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| author |   Eric Sandeen <sandeen@redhat.com> | 2010-05-16 02:00:00 -0400 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2010-05-16 02:00:00 -0400 |
| commit | 6b0310fbf087ad6e9e3b8392adca97cd77184084 (patch) | |
| tree | 6c15fad6ca442d92e8075578a9b04811ca093bda /fs/ext4 | |
| parent | ext4: symlink must be handled via filesystem specific operation (diff) | |
| download | linux-dev-6b0310fbf087ad6e9e3b8392adca97cd77184084.tar.xz linux-dev-6b0310fbf087ad6e9e3b8392adca97cd77184084.zip | |
ext4: don't return to userspace after freezing the fs with a mutex held
ext4_freeze() used jbd2_journal_lock_updates() which takes
the j_barrier mutex, and then returns to userspace. The
kernel does not like this:
================================================
[ BUG: lock held when returning to user space! ]
------------------------------------------------
lvcreate/1075 is leaving the kernel with locks still held!
1 lock held by lvcreate/1075:
#0: (&journal->j_barrier){+.+...}, at: [<ffffffff811c6214>]
jbd2_journal_lock_updates+0xe1/0xf0
Use vfs_check_frozen() added to ext4_journal_start_sb() and
ext4_force_commit() instead.
Addresses-Red-Hat-Bugzilla: #568503
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/super.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index e14d22c170d5..00d09f58f188 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -241,6 +241,7 @@ handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks) if (sb->s_flags & MS_RDONLY) return ERR_PTR(-EROFS); + vfs_check_frozen(sb, SB_FREEZE_WRITE); /* Special case here: if the journal has aborted behind our * backs (eg. EIO in the commit thread), then we still need to * take the FS itself readonly cleanly. */ @@ -3485,8 +3486,10 @@ int ext4_force_commit(struct super_block *sb) return 0; journal = EXT4_SB(sb)->s_journal; - if (journal) + if (journal) { + vfs_check_frozen(sb, SB_FREEZE_WRITE); ret = ext4_journal_force_commit(journal); + } return ret; } @@ -3535,18 +3538,16 @@ static int ext4_freeze(struct super_block *sb) * the journal. */ error = jbd2_journal_flush(journal); - if (error < 0) { - out: - jbd2_journal_unlock_updates(journal); - return error; - } + if (error < 0) + goto out; /* Journal blocked and flushed, clear needs_recovery flag. */ EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER); error = ext4_commit_super(sb, 1); - if (error) - goto out; - return 0; +out: + /* we rely on s_frozen to stop further updates */ + jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal); + return error; } /* @@ -3563,7 +3564,6 @@ static int ext4_unfreeze(struct super_block *sb) EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER); ext4_commit_super(sb, 1); unlock_super(sb); - jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal); return 0; } |