Commit Graph

5 Commits

Author SHA1 Message Date
Dan Carpenter
c715f89c4d cifs: Fix a tiny potential memory leak
The most recent "it" allocation is leaked on this error path.  I
believe that small allocations always succeed in current kernels so
this doesn't really affect run time.

Fixes: 54be1f6c1c ("cifs: Add DFS cache routines")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-10 14:32:30 -06:00
Dan Carpenter
34bca9bbe7 cifs: Use kzfree() to free password
We should zero out the password before we free it.

Fixes: 3d6cacbb5310 ("cifs: Add DFS cache routines")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
2018-12-28 10:09:46 -06:00
Wei Yongjun
3e80be0158 cifs: Fix to use kmem_cache_free() instead of kfree()
memory allocated by kmem_cache_alloc() in alloc_cache_entry()
should be freed using kmem_cache_free(), not kfree().

Fixes: 34a44fb160f9 ("cifs: Add DFS cache routines")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-12-28 10:09:46 -06:00
Stephen Rothwell
54e4f73cbe cifs: update for current_kernel_time64() removal
Fixes cifs build failure after merge of the y2038 tree

After merging the y2038 tree, today's linux-next build (x86_64
allmodconfig) failed like this:

fs/cifs/dfs_cache.c: In function 'cache_entry_expired':
fs/cifs/dfs_cache.c:106:7: error: implicit declaration of function 'current_kernel_time64'; did you mean 'core_kernel_text'? [-Werror=implicit-function-declaration]
  ts = current_kernel_time64();
       ^~~~~~~~~~~~~~~~~~~~~
       core_kernel_text
fs/cifs/dfs_cache.c:106:5: error: incompatible types when assigning to type 'struct timespec64' from type 'int'
  ts = current_kernel_time64();
     ^
fs/cifs/dfs_cache.c: In function 'get_expire_time':
fs/cifs/dfs_cache.c:342:24: error: incompatible type for argument 1 of 'timespec64_add'
  return timespec64_add(current_kernel_time64(), ts);
                        ^~~~~~~~~~~~~~~~~~~~~~~
In file included from include/linux/restart_block.h:10,
                 from include/linux/thread_info.h:13,
                 from arch/x86/include/asm/preempt.h:7,
                 from include/linux/preempt.h:78,
                 from include/linux/rcupdate.h:40,
                 from fs/cifs/dfs_cache.c:8:
include/linux/time64.h:66:66: note: expected 'struct timespec64' but argument is of type 'int'
 static inline struct timespec64 timespec64_add(struct timespec64 lhs,
                                                ~~~~~~~~~~~~~~~~~~^~~
fs/cifs/dfs_cache.c:343:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

Caused by:

  commit ccea641b6742 ("timekeeping: remove obsolete time accessors")

interacting with:
  commit 34a44fb160f9 ("cifs: Add DFS cache routines")

from the cifs tree.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
2018-12-28 10:09:46 -06:00
Paulo Alcantara
54be1f6c1c cifs: Add DFS cache routines
* Add new dfs_cache.[ch] files

* Add new /proc/fs/cifs/dfscache file
  - dump current cache when read
  - clear current cache when writing "0" to it

* Add delayed_work to periodically refresh cache entries

The new interface will be used for caching DFS referrals, as well as
supporting client target failover.

The DFS cache is a hashtable that maps UNC paths to cache entries.

A cache entry contains:
- the UNC path it is mapped on
- how much the the UNC path the entry consumes
- flags
- a Time-To-Live after which the entry expires
- a list of possible targets (linked lists of UNC paths)
- a "hint target" pointing the last known working target or the first
  target if none were tried. This hint lets cifs.ko remember and try
  working targets first.

* Looking for an entry in the cache is done with dfs_cache_find()
  - if no valid entries are found, a DFS query is made, stored in the
    cache and returned
  - the full target list can be copied and returned to avoid race
    conditions and looped on with the help with the
    dfs_cache_tgt_iterator

* Updating the target hint to the next target is done with
  dfs_cache_update_tgthint()

These functions have a dfs_cache_noreq_XXX() version that doesn't
fetches referrals if no entries are found. These versions don't
require the tcp/ses/tcon/cifs_sb parameters as a result.

Expired entries cannot be used and since they have a pretty short TTL
[1] in order for them to be useful for failover the DFS cache adds a
delayed work called periodically to keep them fresh.

Since we might not have available connections to issue the referral
request when refreshing we need to store volume_info structs with
credentials and other needed info to be able to connect to the right
server.

1: Windows defaults: 5mn for domain-based referrals, 30mn for regular
links

Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2018-12-28 10:05:58 -06:00