f2fs: fix to do sanity check for inline inode

Yanming reported a kernel bug in Bugzilla kernel [1], which can be
reproduced. The bug message is:

The kernel message is shown below:

kernel BUG at fs/inode.c:611!
Call Trace:
evict+0x282/0x4e0
__dentry_kill+0x2b2/0x4d0
dput+0x2dd/0x720
do_renameat2+0x596/0x970
__x64_sys_rename+0x78/0x90
do_syscall_64+0x3b/0x90

[1] https://bugzilla.kernel.org/show_bug.cgi?id=215895

The bug is due to fuzzed inode has both inline_data and encrypted flags.
During f2fs_evict_inode(), as the inode was deleted by rename(), it
will cause inline data conversion due to conflicting flags. The page
cache will be polluted and the panic will be triggered in clear_inode().

Try fixing the bug by doing more sanity checks for inline data inode in
sanity_check_inode().

Cc: [e-mail]
Reported-by: Ming Yan <[e-mail]>
Signed-off-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>

fs/f2fs/f2fs.h

···
  * inline.c
  */
 bool f2fs_may_inline_data(struct inode *inode);
+bool f2fs_sanity_check_inline_data(struct inode *inode);
 bool f2fs_may_inline_dentry(struct inode *inode);
 void f2fs_do_read_inline_data(struct page *page, struct page *ipage);
 void f2fs_truncate_inline_inode(struct inode *inode,

fs/f2fs/inline.c

···
 #include "node.h"
 #include <trace/events/f2fs.h>
 
-bool f2fs_may_inline_data(struct inode *inode)
+static bool support_inline_data(struct inode *inode)
 {
 	if (f2fs_is_atomic_file(inode))
 		return false;
-
 	if (!S_ISREG(inode->i_mode) && !S_ISLNK(inode->i_mode))
 		return false;
-
 	if (i_size_read(inode) > MAX_INLINE_DATA(inode))
 		return false;
+	return true;
+}
 
-	if (f2fs_post_read_required(inode))
+bool f2fs_may_inline_data(struct inode *inode)
+{
+	if (!support_inline_data(inode))
 		return false;
 
-	return true;
+	return !f2fs_post_read_required(inode);
+}
+
+bool f2fs_sanity_check_inline_data(struct inode *inode)
+{
+	if (!f2fs_has_inline_data(inode))
+		return false;
+
+	if (!support_inline_data(inode))
+		return true;
+
+	/*
+	 * used by sanity_check_inode(), when disk layout fields has not
+	 * been synchronized to inmem fields.
+	 */
+	return (S_ISREG(inode->i_mode) &&
+		(file_is_encrypt(inode) || file_is_verity(inode) ||
+		(F2FS_I(inode)->i_flags & F2FS_COMPR_FL)));
 }
 
 bool f2fs_may_inline_dentry(struct inode *inode)

fs/f2fs/inode.c

···
 		}
 	}
 
-	if (f2fs_has_inline_data(inode) &&
-			(!S_ISREG(inode->i_mode) && !S_ISLNK(inode->i_mode))) {
+	if (f2fs_sanity_check_inline_data(inode)) {
 		set_sbi_flag(sbi, SBI_NEED_FSCK);
 		f2fs_warn(sbi, "%s: inode (ino=%lx, mode=%u) should not have inline_data, run fsck to fix",
 			  __func__, inode->i_ino, inode->i_mode);