7 files changed, 523 insertions, 2 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0995f4f68d7a..72195378bef9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -295,6 +295,14 @@ static inline unsigned long btrfs_chunk_item_size(int num_stripes)
 #define BTRFS_FSID_SIZE 16
 #define BTRFS_HEADER_FLAG_WRITTEN       (1ULL << 0)
 #define BTRFS_HEADER_FLAG_RELOC         (1ULL << 1)
+
+/*
+ * File system states
+ */
+
+/* Errors detected */
+#define BTRFS_SUPER_FLAG_ERROR          (1ULL << 2)
+
 #define BTRFS_SUPER_FLAG_SEEDING        (1ULL << 32)
 #define BTRFS_SUPER_FLAG_METADUMP       (1ULL << 33)
 
@@ -1058,6 +1066,9 @@ struct btrfs_fs_info {
         unsigned metadata_ratio;
 
         void *bdev_holder;
+
+        /* filesystem state */
+        u64 fs_state;
 };
 
 /*
@@ -2203,6 +2214,11 @@ int btrfs_set_block_group_rw(struct btrfs_root *root,
                              struct btrfs_block_group_cache *cache);
 void btrfs_put_block_group_cache(struct btrfs_fs_info *info);
 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo);
+int btrfs_error_unpin_extent_range(struct btrfs_root *root,
+                                   u64 start, u64 end);
+int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
+                               u64 num_bytes);
+
 /* ctree.c */
 int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
                      int level, int *slot);
@@ -2556,6 +2572,14 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 /* super.c */
 int btrfs_parse_options(struct btrfs_root *root, char *options);
 int btrfs_sync_fs(struct super_block *sb, int wait);
+void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
+                     unsigned int line, int errno);
+
+#define btrfs_std_error(fs_info, errno)                         \
+do {                                                            \
+        if ((errno))                                            \
+                __btrfs_std_error((fs_info), __func__, __LINE__, (errno));\
+} while (0)
 
 /* acl.c */
 #ifdef CONFIG_BTRFS_FS_POSIX_ACL
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9b1dd4138072..1a3af9e8e0c4 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -44,6 +44,20 @@
 static struct extent_io_ops btree_extent_io_ops;
 static void end_workqueue_fn(struct btrfs_work *work);
 static void free_fs_root(struct btrfs_root *root);
+static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
+                                    int read_only);
+static int btrfs_destroy_ordered_operations(struct btrfs_root *root);
+static int btrfs_destroy_ordered_extents(struct btrfs_root *root);
+static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
+                                      struct btrfs_root *root);
+static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t);
+static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
+static int btrfs_destroy_marked_extents(struct btrfs_root *root,
+                                        struct extent_io_tree *dirty_pages,
+                                        int mark);
+static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
+                                       struct extent_io_tree *pinned_extents);
+static int btrfs_cleanup_transaction(struct btrfs_root *root);
 
 /*
  * end_io_wq structs are used to do processing in task context when an IO is
@@ -1738,6 +1752,11 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         if (!btrfs_super_root(disk_super))
                 goto fail_iput;
 
+        /* check FS state, whether FS is broken. */
+        fs_info->fs_state |= btrfs_super_flags(disk_super);
+
+        btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
+
         ret = btrfs_parse_options(tree_root, options);
         if (ret) {
                 err = ret;
@@ -1968,7 +1987,9 @@ struct btrfs_root *open_ctree(struct super_block *sb,
                 btrfs_set_opt(fs_info->mount_opt, SSD);
         }
 
-        if (btrfs_super_log_root(disk_super) != 0) {
+        /* do not make disk changes in broken FS */
+        if (btrfs_super_log_root(disk_super) != 0 &&
+            !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) {
                 u64 bytenr = btrfs_super_log_root(disk_super);
 
                 if (fs_devices->rw_devices == 0) {
@@ -2464,8 +2485,28 @@ int close_ctree(struct btrfs_root *root)
         smp_mb();
 
         btrfs_put_block_group_cache(fs_info);
+
+        /*
+         * Here come 2 situations when btrfs is broken to flip readonly:
+         *
+         * 1. when btrfs flips readonly somewhere else before
+         * btrfs_commit_super, sb->s_flags has MS_RDONLY flag,
+         * and btrfs will skip to write sb directly to keep
+         * ERROR state on disk.
+         *
+         * 2. when btrfs flips readonly just in btrfs_commit_super,
+         * and in such case, btrfs cannnot write sb via btrfs_commit_super,
+         * and since fs_state has been set BTRFS_SUPER_FLAG_ERROR flag,
+         * btrfs will cleanup all FS resources first and write sb then.
+         */
         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
-                ret =  btrfs_commit_super(root);
+                ret = btrfs_commit_super(root);
+                if (ret)
+                        printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
+        }
+
+        if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+                ret = btrfs_error_commit_super(root);
                 if (ret)
                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
         }
@@ -2641,6 +2682,352 @@ out:
         return 0;
 }
 
+static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
+                              int read_only)
+{
+        if (read_only)
+                return;
+
+        if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
+                printk(KERN_WARNING "warning: mount fs with errors, "
+                       "running btrfsck is recommended\n");
+}
+
+int btrfs_error_commit_super(struct btrfs_root *root)
+{
+        int ret;
+
+        mutex_lock(&root->fs_info->cleaner_mutex);
+        btrfs_run_delayed_iputs(root);
+        mutex_unlock(&root->fs_info->cleaner_mutex);
+
+        down_write(&root->fs_info->cleanup_work_sem);
+        up_write(&root->fs_info->cleanup_work_sem);
+
+        /* cleanup FS via transaction */
+        btrfs_cleanup_transaction(root);
+
+        ret = write_ctree_super(NULL, root, 0);
+
+        return ret;
+}
+
+static int btrfs_destroy_ordered_operations(struct btrfs_root *root)
+{
+        struct btrfs_inode *btrfs_inode;
+        struct list_head splice;
+
+        INIT_LIST_HEAD(&splice);
+
+        mutex_lock(&root->fs_info->ordered_operations_mutex);
+        spin_lock(&root->fs_info->ordered_extent_lock);
+
+        list_splice_init(&root->fs_info->ordered_operations, &splice);
+        while (!list_empty(&splice)) {
+                btrfs_inode = list_entry(splice.next, struct btrfs_inode,
+                                         ordered_operations);
+
+                list_del_init(&btrfs_inode->ordered_operations);
+
+                btrfs_invalidate_inodes(btrfs_inode->root);
+        }
+
+        spin_unlock(&root->fs_info->ordered_extent_lock);
+        mutex_unlock(&root->fs_info->ordered_operations_mutex);
+
+        return 0;
+}
+
+static int btrfs_destroy_ordered_extents(struct btrfs_root *root)
+{
+        struct list_head splice;
+        struct btrfs_ordered_extent *ordered;
+        struct inode *inode;
+
+        INIT_LIST_HEAD(&splice);
+
+        spin_lock(&root->fs_info->ordered_extent_lock);
+
+        list_splice_init(&root->fs_info->ordered_extents, &splice);
+        while (!list_empty(&splice)) {
+                ordered = list_entry(splice.next, struct btrfs_ordered_extent,
+                                     root_extent_list);
+
+                list_del_init(&ordered->root_extent_list);
+                atomic_inc(&ordered->refs);
+
+                /* the inode may be getting freed (in sys_unlink path). */
+                inode = igrab(ordered->inode);
+
+                spin_unlock(&root->fs_info->ordered_extent_lock);
+                if (inode)
+                        iput(inode);
+
+                atomic_set(&ordered->refs, 1);
+                btrfs_put_ordered_extent(ordered);
+
+                spin_lock(&root->fs_info->ordered_extent_lock);
+        }
+
+        spin_unlock(&root->fs_info->ordered_extent_lock);
+
+        return 0;
+}
+
+static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
+                                      struct btrfs_root *root)
+{
+        struct rb_node *node;
+        struct btrfs_delayed_ref_root *delayed_refs;
+        struct btrfs_delayed_ref_node *ref;
+        int ret = 0;
+
+        delayed_refs = &trans->delayed_refs;
+
+        spin_lock(&delayed_refs->lock);
+        if (delayed_refs->num_entries == 0) {
+                printk(KERN_INFO "delayed_refs has NO entry\n");
+                return ret;
+        }
+
+        node = rb_first(&delayed_refs->root);
+        while (node) {
+                ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
+                node = rb_next(node);
+
+                ref->in_tree = 0;
+                rb_erase(&ref->rb_node, &delayed_refs->root);
+                delayed_refs->num_entries--;
+
+                atomic_set(&ref->refs, 1);
+                if (btrfs_delayed_ref_is_head(ref)) {
+                        struct btrfs_delayed_ref_head *head;
+
+                        head = btrfs_delayed_node_to_head(ref);
+                        mutex_lock(&head->mutex);
+                        kfree(head->extent_op);
+                        delayed_refs->num_heads--;
+                        if (list_empty(&head->cluster))
+                                delayed_refs->num_heads_ready--;
+                        list_del_init(&head->cluster);
+                        mutex_unlock(&head->mutex);
+                }
+
+                spin_unlock(&delayed_refs->lock);
+                btrfs_put_delayed_ref(ref);
+
+                cond_resched();
+                spin_lock(&delayed_refs->lock);
+        }
+
+        spin_unlock(&delayed_refs->lock);
+
+        return ret;
+}
+
+static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t)
+{
+        struct btrfs_pending_snapshot *snapshot;
+        struct list_head splice;
+
+        INIT_LIST_HEAD(&splice);
+
+        list_splice_init(&t->pending_snapshots, &splice);
+
+        while (!list_empty(&splice)) {
+                snapshot = list_entry(splice.next,
+                                      struct btrfs_pending_snapshot,
+                                      list);
+
+                list_del_init(&snapshot->list);
+
+                kfree(snapshot);
+        }
+
+        return 0;
+}
+
+static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
+{
+        struct btrfs_inode *btrfs_inode;
+        struct list_head splice;
+
+        INIT_LIST_HEAD(&splice);
+
+        list_splice_init(&root->fs_info->delalloc_inodes, &splice);
+
+        spin_lock(&root->fs_info->delalloc_lock);
+
+        while (!list_empty(&splice)) {
+                btrfs_inode = list_entry(splice.next, struct btrfs_inode,
+                                    delalloc_inodes);
+
+                list_del_init(&btrfs_inode->delalloc_inodes);
+
+                btrfs_invalidate_inodes(btrfs_inode->root);
+        }
+
+        spin_unlock(&root->fs_info->delalloc_lock);
+
+        return 0;
+}
+
+static int btrfs_destroy_marked_extents(struct btrfs_root *root,
+                                        struct extent_io_tree *dirty_pages,
+                                        int mark)
+{
+        int ret;
+        struct page *page;
+        struct inode *btree_inode = root->fs_info->btree_inode;
+        struct extent_buffer *eb;
+        u64 start = 0;
+        u64 end;
+        u64 offset;
+        unsigned long index;
+
+        while (1) {
+                ret = find_first_extent_bit(dirty_pages, start, &start, &end,
+                                            mark);
+                if (ret)
+                        break;
+
+                clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
+                while (start <= end) {
+                        index = start >> PAGE_CACHE_SHIFT;
+                        start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
+                        page = find_get_page(btree_inode->i_mapping, index);
+                        if (!page)
+                                continue;
+                        offset = page_offset(page);
+
+                        spin_lock(&dirty_pages->buffer_lock);
+                        eb = radix_tree_lookup(
+                             &(&BTRFS_I(page->mapping->host)->io_tree)->buffer,
+                                               offset >> PAGE_CACHE_SHIFT);
+                        spin_unlock(&dirty_pages->buffer_lock);
+                        if (eb) {
+                                ret = test_and_clear_bit(EXTENT_BUFFER_DIRTY,
+                                                         &eb->bflags);
+                                atomic_set(&eb->refs, 1);
+                        }
+                        if (PageWriteback(page))
+                                end_page_writeback(page);
+
+                        lock_page(page);
+                        if (PageDirty(page)) {
+                                clear_page_dirty_for_io(page);
+                                spin_lock_irq(&page->mapping->tree_lock);
+                                radix_tree_tag_clear(&page->mapping->page_tree,
+                                                        page_index(page),
+                                                        PAGECACHE_TAG_DIRTY);
+                                spin_unlock_irq(&page->mapping->tree_lock);
+                        }
+
+                        page->mapping->a_ops->invalidatepage(page, 0);
+                        unlock_page(page);
+                }
+        }
+
+        return ret;
+}
+
+static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
+                                       struct extent_io_tree *pinned_extents)
+{
+        struct extent_io_tree *unpin;
+        u64 start;
+        u64 end;
+        int ret;
+
+        unpin = pinned_extents;
+        while (1) {
+                ret = find_first_extent_bit(unpin, 0, &start, &end,
+                                            EXTENT_DIRTY);
+                if (ret)
+                        break;
+
+                /* opt_discard */
+                ret = btrfs_error_discard_extent(root, start, end + 1 - start);
+
+                clear_extent_dirty(unpin, start, end, GFP_NOFS);
+                btrfs_error_unpin_extent_range(root, start, end);
+                cond_resched();
+        }
+
+        return 0;
+}
+
+static int btrfs_cleanup_transaction(struct btrfs_root *root)
+{
+        struct btrfs_transaction *t;
+        LIST_HEAD(list);
+
+        WARN_ON(1);
+
+        mutex_lock(&root->fs_info->trans_mutex);
+        mutex_lock(&root->fs_info->transaction_kthread_mutex);
+
+        list_splice_init(&root->fs_info->trans_list, &list);
+        while (!list_empty(&list)) {
+                t = list_entry(list.next, struct btrfs_transaction, list);
+                if (!t)
+                        break;
+
+                btrfs_destroy_ordered_operations(root);
+
+                btrfs_destroy_ordered_extents(root);
+
+                btrfs_destroy_delayed_refs(t, root);
+
+                btrfs_block_rsv_release(root,
+                                        &root->fs_info->trans_block_rsv,
+                                        t->dirty_pages.dirty_bytes);
+
+                /* FIXME: cleanup wait for commit */
+                t->in_commit = 1;
+                t->blocked = 1;
+                if (waitqueue_active(&root->fs_info->transaction_blocked_wait))
+                        wake_up(&root->fs_info->transaction_blocked_wait);
+
+                t->blocked = 0;
+                if (waitqueue_active(&root->fs_info->transaction_wait))
+                        wake_up(&root->fs_info->transaction_wait);
+                mutex_unlock(&root->fs_info->trans_mutex);
+
+                mutex_lock(&root->fs_info->trans_mutex);
+                t->commit_done = 1;
+                if (waitqueue_active(&t->commit_wait))
+                        wake_up(&t->commit_wait);
+                mutex_unlock(&root->fs_info->trans_mutex);
+
+                mutex_lock(&root->fs_info->trans_mutex);
+
+                btrfs_destroy_pending_snapshots(t);
+
+                btrfs_destroy_delalloc_inodes(root);
+
+                spin_lock(&root->fs_info->new_trans_lock);
+                root->fs_info->running_transaction = NULL;
+                spin_unlock(&root->fs_info->new_trans_lock);
+
+                btrfs_destroy_marked_extents(root, &t->dirty_pages,
+                                             EXTENT_DIRTY);
+
+                btrfs_destroy_pinned_extent(root,
+                                            root->fs_info->pinned_extents);
+
+                t->use_count = 0;
+                list_del_init(&t->list);
+                memset(t, 0, sizeof(*t));
+                kmem_cache_free(btrfs_transaction_cachep, t);
+        }
+
+        mutex_unlock(&root->fs_info->transaction_kthread_mutex);
+        mutex_unlock(&root->fs_info->trans_mutex);
+
+        return 0;
+}
+
 static struct extent_io_ops btree_extent_io_ops = {
         .write_cache_pages_lock_hook = btree_lock_page_hook,
         .readpage_end_io_hook = btree_readpage_end_io_hook,
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 88e825a0bf21..07b20dc2fd95 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -52,6 +52,7 @@ int write_ctree_super(struct btrfs_trans_handle *trans,
                       struct btrfs_root *root, int max_mirrors);
 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev);
 int btrfs_commit_super(struct btrfs_root *root);
+int btrfs_error_commit_super(struct btrfs_root *root);
 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
                                             u64 bytenr, u32 blocksize);
 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 055b837eab19..bcf303204f7f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -8642,3 +8642,14 @@ out:
         btrfs_free_path(path);
         return ret;
 }
+
+int btrfs_error_unpin_extent_range(struct btrfs_root *root, u64 start, u64 end)
+{
+        return unpin_extent_range(root, start, end);
+}
+
+int btrfs_error_discard_extent(struct btrfs_root *root, u64 bytenr,
+                               u64 num_bytes)
+{
+        return btrfs_discard_extent(root, bytenr, num_bytes);
+}
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 05df688c96f4..f903433f5bdf 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -892,6 +892,17 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
         if (err)
                 goto out;
 
+        /*
+         * If BTRFS flips readonly due to some impossible error
+         * (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
+         * although we have opened a file as writable, we have
+         * to stop this write operation to ensure FS consistency.
+         */
+        if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+                err = -EROFS;
+                goto out;
+        }
+
         file_update_time(file);
         BTRFS_I(inode)->sequence++;
 
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 2963376e77f4..52e903b0a293 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -54,6 +54,90 @@
 
 static const struct super_operations btrfs_super_ops;
 
+static const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno,
+                                      char nbuf[16])
+{
+        char *errstr = NULL;
+
+        switch (errno) {
+        case -EIO:
+                errstr = "IO failure";
+                break;
+        case -ENOMEM:
+                errstr = "Out of memory";
+                break;
+        case -EROFS:
+                errstr = "Readonly filesystem";
+                break;
+        default:
+                if (nbuf) {
+                        if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
+                                errstr = nbuf;
+                }
+                break;
+        }
+
+        return errstr;
+}
+
+static void __save_error_info(struct btrfs_fs_info *fs_info)
+{
+        /*
+         * today we only save the error info into ram.  Long term we'll
+         * also send it down to the disk
+         */
+        fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
+}
+
+/* NOTE:
+ *      We move write_super stuff at umount in order to avoid deadlock
+ *      for umount hold all lock.
+ */
+static void save_error_info(struct btrfs_fs_info *fs_info)
+{
+        __save_error_info(fs_info);
+}
+
+/* btrfs handle error by forcing the filesystem readonly */
+static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
+{
+        struct super_block *sb = fs_info->sb;
+
+        if (sb->s_flags & MS_RDONLY)
+                return;
+
+        if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
+                sb->s_flags |= MS_RDONLY;
+                printk(KERN_INFO "btrfs is forced readonly\n");
+        }
+}
+
+/*
+ * __btrfs_std_error decodes expected errors from the caller and
+ * invokes the approciate error response.
+ */
+void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
+                     unsigned int line, int errno)
+{
+        struct super_block *sb = fs_info->sb;
+        char nbuf[16];
+        const char *errstr;
+
+        /*
+         * Special case: if the error is EROFS, and we're already
+         * under MS_RDONLY, then it is safe here.
+         */
+        if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
+                return;
+
+        errstr = btrfs_decode_error(fs_info, errno, nbuf);
+        printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
+                sb->s_id, function, line, errstr);
+        save_error_info(fs_info);
+
+        btrfs_handle_error(fs_info);
+}
+
 static void btrfs_put_super(struct super_block *sb)
 {
         struct btrfs_root *root = btrfs_sb(sb);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 29e30d832ec9..bae5c7b8bbe2 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -181,6 +181,9 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
         struct btrfs_trans_handle *h;
         struct btrfs_transaction *cur_trans;
         int ret;
+
+        if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
+                return ERR_PTR(-EROFS);
 again:
         h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
         if (!h)