[PATCH v2 4/7] ext4: add more ext4_emergency_state() checks around sb_rdonly()

[libaokun]

From: Baokun Li <libaokun1@xxxxxxxxxx>

Some functions check sb_rdonly() to make sure the file system isn't
modified after it's read-only. Since we also don't want the file system
modified if it's in an emergency state (shutdown or emergency_ro),
we're adding additional ext4_emergency_state() checks where sb_rdonly()
is checked.

Suggested-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
Reviewed-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
 fs/ext4/file.c  |  3 ++-
 fs/ext4/ioctl.c |  2 +-
 fs/ext4/super.c | 26 +++++++++++++++-----------
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index d0c21e6503c6..45fc6586d41b 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -844,7 +844,8 @@ 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_emergency_state(sb) || 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..0c5ce9c2cdfc 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_emergency_state(sb) || sb_rdonly(sb))
 		return 0;
 	if (!force &&
 	    (sbi->s_overhead == 0 ||
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 4b089a5b760a..d8116c9c2bd0 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -473,8 +473,9 @@ 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) ||
-	    !journal || (journal->j_flags & JBD2_UNMOUNT))
+	if (ext4_emergency_state(sb) || sb_rdonly(sb) ||
+	    !(sb->s_flags & SB_ACTIVE) || !journal ||
+	    journal->j_flags & JBD2_UNMOUNT)
 		return;
 
 	now = ktime_get_real_seconds();
@@ -765,7 +766,8 @@ 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_emergency_state(sbi->s_sb) &&
+	    !sb_rdonly(sbi->s_sb) && journal) {
 		struct buffer_head *sbh = sbi->s_sbh;
 		bool call_notify_err = false;
 
@@ -1325,13 +1327,14 @@ static void ext4_put_super(struct super_block *sb)
 	ext4_mb_release(sb);
 	ext4_ext_release(sb);
 
-	if (!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_emergency_state(sb) && !sb_rdonly(sb)) {
+		if (!aborted) {
+			ext4_clear_feature_journal_needs_recovery(sb);
+			ext4_clear_feature_orphan_present(sb);
+			es->s_state = cpu_to_le16(sbi->s_mount_state);
+		}
 		ext4_commit_super(sb);
+	}
 
 	ext4_group_desc_free(sbi);
 	ext4_flex_groups_free(sbi);
@@ -3699,7 +3702,8 @@ 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_emergency_state(sb) && !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;
@@ -4004,7 +4008,7 @@ int ext4_register_li_request(struct super_block *sb,
 		goto out;
 	}
 
-	if (sb_rdonly(sb) ||
+	if (ext4_emergency_state(sb) || 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