From 0d72ab35a925d66b044cb62b709e53141c3f0143 Mon Sep 17 00:00:00 2001
From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Fri, 29 Dec 2023 21:16:32 -0500
Subject: [PATCH] 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>
---
fs/bcachefs/acl.c | 3 ++-
fs/bcachefs/fs-ioctl.c | 12 +++++-------
fs/bcachefs/fs.c | 38 +++++++++++++++++++++++++++++++++-----
fs/bcachefs/subvolume.c | 18 ++++++++++++++++++
fs/bcachefs/subvolume.h | 3 +++
fs/bcachefs/xattr.c | 3 ++-
6 files changed, 63 insertions(+), 14 deletions(-)
diff --git a/fs/bcachefs/acl.c b/fs/bcachefs/acl.c
index f3809897f00a7..3640f417cce11 100644
--- 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 a70b7a03057d7..14d5cc6f90d7d 100644
--- 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 ba93e32d7708e..49da8db1d9e9f 100644
--- 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 fccd25aa32426..22b34a8e4d6ef 100644
--- 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 a1003d30ab0a0..a6f56f66e27cb 100644
--- 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 79d982674c180..5a1858fb9879a 100644
--- 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;
--
2.30.2