3.16.61-rc1 review patch. If anyone has any objections, please let me know.
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From: Amir Goldstein amir73il@gmail.com
commit db6516a5e7ddb6dc72d167b920f2f272596ea22d upstream.
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()]
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 [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/ext4/file.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
--- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -220,7 +220,7 @@ static int ext4_sample_last_mounted(stru if (likely(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED)) return 0;
- if (sb->s_flags & MS_RDONLY) + if (sb->s_flags & MS_RDONLY || !sb_start_intwrite_trylock(sb)) return 0;
sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED; @@ -234,21 +234,25 @@ static int ext4_sample_last_mounted(stru 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; }