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Message-ID: <lsq.1444349548.503556510@decadent.org.uk> Date: Fri, 09 Oct 2015 01:12:28 +0100 From: Ben Hutchings <ben@...adent.org.uk> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org CC: akpm@...ux-foundation.org, "Roland Dreier" <roland@...nel.org>, "Eryu Guan" <guaneryu@...il.com>, "Theodore Ts'o" <tytso@....edu>, "Jan Kara" <jack@...e.com> Subject: [PATCH 3.2 106/107] jbd2: avoid infinite loop when destroying aborted journal 3.2.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara <jack@...e.com> commit 841df7df196237ea63233f0f9eaa41db53afd70f upstream. Commit 6f6a6fda2945 "jbd2: fix ocfs2 corrupt when updating journal superblock fails" changed jbd2_cleanup_journal_tail() to return EIO when the journal is aborted. That makes logic in jbd2_log_do_checkpoint() bail out which is fine, except that jbd2_journal_destroy() expects jbd2_log_do_checkpoint() to always make a progress in cleaning the journal. Without it jbd2_journal_destroy() just loops in an infinite loop. Fix jbd2_journal_destroy() to cleanup journal checkpoint lists of jbd2_log_do_checkpoint() fails with error. Reported-by: Eryu Guan <guaneryu@...il.com> Tested-by: Eryu Guan <guaneryu@...il.com> Fixes: 6f6a6fda294506dfe0e3e0a253bb2d2923f28f0a Signed-off-by: Jan Kara <jack@...e.com> Signed-off-by: Theodore Ts'o <tytso@....edu> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@...adent.org.uk> Cc: Roland Dreier <roland@...nel.org> --- --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c @@ -509,14 +509,15 @@ int jbd2_cleanup_journal_tail(journal_t * journal_clean_one_cp_list * * Find all the written-back checkpoint buffers in the given list and - * release them. + * release them. If 'destroy' is set, clean all buffers unconditionally. * * Called with the journal locked. * Called with j_list_lock held. * Returns number of bufers reaped (for debug) */ -static int journal_clean_one_cp_list(struct journal_head *jh, int *released) +static int journal_clean_one_cp_list(struct journal_head *jh, bool destroy, + int *released) { struct journal_head *last_jh; struct journal_head *next_jh = jh; @@ -532,7 +533,10 @@ static int journal_clean_one_cp_list(str next_jh = jh->b_cpnext; /* Use trylock because of the ranking */ if (jbd_trylock_bh_state(jh2bh(jh))) { - ret = __try_to_free_cp_buf(jh); + if (!destroy) + ret = __try_to_free_cp_buf(jh); + else + ret = __jbd2_journal_remove_checkpoint(jh) + 1; if (ret) { freed++; if (ret == 2) { @@ -558,13 +562,14 @@ static int journal_clean_one_cp_list(str * journal_clean_checkpoint_list * * Find all the written-back checkpoint buffers in the journal and release them. + * If 'destroy' is set, release all buffers unconditionally. * * Called with the journal locked. * Called with j_list_lock held. * Returns number of buffers reaped (for debug) */ -int __jbd2_journal_clean_checkpoint_list(journal_t *journal) +int __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy) { transaction_t *transaction, *last_transaction, *next_transaction; int ret = 0; @@ -580,7 +585,7 @@ int __jbd2_journal_clean_checkpoint_list transaction = next_transaction; next_transaction = transaction->t_cpnext; ret += journal_clean_one_cp_list(transaction-> - t_checkpoint_list, &released); + t_checkpoint_list, destroy, &released); /* * This function only frees up some memory if possible so we * dont have an obligation to finish processing. Bail out if @@ -596,7 +601,7 @@ int __jbd2_journal_clean_checkpoint_list * we can possibly see not yet submitted buffers on io_list */ ret += journal_clean_one_cp_list(transaction-> - t_checkpoint_io_list, &released); + t_checkpoint_io_list, destroy, &released); if (need_resched()) goto out; } while (transaction != last_transaction); @@ -605,6 +610,28 @@ out: } /* + * Remove buffers from all checkpoint lists as journal is aborted and we just + * need to free memory + */ +void jbd2_journal_destroy_checkpoint(journal_t *journal) +{ + /* + * We loop because __jbd2_journal_clean_checkpoint_list() may abort + * early due to a need of rescheduling. + */ + while (1) { + spin_lock(&journal->j_list_lock); + if (!journal->j_checkpoint_transactions) { + spin_unlock(&journal->j_list_lock); + break; + } + __jbd2_journal_clean_checkpoint_list(journal, true); + spin_unlock(&journal->j_list_lock); + cond_resched(); + } +} + +/* * journal_remove_checkpoint: called after a buffer has been committed * to disk (either by being write-back flushed to disk, or being * committed to the log). --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -435,7 +435,7 @@ void jbd2_journal_commit_transaction(jou * frees some memory */ spin_lock(&journal->j_list_lock); - __jbd2_journal_clean_checkpoint_list(journal); + __jbd2_journal_clean_checkpoint_list(journal, false); spin_unlock(&journal->j_list_lock); jbd_debug(3, "JBD2: commit phase 1\n"); --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -1571,8 +1571,17 @@ int jbd2_journal_destroy(journal_t *jour while (journal->j_checkpoint_transactions != NULL) { spin_unlock(&journal->j_list_lock); mutex_lock(&journal->j_checkpoint_mutex); - jbd2_log_do_checkpoint(journal); + err = jbd2_log_do_checkpoint(journal); mutex_unlock(&journal->j_checkpoint_mutex); + /* + * If checkpointing failed, just free the buffers to avoid + * looping forever + */ + if (err) { + jbd2_journal_destroy_checkpoint(journal); + spin_lock(&journal->j_list_lock); + break; + } spin_lock(&journal->j_list_lock); } --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -980,8 +980,9 @@ int __jbd2_update_log_tail(journal_t *jo extern void jbd2_journal_commit_transaction(journal_t *); /* Checkpoint list management */ -int __jbd2_journal_clean_checkpoint_list(journal_t *journal); +int __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy); int __jbd2_journal_remove_checkpoint(struct journal_head *); +void jbd2_journal_destroy_checkpoint(journal_t *journal); void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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