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| author | Josef Bacik | 2012-06-04 20:03:51 +0200 |
|---|---|---|
| committer | Chris Mason | 2012-06-15 03:29:16 +0200 |
| commit | 606686eeac4550d2212bf3d621a810407ef5e9bf (patch) | |
| tree | 50adade3a750137b68304dc280d7a75436417b12 /fs/btrfs/extent_io.c | |
| parent | Btrfs: unlock everything properly in the error case for nocow (diff) | |
| download | kernel-qcow2-linux-606686eeac4550d2212bf3d621a810407ef5e9bf.tar.gz kernel-qcow2-linux-606686eeac4550d2212bf3d621a810407ef5e9bf.tar.xz kernel-qcow2-linux-606686eeac4550d2212bf3d621a810407ef5e9bf.zip | |
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 2c8f7b204617..aaa12c1eb348 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; |