[PATCH v4 3/6] btrfs: reject file operations if in shutdown state

Qu Wenruo
2025-07-04T00:43:09Z

This includes the following callbacks of file_operations:

- read_iter()
- write_iter()
- mmap()
- open()
- remap_file_range()
- uring_cmd()
- splice_read()
This requires a small wrapper to do the extra shutdown check, then call
the regular filemap_splice_read() function

This should reject most of the file operations on a shutdown btrfs.

The callback ioctl() is intentionally skipped, as ext4 doesn't do the
shutdown check on ioctl() either, thus I believe there is some special
require for ioctl() callback even if the fs is fully shutdown.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
fs/btrfs/file.c | 25 ++++++++++++++++++++++++-
fs/btrfs/ioctl.c | 3 +++
fs/btrfs/reflink.c | 3 +++
3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 05b046c6806f..cb7d1d53fc13 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1419,6 +1419,8 @@ ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
struct btrfs_inode *inode = BTRFS_I(file_inode(file));
ssize_t num_written, num_sync;

+ if (unlikely(btrfs_is_shutdown(inode->root->fs_info)))
+ return -EIO;
/*
* If the fs flips readonly due to some impossible error, although we
* have opened a file as writable, we have to stop this write operation
@@ -1981,6 +1983,8 @@ static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct address_space *mapping = filp->f_mapping;

+ if (unlikely(btrfs_is_shutdown(inode_to_fs_info(file_inode(filp)))))
+ return -EIO;
if (!mapping->a_ops->read_folio)
return -ENOEXEC;

@@ -3040,6 +3044,9 @@ static long btrfs_fallocate(struct file *file, int mode,
int blocksize = BTRFS_I(inode)->root->fs_info->sectorsize;
int ret;

+ if (unlikely(btrfs_is_shutdown(inode_to_fs_info(inode))))
+ return -EIO;
+
/* Do not allow fallocate in ZONED mode */
if (btrfs_is_zoned(inode_to_fs_info(inode)))
return -EOPNOTSUPP;
@@ -3731,6 +3738,9 @@ static int btrfs_file_open(struct inode *inode, struct file *filp)
{
int ret;

+ if (unlikely(btrfs_is_shutdown(inode_to_fs_info(inode))))
+ return -EIO;
+
filp->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;

ret = fsverity_file_open(inode, filp);
@@ -3743,6 +3753,9 @@ static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t ret = 0;

+ if (unlikely(btrfs_is_shutdown(inode_to_fs_info(file_inode(iocb->ki_filp)))))
+ return -EIO;
+
if (iocb->ki_flags & IOCB_DIRECT) {
ret = btrfs_direct_read(iocb, to);
if (ret < 0 || !iov_iter_count(to) ||
@@ -3753,10 +3766,20 @@ static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return filemap_read(iocb, to, ret);
}

+static ssize_t btrfs_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len, unsigned int flags)
+{
+ if (unlikely(btrfs_is_shutdown(inode_to_fs_info(file_inode(in)))))
+ return -EIO;
+
+ return filemap_splice_read(in, ppos, pipe, len, flags);
+}
+
const struct file_operations btrfs_file_operations = {
.llseek = btrfs_file_llseek,
.read_iter = btrfs_file_read_iter,
- .splice_read = filemap_splice_read,
+ .splice_read = btrfs_file_splice_read,
.write_iter = btrfs_file_write_iter,
.splice_write = iter_file_splice_write,
.mmap = btrfs_file_mmap,
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 503c469249e5..2f3b7be13bea 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -5048,6 +5048,9 @@ static int btrfs_uring_encoded_write(struct io_uring_cmd *cmd, unsigned int issu

int btrfs_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
{
+ if (unlikely(btrfs_is_shutdown(inode_to_fs_info(file_inode(cmd->file)))))
+ return -EIO;
+
switch (cmd->cmd_op) {
case BTRFS_IOC_ENCODED_READ:
#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
index 0197bd9160a7..123a5682514b 100644
--- a/fs/btrfs/reflink.c
+++ b/fs/btrfs/reflink.c
@@ -869,6 +869,9 @@ loff_t btrfs_remap_file_range(struct file *src_file, loff_t off,
bool same_inode = dst_inode == src_inode;
int ret;

+ if (unlikely(btrfs_is_shutdown(inode_to_fs_info(file_inode(src_file)))))
+ return -EIO;
+
if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
return -EINVAL;

--
2.50.0