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    Subject[PATCH 2/3] reiserfs: Don't lock journal_init()
    Date
    journal_init() doesn't need the lock since no operation
    on the filesystem is involved there. journal_read() and
    get_list_bitmap() have yet to be reviewed carefully though
    before removing the lock there. Just keep the it around these
    two calls for safety.

    Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Al Viro <viro@zeniv.linux.org.uk>
    Cc: Christoph Hellwig <hch@lst.de>
    Cc: Jeff Mahoney <jeffm@suse.com>
    ---
    fs/reiserfs/journal.c | 53 ++++++++++++++++++------------------------------
    fs/reiserfs/super.c | 21 ++++++++++---------
    2 files changed, 31 insertions(+), 43 deletions(-)

    diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
    index eb71106..728fb3fd 100644
    --- a/fs/reiserfs/journal.c
    +++ b/fs/reiserfs/journal.c
    @@ -2678,16 +2678,10 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
    char b[BDEVNAME_SIZE];
    int ret;

    - /*
    - * Unlock here to avoid various RECLAIM-FS-ON <-> IN-RECLAIM-FS
    - * dependency inversion warnings.
    - */
    - reiserfs_write_unlock(sb);
    journal = SB_JOURNAL(sb) = vzalloc(sizeof(struct reiserfs_journal));
    if (!journal) {
    reiserfs_warning(sb, "journal-1256",
    "unable to get memory for journal structure");
    - reiserfs_write_lock(sb);
    return 1;
    }
    INIT_LIST_HEAD(&journal->j_bitmap_nodes);
    @@ -2695,10 +2689,8 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
    INIT_LIST_HEAD(&journal->j_working_list);
    INIT_LIST_HEAD(&journal->j_journal_list);
    journal->j_persistent_trans = 0;
    - ret = reiserfs_allocate_list_bitmaps(sb, journal->j_list_bitmap,
    - reiserfs_bmap_count(sb));
    - reiserfs_write_lock(sb);
    - if (ret)
    + if (reiserfs_allocate_list_bitmaps(sb, journal->j_list_bitmap,
    + reiserfs_bmap_count(sb)))
    goto free_and_return;

    allocate_bitmap_nodes(sb);
    @@ -2727,27 +2719,11 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
    goto free_and_return;
    }

    - /*
    - * We need to unlock here to avoid creating the following
    - * dependency:
    - * reiserfs_lock -> sysfs_mutex
    - * Because the reiserfs mmap path creates the following dependency:
    - * mm->mmap -> reiserfs_lock, hence we have
    - * mm->mmap -> reiserfs_lock ->sysfs_mutex
    - * This would ends up in a circular dependency with sysfs readdir path
    - * which does sysfs_mutex -> mm->mmap_sem
    - * This is fine because the reiserfs lock is useless in mount path,
    - * at least until we call journal_begin. We keep it for paranoid
    - * reasons.
    - */
    - reiserfs_write_unlock(sb);
    if (journal_init_dev(sb, journal, j_dev_name) != 0) {
    - reiserfs_write_lock(sb);
    reiserfs_warning(sb, "sh-462",
    "unable to initialize jornal device");
    goto free_and_return;
    }
    - reiserfs_write_lock(sb);

    rs = SB_DISK_SUPER_BLOCK(sb);

    @@ -2829,9 +2805,7 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
    journal->j_mount_id = 10;
    journal->j_state = 0;
    atomic_set(&(journal->j_jlock), 0);
    - reiserfs_write_unlock(sb);
    journal->j_cnode_free_list = allocate_cnodes(num_cnodes);
    - reiserfs_write_lock(sb);
    journal->j_cnode_free_orig = journal->j_cnode_free_list;
    journal->j_cnode_free = journal->j_cnode_free_list ? num_cnodes : 0;
    journal->j_cnode_used = 0;
    @@ -2848,24 +2822,37 @@ int journal_init(struct super_block *sb, const char *j_dev_name,

    init_journal_hash(sb);
    jl = journal->j_current_jl;
    +
    + /*
    + * get_list_bitmap() may call flush_commit_list() which
    + * requires the lock. Calling flush_commit_list() shouldn't happen
    + * this early but I like to be paranoid.
    + */
    + reiserfs_write_lock(sb);
    jl->j_list_bitmap = get_list_bitmap(sb, jl);
    + reiserfs_write_unlock(sb);
    if (!jl->j_list_bitmap) {
    reiserfs_warning(sb, "journal-2005",
    "get_list_bitmap failed for journal list 0");
    goto free_and_return;
    }
    - if (journal_read(sb) < 0) {
    +
    + /*
    + * 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");
    goto free_and_return;
    }

    reiserfs_mounted_fs_count++;
    - if (reiserfs_mounted_fs_count <= 1) {
    - reiserfs_write_unlock(sb);
    + if (reiserfs_mounted_fs_count <= 1)
    commit_wq = alloc_workqueue("reiserfs", WQ_MEM_RECLAIM, 0);
    - reiserfs_write_lock(sb);
    - }

    INIT_DELAYED_WORK(&journal->j_work, flush_async_commits);
    journal->j_work_sb = sb;
    diff --git a/fs/reiserfs/super.c b/fs/reiserfs/super.c
    index 1f0d4fa..b5f167c 100644
    --- a/fs/reiserfs/super.c
    +++ b/fs/reiserfs/super.c
    @@ -1727,6 +1727,17 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
    printk("reiserfs: using flush barriers\n");
    }

    + // set_device_ro(s->s_dev, 1) ;
    + if (journal_init(s, jdev_name, old_format, commit_max_age)) {
    + SWARN(silent, s, "sh-2022",
    + "unable to initialize journal space");
    + goto error_unlocked;
    + } else {
    + jinit_done = 1; /* once this is set, journal_release must be called
    + ** if we error out of the mount
    + */
    + }
    +
    /*
    * This path assumed to be called with the BKL in the old times.
    * Now we have inherited the big reiserfs lock from it and many
    @@ -1737,16 +1748,6 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
    */
    reiserfs_write_lock(s);

    - // set_device_ro(s->s_dev, 1) ;
    - if (journal_init(s, jdev_name, old_format, commit_max_age)) {
    - SWARN(silent, s, "sh-2022",
    - "unable to initialize journal space");
    - goto error;
    - } else {
    - jinit_done = 1; /* once this is set, journal_release must be called
    - ** if we error out of the mount
    - */
    - }
    if (reread_meta_blocks(s)) {
    SWARN(silent, s, "jmacd-9",
    "unable to reread meta blocks after journal init");
    --
    1.7.5.4


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