]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/fs.c
Update bcachefs sources to 0a9f0fc68a bcachefs: Don't unconditially version_upgrade...
[bcachefs-tools-debian] / libbcachefs / fs.c
index f9b3650b2f375e7e2dedf08580433f74f0930fc5..1cca02f0aa3de2cf3ddb0e714e79e4b685cda278 100644 (file)
@@ -3,6 +3,7 @@
 
 #include "bcachefs.h"
 #include "acl.h"
+#include "bkey_buf.h"
 #include "btree_update.h"
 #include "buckets.h"
 #include "chardev.h"
@@ -24,6 +25,7 @@
 #include <linux/aio.h>
 #include <linux/backing-dev.h>
 #include <linux/exportfs.h>
+#include <linux/fiemap.h>
 #include <linux/module.h>
 #include <linux/posix_acl.h>
 #include <linux/random.h>
@@ -36,9 +38,15 @@ static void bch2_vfs_inode_init(struct bch_fs *,
                                struct bch_inode_info *,
                                struct bch_inode_unpacked *);
 
-static void journal_seq_copy(struct bch_inode_info *dst,
+static void journal_seq_copy(struct bch_fs *c,
+                            struct bch_inode_info *dst,
                             u64 journal_seq)
 {
+       /*
+        * atomic64_cmpxchg has a fallback for archs that don't support it,
+        * cmpxchg does not:
+        */
+       atomic64_t *dst_seq = (void *) &dst->ei_journal_seq;
        u64 old, v = READ_ONCE(dst->ei_journal_seq);
 
        do {
@@ -46,7 +54,61 @@ static void journal_seq_copy(struct bch_inode_info *dst,
 
                if (old >= journal_seq)
                        break;
-       } while ((v = cmpxchg(&dst->ei_journal_seq, old, journal_seq)) != old);
+       } while ((v = atomic64_cmpxchg(dst_seq, old, journal_seq)) != old);
+
+       bch2_journal_set_has_inum(&c->journal, dst->v.i_ino, journal_seq);
+}
+
+static void __pagecache_lock_put(struct pagecache_lock *lock, long i)
+{
+       BUG_ON(atomic_long_read(&lock->v) == 0);
+
+       if (atomic_long_sub_return_release(i, &lock->v) == 0)
+               wake_up_all(&lock->wait);
+}
+
+static bool __pagecache_lock_tryget(struct pagecache_lock *lock, long i)
+{
+       long v = atomic_long_read(&lock->v), old;
+
+       do {
+               old = v;
+
+               if (i > 0 ? v < 0 : v > 0)
+                       return false;
+       } while ((v = atomic_long_cmpxchg_acquire(&lock->v,
+                                       old, old + i)) != old);
+       return true;
+}
+
+static void __pagecache_lock_get(struct pagecache_lock *lock, long i)
+{
+       wait_event(lock->wait, __pagecache_lock_tryget(lock, i));
+}
+
+void bch2_pagecache_add_put(struct pagecache_lock *lock)
+{
+       __pagecache_lock_put(lock, 1);
+}
+
+bool bch2_pagecache_add_tryget(struct pagecache_lock *lock)
+{
+       return __pagecache_lock_tryget(lock, 1);
+}
+
+void bch2_pagecache_add_get(struct pagecache_lock *lock)
+{
+       __pagecache_lock_get(lock, 1);
+}
+
+void bch2_pagecache_block_put(struct pagecache_lock *lock)
+{
+       __pagecache_lock_put(lock, -1);
+}
+
+void bch2_pagecache_block_get(struct pagecache_lock *lock)
+{
+       __pagecache_lock_get(lock, -1);
 }
 
 void bch2_inode_update_after_write(struct bch_fs *c,
@@ -92,11 +154,8 @@ retry:
                bch2_inode_write(&trans, iter, &inode_u) ?:
                bch2_trans_commit(&trans, NULL,
                                  &inode->ei_journal_seq,
-                                 BTREE_INSERT_ATOMIC|
                                  BTREE_INSERT_NOUNLOCK|
                                  BTREE_INSERT_NOFAIL);
-       if (ret == -EINTR)
-               goto retry;
 
        /*
         * the btree node lock protects inode->ei_inode, not ei_update_lock;
@@ -105,6 +164,11 @@ retry:
        if (!ret)
                bch2_inode_update_after_write(c, inode, &inode_u, fields);
 
+       bch2_trans_iter_put(&trans, iter);
+
+       if (ret == -EINTR)
+               goto retry;
+
        bch2_trans_exit(&trans);
        return ret < 0 ? ret : 0;
 }
@@ -171,6 +235,13 @@ struct inode *bch2_vfs_inode_get(struct bch_fs *c, u64 inum)
        return &inode->v;
 }
 
+static int inum_test(struct inode *inode, void *p)
+{
+       unsigned long *ino = p;
+
+       return *ino == inode->i_ino;
+}
+
 static struct bch_inode_info *
 __bch2_create(struct bch_inode_info *dir, struct dentry *dentry,
              umode_t mode, dev_t rdev, bool tmpfile)
@@ -205,7 +276,8 @@ __bch2_create(struct bch_inode_info *dir, struct dentry *dentry,
        if (!tmpfile)
                mutex_lock(&dir->ei_update_lock);
 
-       bch2_trans_init(&trans, c, 8, 1024);
+       bch2_trans_init(&trans, c, 8,
+                       2048 + (!tmpfile ? dentry->d_name.len : 0));
 retry:
        bch2_trans_begin(&trans);
 
@@ -221,7 +293,6 @@ retry:
                goto err_before_quota;
 
        ret   = bch2_trans_commit(&trans, NULL, &journal_seq,
-                                 BTREE_INSERT_ATOMIC|
                                  BTREE_INSERT_NOUNLOCK);
        if (unlikely(ret)) {
                bch2_quota_acct(c, bch_qid(&inode_u), Q_INO, -1,
@@ -235,12 +306,12 @@ err_before_quota:
        if (!tmpfile) {
                bch2_inode_update_after_write(c, dir, &dir_u,
                                              ATTR_MTIME|ATTR_CTIME);
-               journal_seq_copy(dir, journal_seq);
+               journal_seq_copy(c, dir, journal_seq);
                mutex_unlock(&dir->ei_update_lock);
        }
 
        bch2_vfs_inode_init(c, inode, &inode_u);
-       journal_seq_copy(inode, journal_seq);
+       journal_seq_copy(c, inode, journal_seq);
 
        set_cached_acl(&inode->v, ACL_TYPE_ACCESS, acl);
        set_cached_acl(&inode->v, ACL_TYPE_DEFAULT, default_acl);
@@ -251,13 +322,17 @@ err_before_quota:
         * thread pulling the inode in and modifying it:
         */
 
-       old = to_bch_ei(insert_inode_locked2(&inode->v));
-       if (unlikely(old)) {
+       inode->v.i_state |= I_CREATING;
+       old = to_bch_ei(inode_insert5(&inode->v, inode->v.i_ino,
+                                     inum_test, NULL, &inode->v.i_ino));
+       BUG_ON(!old);
+
+       if (unlikely(old != inode)) {
                /*
                 * We raced, another process pulled the new inode into cache
                 * before us:
                 */
-               journal_seq_copy(old, journal_seq);
+               journal_seq_copy(c, old, journal_seq);
                make_bad_inode(&inode->v);
                iput(&inode->v);
 
@@ -293,11 +368,11 @@ static struct dentry *bch2_lookup(struct inode *vdir, struct dentry *dentry,
 {
        struct bch_fs *c = vdir->i_sb->s_fs_info;
        struct bch_inode_info *dir = to_bch_ei(vdir);
+       struct bch_hash_info hash = bch2_hash_info_init(c, &dir->ei_inode);
        struct inode *vinode = NULL;
        u64 inum;
 
-       inum = bch2_dirent_lookup(c, dir->v.i_ino,
-                                 &dir->ei_str_hash,
+       inum = bch2_dirent_lookup(c, dir->v.i_ino, &hash,
                                  &dentry->d_name);
 
        if (inum)
@@ -331,26 +406,27 @@ static int __bch2_link(struct bch_fs *c,
                       struct dentry *dentry)
 {
        struct btree_trans trans;
-       struct bch_inode_unpacked inode_u;
+       struct bch_inode_unpacked dir_u, inode_u;
        int ret;
 
        mutex_lock(&inode->ei_update_lock);
        bch2_trans_init(&trans, c, 4, 1024);
 
-       do {
-               bch2_trans_begin(&trans);
-               ret   = bch2_link_trans(&trans,
+       ret = __bch2_trans_do(&trans, NULL, &inode->ei_journal_seq,
+                             BTREE_INSERT_NOUNLOCK,
+                       bch2_link_trans(&trans,
                                        dir->v.i_ino,
-                                       inode->v.i_ino, &inode_u,
-                                       &dentry->d_name) ?:
-                       bch2_trans_commit(&trans, NULL,
-                                       &inode->ei_journal_seq,
-                                       BTREE_INSERT_ATOMIC|
-                                       BTREE_INSERT_NOUNLOCK);
-       } while (ret == -EINTR);
-
-       if (likely(!ret))
+                                       inode->v.i_ino, &dir_u, &inode_u,
+                                       &dentry->d_name));
+
+       if (likely(!ret)) {
+               BUG_ON(inode_u.bi_inum != inode->v.i_ino);
+
+               journal_seq_copy(c, inode, dir->ei_journal_seq);
+               bch2_inode_update_after_write(c, dir, &dir_u,
+                                             ATTR_MTIME|ATTR_CTIME);
                bch2_inode_update_after_write(c, inode, &inode_u, ATTR_CTIME);
+       }
 
        bch2_trans_exit(&trans);
        mutex_unlock(&inode->ei_update_lock);
@@ -388,23 +464,17 @@ static int bch2_unlink(struct inode *vdir, struct dentry *dentry)
        bch2_lock_inodes(INODE_UPDATE_LOCK, dir, inode);
        bch2_trans_init(&trans, c, 4, 1024);
 
-       do {
-               bch2_trans_begin(&trans);
-
-               ret   = bch2_unlink_trans(&trans,
+       ret = __bch2_trans_do(&trans, NULL, &dir->ei_journal_seq,
+                             BTREE_INSERT_NOUNLOCK|
+                             BTREE_INSERT_NOFAIL,
+                       bch2_unlink_trans(&trans,
                                          dir->v.i_ino, &dir_u,
-                                         &inode_u, &dentry->d_name) ?:
-                       bch2_trans_commit(&trans, NULL,
-                                         &dir->ei_journal_seq,
-                                         BTREE_INSERT_ATOMIC|
-                                         BTREE_INSERT_NOUNLOCK|
-                                         BTREE_INSERT_NOFAIL);
-       } while (ret == -EINTR);
+                                         &inode_u, &dentry->d_name));
 
        if (likely(!ret)) {
                BUG_ON(inode_u.bi_inum != inode->v.i_ino);
 
-               journal_seq_copy(inode, dir->ei_journal_seq);
+               journal_seq_copy(c, inode, dir->ei_journal_seq);
                bch2_inode_update_after_write(c, dir, &dir_u,
                                              ATTR_MTIME|ATTR_CTIME);
                bch2_inode_update_after_write(c, inode, &inode_u,
@@ -439,7 +509,7 @@ static int bch2_symlink(struct inode *vdir, struct dentry *dentry,
        if (unlikely(ret))
                goto err;
 
-       journal_seq_copy(dir, inode->ei_journal_seq);
+       journal_seq_copy(c, dir, inode->ei_journal_seq);
 
        ret = __bch2_link(c, inode, dir, dentry);
        if (unlikely(ret))
@@ -513,22 +583,16 @@ static int bch2_rename2(struct inode *src_vdir, struct dentry *src_dentry,
                        goto err;
        }
 
-retry:
-       bch2_trans_begin(&trans);
-       ret   = bch2_rename_trans(&trans,
-                                 src_dir->v.i_ino, &src_dir_u,
-                                 dst_dir->v.i_ino, &dst_dir_u,
-                                 &src_inode_u,
-                                 &dst_inode_u,
-                                 &src_dentry->d_name,
-                                 &dst_dentry->d_name,
-                                 mode) ?:
-               bch2_trans_commit(&trans, NULL,
-                                 &journal_seq,
-                                 BTREE_INSERT_ATOMIC|
-                                 BTREE_INSERT_NOUNLOCK);
-       if (ret == -EINTR)
-               goto retry;
+       ret = __bch2_trans_do(&trans, NULL, &journal_seq,
+                             BTREE_INSERT_NOUNLOCK,
+                       bch2_rename_trans(&trans,
+                                         src_dir->v.i_ino, &src_dir_u,
+                                         dst_dir->v.i_ino, &dst_dir_u,
+                                         &src_inode_u,
+                                         &dst_inode_u,
+                                         &src_dentry->d_name,
+                                         &dst_dentry->d_name,
+                                         mode));
        if (unlikely(ret))
                goto err;
 
@@ -538,22 +602,22 @@ retry:
 
        bch2_inode_update_after_write(c, src_dir, &src_dir_u,
                                      ATTR_MTIME|ATTR_CTIME);
-       journal_seq_copy(src_dir, journal_seq);
+       journal_seq_copy(c, src_dir, journal_seq);
 
        if (src_dir != dst_dir) {
                bch2_inode_update_after_write(c, dst_dir, &dst_dir_u,
                                              ATTR_MTIME|ATTR_CTIME);
-               journal_seq_copy(dst_dir, journal_seq);
+               journal_seq_copy(c, dst_dir, journal_seq);
        }
 
        bch2_inode_update_after_write(c, src_inode, &src_inode_u,
                                      ATTR_CTIME);
-       journal_seq_copy(src_inode, journal_seq);
+       journal_seq_copy(c, src_inode, journal_seq);
 
        if (dst_inode) {
                bch2_inode_update_after_write(c, dst_inode, &dst_inode_u,
                                              ATTR_CTIME);
-               journal_seq_copy(dst_inode, journal_seq);
+               journal_seq_copy(c, dst_inode, journal_seq);
        }
 err:
        bch2_trans_exit(&trans);
@@ -650,7 +714,7 @@ retry:
        bch2_setattr_copy(inode, &inode_u, attr);
 
        if (attr->ia_valid & ATTR_MODE) {
-               ret = bch2_acl_chmod(&trans, inode, inode_u.bi_mode, &acl);
+               ret = bch2_acl_chmod(&trans, &inode_u, inode_u.bi_mode, &acl);
                if (ret)
                        goto btree_err;
        }
@@ -658,10 +722,11 @@ retry:
        ret =   bch2_inode_write(&trans, inode_iter, &inode_u) ?:
                bch2_trans_commit(&trans, NULL,
                                  &inode->ei_journal_seq,
-                                 BTREE_INSERT_ATOMIC|
                                  BTREE_INSERT_NOUNLOCK|
                                  BTREE_INSERT_NOFAIL);
 btree_err:
+       bch2_trans_iter_put(&trans, inode_iter);
+
        if (ret == -EINTR)
                goto retry;
        if (unlikely(ret))
@@ -706,10 +771,15 @@ static int bch2_getattr(const struct path *path, struct kstat *stat,
 
        if (inode->ei_inode.bi_flags & BCH_INODE_IMMUTABLE)
                stat->attributes |= STATX_ATTR_IMMUTABLE;
+       stat->attributes_mask    |= STATX_ATTR_IMMUTABLE;
+
        if (inode->ei_inode.bi_flags & BCH_INODE_APPEND)
                stat->attributes |= STATX_ATTR_APPEND;
+       stat->attributes_mask    |= STATX_ATTR_APPEND;
+
        if (inode->ei_inode.bi_flags & BCH_INODE_NODUMP)
                stat->attributes |= STATX_ATTR_NODUMP;
+       stat->attributes_mask    |= STATX_ATTR_NODUMP;
 
        return 0;
 }
@@ -747,7 +817,7 @@ static int bch2_fill_extent(struct bch_fs *c,
                            struct fiemap_extent_info *info,
                            struct bkey_s_c k, unsigned flags)
 {
-       if (bkey_extent_is_data(k.k)) {
+       if (bkey_extent_is_direct_data(k.k)) {
                struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
                const union bch_extent_entry *entry;
                struct extent_ptr_decoded p;
@@ -778,6 +848,12 @@ static int bch2_fill_extent(struct bch_fs *c,
                }
 
                return 0;
+       } else if (bkey_extent_is_inline_data(k.k)) {
+               return fiemap_fill_next_extent(info,
+                                              bkey_start_offset(k.k) << 9,
+                                              0, k.k->size << 9,
+                                              flags|
+                                              FIEMAP_EXTENT_DATA_INLINE);
        } else if (k.k->type == KEY_TYPE_reservation) {
                return fiemap_fill_next_extent(info,
                                               bkey_start_offset(k.k) << 9,
@@ -798,81 +874,91 @@ static int bch2_fiemap(struct inode *vinode, struct fiemap_extent_info *info,
        struct btree_trans trans;
        struct btree_iter *iter;
        struct bkey_s_c k;
-       BKEY_PADDED(k) cur, prev;
+       struct bkey_buf cur, prev;
        struct bpos end = POS(ei->v.i_ino, (start + len) >> 9);
        unsigned offset_into_extent, sectors;
        bool have_extent = false;
        int ret = 0;
 
+       ret = fiemap_prep(&ei->v, info, start, &len, FIEMAP_FLAG_SYNC);
+       if (ret)
+               return ret;
+
        if (start + len < start)
                return -EINVAL;
 
+       bch2_bkey_buf_init(&cur);
+       bch2_bkey_buf_init(&prev);
        bch2_trans_init(&trans, c, 0, 0);
 
-       iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS,
+       iter = bch2_trans_get_iter(&trans, BTREE_ID_extents,
                                   POS(ei->v.i_ino, start >> 9), 0);
 retry:
        while ((k = bch2_btree_iter_peek(iter)).k &&
               !(ret = bkey_err(k)) &&
               bkey_cmp(iter->pos, end) < 0) {
+               enum btree_id data_btree = BTREE_ID_extents;
+
                if (!bkey_extent_is_data(k.k) &&
                    k.k->type != KEY_TYPE_reservation) {
                        bch2_btree_iter_next(iter);
                        continue;
                }
 
-               bkey_reassemble(&cur.k, k);
-               k = bkey_i_to_s_c(&cur.k);
-
                offset_into_extent      = iter->pos.offset -
                        bkey_start_offset(k.k);
                sectors                 = k.k->size - offset_into_extent;
 
-               ret = bch2_read_indirect_extent(&trans,
-                                       &offset_into_extent, &cur.k);
+               bch2_bkey_buf_reassemble(&cur, c, k);
+
+               ret = bch2_read_indirect_extent(&trans, &data_btree,
+                                       &offset_into_extent, &cur);
                if (ret)
                        break;
 
+               k = bkey_i_to_s_c(cur.k);
+               bch2_bkey_buf_realloc(&prev, c, k.k->u64s);
+
                sectors = min(sectors, k.k->size - offset_into_extent);
 
-               if (offset_into_extent)
-                       bch2_cut_front(POS(k.k->p.inode,
-                                          bkey_start_offset(k.k) +
-                                          offset_into_extent),
-                                      &cur.k);
-               bch2_key_resize(&cur.k.k, sectors);
-               cur.k.k.p = iter->pos;
-               cur.k.k.p.offset += cur.k.k.size;
+               bch2_cut_front(POS(k.k->p.inode,
+                                  bkey_start_offset(k.k) +
+                                  offset_into_extent),
+                              cur.k);
+               bch2_key_resize(&cur.k->k, sectors);
+               cur.k->k.p = iter->pos;
+               cur.k->k.p.offset += cur.k->k.size;
 
                if (have_extent) {
                        ret = bch2_fill_extent(c, info,
-                                       bkey_i_to_s_c(&prev.k), 0);
+                                       bkey_i_to_s_c(prev.k), 0);
                        if (ret)
                                break;
                }
 
-               bkey_copy(&prev.k, &cur.k);
+               bkey_copy(prev.k, cur.k);
                have_extent = true;
 
-               if (k.k->type == KEY_TYPE_reflink_v)
-                       bch2_btree_iter_set_pos(iter, k.k->p);
-               else
-                       bch2_btree_iter_next(iter);
+               bch2_btree_iter_set_pos(iter,
+                       POS(iter->pos.inode, iter->pos.offset + sectors));
        }
 
        if (ret == -EINTR)
                goto retry;
 
        if (!ret && have_extent)
-               ret = bch2_fill_extent(c, info, bkey_i_to_s_c(&prev.k),
+               ret = bch2_fill_extent(c, info, bkey_i_to_s_c(prev.k),
                                       FIEMAP_EXTENT_LAST);
 
+       bch2_trans_iter_put(&trans, iter);
        ret = bch2_trans_exit(&trans) ?: ret;
+       bch2_bkey_buf_exit(&cur, c);
+       bch2_bkey_buf_exit(&prev, c);
        return ret < 0 ? ret : 0;
 }
 
 static const struct vm_operations_struct bch_vm_ops = {
-       .fault          = filemap_fault,
+       .fault          = bch2_page_fault,
        .map_pages      = filemap_map_pages,
        .page_mkwrite   = bch2_page_mkwrite,
 };
@@ -906,13 +992,16 @@ static int bch2_vfs_readdir(struct file *file, struct dir_context *ctx)
 
 static const struct file_operations bch_file_operations = {
        .llseek         = bch2_llseek,
-       .read_iter      = generic_file_read_iter,
+       .read_iter      = bch2_read_iter,
        .write_iter     = bch2_write_iter,
        .mmap           = bch2_mmap,
        .open           = generic_file_open,
        .fsync          = bch2_fsync,
        .splice_read    = generic_file_splice_read,
+#if 0
+       /* Busted: */
        .splice_write   = iter_file_splice_write,
+#endif
        .fallocate      = bch2_fallocate_dispatch,
        .unlocked_ioctl = bch2_fs_file_ioctl,
 #ifdef CONFIG_COMPAT
@@ -988,13 +1077,13 @@ static const struct address_space_operations bch_address_space_operations = {
        .writepage      = bch2_writepage,
        .readpage       = bch2_readpage,
        .writepages     = bch2_writepages,
-       .readpages      = bch2_readpages,
+       .readahead      = bch2_readahead,
        .set_page_dirty = __set_page_dirty_nobuffers,
        .write_begin    = bch2_write_begin,
        .write_end      = bch2_write_end,
        .invalidatepage = bch2_invalidatepage,
        .releasepage    = bch2_releasepage,
-       .direct_IO      = bch2_direct_IO,
+       .direct_IO      = noop_direct_IO,
 #ifdef CONFIG_MIGRATION
        .migratepage    = bch2_migrate_page,
 #endif
@@ -1053,9 +1142,9 @@ static void bch2_vfs_inode_init(struct bch_fs *c,
        inode->v.i_generation   = bi->bi_generation;
        inode->v.i_size         = bi->bi_size;
 
+       inode->ei_flags         = 0;
        inode->ei_journal_seq   = 0;
        inode->ei_quota_reserved = 0;
-       inode->ei_str_hash      = bch2_hash_info_init(c, bi);
        inode->ei_qid           = bch_qid(bi);
 
        inode->v.i_mapping->a_ops = &bch_address_space_operations;
@@ -1090,6 +1179,7 @@ static struct inode *bch2_alloc_inode(struct super_block *sb)
 
        inode_init_once(&inode->v);
        mutex_init(&inode->ei_update_lock);
+       pagecache_lock_init(&inode->ei_pagecache_lock);
        mutex_init(&inode->ei_quota_lock);
        inode->ei_journal_seq = 0;
 
@@ -1153,7 +1243,7 @@ static void bch2_evict_inode(struct inode *vinode)
                                KEY_TYPE_QUOTA_WARN);
                bch2_quota_acct(c, inode->ei_qid, Q_INO, -1,
                                KEY_TYPE_QUOTA_WARN);
-               bch2_inode_rm(c, inode->v.i_ino);
+               bch2_inode_rm(c, inode->v.i_ino, true);
        }
 }
 
@@ -1163,6 +1253,11 @@ static int bch2_statfs(struct dentry *dentry, struct kstatfs *buf)
        struct bch_fs *c = sb->s_fs_info;
        struct bch_fs_usage_short usage = bch2_fs_usage_read_short(c);
        unsigned shift = sb->s_blocksize_bits - 9;
+       /*
+        * this assumes inodes take up 64 bytes, which is a decent average
+        * number:
+        */
+       u64 avail_inodes = ((usage.capacity - usage.used) << 3);
        u64 fsid;
 
        buf->f_type     = BCACHEFS_STATFS_MAGIC;
@@ -1170,8 +1265,9 @@ static int bch2_statfs(struct dentry *dentry, struct kstatfs *buf)
        buf->f_blocks   = usage.capacity >> shift;
        buf->f_bfree    = (usage.capacity - usage.used) >> shift;
        buf->f_bavail   = buf->f_bfree;
-       buf->f_files    = usage.nr_inodes;
-       buf->f_ffree    = U64_MAX;
+
+       buf->f_files    = usage.nr_inodes + avail_inodes;
+       buf->f_ffree    = avail_inodes;
 
        fsid = le64_to_cpup((void *) c->sb.user_uuid.b) ^
               le64_to_cpup((void *) c->sb.user_uuid.b + sizeof(u64));
@@ -1207,91 +1303,36 @@ static struct bch_fs *bch2_path_to_fs(const char *dev)
 
        c = bch2_bdev_to_fs(bdev);
        bdput(bdev);
-       return c ?: ERR_PTR(-ENOENT);
-}
-
-static struct bch_fs *__bch2_open_as_blockdevs(const char *dev_name, char * const *devs,
-                                              unsigned nr_devs, struct bch_opts opts)
-{
-       struct bch_fs *c, *c1, *c2;
-       size_t i;
-
-       if (!nr_devs)
-               return ERR_PTR(-EINVAL);
-
-       c = bch2_fs_open(devs, nr_devs, opts);
-
-       if (IS_ERR(c) && PTR_ERR(c) == -EBUSY) {
-               /*
-                * Already open?
-                * Look up each block device, make sure they all belong to a
-                * filesystem and they all belong to the _same_ filesystem
-                */
-
-               c1 = bch2_path_to_fs(devs[0]);
-               if (IS_ERR(c1))
-                       return c;
-
-               for (i = 1; i < nr_devs; i++) {
-                       c2 = bch2_path_to_fs(devs[i]);
-                       if (!IS_ERR(c2))
-                               closure_put(&c2->cl);
-
-                       if (c1 != c2) {
-                               closure_put(&c1->cl);
-                               return c;
-                       }
-               }
-
-               c = c1;
-       }
-
-       if (IS_ERR(c))
-               return c;
-
-       mutex_lock(&c->state_lock);
-
-       if (!test_bit(BCH_FS_STARTED, &c->flags)) {
-               mutex_unlock(&c->state_lock);
+       if (c)
                closure_put(&c->cl);
-               pr_err("err mounting %s: incomplete filesystem", dev_name);
-               return ERR_PTR(-EINVAL);
-       }
-
-       mutex_unlock(&c->state_lock);
-
-       set_bit(BCH_FS_BDEV_MOUNTED, &c->flags);
-       return c;
+       return c ?: ERR_PTR(-ENOENT);
 }
 
-static struct bch_fs *bch2_open_as_blockdevs(const char *_dev_name,
-                                            struct bch_opts opts)
+static char **split_devs(const char *_dev_name, unsigned *nr)
 {
        char *dev_name = NULL, **devs = NULL, *s;
-       struct bch_fs *c = ERR_PTR(-ENOMEM);
        size_t i, nr_devs = 0;
 
        dev_name = kstrdup(_dev_name, GFP_KERNEL);
        if (!dev_name)
-               goto err;
+               return NULL;
 
        for (s = dev_name; s; s = strchr(s + 1, ':'))
                nr_devs++;
 
-       devs = kcalloc(nr_devs, sizeof(const char *), GFP_KERNEL);
-       if (!devs)
-               goto err;
+       devs = kcalloc(nr_devs + 1, sizeof(const char *), GFP_KERNEL);
+       if (!devs) {
+               kfree(dev_name);
+               return NULL;
+       }
 
        for (i = 0, s = dev_name;
             s;
             (s = strchr(s, ':')) && (*s++ = '\0'))
                devs[i++] = s;
 
-       c = __bch2_open_as_blockdevs(_dev_name, devs, nr_devs, opts);
-err:
-       kfree(devs);
-       kfree(dev_name);
-       return c;
+       *nr = nr_devs;
+       return devs;
 }
 
 static int bch2_remount(struct super_block *sb, int *flags, char *data)
@@ -1302,12 +1343,12 @@ static int bch2_remount(struct super_block *sb, int *flags, char *data)
 
        opt_set(opts, read_only, (*flags & SB_RDONLY) != 0);
 
-       ret = bch2_parse_mount_opts(&opts, data);
+       ret = bch2_parse_mount_opts(c, &opts, data);
        if (ret)
                return ret;
 
        if (opts.read_only != c->opts.read_only) {
-               mutex_lock(&c->state_lock);
+               down_write(&c->state_lock);
 
                if (opts.read_only) {
                        bch2_fs_read_only(c);
@@ -1317,7 +1358,7 @@ static int bch2_remount(struct super_block *sb, int *flags, char *data)
                        ret = bch2_fs_read_write(c);
                        if (ret) {
                                bch_err(c, "error going rw: %i", ret);
-                               mutex_unlock(&c->state_lock);
+                               up_write(&c->state_lock);
                                return -EINVAL;
                        }
 
@@ -1326,7 +1367,7 @@ static int bch2_remount(struct super_block *sb, int *flags, char *data)
 
                c->opts.read_only = opts.read_only;
 
-               mutex_unlock(&c->state_lock);
+               up_write(&c->state_lock);
        }
 
        if (opts.errors >= 0)
@@ -1335,6 +1376,24 @@ static int bch2_remount(struct super_block *sb, int *flags, char *data)
        return ret;
 }
 
+static int bch2_show_devname(struct seq_file *seq, struct dentry *root)
+{
+       struct bch_fs *c = root->d_sb->s_fs_info;
+       struct bch_dev *ca;
+       unsigned i;
+       bool first = true;
+
+       for_each_online_member(ca, c, i) {
+               if (!first)
+                       seq_putc(seq, ':');
+               first = false;
+               seq_puts(seq, "/dev/");
+               seq_puts(seq, ca->name);
+       }
+
+       return 0;
+}
+
 static int bch2_show_options(struct seq_file *seq, struct dentry *root)
 {
        struct bch_fs *c = root->d_sb->s_fs_info;
@@ -1358,7 +1417,13 @@ static int bch2_show_options(struct seq_file *seq, struct dentry *root)
        }
 
        return 0;
+}
 
+static void bch2_put_super(struct super_block *sb)
+{
+       struct bch_fs *c = sb->s_fs_info;
+
+       __bch2_fs_stop(c);
 }
 
 static const struct super_operations bch_super_operations = {
@@ -1368,26 +1433,42 @@ static const struct super_operations bch_super_operations = {
        .evict_inode    = bch2_evict_inode,
        .sync_fs        = bch2_sync_fs,
        .statfs         = bch2_statfs,
+       .show_devname   = bch2_show_devname,
        .show_options   = bch2_show_options,
        .remount_fs     = bch2_remount,
-#if 0
        .put_super      = bch2_put_super,
+#if 0
        .freeze_fs      = bch2_freeze,
        .unfreeze_fs    = bch2_unfreeze,
 #endif
 };
 
-static int bch2_test_super(struct super_block *s, void *data)
-{
-       return s->s_fs_info == data;
-}
-
 static int bch2_set_super(struct super_block *s, void *data)
 {
        s->s_fs_info = data;
        return 0;
 }
 
+static int bch2_noset_super(struct super_block *s, void *data)
+{
+       return -EBUSY;
+}
+
+static int bch2_test_super(struct super_block *s, void *data)
+{
+       struct bch_fs *c = s->s_fs_info;
+       struct bch_fs **devs = data;
+       unsigned i;
+
+       if (!c)
+               return false;
+
+       for (i = 0; devs[i]; i++)
+               if (c != devs[i])
+                       return false;
+       return true;
+}
+
 static struct dentry *bch2_mount(struct file_system_type *fs_type,
                                 int flags, const char *dev_name, void *data)
 {
@@ -1396,30 +1477,65 @@ static struct dentry *bch2_mount(struct file_system_type *fs_type,
        struct super_block *sb;
        struct inode *vinode;
        struct bch_opts opts = bch2_opts_empty();
-       unsigned i;
+       char **devs;
+       struct bch_fs **devs_to_fs = NULL;
+       unsigned i, nr_devs;
        int ret;
 
        opt_set(opts, read_only, (flags & SB_RDONLY) != 0);
 
-       ret = bch2_parse_mount_opts(&opts, data);
+       ret = bch2_parse_mount_opts(NULL, &opts, data);
        if (ret)
                return ERR_PTR(ret);
 
-       c = bch2_open_as_blockdevs(dev_name, opts);
-       if (IS_ERR(c))
-               return ERR_CAST(c);
+       devs = split_devs(dev_name, &nr_devs);
+       if (!devs)
+               return ERR_PTR(-ENOMEM);
 
-       sb = sget(fs_type, bch2_test_super, bch2_set_super, flags|SB_NOSEC, c);
-       if (IS_ERR(sb)) {
-               closure_put(&c->cl);
-               return ERR_CAST(sb);
+       devs_to_fs = kcalloc(nr_devs + 1, sizeof(void *), GFP_KERNEL);
+       if (!devs_to_fs) {
+               sb = ERR_PTR(-ENOMEM);
+               goto got_sb;
        }
 
-       BUG_ON(sb->s_fs_info != c);
+       for (i = 0; i < nr_devs; i++)
+               devs_to_fs[i] = bch2_path_to_fs(devs[i]);
 
-       if (sb->s_root) {
-               closure_put(&c->cl);
+       sb = sget(fs_type, bch2_test_super, bch2_noset_super,
+                 flags|SB_NOSEC, devs_to_fs);
+       if (!IS_ERR(sb))
+               goto got_sb;
+
+       c = bch2_fs_open(devs, nr_devs, opts);
+       if (IS_ERR(c)) {
+               sb = ERR_CAST(c);
+               goto got_sb;
+       }
+
+       /* Some options can't be parsed until after the fs is started: */
+       ret = bch2_parse_mount_opts(c, &opts, data);
+       if (ret) {
+               bch2_fs_stop(c);
+               sb = ERR_PTR(ret);
+               goto got_sb;
+       }
+
+       bch2_opts_apply(&c->opts, opts);
 
+       sb = sget(fs_type, NULL, bch2_set_super, flags|SB_NOSEC, c);
+       if (IS_ERR(sb))
+               bch2_fs_stop(c);
+got_sb:
+       kfree(devs_to_fs);
+       kfree(devs[0]);
+       kfree(devs);
+
+       if (IS_ERR(sb))
+               return ERR_CAST(sb);
+
+       c = sb->s_fs_info;
+
+       if (sb->s_root) {
                if ((flags ^ sb->s_flags) & SB_RDONLY) {
                        ret = -EBUSY;
                        goto err_put_super;
@@ -1446,8 +1562,6 @@ static struct dentry *bch2_mount(struct file_system_type *fs_type,
        if (ret)
                goto err_put_super;
 
-       sb->s_bdi->congested_fn         = bch2_congested;
-       sb->s_bdi->congested_data       = c;
        sb->s_bdi->ra_pages             = VM_READAHEAD_PAGES;
 
        for_each_online_member(ca, c, i) {
@@ -1494,11 +1608,7 @@ static void bch2_kill_sb(struct super_block *sb)
        struct bch_fs *c = sb->s_fs_info;
 
        generic_shutdown_super(sb);
-
-       if (test_bit(BCH_FS_BDEV_MOUNTED, &c->flags))
-               bch2_fs_stop(c);
-       else
-               closure_put(&c->cl);
+       bch2_fs_free(c);
 }
 
 static struct file_system_type bcache_fs_type = {