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Commit db6516a5 authored by Amir Goldstein's avatar Amir Goldstein Committed by Theodore Ts'o
Browse files

ext4: do not update s_last_mounted of a frozen fs 



If fs is frozen after mount and before the first file open, the
update of s_last_mounted bypasses freeze protection and prints out
a WARNING splat:

$ mount /vdf
$ fsfreeze -f /vdf
$ cat /vdf/foo

[   31.578555] WARNING: CPU: 1 PID: 1415 at
fs/ext4/ext4_jbd2.c:53 ext4_journal_check_start+0x48/0x82

[   31.614016] Call Trace:
[   31.614997]  __ext4_journal_start_sb+0xe4/0x1a4
[   31.616771]  ? ext4_file_open+0xb6/0x189
[   31.618094]  ext4_file_open+0xb6/0x189

If fs is frozen, skip s_last_mounted update.

[backport hint: to apply to stable tree, need to apply also patches
 vfs: add the sb_start_intwrite_trylock() helper
 ext4: factor out helper ext4_sample_last_mounted()]

Cc: stable@vger.kernel.org
Fixes: bc0b0d6d ("ext4: update the s_last_mounted field in the superblock")
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
parent 833a9508

fs/ext4/file.c

+9 −5
Original line number Original line Diff line number Diff line
@@ -393,7 +393,7 @@ static int ext4_sample_last_mounted(struct super_block *sb, 
	if (likely(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED))

	if (likely(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED))

		return 0;

		return 0;





	if (sb_rdonly(sb))

	if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))

		return 0;

		return 0;





	sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;

	sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
@@ -407,21 +407,25 @@ static int ext4_sample_last_mounted(struct super_block *sb, 
	path.mnt = mnt;

	path.mnt = mnt;

	path.dentry = mnt->mnt_root;

	path.dentry = mnt->mnt_root;

	cp = d_path(&path, buf, sizeof(buf));

	cp = d_path(&path, buf, sizeof(buf));

	err = 0;

	if (IS_ERR(cp))

	if (IS_ERR(cp))

		return 0;

		goto out;





	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);

	handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);

	err = PTR_ERR(handle);

	if (IS_ERR(handle))

	if (IS_ERR(handle))

		return PTR_ERR(handle);

		goto out;

	BUFFER_TRACE(sbi->s_sbh, "get_write_access");

	BUFFER_TRACE(sbi->s_sbh, "get_write_access");

	err = ext4_journal_get_write_access(handle, sbi->s_sbh);

	err = ext4_journal_get_write_access(handle, sbi->s_sbh);

	if (err)

	if (err)

		goto out;

		goto out_journal;

	strlcpy(sbi->s_es->s_last_mounted, cp,

	strlcpy(sbi->s_es->s_last_mounted, cp,

		sizeof(sbi->s_es->s_last_mounted));

		sizeof(sbi->s_es->s_last_mounted));

	ext4_handle_dirty_super(handle, sb);

	ext4_handle_dirty_super(handle, sb);

out:

out_journal:

	ext4_journal_stop(handle);

	ext4_journal_stop(handle);

out:

	sb_end_intwrite(sb);

	return err;

	return err;

}

}