e2fsck: Open the external journal in exclusive mode

This prevents accidentally replaying and resetting the journal while
it is mounted, due to an accidental attempt to run e2fsck on an LVM
snapshot of a file system with an external journal.

Addresses-Debian-Bug: #587531

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/e2fsck/journal.c b/e2fsck/journal.c
index 64a0fd6..b741eb9 100644 (file)
--- a/e2fsck/journal.c
+++ b/e2fsck/journal.c
@@ -368,7 +368,8 @@ static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
 #ifndef USE_INODE_IO
        if (ext_journal)
 #endif
-               retval = io_ptr->open(journal_name, IO_FLAG_RW,
+               retval = io_ptr->open(journal_name,
+                                     IO_FLAG_RW | IO_FLAG_EXCLUSIVE,
                                      &ctx->journal_io);
        if (retval)
                goto errout;