[PATCH] ext3: journalled quotas

From: Jan Kara <jack@ucw.cz>

Journalled quota support for ext3: The patch consists of two parts - ext3
changes and changes in generic quota code.  The main idea of the changes is
that a transaction is always started before any operation which changes quota
file and dirtifying of the quota causes its write to disk.  These two changes
assure that quota change is journalled into the same transaction as the file
change and hence after journal replay quota is consistent with the filesystem
state.  As during journal replay inodes from orphan list are deleted/truncated
we have to do quota_on before the replay of the orphan list - this problem is
solved by additional mount options to ext3 with quota file names and format.

Some changes in generic code were also needed to assure that quota structure
in file is always allocated and so ordinary quota operations (like
adding/deleting a block/inode) need only a few blocks from the transaction.

1 files changed, 26 insertions, 27 deletions

diff --git a/include/linux/quota.h b/include/linux/quota.h
index 2f65eb567384..7d8c601ec2da 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -138,6 +138,10 @@ struct if_dqinfo {
 #include <linux/dqblk_v1.h>
 #include <linux/dqblk_v2.h>
 
+/* Maximal numbers of writes for quota operation (insert/delete/update)
+ * (over all formats) - info block, 4 pointer blocks, data block */
+#define DQUOT_MAX_WRITES	6
+
 /*
  * Data for one user/group kept in memory
  */
@@ -168,22 +172,21 @@ struct mem_dqinfo {
 	} u;
 };
 
+struct super_block;
+
 #define DQF_MASK 0xffff		/* Mask for format specific flags */
 #define DQF_INFO_DIRTY_B 16
 #define DQF_ANY_DQUOT_DIRTY_B 17
 #define DQF_INFO_DIRTY (1 << DQF_INFO_DIRTY_B)	/* Is info dirty? */
 #define DQF_ANY_DQUOT_DIRTY (1 << DQF_ANY_DQUOT_DIRTY_B) /* Is any dquot dirty? */
 
-extern inline void mark_info_dirty(struct mem_dqinfo *info)
-{
-	set_bit(DQF_INFO_DIRTY_B, &info->dqi_flags);
-}
-
+extern void mark_info_dirty(struct super_block *sb, int type);
 #define info_dirty(info) test_bit(DQF_INFO_DIRTY_B, &(info)->dqi_flags)
 #define info_any_dquot_dirty(info) test_bit(DQF_ANY_DQUOT_DIRTY_B, &(info)->dqi_flags)
 #define info_any_dirty(info) (info_dirty(info) || info_any_dquot_dirty(info))
 
 #define sb_dqopt(sb) (&(sb)->s_dquot)
+#define sb_dqinfo(sb, type) (sb_dqopt(sb)->info+(type))
 
 struct dqstats {
 	int lookups;
@@ -200,15 +203,13 @@ extern struct dqstats dqstats;
 
 #define NR_DQHASH 43            /* Just an arbitrary number */
 
-#define DQ_MOD_B	0
-#define DQ_BLKS_B	1
-#define DQ_INODES_B	2
-#define DQ_FAKE_B	3
-
-#define DQ_MOD        (1 << DQ_MOD_B)	/* dquot modified since read */
-#define DQ_BLKS       (1 << DQ_BLKS_B)	/* uid/gid has been warned about blk limit */
-#define DQ_INODES     (1 << DQ_INODES_B)	/* uid/gid has been warned about inode limit */
-#define DQ_FAKE       (1 << DQ_FAKE_B)	/* no limits only usage */
+#define DQ_MOD_B	0	/* dquot modified since read */
+#define DQ_BLKS_B	1	/* uid/gid has been warned about blk limit */
+#define DQ_INODES_B	2	/* uid/gid has been warned about inode limit */
+#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_WAITFREE_B	6	/* dquot being waited (by invalidate_dquots) */
 
 struct dquot {
 	struct list_head dq_hash;	/* Hash list in memory */
@@ -216,8 +217,7 @@ struct dquot {
 	struct list_head dq_free;	/* Free list element */
 	struct semaphore dq_lock;	/* dquot IO lock */
 	atomic_t dq_count;		/* Use count */
-
-	/* fields after this point are cleared when invalidating */
+	wait_queue_head_t dq_wait_unused;	/* Wait queue for dquot to become unused */
 	struct super_block *dq_sb;	/* superblock this applies to */
 	unsigned int dq_id;		/* ID this applies to (uid, gid) */
 	loff_t dq_off;			/* Offset of dquot on disk */
@@ -238,19 +238,22 @@ struct quota_format_ops {
 	int (*write_file_info)(struct super_block *sb, int type);	/* Write main info about file */
 	int (*free_file_info)(struct super_block *sb, int type);	/* Called on quotaoff() */
 	int (*read_dqblk)(struct dquot *dquot);		/* Read structure for one user */
-	int (*commit_dqblk)(struct dquot *dquot);	/* Write (or delete) structure for one user */
+	int (*commit_dqblk)(struct dquot *dquot);	/* Write structure for one user */
+	int (*release_dqblk)(struct dquot *dquot);	/* Called when last reference to dquot is being dropped */
 };
 
 /* Operations working with dquots */
 struct dquot_operations {
-	void (*initialize) (struct inode *, int);
-	void (*drop) (struct inode *);
+	int (*initialize) (struct inode *, int);
+	int (*drop) (struct inode *);
 	int (*alloc_space) (struct inode *, qsize_t, int);
 	int (*alloc_inode) (const struct inode *, unsigned long);
-	void (*free_space) (struct inode *, qsize_t);
-	void (*free_inode) (const struct inode *, unsigned long);
+	int (*free_space) (struct inode *, qsize_t);
+	int (*free_inode) (const struct inode *, unsigned long);
 	int (*transfer) (struct inode *, struct iattr *);
-	int (*write_dquot) (struct dquot *);
+	int (*write_dquot) (struct dquot *);		/* Ordinary dquot write */
+	int (*mark_dirty) (struct dquot *);		/* Dquot is marked dirty */
+	int (*write_info) (struct super_block *, int);	/* Write of quota "superblock" */
 };
 
 /* Operations handling requests from userspace */
@@ -289,10 +292,7 @@ struct quota_info {
 };
 
 /* Inline would be better but we need to dereference super_block which is not defined yet */
-#define mark_dquot_dirty(dquot) do {\
-	set_bit(DQF_ANY_DQUOT_DIRTY_B, &(sb_dqopt((dquot)->dq_sb)->info[(dquot)->dq_type].dqi_flags));\
-	set_bit(DQ_MOD_B, &(dquot)->dq_flags);\
-} while (0)
+int mark_dquot_dirty(struct dquot *dquot);
 
 #define dquot_dirty(dquot) test_bit(DQ_MOD_B, &(dquot)->dq_flags)
 
@@ -304,7 +304,6 @@ struct quota_info {
 
 int register_quota_format(struct quota_format_type *fmt);
 void unregister_quota_format(struct quota_format_type *fmt);
-void init_dquot_operations(struct dquot_operations *fsdqops);
 
 struct quota_module_name {
 	int qm_fmt_id;