Btrfs: mount ro and remount support

This patch adds mount ro and remount support. The main
changes in patch are: adding btrfs_remount and related
helper function; splitting the transaction related code
out of close_ctree into btrfs_commit_super; updating
allocator to properly handle read only block group.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index f575939..c4c6c12 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -541,6 +541,7 @@ struct btrfs_space_info {
        u64 bytes_used;
        u64 bytes_pinned;
        u64 bytes_reserved;
+       u64 bytes_readonly;
        int full;
        int force_alloc;
        struct list_head list;

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 3b0e974..c599f0e 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1075,10 +1075,12 @@ struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
                kfree(root);
                return ERR_PTR(ret);
        }
-       ret = btrfs_find_dead_roots(fs_info->tree_root,
-                                   root->root_key.objectid, root);
-       BUG_ON(ret);
-
+       if (!(fs_info->sb->s_flags & MS_RDONLY)) {
+               ret = btrfs_find_dead_roots(fs_info->tree_root,
+                                           root->root_key.objectid, root);
+               BUG_ON(ret);
+               btrfs_orphan_cleanup(root);
+       }
        return root;
 }
 
@@ -1700,7 +1702,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 
        btrfs_read_block_groups(extent_root);
 
-       fs_info->generation = btrfs_super_generation(disk_super) + 1;
+       fs_info->generation = generation + 1;
+       fs_info->last_trans_committed = generation;
        fs_info->data_alloc_profile = (u64)-1;
        fs_info->metadata_alloc_profile = (u64)-1;
        fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
@@ -1715,6 +1718,9 @@ struct btrfs_root *open_ctree(struct super_block *sb,
        if (!fs_info->transaction_kthread)
                goto fail_cleaner;
 
+       if (sb->s_flags & MS_RDONLY)
+               return tree_root;
+
        if (btrfs_super_log_root(disk_super) != 0) {
                u32 blocksize;
                u64 bytenr = btrfs_super_log_root(disk_super);
@@ -1735,7 +1741,6 @@ struct btrfs_root *open_ctree(struct super_block *sb,
                ret = btrfs_recover_log_trees(log_tree_root);
                BUG_ON(ret);
        }
-       fs_info->last_trans_committed = btrfs_super_generation(disk_super);
 
        ret = btrfs_cleanup_reloc_trees(tree_root);
        BUG_ON(ret);
@@ -1955,28 +1960,69 @@ static int del_fs_roots(struct btrfs_fs_info *fs_info)
        return 0;
 }
 
-int close_ctree(struct btrfs_root *root)
+int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
 {
+       u64 root_objectid = 0;
+       struct btrfs_root *gang[8];
+       int i;
        int ret;
-       struct btrfs_trans_handle *trans;
-       struct btrfs_fs_info *fs_info = root->fs_info;
 
-       fs_info->closing = 1;
-       smp_mb();
+       while (1) {
+               ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
+                                            (void **)gang, root_objectid,
+                                            ARRAY_SIZE(gang));
+               if (!ret)
+                       break;
+               for (i = 0; i < ret; i++) {
+                       root_objectid = gang[i]->root_key.objectid;
+                       ret = btrfs_find_dead_roots(fs_info->tree_root,
+                                                   root_objectid, gang[i]);
+                       BUG_ON(ret);
+                       btrfs_orphan_cleanup(gang[i]);
+               }
+               root_objectid++;
+       }
+       return 0;
+}
 
-       kthread_stop(root->fs_info->transaction_kthread);
-       kthread_stop(root->fs_info->cleaner_kthread);
+int btrfs_commit_super(struct btrfs_root *root)
+{
+       struct btrfs_trans_handle *trans;
+       int ret;
 
+       mutex_lock(&root->fs_info->cleaner_mutex);
        btrfs_clean_old_snapshots(root);
+       mutex_unlock(&root->fs_info->cleaner_mutex);
        trans = btrfs_start_transaction(root, 1);
        ret = btrfs_commit_transaction(trans, root);
-       /* run commit again to  drop the original snapshot */
+       BUG_ON(ret);
+       /* run commit again to drop the original snapshot */
        trans = btrfs_start_transaction(root, 1);
        btrfs_commit_transaction(trans, root);
        ret = btrfs_write_and_wait_transaction(NULL, root);
        BUG_ON(ret);
 
-       write_ctree_super(NULL, root);
+       ret = write_ctree_super(NULL, root);
+       return ret;
+}
+
+int close_ctree(struct btrfs_root *root)
+{
+       struct btrfs_fs_info *fs_info = root->fs_info;
+       int ret;
+
+       fs_info->closing = 1;
+       smp_mb();
+
+       kthread_stop(root->fs_info->transaction_kthread);
+       kthread_stop(root->fs_info->cleaner_kthread);
+
+       if (!(fs_info->sb->s_flags & MS_RDONLY)) {
+               ret =  btrfs_commit_super(root);
+               if (ret) {
+                       printk("btrfs: commit super returns %d\n", ret);
+               }
+       }
 
        if (fs_info->delalloc_bytes) {
                printk("btrfs: at unmount delalloc count %Lu\n",
@@ -2000,12 +2046,10 @@ int close_ctree(struct btrfs_root *root)
                free_extent_buffer(root->fs_info->dev_root->node);
 
        btrfs_free_block_groups(root->fs_info);
-       fs_info->closing = 2;
-       del_fs_roots(fs_info);
 
-       filemap_write_and_wait(fs_info->btree_inode->i_mapping);
+       del_fs_roots(fs_info);
 
-       truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
+       iput(fs_info->btree_inode);
 
        btrfs_stop_workers(&fs_info->fixup_workers);
        btrfs_stop_workers(&fs_info->delalloc_workers);
@@ -2014,7 +2058,6 @@ int close_ctree(struct btrfs_root *root)
        btrfs_stop_workers(&fs_info->endio_write_workers);
        btrfs_stop_workers(&fs_info->submit_workers);
 
-       iput(fs_info->btree_inode);
 #if 0
        while(!list_empty(&fs_info->hashers)) {
                struct btrfs_hasher *hasher;

diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index b8d5948..717e948 100644 (file)
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -38,6 +38,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 int close_ctree(struct btrfs_root *root);
 int write_ctree_super(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root);
+int btrfs_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,
@@ -49,6 +50,7 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
                                               struct btrfs_key *location);
 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
                                              struct btrfs_key *location);
+int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info);
 int btrfs_insert_dev_radix(struct btrfs_root *root,
                           struct block_device *bdev,
                           u64 device_id,

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e785f0a..af2de30 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1794,7 +1794,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
                *space_info = found;
                return 0;
        }
-       found = kmalloc(sizeof(*found), GFP_NOFS);
+       found = kzalloc(sizeof(*found), GFP_NOFS);
        if (!found)
                return -ENOMEM;
 
@@ -1807,6 +1807,7 @@ static int update_space_info(struct btrfs_fs_info *info, u64 flags,
        found->bytes_used = bytes_used;
        found->bytes_pinned = 0;
        found->bytes_reserved = 0;
+       found->bytes_readonly = 0;
        found->full = 0;
        found->force_alloc = 0;
        *space_info = found;
@@ -1829,6 +1830,19 @@ static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
        }
 }
 
+static void set_block_group_readonly(struct btrfs_block_group_cache *cache)
+{
+       spin_lock(&cache->space_info->lock);
+       spin_lock(&cache->lock);
+       if (!cache->ro) {
+               cache->space_info->bytes_readonly += cache->key.offset -
+                                       btrfs_block_group_used(&cache->item);
+               cache->ro = 1;
+       }
+       spin_unlock(&cache->lock);
+       spin_unlock(&cache->space_info->lock);
+}
+
 static u64 reduce_alloc_profile(struct btrfs_root *root, u64 flags)
 {
        u64 num_devices = root->fs_info->fs_devices->num_devices;
@@ -1865,7 +1879,9 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
        u64 thresh;
        u64 start;
        u64 num_bytes;
-       int ret = 0, waited = 0;
+       int ret = 0;
+
+       mutex_lock(&extent_root->fs_info->chunk_mutex);
 
        flags = reduce_alloc_profile(extent_root, flags);
 
@@ -1887,46 +1903,28 @@ static int do_chunk_alloc(struct btrfs_trans_handle *trans,
                goto out;
        }
 
-       thresh = div_factor(space_info->total_bytes, 6);
+       thresh = space_info->total_bytes - space_info->bytes_readonly;
+       thresh = div_factor(thresh, 6);
        if (!force &&
           (space_info->bytes_used + space_info->bytes_pinned +
            space_info->bytes_reserved + alloc_bytes) < thresh) {
                spin_unlock(&space_info->lock);
                goto out;
        }
-
        spin_unlock(&space_info->lock);
 
-       ret = mutex_trylock(&extent_root->fs_info->chunk_mutex);
-       if (!ret && !force) {
-               goto out;
-       } else if (!ret) {
-               mutex_lock(&extent_root->fs_info->chunk_mutex);
-               waited = 1;
-       }
-
-       if (waited) {
-               spin_lock(&space_info->lock);
-               if (space_info->full) {
-                       spin_unlock(&space_info->lock);
-                       goto out_unlock;
-               }
-               spin_unlock(&space_info->lock);
-       }
-
        ret = btrfs_alloc_chunk(trans, extent_root, &start, &num_bytes, flags);
        if (ret) {
 printk("space info full %Lu\n", flags);
                space_info->full = 1;
-               goto out_unlock;
+               goto out;
        }
 
        ret = btrfs_make_block_group(trans, extent_root, 0, flags,
                     BTRFS_FIRST_CHUNK_TREE_OBJECTID, start, num_bytes);
        BUG_ON(ret);
-out_unlock:
-       mutex_unlock(&extent_root->fs_info->chunk_mutex);
 out:
+       mutex_unlock(&extent_root->fs_info->chunk_mutex);
        return ret;
 }
 
@@ -1956,12 +1954,18 @@ static int update_block_group(struct btrfs_trans_handle *trans,
                if (alloc) {
                        old_val += num_bytes;
                        cache->space_info->bytes_used += num_bytes;
+                       if (cache->ro) {
+                               cache->space_info->bytes_readonly -= num_bytes;
+                               WARN_ON(1);
+                       }
                        btrfs_set_block_group_used(&cache->item, old_val);
                        spin_unlock(&cache->lock);
                        spin_unlock(&cache->space_info->lock);
                } else {
                        old_val -= num_bytes;
                        cache->space_info->bytes_used -= num_bytes;
+                       if (cache->ro)
+                               cache->space_info->bytes_readonly += num_bytes;
                        btrfs_set_block_group_used(&cache->item, old_val);
                        spin_unlock(&cache->lock);
                        spin_unlock(&cache->space_info->lock);
@@ -5560,8 +5564,7 @@ int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start)
        BUG_ON(IS_ERR(reloc_inode));
 
        __alloc_chunk_for_shrink(root, block_group, 1);
-       block_group->ro = 1;
-       block_group->space_info->total_bytes -= block_group->key.offset;
+       set_block_group_readonly(block_group);
 
        btrfs_start_delalloc_inodes(info->tree_root);
        btrfs_wait_ordered_extents(info->tree_root, 0);
@@ -5868,6 +5871,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 
        block_group = btrfs_lookup_block_group(root->fs_info, group_start);
        BUG_ON(!block_group);
+       BUG_ON(!block_group->ro);
 
        memcpy(&key, &block_group->key, sizeof(key));
 
@@ -5881,6 +5885,11 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
        list_del(&block_group->list);
        up_write(&block_group->space_info->groups_sem);
 
+       spin_lock(&block_group->space_info->lock);
+       block_group->space_info->total_bytes -= block_group->key.offset;
+       block_group->space_info->bytes_readonly -= block_group->key.offset;
+       spin_unlock(&block_group->space_info->lock);
+
        /*
        memset(shrink_block_group, 0, sizeof(*shrink_block_group));
        kfree(shrink_block_group);

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2ed2dea..3e3620e 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1808,10 +1808,6 @@ void btrfs_orphan_cleanup(struct btrfs_root *root)
        struct inode *inode;
        int ret = 0, nr_unlink = 0, nr_truncate = 0;
 
-       /* don't do orphan cleanup if the fs is readonly. */
-       if (root->fs_info->sb->s_flags & MS_RDONLY)
-               return;
-
        path = btrfs_alloc_path();
        if (!path)
                return;
@@ -3050,7 +3046,7 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
        struct btrfs_root *root = bi->root;
        struct btrfs_root *sub_root = root;
        struct btrfs_key location;
-       int ret, new, do_orphan = 0;
+       int ret, new;
 
        if (dentry->d_name.len > BTRFS_NAME_LEN)
                return ERR_PTR(-ENAMETOOLONG);
@@ -3076,13 +3072,9 @@ static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
                if (new && root != sub_root) {
                        igrab(inode);
                        sub_root->inode = inode;
-                       do_orphan = 1;
                }
        }
 
-       if (unlikely(do_orphan))
-               btrfs_orphan_cleanup(sub_root);
-
        return d_splice_alias(inode, dentry);
 }
 
@@ -3237,7 +3229,7 @@ int btrfs_write_inode(struct inode *inode, int wait)
        struct btrfs_trans_handle *trans;
        int ret = 0;
 
-       if (root->fs_info->closing > 1)
+       if (root->fs_info->btree_inode == inode)
                return 0;
 
        if (wait) {
@@ -4625,6 +4617,9 @@ int btrfs_start_delalloc_inodes(struct btrfs_root *root)
        struct inode *inode;
        unsigned long flags;
 
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
+
        spin_lock_irqsave(&root->fs_info->delalloc_lock, flags);
        while(!list_empty(head)) {
                binode = list_entry(head->next, struct btrfs_inode,

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 4d7cc7c..52863ce 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -378,6 +378,9 @@ static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
        int namelen;
        int mod = 0;
 
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
+
        vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 
        if (!vol_args)
@@ -478,6 +481,9 @@ static noinline int btrfs_ioctl_snap_create(struct file *file,
        int namelen;
        int ret;
 
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
+
        vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 
        if (!vol_args)
@@ -534,6 +540,11 @@ static int btrfs_ioctl_defrag(struct file *file)
 {
        struct inode *inode = fdentry(file)->d_inode;
        struct btrfs_root *root = BTRFS_I(inode)->root;
+       int ret;
+
+       ret = mnt_want_write(file->f_path.mnt);
+       if (ret)
+               return ret;
 
        switch (inode->i_mode & S_IFMT) {
        case S_IFDIR:
@@ -575,6 +586,9 @@ long btrfs_ioctl_rm_dev(struct btrfs_root *root, void __user *arg)
        struct btrfs_ioctl_vol_args *vol_args;
        int ret;
 
+       if (root->fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
+
        vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
 
        if (!vol_args)
@@ -621,6 +635,10 @@ long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, u64 off,
         *   they don't overlap)?
         */
 
+       ret = mnt_want_write(file->f_path.mnt);
+       if (ret)
+               return ret;
+
        src_file = fget(srcfd);
        if (!src_file)
                return -EBADF;
@@ -958,6 +976,10 @@ long btrfs_ioctl_trans_start(struct file *file)
                goto out;
        }
 
+       ret = mnt_want_write(file->f_path.mnt);
+       if (ret)
+               goto out;
+
        mutex_lock(&root->fs_info->trans_mutex);
        root->fs_info->open_ioctl_trans++;
        mutex_unlock(&root->fs_info->trans_mutex);

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index ab9d5e8..04a3bf8 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -370,6 +370,9 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
        int ret;
        root = btrfs_sb(sb);
 
+       if (sb->s_flags & MS_RDONLY)
+               return 0;
+
        sb->s_dirt = 0;
        if (!wait) {
                filemap_flush(root->fs_info->btree_inode->i_mapping);
@@ -438,7 +441,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
                        up_write(&s->s_umount);
                        deactivate_super(s);
                        error = -EBUSY;
-                       goto error_bdev;
+                       goto error_close_devices;
                }
 
        } else {
@@ -487,7 +490,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
 
 error_s:
        error = PTR_ERR(s);
-error_bdev:
+error_close_devices:
        btrfs_close_devices(fs_devices);
 error_free_subvol_name:
        kfree(subvol_name);
@@ -495,6 +498,35 @@ error:
        return error;
 }
 
+static int btrfs_remount(struct super_block *sb, int *flags, char *data)
+{
+       struct btrfs_root *root = btrfs_sb(sb);
+       int ret;
+
+       if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
+               return 0;
+
+       if (*flags & MS_RDONLY) {
+               sb->s_flags |= MS_RDONLY;
+
+               ret =  btrfs_commit_super(root);
+               WARN_ON(ret);
+       } else {
+               if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
+                       return -EINVAL;
+
+               ret = btrfs_cleanup_reloc_trees(root);
+               WARN_ON(ret);
+
+               ret = btrfs_cleanup_fs_roots(root->fs_info);
+               WARN_ON(ret);
+
+               sb->s_flags &= ~MS_RDONLY;
+       }
+
+       return 0;
+}
+
 static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
        struct btrfs_root *root = btrfs_sb(dentry->d_sb);
@@ -582,6 +614,7 @@ static struct super_operations btrfs_super_ops = {
        .alloc_inode    = btrfs_alloc_inode,
        .destroy_inode  = btrfs_destroy_inode,
        .statfs         = btrfs_statfs,
+       .remount_fs     = btrfs_remount,
        .write_super_lockfs = btrfs_write_super_lockfs,
        .unlockfs       = btrfs_unlockfs,
 };