[PATCH AUTOSEL 4.19 06/52] ext4: avoid panic during forced reboot

[PATCH AUTOSEL 4.19 06/52] ext4: avoid panic during forced reboot

[Sasha Levin]

From: Jan Kara <jack@suse.cz>

[ Upstream commit 1dc1097ff60e4105216da7cd0aa99032b039a994 ]

When admin calls "reboot -f" - i.e., does a hard system reboot by
directly calling reboot(2) - ext4 filesystem mounted with errors=panic
can panic the system. This happens because the underlying device gets
disabled without unmounting the filesystem and thus some syscall running
in parallel to reboot(2) can result in the filesystem getting IO errors.

This is somewhat surprising to the users so try improve the behavior by
switching to errors=remount-ro behavior when the system is running
reboot(2).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ext4/super.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a1cf7d68b4f0..abba7ece78e9 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -430,6 +430,12 @@ static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
 	spin_unlock(&sbi->s_md_lock);
 }
 
+static bool system_going_down(void)
+{
+	return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
+		|| system_state == SYSTEM_RESTART;
+}
+
 /* Deal with the reporting of failure conditions on a filesystem such as
  * inconsistencies detected or read IO failures.
  *
@@ -460,7 +466,12 @@ static void ext4_handle_error(struct super_block *sb)
 		if (journal)
 			jbd2_journal_abort(journal, -EIO);
 	}
-	if (test_opt(sb, ERRORS_RO)) {
+	/*
+	 * We force ERRORS_RO behavior when system is rebooting. Otherwise we
+	 * could panic during 'reboot -f' as the underlying device got already
+	 * disabled.
+	 */
+	if (test_opt(sb, ERRORS_RO) || system_going_down()) {
 		ext4_msg(sb, KERN_CRIT, "Remounting filesystem read-only");
 		/*
 		 * Make sure updated value of ->s_mount_flags will be visible
@@ -468,8 +479,7 @@ static void ext4_handle_error(struct super_block *sb)
 		 */
 		smp_wmb();
 		sb->s_flags |= SB_RDONLY;
-	}
-	if (test_opt(sb, ERRORS_PANIC)) {
+	} else if (test_opt(sb, ERRORS_PANIC)) {
 		if (EXT4_SB(sb)->s_journal &&
 		  !(EXT4_SB(sb)->s_journal->j_flags & JBD2_REC_ERR))
 			return;
-- 
2.19.1

[PATCH AUTOSEL 4.19 07/52] ext4: add missing brelse() in add_new_gdb_meta_bg()

[Sasha Levin]

From: Lukas Czerner <lczerner@redhat.com>

[ Upstream commit d64264d6218e6892edd832dc3a5a5857c2856c53 ]

Currently in add_new_gdb_meta_bg() there is a missing brelse of gdb_bh
in case ext4_journal_get_write_access() fails.
Additionally kvfree() is missing in the same error path. Fix it by
moving the ext4_journal_get_write_access() before the ext4 sb update as
Ted suggested and release n_group_desc and gdb_bh in case it fails.

Fixes: 61a9c11e5e7a ("ext4: add missing brelse() add_new_gdb_meta_bg()'s error path")
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ext4/resize.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 3d9b18505c0c..90061c3d048b 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -932,11 +932,18 @@ static int add_new_gdb_meta_bg(struct super_block *sb,
 	memcpy(n_group_desc, o_group_desc,
 	       EXT4_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
 	n_group_desc[gdb_num] = gdb_bh;
+
+	BUFFER_TRACE(gdb_bh, "get_write_access");
+	err = ext4_journal_get_write_access(handle, gdb_bh);
+	if (err) {
+		kvfree(n_group_desc);
+		brelse(gdb_bh);
+		return err;
+	}
+
 	EXT4_SB(sb)->s_group_desc = n_group_desc;
 	EXT4_SB(sb)->s_gdb_count++;
 	kvfree(o_group_desc);
-	BUFFER_TRACE(gdb_bh, "get_write_access");
-	err = ext4_journal_get_write_access(handle, gdb_bh);
 	return err;
 }
 
-- 
2.19.1

[PATCH AUTOSEL 4.19 08/52] ext4: report real fs size after failed resize

[Sasha Levin]

From: Lukas Czerner <lczerner@redhat.com>

[ Upstream commit 6c7328400e0488f7d49e19e02290ba343b6811b2 ]

Currently when the file system resize using ext4_resize_fs() fails it
will report into log that "resized filesystem to <requested block
count>".  However this may not be true in the case of failure.  Use the
current block count as returned by ext4_blocks_count() to report the
block count.

Additionally, report a warning that "error occurred during file system
resize"

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ext4/resize.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 90061c3d048b..e7ae26e36c9c 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -2080,6 +2080,10 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
 		free_flex_gd(flex_gd);
 	if (resize_inode != NULL)
 		iput(resize_inode);
-	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu", n_blocks_count);
+	if (err)
+		ext4_warning(sb, "error (%d) occurred during "
+			     "file system resize", err);
+	ext4_msg(sb, KERN_INFO, "resized filesystem to %llu",
+		 ext4_blocks_count(es));
 	return err;
 }
-- 
2.19.1

[PATCH AUTOSEL 4.19 52/52] ext4: prohibit fstrim in norecovery mode

[Sasha Levin]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

[ Upstream commit 18915b5873f07e5030e6fb108a050fa7c71c59fb ]

The ext4 fstrim implementation uses the block bitmaps to find free space
that can be discarded.  If we haven't replayed the journal, the bitmaps
will be stale and we absolutely *cannot* use stale metadata to zap the
underlying storage.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/ext4/ioctl.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 2e76fb55d94a..5f24fdc140ad 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -999,6 +999,13 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		if (!blk_queue_discard(q))
 			return -EOPNOTSUPP;
 
+		/*
+		 * We haven't replayed the journal, so we cannot use our
+		 * block-bitmap-guided storage zapping commands.
+		 */
+		if (test_opt(sb, NOLOAD) && ext4_has_feature_journal(sb))
+			return -EROFS;
+
 		if (copy_from_user(&range, (struct fstrim_range __user *)arg,
 		    sizeof(range)))
 			return -EFAULT;
-- 
2.19.1