bcachefs: make RO snapshots actually RO

Add checks to all the VFS paths for "are we in a RO snapshot?".

Note - we don't check this when setting inode options via our xattr
interface, since those generally only affect data placement, not
contents of data.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Reported-by: "Carl E. Thompson" <list-bcachefs@carlthompson.net>

diff --git a/fs/bcachefs/acl.c b/fs/bcachefs/acl.c
index f3809897f00a7d5c98c7f33f36bc2fd587939dcc..3640f417cce118b06e43ae4c8b38bb275b0097fc 100644 (file)
--- a/fs/bcachefs/acl.c
+++ b/fs/bcachefs/acl.c
@@ -366,7 +366,8 @@ retry:
        bch2_trans_begin(trans);
        acl = _acl;
 
-       ret = bch2_inode_peek(trans, &inode_iter, &inode_u, inode_inum(inode),
+       ret   = bch2_subvol_is_ro_trans(trans, inode->ei_subvol) ?:
+               bch2_inode_peek(trans, &inode_iter, &inode_u, inode_inum(inode),
                              BTREE_ITER_INTENT);
        if (ret)
                goto btree_err;

diff --git a/fs/bcachefs/fs-ioctl.c b/fs/bcachefs/fs-ioctl.c
index a70b7a03057d7fdd9921a7e3e4fdddd742866508..14d5cc6f90d7ddb62e4ff1ecd365c3b34e972794 100644 (file)
--- a/fs/bcachefs/fs-ioctl.c
+++ b/fs/bcachefs/fs-ioctl.c
@@ -100,7 +100,8 @@ static int bch2_ioc_setflags(struct bch_fs *c,
        }
 
        mutex_lock(&inode->ei_update_lock);
-       ret = bch2_write_inode(c, inode, bch2_inode_flags_set, &s,
+       ret   = bch2_subvol_is_ro(c, inode->ei_subvol) ?:
+               bch2_write_inode(c, inode, bch2_inode_flags_set, &s,
                               ATTR_CTIME);
        mutex_unlock(&inode->ei_update_lock);
 
@@ -183,13 +184,10 @@ static int bch2_ioc_fssetxattr(struct bch_fs *c,
        }
 
        mutex_lock(&inode->ei_update_lock);
-       ret = bch2_set_projid(c, inode, fa.fsx_projid);
-       if (ret)
-               goto err_unlock;
-
-       ret = bch2_write_inode(c, inode, fssetxattr_inode_update_fn, &s,
+       ret   = bch2_subvol_is_ro(c, inode->ei_subvol) ?:
+               bch2_set_projid(c, inode, fa.fsx_projid) ?:
+               bch2_write_inode(c, inode, fssetxattr_inode_update_fn, &s,
                               ATTR_CTIME);
-err_unlock:
        mutex_unlock(&inode->ei_update_lock);
 err:
        inode_unlock(&inode->v);

diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index ba93e32d7708e6b877d627971b5b63eefa632bc4..49da8db1d9e9fc21325b7a5602cdf441ff494285 100644 (file)
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -258,7 +258,8 @@ __bch2_create(struct mnt_idmap *idmap,
 retry:
        bch2_trans_begin(trans);
 
-       ret   = bch2_create_trans(trans,
+       ret   = bch2_subvol_is_ro_trans(trans, dir->ei_subvol) ?:
+               bch2_create_trans(trans,
                                  inode_inum(dir), &dir_u, &inode_u,
                                  !(flags & BCH_CREATE_TMPFILE)
                                  ? &dentry->d_name : NULL,
@@ -430,7 +431,9 @@ static int bch2_link(struct dentry *old_dentry, struct inode *vdir,
 
        lockdep_assert_held(&inode->v.i_rwsem);
 
-       ret = __bch2_link(c, inode, dir, dentry);
+       ret   = bch2_subvol_is_ro(c, dir->ei_subvol) ?:
+               bch2_subvol_is_ro(c, inode->ei_subvol) ?:
+               __bch2_link(c, inode, dir, dentry);
        if (unlikely(ret))
                return ret;
 
@@ -481,7 +484,11 @@ err:
 
 static int bch2_unlink(struct inode *vdir, struct dentry *dentry)
 {
-       return __bch2_unlink(vdir, dentry, false);
+       struct bch_inode_info *dir= to_bch_ei(vdir);
+       struct bch_fs *c = dir->v.i_sb->s_fs_info;
+
+       return bch2_subvol_is_ro(c, dir->ei_subvol) ?:
+               __bch2_unlink(vdir, dentry, false);
 }
 
 static int bch2_symlink(struct mnt_idmap *idmap,
@@ -562,6 +569,11 @@ static int bch2_rename2(struct mnt_idmap *idmap,
                         src_inode,
                         dst_inode);
 
+       ret   = bch2_subvol_is_ro_trans(trans, src_dir->ei_subvol) ?:
+               bch2_subvol_is_ro_trans(trans, dst_dir->ei_subvol);
+       if (ret)
+               goto err;
+
        if (inode_attr_changing(dst_dir, src_inode, Inode_opt_project)) {
                ret = bch2_fs_quota_transfer(c, src_inode,
                                             dst_dir->ei_qid,
@@ -783,11 +795,13 @@ static int bch2_setattr(struct mnt_idmap *idmap,
                        struct dentry *dentry, struct iattr *iattr)
 {
        struct bch_inode_info *inode = to_bch_ei(dentry->d_inode);
+       struct bch_fs *c = inode->v.i_sb->s_fs_info;
        int ret;
 
        lockdep_assert_held(&inode->v.i_rwsem);
 
-       ret = setattr_prepare(idmap, dentry, iattr);
+       ret   = bch2_subvol_is_ro(c, inode->ei_subvol) ?:
+               setattr_prepare(idmap, dentry, iattr);
        if (ret)
                return ret;
 
@@ -1010,12 +1024,26 @@ static int bch2_vfs_readdir(struct file *file, struct dir_context *ctx)
        return bch2_err_class(ret);
 }
 
+static int bch2_open(struct inode *vinode, struct file *file)
+{
+       if (file->f_flags & (O_WRONLY|O_RDWR)) {
+               struct bch_inode_info *inode = to_bch_ei(vinode);
+               struct bch_fs *c = inode->v.i_sb->s_fs_info;
+
+               int ret = bch2_subvol_is_ro(c, inode->ei_subvol);
+               if (ret)
+                       return ret;
+       }
+
+       return generic_file_open(vinode, file);
+}
+
 static const struct file_operations bch_file_operations = {
+       .open           = bch2_open,
        .llseek         = bch2_llseek,
        .read_iter      = bch2_read_iter,
        .write_iter     = bch2_write_iter,
        .mmap           = bch2_mmap,
-       .open           = generic_file_open,
        .fsync          = bch2_fsync,
        .splice_read    = filemap_splice_read,
        .splice_write   = iter_file_splice_write,

diff --git a/fs/bcachefs/subvolume.c b/fs/bcachefs/subvolume.c
index fccd25aa32426a4233882a9d97cc214cba9dc6f5..22b34a8e4d6efe9e3cb67d77bafa591eeaf22b02 100644 (file)
--- a/fs/bcachefs/subvolume.c
+++ b/fs/bcachefs/subvolume.c
@@ -146,6 +146,24 @@ int bch2_subvolume_get(struct btree_trans *trans, unsigned subvol,
        return bch2_subvolume_get_inlined(trans, subvol, inconsistent_if_not_found, iter_flags, s);
 }
 
+int bch2_subvol_is_ro_trans(struct btree_trans *trans, u32 subvol)
+{
+       struct bch_subvolume s;
+       int ret = bch2_subvolume_get_inlined(trans, subvol, true, 0, &s);
+       if (ret)
+               return ret;
+
+       if (BCH_SUBVOLUME_RO(&s))
+               return -EROFS;
+       return 0;
+}
+
+int bch2_subvol_is_ro(struct bch_fs *c, u32 subvol)
+{
+       return bch2_trans_do(c, NULL, NULL, 0,
+               bch2_subvol_is_ro_trans(trans, subvol));
+}
+
 int bch2_snapshot_get_subvol(struct btree_trans *trans, u32 snapshot,
                             struct bch_subvolume *subvol)
 {

diff --git a/fs/bcachefs/subvolume.h b/fs/bcachefs/subvolume.h
index a1003d30ab0a0c613b644c54fba09964d9ec4b29..a6f56f66e27cb7699402f089ef89a2f1355077c4 100644 (file)
--- a/fs/bcachefs/subvolume.h
+++ b/fs/bcachefs/subvolume.h
@@ -23,6 +23,9 @@ int bch2_subvolume_get(struct btree_trans *, unsigned,
                       bool, int, struct bch_subvolume *);
 int bch2_subvolume_get_snapshot(struct btree_trans *, u32, u32 *);
 
+int bch2_subvol_is_ro_trans(struct btree_trans *, u32);
+int bch2_subvol_is_ro(struct bch_fs *, u32);
+
 int bch2_delete_dead_snapshots(struct bch_fs *);
 void bch2_delete_dead_snapshots_async(struct bch_fs *);
 

diff --git a/fs/bcachefs/xattr.c b/fs/bcachefs/xattr.c
index 79d982674c180307f5d5a4da42fabaa480878573..5a1858fb9879afd1c70c3d5a64883315090d6dbe 100644 (file)
--- a/fs/bcachefs/xattr.c
+++ b/fs/bcachefs/xattr.c
@@ -176,7 +176,8 @@ int bch2_xattr_set(struct btree_trans *trans, subvol_inum inum,
        struct btree_iter inode_iter = { NULL };
        int ret;
 
-       ret = bch2_inode_peek(trans, &inode_iter, inode_u, inum, BTREE_ITER_INTENT);
+       ret   = bch2_subvol_is_ro_trans(trans, inum.subvol) ?:
+               bch2_inode_peek(trans, &inode_iter, inode_u, inum, BTREE_ITER_INTENT);
        if (ret)
                return ret;