal_cnode *cn; + reiserfs_write_lock(sb); cn = get_journal_hash_dev(sb, journal->j_list_hash_table, bh->b_blocknr); @@ -3828,6 +3836,7 @@ void reiserfs_restore_prepared_buffer(struct super_block *sb, set_buffer_journal_test(bh); mark_buffer_dirty(bh); } + reiserfs_write_unlock(sb); } clear_buffer_journal_prepared(bh); } @@ -3911,6 +3920,7 @@ static int do_journal_end(struct reiserfs_transaction_handle *th, unsigned long jindex; unsigned int commit_trans_id; int trans_half; + int depth; BUG_ON(th->t_refcount > 1); BUG_ON(!th->t_trans_id); @@ -4116,9 +4126,7 @@ static int do_journal_end(struct reiserfs_transaction_handle *th, next = cn->next; free_cnode(sb, cn); cn = next; - reiserfs_write_unlock(sb); - cond_resched(); - reiserfs_write_lock(sb); + reiserfs_cond_resched(sb); } /* we are done with both the c_bh and d_bh, but @@ -4165,10 +4173,10 @@ static int do_journal_end(struct reiserfs_transaction_handle *th, * is lost. */ if (!list_empty(&jl->j_tail_bh_list)) { - reiserfs_write_unlock(sb); + depth = reiserfs_write_unlock_nested(sb); write_ordered_buffers(&journal->j_dirty_buffers_lock, journal, jl, &jl->j_tail_bh_list); - reiserfs_write_lock(sb); + reiserfs_write_lock_nested(sb, depth); } BUG_ON(!list_empty(&jl->j_tail_bh_list)); mutex_unlock(&jl->j_commit_mutex); -- cgit v1.2.3