mirror_zfs/module/os/linux
John Poduska 73c383f541
Prevent incorrect datasets being mounted
During a mount, zpl_mount_impl(), uses sget() with the callback
zpl_test_super() to find a super_block with a matching objset,
stored in z_os. It does so without taking the teardown lock on
the zfsvfs.

The problem is that operations like rollback will replace the
z_os. And, there is a window where the objset in the rollback
is freed, but z_os still points to it. Then, a mount like
operation, for instance a clone, can reallocate that exact same
pointer and zpl_test_super() will then match the super_block
associated with the rollback as opposed to the clone.

This fix tests for a match and if so, takes the teardown lock
before doing the final match test.

Reviewed-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: John Poduska <jpoduska@datto.com>
Closes #14518
2023-02-27 16:49:34 -08:00
..
spl Cleanup of dead code suggested by Clang Static Analyzer (#14380) 2023-01-17 09:57:12 -08:00
zfs Prevent incorrect datasets being mounted 2023-02-27 16:49:34 -08:00