f2fs: use generic checking and prep function for FS_IOC_SETFLAGS
Make the f2fs implementation of FS_IOC_SETFLAGS use the new VFS helper
function vfs_ioc_setflags_prepare().
This is based on a patch from Darrick Wong, but reworked to apply after
commit 360985573b55 ("f2fs: separate f2fs i_flags from fs_flags and ext4
i_flags").
Originally-from: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 86016d3..275b766 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1773,7 +1773,8 @@
static int f2fs_ioc_setflags(struct file *filp, unsigned long arg)
{
struct inode *inode = file_inode(filp);
- u32 fsflags;
+ struct f2fs_inode_info *fi = F2FS_I(inode);
+ u32 fsflags, old_fsflags;
u32 iflags;
int ret;
@@ -1797,8 +1798,14 @@
inode_lock(inode);
+ old_fsflags = f2fs_iflags_to_fsflags(fi->i_flags);
+ ret = vfs_ioc_setflags_prepare(inode, old_fsflags, fsflags);
+ if (ret)
+ goto out;
+
ret = f2fs_setflags_common(inode, iflags,
f2fs_fsflags_to_iflags(F2FS_SETTABLE_FS_FL));
+out:
inode_unlock(inode);
mnt_drop_write_file(filp);
return ret;
diff --git a/fs/inode.c b/fs/inode.c
index 920aa0b..cf70c9c 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2123,3 +2123,27 @@
return timespec_trunc(now, inode->i_sb->s_time_gran);
}
EXPORT_SYMBOL(current_time);
+
+/*
+ * Generic function to check FS_IOC_SETFLAGS values and reject any invalid
+ * configurations.
+ *
+ * Note: the caller should be holding i_mutex, or else be sure that they have
+ * exclusive access to the inode structure.
+ */
+int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
+ unsigned int flags)
+{
+ /*
+ * The IMMUTABLE and APPEND_ONLY flags can only be changed by
+ * the relevant capability.
+ *
+ * This test looks nicer. Thanks to Pauline Middelink
+ */
+ if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
+ !capable(CAP_LINUX_IMMUTABLE))
+ return -EPERM;
+
+ return 0;
+}
+EXPORT_SYMBOL(vfs_ioc_setflags_prepare);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 1dfbb0d..5904004 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3235,4 +3235,7 @@
extern bool path_noexec(const struct path *path);
extern void inode_nohighmem(struct inode *inode);
+int vfs_ioc_setflags_prepare(struct inode *inode, unsigned int oldflags,
+ unsigned int flags);
+
#endif /* _LINUX_FS_H */