quota: Keep which entries were set by SETQUOTA quotactl

Quota in a clustered environment needs to synchronize quota information
among cluster nodes. This means we have to occasionally update some
information in dquot from disk / network. On the other hand we have to
be careful not to overwrite changes administrator did via SETQUOTA.
So indicate in dquot->dq_flags which entries have been set by SETQUOTA
and quota format can clear these flags when it properly propagated
the changes.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

2 files changed, 30 insertions, 8 deletions

diff --git a/fs/dquot.c b/fs/dquot.c
index 9c78ffe1aad2..89226726daa8 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -2010,25 +2010,33 @@ static int do_set_dqblk(struct dquot *dquot, struct if_dqblk *di)
         if (di->dqb_valid & QIF_SPACE) {
                 dm->dqb_curspace = di->dqb_curspace;
                 check_blim = 1;
+                __set_bit(DQ_LASTSET_B + QIF_SPACE_B, &dquot->dq_flags);
         }
         if (di->dqb_valid & QIF_BLIMITS) {
                 dm->dqb_bsoftlimit = qbtos(di->dqb_bsoftlimit);
                 dm->dqb_bhardlimit = qbtos(di->dqb_bhardlimit);
                 check_blim = 1;
+                __set_bit(DQ_LASTSET_B + QIF_BLIMITS_B, &dquot->dq_flags);
         }
         if (di->dqb_valid & QIF_INODES) {
                 dm->dqb_curinodes = di->dqb_curinodes;
                 check_ilim = 1;
+                __set_bit(DQ_LASTSET_B + QIF_INODES_B, &dquot->dq_flags);
         }
         if (di->dqb_valid & QIF_ILIMITS) {
                 dm->dqb_isoftlimit = di->dqb_isoftlimit;
                 dm->dqb_ihardlimit = di->dqb_ihardlimit;
                 check_ilim = 1;
+                __set_bit(DQ_LASTSET_B + QIF_ILIMITS_B, &dquot->dq_flags);
         }
-        if (di->dqb_valid & QIF_BTIME)
+        if (di->dqb_valid & QIF_BTIME) {
                 dm->dqb_btime = di->dqb_btime;
-        if (di->dqb_valid & QIF_ITIME)
+                __set_bit(DQ_LASTSET_B + QIF_BTIME_B, &dquot->dq_flags);
+        }
+        if (di->dqb_valid & QIF_ITIME) {
                 dm->dqb_itime = di->dqb_itime;
+                __set_bit(DQ_LASTSET_B + QIF_ITIME_B, &dquot->dq_flags);
+        }
 
         if (check_blim) {
                 if (!dm->dqb_bsoftlimit || dm->dqb_curspace < dm->dqb_bsoftlimit) {
diff --git a/include/linux/quota.h b/include/linux/quota.h
index 75bf761caef2..6d98885c16da 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -80,12 +80,21 @@
  * Quota structure used for communication with userspace via quotactl
  * Following flags are used to specify which fields are valid
  */
-#define QIF_BLIMITS     1
-#define QIF_SPACE       2
-#define QIF_ILIMITS     4
-#define QIF_INODES      8
-#define QIF_BTIME       16
-#define QIF_ITIME       32
+enum {
+        QIF_BLIMITS_B = 0,
+        QIF_SPACE_B,
+        QIF_ILIMITS_B,
+        QIF_INODES_B,
+        QIF_BTIME_B,
+        QIF_ITIME_B,
+};
+
+#define QIF_BLIMITS     (1 << QIF_BLIMITS_B)
+#define QIF_SPACE       (1 << QIF_SPACE_B)
+#define QIF_ILIMITS     (1 << QIF_ILIMITS_B)
+#define QIF_INODES      (1 << QIF_INODES_B)
+#define QIF_BTIME       (1 << QIF_BTIME_B)
+#define QIF_ITIME       (1 << QIF_ITIME_B)
 #define QIF_LIMITS      (QIF_BLIMITS | QIF_ILIMITS)
 #define QIF_USAGE       (QIF_SPACE | QIF_INODES)
 #define QIF_TIMES       (QIF_BTIME | QIF_ITIME)
@@ -242,6 +251,11 @@ extern struct dqstats dqstats;
 #define DQ_FAKE_B       3       /* no limits only usage */
 #define DQ_READ_B       4       /* dquot was read into memory */
 #define DQ_ACTIVE_B     5       /* dquot is active (dquot_release not called) */
+#define DQ_LASTSET_B    6       /* Following 6 bits (see QIF_) are reserved\
+                                 * for the mask of entries set via SETQUOTA\
+                                 * quotactl. They are set under dq_data_lock\
+                                 * and the quota format handling dquot can\
+                                 * clear them when it sees fit. */
 
 struct dquot {
         struct hlist_node dq_hash;      /* Hash list in memory */