diff options
| author | Josef Bacik <josef@redhat.com> | 2012-06-04 14:03:51 -0400 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2012-06-14 21:29:16 -0400 |
| commit | 606686eeac4550d2212bf3d621a810407ef5e9bf (patch) | |
| tree | 50adade3a750137b68304dc280d7a75436417b12 /fs/btrfs/extent_io.c | |
| parent | 17ca04aff7e6171df684b7b65804df8830eb8c15 (diff) | |
Btrfs: use rcu to protect device->name
Al pointed out that we can just toss out the old name on a device and add a
new one arbitrarily, so anybody who uses device->name in printk could
possibly use free'd memory. Instead of adding locking around all of this he
suggested doing it with RCU, so I've introduced a struct rcu_string that
does just that and have gone through and protected all accesses to
device->name that aren't under the uuid_mutex with rcu_read_lock(). This
protects us and I will use it for dealing with removing the device that we
used to mount the file system in a later patch. Thanks,
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
Diffstat (limited to 'fs/btrfs/extent_io.c')
| -rw-r--r-- | fs/btrfs/extent_io.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 2c8f7b20461..aaa12c1eb34 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -20,6 +20,7 @@ #include "volumes.h" #include "check-integrity.h" #include "locking.h" +#include "rcu-string.h" static struct kmem_cache *extent_state_cache; static struct kmem_cache *extent_buffer_cache; @@ -1917,9 +1918,9 @@ int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start, return -EIO; } - printk(KERN_INFO "btrfs read error corrected: ino %lu off %llu (dev %s " - "sector %llu)\n", page->mapping->host->i_ino, start, - dev->name, sector); + printk_in_rcu(KERN_INFO "btrfs read error corrected: ino %lu off %llu " + "(dev %s sector %llu)\n", page->mapping->host->i_ino, + start, rcu_str_deref(dev->name), sector); bio_put(bio); return 0; |