[PATCH 4/7] ext4: add ext4_sb_rdonly() helper function

[libaokun]

From: Baokun Li <libaokun1@xxxxxxxxxx>

Because both SB_RDONLY and EXT4_FLAGS_EMERGENCY_RO indicate the file system
is read-only, the ext4_sb_rdonly() helper function is added. This function
returns true if either flag is set, signifying that the file system is
read-only.

Then replace some sb_rdonly() with ext4_sb_rdonly() to avoid unexpected
failures of some read-only operations or modification of the superblock
after setting EXT4_FLAGS_EMERGENCY_RO.

Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
---
 fs/ext4/ext4.h  |  5 +++++
 fs/ext4/file.c  |  2 +-
 fs/ext4/ioctl.c |  2 +-
 fs/ext4/super.c | 17 +++++++++--------
 4 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ca01b476e42b..610c18036dc8 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2258,6 +2258,11 @@ static inline int ext4_is_emergency(struct super_block *sb)
 	return 0;
 }
 
+static inline int ext4_sb_rdonly(struct super_block *sb)
+{
+	return sb_rdonly(sb) || ext4_emergency_ro(sb);
+}
+
 /*
  * Default values for user and/or group using reserved blocks
  */
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 6db052a87b9b..70b556c87b88 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -844,7 +844,7 @@ static int ext4_sample_last_mounted(struct super_block *sb,
 	if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
 		return 0;
 
-	if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
+	if (ext4_sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
 		return 0;
 
 	ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 7b9ce71c1c81..0807ee8cbcdc 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -1705,7 +1705,7 @@ int ext4_update_overhead(struct super_block *sb, bool force)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 
-	if (sb_rdonly(sb))
+	if (ext4_sb_rdonly(sb))
 		return 0;
 	if (!force &&
 	    (sbi->s_overhead == 0 ||
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c12133628ee9..fc5d30123f22 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -473,7 +473,7 @@ static void ext4_maybe_update_superblock(struct super_block *sb)
 	__u64 lifetime_write_kbytes;
 	__u64 diff_size;
 
-	if (sb_rdonly(sb) || !(sb->s_flags & SB_ACTIVE) ||
+	if (ext4_sb_rdonly(sb) || !(sb->s_flags & SB_ACTIVE) ||
 	    !journal || (journal->j_flags & JBD2_UNMOUNT))
 		return;
 
@@ -707,7 +707,7 @@ static void ext4_handle_error(struct super_block *sb, bool force_ro, int error,
 	if (test_opt(sb, WARN_ON_ERROR))
 		WARN_ON_ONCE(1);
 
-	if (!continue_fs && !sb_rdonly(sb)) {
+	if (!continue_fs && !ext4_sb_rdonly(sb)) {
 		set_bit(EXT4_FLAGS_SHUTDOWN, &EXT4_SB(sb)->s_ext4_flags);
 		if (journal)
 			jbd2_journal_abort(journal, -EIO);
@@ -737,7 +737,7 @@ static void ext4_handle_error(struct super_block *sb, bool force_ro, int error,
 			sb->s_id);
 	}
 
-	if (sb_rdonly(sb) || continue_fs)
+	if (ext4_sb_rdonly(sb) || continue_fs)
 		return;
 
 	ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
@@ -765,7 +765,7 @@ static void update_super_work(struct work_struct *work)
 	 * We use directly jbd2 functions here to avoid recursing back into
 	 * ext4 error handling code during handling of previous errors.
 	 */
-	if (!sb_rdonly(sbi->s_sb) && journal) {
+	if (!ext4_sb_rdonly(sbi->s_sb) && journal) {
 		struct buffer_head *sbh = sbi->s_sbh;
 		bool call_notify_err = false;
 
@@ -1325,12 +1325,12 @@ static void ext4_put_super(struct super_block *sb)
 	ext4_mb_release(sb);
 	ext4_ext_release(sb);
 
-	if (!sb_rdonly(sb) && !aborted) {
+	if (!ext4_sb_rdonly(sb) && !aborted) {
 		ext4_clear_feature_journal_needs_recovery(sb);
 		ext4_clear_feature_orphan_present(sb);
 		es->s_state = cpu_to_le16(sbi->s_mount_state);
 	}
-	if (!sb_rdonly(sb))
+	if (!ext4_sb_rdonly(sb))
 		ext4_commit_super(sb);
 
 	ext4_group_desc_free(sbi);
@@ -3693,7 +3693,8 @@ static int ext4_run_li_request(struct ext4_li_request *elr)
 		if (group >= elr->lr_next_group) {
 			ret = 1;
 			if (elr->lr_first_not_zeroed != ngroups &&
-			    !sb_rdonly(sb) && test_opt(sb, INIT_INODE_TABLE)) {
+			    !ext4_sb_rdonly(sb) &&
+			    test_opt(sb, INIT_INODE_TABLE)) {
 				elr->lr_next_group = elr->lr_first_not_zeroed;
 				elr->lr_mode = EXT4_LI_MODE_ITABLE;
 				ret = 0;
@@ -3998,7 +3999,7 @@ int ext4_register_li_request(struct super_block *sb,
 		goto out;
 	}
 
-	if (sb_rdonly(sb) ||
+	if (ext4_sb_rdonly(sb) ||
 	    (test_opt(sb, NO_PREFETCH_BLOCK_BITMAPS) &&
 	     (first_not_zeroed == ngroups || !test_opt(sb, INIT_INODE_TABLE))))
 		goto out;
-- 
2.39.2