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authorJeff Layton <jlayton@redhat.com>2012-12-03 06:05:29 -0500
committerSteve French <smfrench@gmail.com>2012-12-08 22:04:25 -0600
commitfaa65f07d21e7d37190c91fdcf9f940d733ae3cc (patch)
tree68f77248b24fa59c3ec6218c6accfe0404f10f32 /fs/cifs/cifsacl.h
parent03eca704cfa426aebf6edcc0208536835c109a9f (diff)
downloadblackbird-op-linux-faa65f07d21e7d37190c91fdcf9f940d733ae3cc.tar.gz
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cifs: simplify id_to_sid and sid_to_id mapping code
The cifs.idmap handling code currently causes the kernel to cache the data from userspace twice. It first looks in a rbtree to see if there is a matching entry for the given id. If there isn't then it calls request_key which then checks its cache and then calls out to userland if it doesn't have one. If the userland program establishes a mapping and downcalls with that info, it then gets cached in the keyring and in this rbtree. Aside from the double memory usage and the performance penalty in doing all of these extra copies, there are some nasty bugs in here too. The code declares four rbtrees and spinlocks to protect them, but only seems to use two of them. The upshot is that the same tree is used to hold (eg) uid:sid and sid:uid mappings. The comparitors aren't equipped to deal with that. I think we'd be best off to remove a layer of caching in this code. If this was originally done for performance reasons, then that really seems like a premature optimization. This patch does that -- it removes the rbtrees and the locks that protect them and simply has the code do a request_key call on each call into sid_to_id and id_to_sid. This greatly simplifies this code and should roughly halve the memory utilization from using the idmapping code. Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
Diffstat (limited to 'fs/cifs/cifsacl.h')
-rw-r--r--fs/cifs/cifsacl.h28
1 files changed, 5 insertions, 23 deletions
diff --git a/fs/cifs/cifsacl.h b/fs/cifs/cifsacl.h
index 249c94f39635..46cd444ea2f2 100644
--- a/fs/cifs/cifsacl.h
+++ b/fs/cifs/cifsacl.h
@@ -23,7 +23,7 @@
#define _CIFSACL_H
-#define NUM_AUTHS 6 /* number of authority fields */
+#define NUM_AUTHS (6) /* number of authority fields */
#define SID_MAX_SUB_AUTHORITIES (15) /* max number of sub authority fields */
#define NUM_WK_SIDS 7 /* number of well known sids */
#define SIDNAMELENGTH 20 /* long enough for the ones we care about */
@@ -51,15 +51,12 @@
* u32: max 10 bytes in decimal
*
* "S-" + 3 bytes for version field + 4 bytes for each authority field (3 bytes
- * per number + 1 for '-') + 11 bytes for each subauthority field (10 bytes
* per number + 1 for '-') + NULL terminator.
+ *
+ * Add 11 bytes for each subauthority field (10 bytes each + 1 for '-')
*/
-#define SID_STRING_MAX (195)
-
-#define SID_ID_MAPPED 0
-#define SID_ID_PENDING 1
-#define SID_MAP_EXPIRE (3600 * HZ) /* map entry expires after one hour */
-#define SID_MAP_RETRY (300 * HZ) /* wait 5 minutes for next attempt to map */
+#define SID_STRING_BASE_SIZE (2 + 3 + (4 * NUM_AUTHS) + 1)
+#define SID_STRING_SUBAUTH_SIZE (11) /* size of a single subauth string */
struct cifs_ntsd {
__le16 revision; /* revision level */
@@ -94,19 +91,4 @@ struct cifs_ace {
struct cifs_sid sid; /* ie UUID of user or group who gets these perms */
} __attribute__((packed));
-struct cifs_wksid {
- struct cifs_sid cifssid;
- char sidname[SIDNAMELENGTH];
-} __attribute__((packed));
-
-struct cifs_sid_id {
- unsigned int refcount; /* increment with spinlock, decrement without */
- unsigned long id;
- unsigned long time;
- unsigned long state;
- char *sidstr;
- struct rb_node rbnode;
- struct cifs_sid sid;
-};
-
#endif /* _CIFSACL_H */
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