ext4: add ext4_emergency_state() helper function

Since both SHUTDOWN and EMERGENCY_RO are emergency states of the ext4 file
system, and they are checked in similar locations, we have added a helper
function, ext4_emergency_state(), to determine whether the current file
system is in one of these two emergency states.

Then, replace calls to ext4_forced_shutdown() with ext4_emergency_state()
in those functions that could potentially trigger write operations.

Signed-off-by: Baokun Li <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Zhang Yi <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>

Author: LiBaokun96

fs/ext4/ext4.h

@@ -2252,6 +2252,15 @@ static inline int ext4_emergency_ro(struct super_block *sb)
 	return test_bit(EXT4_FLAGS_EMERGENCY_RO, &EXT4_SB(sb)->s_ext4_flags);
 }
 
+static inline int ext4_emergency_state(struct super_block *sb)
+{
+	if (unlikely(ext4_forced_shutdown(sb)))
+		return -EIO;
+	if (unlikely(ext4_emergency_ro(sb)))
+		return -EROFS;
+	return 0;
+}
+
 /*
  * Default values for user and/or group using reserved blocks
  */

fs/ext4/ext4_jbd2.c

@@ -63,12 +63,14 @@ static void ext4_put_nojournal(handle_t *handle)
  */
 static int ext4_journal_check_start(struct super_block *sb)
 {
+	int ret;
 	journal_t *journal;
 
 	might_sleep();
 
-	if (unlikely(ext4_forced_shutdown(sb)))
-		return -EIO;
+	ret = ext4_emergency_state(sb);
+	if (unlikely(ret))
+		return ret;
 
 	if (WARN_ON_ONCE(sb_rdonly(sb)))
 		return -EROFS;

fs/ext4/file.c

@@ -688,10 +688,12 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
 static ssize_t
 ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
+	int ret;
 	struct inode *inode = file_inode(iocb->ki_filp);
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	ret = ext4_emergency_state(inode->i_sb);
+	if (unlikely(ret))
+		return ret;
 
 #ifdef CONFIG_FS_DAX
 	if (IS_DAX(inode))
@@ -700,7 +702,6 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 
 	if (iocb->ki_flags & IOCB_ATOMIC) {
 		size_t len = iov_iter_count(from);
-		int ret;
 
 		if (len < EXT4_SB(inode->i_sb)->s_awu_min ||
 		    len > EXT4_SB(inode->i_sb)->s_awu_max)
@@ -803,11 +804,16 @@ static const struct vm_operations_struct ext4_file_vm_ops = {
 
 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
+	int ret;
 	struct inode *inode = file->f_mapping->host;
 	struct dax_device *dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	if (file->f_mode & FMODE_WRITE)
+		ret = ext4_emergency_state(inode->i_sb);
+	else
+		ret = ext4_forced_shutdown(inode->i_sb) ? -EIO : 0;
+	if (unlikely(ret))
+		return ret;
 
 	/*
 	 * We don't support synchronous mappings for non-DAX files and
@@ -881,8 +887,12 @@ static int ext4_file_open(struct inode *inode, struct file *filp)
 {
 	int ret;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	if (filp->f_mode & FMODE_WRITE)
+		ret = ext4_emergency_state(inode->i_sb);
+	else
+		ret = ext4_forced_shutdown(inode->i_sb) ? -EIO : 0;
+	if (unlikely(ret))
+		return ret;
 
 	ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
 	if (ret)

fs/ext4/fsync.c

@@ -132,20 +132,16 @@ int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
 	bool needs_barrier = false;
 	struct inode *inode = file->f_mapping->host;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	ret = ext4_emergency_state(inode->i_sb);
+	if (unlikely(ret))
+		return ret;
 
 	ASSERT(ext4_journal_current_handle() == NULL);
 
 	trace_ext4_sync_file_enter(file, datasync);
 
-	if (sb_rdonly(inode->i_sb)) {
-		/* Make sure that we read updated s_ext4_flags value */
-		smp_rmb();
-		if (ext4_forced_shutdown(inode->i_sb))
-			ret = -EROFS;
+	if (sb_rdonly(inode->i_sb))
 		goto out;
-	}
 
 	if (!EXT4_SB(inode->i_sb)->s_journal) {
 		ret = ext4_fsync_nojournal(file, start, end, datasync,

fs/ext4/ialloc.c

@@ -951,8 +951,9 @@ struct inode *__ext4_new_inode(struct mnt_idmap *idmap,
 	sb = dir->i_sb;
 	sbi = EXT4_SB(sb);
 
-	if (unlikely(ext4_forced_shutdown(sb)))
-		return ERR_PTR(-EIO);
+	ret2 = ext4_emergency_state(sb);
+	if (unlikely(ret2))
+		return ERR_PTR(ret2);
 
 	ngroups = ext4_get_groups_count(sb);
 	trace_ext4_request_inode(dir, mode);

fs/ext4/inline.c

@@ -233,7 +233,7 @@ static void ext4_write_inline_data(struct inode *inode, struct ext4_iloc *iloc,
 	struct ext4_inode *raw_inode;
 	int cp_len = 0;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
+	if (unlikely(ext4_emergency_state(inode->i_sb)))
 		return;
 
 	BUG_ON(!EXT4_I(inode)->i_inline_off);

fs/ext4/inode.c

@@ -1150,8 +1150,9 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
 	pgoff_t index;
 	unsigned from, to;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	ret = ext4_emergency_state(inode->i_sb);
+	if (unlikely(ret))
+		return ret;
 
 	trace_ext4_write_begin(inode, pos, len);
 	/*
@@ -2274,7 +2275,7 @@ static int mpage_map_and_submit_extent(handle_t *handle,
 		if (err < 0) {
 			struct super_block *sb = inode->i_sb;
 
-			if (ext4_forced_shutdown(sb))
+			if (ext4_emergency_state(sb))
 				goto invalidate_dirty_pages;
 			/*
 			 * Let the uper layers retry transient errors.
@@ -2600,10 +2601,9 @@ static int ext4_do_writepages(struct mpage_da_data *mpd)
 	 * *never* be called, so if that ever happens, we would want
 	 * the stack trace.
 	 */
-	if (unlikely(ext4_forced_shutdown(mapping->host->i_sb))) {
-		ret = -EROFS;
+	ret = ext4_emergency_state(mapping->host->i_sb);
+	if (unlikely(ret))
 		goto out_writepages;
-	}
 
 	/*
 	 * If we have inline data and arrive here, it means that
@@ -2818,8 +2818,9 @@ static int ext4_writepages(struct address_space *mapping,
 	int ret;
 	int alloc_ctx;
 
-	if (unlikely(ext4_forced_shutdown(sb)))
-		return -EIO;
+	ret = ext4_emergency_state(sb);
+	if (unlikely(ret))
+		return ret;
 
 	alloc_ctx = ext4_writepages_down_read(sb);
 	ret = ext4_do_writepages(&mpd);
@@ -2859,8 +2860,9 @@ static int ext4_dax_writepages(struct address_space *mapping,
 	struct inode *inode = mapping->host;
 	int alloc_ctx;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	ret = ext4_emergency_state(inode->i_sb);
+	if (unlikely(ret))
+		return ret;
 
 	alloc_ctx = ext4_writepages_down_read(inode->i_sb);
 	trace_ext4_writepages(inode, wbc);
@@ -2916,8 +2918,9 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
 	pgoff_t index;
 	struct inode *inode = mapping->host;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	ret = ext4_emergency_state(inode->i_sb);
+	if (unlikely(ret))
+		return ret;
 
 	index = pos >> PAGE_SHIFT;
 
@@ -5247,8 +5250,9 @@ int ext4_write_inode(struct inode *inode, struct writeback_control *wbc)
 	if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
 		return 0;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	err = ext4_emergency_state(inode->i_sb);
+	if (unlikely(err))
+		return err;
 
 	if (EXT4_SB(inode->i_sb)->s_journal) {
 		if (ext4_journal_current_handle()) {
@@ -5370,8 +5374,9 @@ int ext4_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 	const unsigned int ia_valid = attr->ia_valid;
 	bool inc_ivers = true;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	error = ext4_emergency_state(inode->i_sb);
+	if (unlikely(error))
+		return error;
 
 	if (unlikely(IS_IMMUTABLE(inode)))
 		return -EPERM;
@@ -5815,9 +5820,10 @@ int ext4_mark_iloc_dirty(handle_t *handle,
 {
 	int err = 0;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb))) {
+	err = ext4_emergency_state(inode->i_sb);
+	if (unlikely(err)) {
 		put_bh(iloc->bh);
-		return -EIO;
+		return err;
 	}
 	ext4_fc_track_inode(handle, inode);
 
@@ -5841,8 +5847,9 @@ ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
 {
 	int err;
 
-	if (unlikely(ext4_forced_shutdown(inode->i_sb)))
-		return -EIO;
+	err = ext4_emergency_state(inode->i_sb);
+	if (unlikely(err))
+		return err;
 
 	err = ext4_get_inode_loc(inode, iloc);
 	if (!err) {

fs/ext4/mballoc.c

@@ -5653,7 +5653,7 @@ static inline void ext4_mb_show_pa(struct super_block *sb)
 {
 	ext4_group_t i, ngroups;
 
-	if (ext4_forced_shutdown(sb))
+	if (ext4_emergency_state(sb))
 		return;
 
 	ngroups = ext4_get_groups_count(sb);
@@ -5687,7 +5687,7 @@ static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
 {
 	struct super_block *sb = ac->ac_sb;
 
-	if (ext4_forced_shutdown(sb))
+	if (ext4_emergency_state(sb))
 		return;
 
 	mb_debug(sb, "Can't allocate:"

fs/ext4/mmp.c

@@ -162,7 +162,7 @@ static int kmmpd(void *data)
 	memcpy(mmp->mmp_nodename, init_utsname()->nodename,
 	       sizeof(mmp->mmp_nodename));
 
-	while (!kthread_should_stop() && !ext4_forced_shutdown(sb)) {
+	while (!kthread_should_stop() && !ext4_emergency_state(sb)) {
 		if (!ext4_has_feature_mmp(sb)) {
 			ext4_warning(sb, "kmmpd being stopped since MMP feature"
 				     " has been disabled.");

fs/ext4/namei.c

@@ -3157,8 +3157,9 @@ static int ext4_rmdir(struct inode *dir, struct dentry *dentry)
 	struct ext4_dir_entry_2 *de;
 	handle_t *handle = NULL;
 
-	if (unlikely(ext4_forced_shutdown(dir->i_sb)))
-		return -EIO;
+	retval = ext4_emergency_state(dir->i_sb);
+	if (unlikely(retval))
+		return retval;
 
 	/* Initialize quotas before so that eventual writes go in
 	 * separate transaction */
@@ -3315,8 +3316,9 @@ static int ext4_unlink(struct inode *dir, struct dentry *dentry)
 {
 	int retval;
 
-	if (unlikely(ext4_forced_shutdown(dir->i_sb)))
-		return -EIO;
+	retval = ext4_emergency_state(dir->i_sb);
+	if (unlikely(retval))
+		return retval;
 
 	trace_ext4_unlink_enter(dir, dentry);
 	/*
@@ -3382,8 +3384,9 @@ static int ext4_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	struct fscrypt_str disk_link;
 	int retries = 0;
 
-	if (unlikely(ext4_forced_shutdown(dir->i_sb)))
-		return -EIO;
+	err = ext4_emergency_state(dir->i_sb);
+	if (unlikely(err))
+		return err;
 
 	err = fscrypt_prepare_symlink(dir, symname, len, dir->i_sb->s_blocksize,
 				      &disk_link);
@@ -4205,8 +4208,9 @@ static int ext4_rename2(struct mnt_idmap *idmap,
 {
 	int err;
 
-	if (unlikely(ext4_forced_shutdown(old_dir->i_sb)))
-		return -EIO;
+	err = ext4_emergency_state(old_dir->i_sb);
+	if (unlikely(err))
+		return err;
 
 	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
 		return -EINVAL;