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authorAmir Goldstein <amir73il@gmail.com>2018-05-13 22:54:44 -0400
committerTheodore Ts'o <tytso@mit.edu>2018-05-13 22:54:44 -0400
commitdb6516a5e7ddb6dc72d167b920f2f272596ea22d (patch)
treece820da46d4ef3e3f6f0a688f326d408ba8c506f
parent833a950882d33a7dfc319d5e152fdf35028936eb (diff)
downloadlinux-db6516a5e7ddb6dc72d167b920f2f272596ea22d.tar.bz2
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: bc0b0d6d69ee ("ext4: update the s_last_mounted field in the superblock") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/ext4/file.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index c48ea76b63e4..7f8023340eb8 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -393,7 +393,7 @@ static int ext4_sample_last_mounted(struct super_block *sb,
if (likely(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED))
return 0;
- if (sb_rdonly(sb))
+ if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
return 0;
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.dentry = mnt->mnt_root;
cp = d_path(&path, buf, sizeof(buf));
+ err = 0;
if (IS_ERR(cp))
- return 0;
+ goto out;
handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
+ err = PTR_ERR(handle);
if (IS_ERR(handle))
- return PTR_ERR(handle);
+ goto out;
BUFFER_TRACE(sbi->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, sbi->s_sbh);
if (err)
- goto out;
+ goto out_journal;
strlcpy(sbi->s_es->s_last_mounted, cp,
sizeof(sbi->s_es->s_last_mounted));
ext4_handle_dirty_super(handle, sb);
-out:
+out_journal:
ext4_journal_stop(handle);
+out:
+ sb_end_intwrite(sb);
return err;
}