Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2: (21 commits)
  fs/Kconfig: move nilfs2 outside misc filesystems
  nilfs2: convert nilfs_bmap_lookup to an inline function
  nilfs2: allow btree code to directly call dat operations
  nilfs2: add update functions of virtual block address to dat
  nilfs2: remove individual gfp constants for each metadata file
  nilfs2: stop zero-fill of btree path just before free it
  nilfs2: remove unused btree argument from btree functions
  nilfs2: remove nilfs_dat_abort_start and nilfs_dat_abort_free
  nilfs2: shorten freeze period due to GC in write operation v3
  nilfs2: add more check routines in mount process
  nilfs2: An unassigned variable is assigned to a never used structure member
  nilfs2: use GFP_NOIO for bio_alloc instead of GFP_NOWAIT
  nilfs2: stop using periodic write_super callback
  nilfs2: clean up nilfs_write_super
  nilfs2: fix disorder of nilfs_write_super in nilfs_sync_fs
  nilfs2: remove redundant super block commit
  nilfs2: implement nilfs_show_options to display mount options in /proc/mounts
  nilfs2: always lookup disk block address before reading metadata block
  nilfs2: use semaphore to protect pointer to a writable FS-instance
  nilfs2: fix format string compile warning (ino_t)
  ...

fs/Kconfig

@@ -43,6 +43,7 @@ source "fs/xfs/Kconfig"
 source "fs/gfs2/Kconfig"
 source "fs/ocfs2/Kconfig"
 source "fs/btrfs/Kconfig"
+source "fs/nilfs2/Kconfig"
 
 endif # BLOCK
 
@@ -186,7 +187,6 @@ source "fs/romfs/Kconfig"
 source "fs/sysv/Kconfig"
 source "fs/ufs/Kconfig"
 source "fs/exofs/Kconfig"
-source "fs/nilfs2/Kconfig"
 
 endif # MISC_FILESYSTEMS
 

fs/nilfs2/Kconfig

 config NILFS2_FS
 	tristate "NILFS2 file system support (EXPERIMENTAL)"
-	depends on BLOCK && EXPERIMENTAL
+	depends on EXPERIMENTAL
 	select CRC32
 	help
 	  NILFS2 is a log-structured file system (LFS) supporting continuous

fs/nilfs2/bmap.c

@@ -36,6 +36,26 @@ struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *bmap)
 	return nilfs_dat_inode(NILFS_I_NILFS(bmap->b_inode));
 }
 
+/**
+ * nilfs_bmap_lookup_at_level - find a data block or node block
+ * @bmap: bmap
+ * @key: key
+ * @level: level
+ * @ptrp: place to store the value associated to @key
+ *
+ * Description: nilfs_bmap_lookup_at_level() finds a record whose key
+ * matches @key in the block at @level of the bmap.
+ *
+ * Return Value: On success, 0 is returned and the record associated with @key
+ * is stored in the place pointed by @ptrp. On error, one of the following
+ * negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOENT - A record associated with @key does not exist.
+ */
 int nilfs_bmap_lookup_at_level(struct nilfs_bmap *bmap, __u64 key, int level,
 			       __u64 *ptrp)
 {
@@ -69,39 +89,6 @@ int nilfs_bmap_lookup_contig(struct nilfs_bmap *bmap, __u64 key, __u64 *ptrp,
 	return ret;
 }
 
-/**
- * nilfs_bmap_lookup - find a record
- * @bmap: bmap
- * @key: key
- * @recp: pointer to record
- *
- * Description: nilfs_bmap_lookup() finds a record whose key matches @key in
- * @bmap.
- *
- * Return Value: On success, 0 is returned and the record associated with @key
- * is stored in the place pointed by @recp. On error, one of the following
- * negative error codes is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- *
- * %-ENOENT - A record associated with @key does not exist.
- */
-int nilfs_bmap_lookup(struct nilfs_bmap *bmap,
-		      unsigned long key,
-		      unsigned long *recp)
-{
-	__u64 ptr;
-	int ret;
-
-	/* XXX: use macro for level 1 */
-	ret = nilfs_bmap_lookup_at_level(bmap, key, 1, &ptr);
-	if (recp != NULL)
-		*recp = ptr;
-	return ret;
-}
-
 static int nilfs_bmap_do_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
 {
 	__u64 keys[NILFS_BMAP_SMALL_HIGH + 1];
@@ -469,104 +456,6 @@ __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *bmap)
 		(entries_per_group / NILFS_BMAP_GROUP_DIV);
 }
 
-int nilfs_bmap_prepare_alloc_v(struct nilfs_bmap *bmap,
-				 union nilfs_bmap_ptr_req *req)
-{
-	return nilfs_dat_prepare_alloc(nilfs_bmap_get_dat(bmap), &req->bpr_req);
-}
-
-void nilfs_bmap_commit_alloc_v(struct nilfs_bmap *bmap,
-				 union nilfs_bmap_ptr_req *req)
-{
-	nilfs_dat_commit_alloc(nilfs_bmap_get_dat(bmap), &req->bpr_req);
-}
-
-void nilfs_bmap_abort_alloc_v(struct nilfs_bmap *bmap,
-			      union nilfs_bmap_ptr_req *req)
-{
-	nilfs_dat_abort_alloc(nilfs_bmap_get_dat(bmap), &req->bpr_req);
-}
-
-int nilfs_bmap_start_v(struct nilfs_bmap *bmap, union nilfs_bmap_ptr_req *req,
-		       sector_t blocknr)
-{
-	struct inode *dat = nilfs_bmap_get_dat(bmap);
-	int ret;
-
-	ret = nilfs_dat_prepare_start(dat, &req->bpr_req);
-	if (likely(!ret))
-		nilfs_dat_commit_start(dat, &req->bpr_req, blocknr);
-	return ret;
-}
-
-int nilfs_bmap_prepare_end_v(struct nilfs_bmap *bmap,
-			     union nilfs_bmap_ptr_req *req)
-{
-	return nilfs_dat_prepare_end(nilfs_bmap_get_dat(bmap), &req->bpr_req);
-}
-
-void nilfs_bmap_commit_end_v(struct nilfs_bmap *bmap,
-			     union nilfs_bmap_ptr_req *req)
-{
-	nilfs_dat_commit_end(nilfs_bmap_get_dat(bmap), &req->bpr_req,
-			     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
-}
-
-void nilfs_bmap_abort_end_v(struct nilfs_bmap *bmap,
-			    union nilfs_bmap_ptr_req *req)
-{
-	nilfs_dat_abort_end(nilfs_bmap_get_dat(bmap), &req->bpr_req);
-}
-
-int nilfs_bmap_move_v(const struct nilfs_bmap *bmap, __u64 vblocknr,
-		      sector_t blocknr)
-{
-	return nilfs_dat_move(nilfs_bmap_get_dat(bmap), vblocknr, blocknr);
-}
-
-int nilfs_bmap_mark_dirty(const struct nilfs_bmap *bmap, __u64 vblocknr)
-{
-	return nilfs_dat_mark_dirty(nilfs_bmap_get_dat(bmap), vblocknr);
-}
-
-int nilfs_bmap_prepare_update_v(struct nilfs_bmap *bmap,
-				union nilfs_bmap_ptr_req *oldreq,
-				union nilfs_bmap_ptr_req *newreq)
-{
-	struct inode *dat = nilfs_bmap_get_dat(bmap);
-	int ret;
-
-	ret = nilfs_dat_prepare_end(dat, &oldreq->bpr_req);
-	if (ret < 0)
-		return ret;
-	ret = nilfs_dat_prepare_alloc(dat, &newreq->bpr_req);
-	if (ret < 0)
-		nilfs_dat_abort_end(dat, &oldreq->bpr_req);
-
-	return ret;
-}
-
-void nilfs_bmap_commit_update_v(struct nilfs_bmap *bmap,
-				union nilfs_bmap_ptr_req *oldreq,
-				union nilfs_bmap_ptr_req *newreq)
-{
-	struct inode *dat = nilfs_bmap_get_dat(bmap);
-
-	nilfs_dat_commit_end(dat, &oldreq->bpr_req,
-			     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
-	nilfs_dat_commit_alloc(dat, &newreq->bpr_req);
-}
-
-void nilfs_bmap_abort_update_v(struct nilfs_bmap *bmap,
-			       union nilfs_bmap_ptr_req *oldreq,
-			       union nilfs_bmap_ptr_req *newreq)
-{
-	struct inode *dat = nilfs_bmap_get_dat(bmap);
-
-	nilfs_dat_abort_end(dat, &oldreq->bpr_req);
-	nilfs_dat_abort_alloc(dat, &newreq->bpr_req);
-}
-
 static struct lock_class_key nilfs_bmap_dat_lock_key;
 static struct lock_class_key nilfs_bmap_mdt_lock_key;
 

fs/nilfs2/bmap.h

@@ -28,6 +28,7 @@
 #include <linux/buffer_head.h>
 #include <linux/nilfs2_fs.h>
 #include "alloc.h"
+#include "dat.h"
 
 #define NILFS_BMAP_INVALID_PTR	0
 
@@ -141,7 +142,6 @@ struct nilfs_bmap {
 int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
 int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
 void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
-int nilfs_bmap_lookup(struct nilfs_bmap *, unsigned long, unsigned long *);
 int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
 int nilfs_bmap_insert(struct nilfs_bmap *, unsigned long, unsigned long);
 int nilfs_bmap_delete(struct nilfs_bmap *, unsigned long);
@@ -160,90 +160,76 @@ void nilfs_bmap_init_gcdat(struct nilfs_bmap *, struct nilfs_bmap *);
 void nilfs_bmap_commit_gcdat(struct nilfs_bmap *, struct nilfs_bmap *);
 
 
+static inline int nilfs_bmap_lookup(struct nilfs_bmap *bmap, __u64 key,
+				    __u64 *ptr)
+{
+	return nilfs_bmap_lookup_at_level(bmap, key, 1, ptr);
+}
+
 /*
  * Internal use only
  */
 struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);
-int nilfs_bmap_prepare_alloc_v(struct nilfs_bmap *,
-			       union nilfs_bmap_ptr_req *);
-void nilfs_bmap_commit_alloc_v(struct nilfs_bmap *,
-			       union nilfs_bmap_ptr_req *);
-void nilfs_bmap_abort_alloc_v(struct nilfs_bmap *,
-			      union nilfs_bmap_ptr_req *);
 
 static inline int nilfs_bmap_prepare_alloc_ptr(struct nilfs_bmap *bmap,
-					       union nilfs_bmap_ptr_req *req)
+					       union nilfs_bmap_ptr_req *req,
+					       struct inode *dat)
 {
-	if (NILFS_BMAP_USE_VBN(bmap))
-		return nilfs_bmap_prepare_alloc_v(bmap, req);
+	if (dat)
+		return nilfs_dat_prepare_alloc(dat, &req->bpr_req);
 	/* ignore target ptr */
 	req->bpr_ptr = bmap->b_last_allocated_ptr++;
 	return 0;
 }
 
 static inline void nilfs_bmap_commit_alloc_ptr(struct nilfs_bmap *bmap,
-					       union nilfs_bmap_ptr_req *req)
+					       union nilfs_bmap_ptr_req *req,
+					       struct inode *dat)
 {
-	if (NILFS_BMAP_USE_VBN(bmap))
-		nilfs_bmap_commit_alloc_v(bmap, req);
+	if (dat)
+		nilfs_dat_commit_alloc(dat, &req->bpr_req);
 }
 
 static inline void nilfs_bmap_abort_alloc_ptr(struct nilfs_bmap *bmap,
-					      union nilfs_bmap_ptr_req *req)
+					      union nilfs_bmap_ptr_req *req,
+					      struct inode *dat)
 {
-	if (NILFS_BMAP_USE_VBN(bmap))
-		nilfs_bmap_abort_alloc_v(bmap, req);
+	if (dat)
+		nilfs_dat_abort_alloc(dat, &req->bpr_req);
 	else
 		bmap->b_last_allocated_ptr--;
 }
 
-int nilfs_bmap_prepare_end_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *);
-void nilfs_bmap_commit_end_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *);
-void nilfs_bmap_abort_end_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *);
-
 static inline int nilfs_bmap_prepare_end_ptr(struct nilfs_bmap *bmap,
-					     union nilfs_bmap_ptr_req *req)
+					     union nilfs_bmap_ptr_req *req,
+					     struct inode *dat)
 {
-	return NILFS_BMAP_USE_VBN(bmap) ?
-		nilfs_bmap_prepare_end_v(bmap, req) : 0;
+	return dat ? nilfs_dat_prepare_end(dat, &req->bpr_req) : 0;
 }
 
 static inline void nilfs_bmap_commit_end_ptr(struct nilfs_bmap *bmap,
-					     union nilfs_bmap_ptr_req *req)
+					     union nilfs_bmap_ptr_req *req,
+					     struct inode *dat)
 {
-	if (NILFS_BMAP_USE_VBN(bmap))
-		nilfs_bmap_commit_end_v(bmap, req);
+	if (dat)
+		nilfs_dat_commit_end(dat, &req->bpr_req,
+				     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
 }
 
 static inline void nilfs_bmap_abort_end_ptr(struct nilfs_bmap *bmap,
-					    union nilfs_bmap_ptr_req *req)
+					    union nilfs_bmap_ptr_req *req,
+					    struct inode *dat)
 {
-	if (NILFS_BMAP_USE_VBN(bmap))
-		nilfs_bmap_abort_end_v(bmap, req);
+	if (dat)
+		nilfs_dat_abort_end(dat, &req->bpr_req);
 }
 
-int nilfs_bmap_start_v(struct nilfs_bmap *, union nilfs_bmap_ptr_req *,
-		       sector_t);
-int nilfs_bmap_move_v(const struct nilfs_bmap *, __u64, sector_t);
-int nilfs_bmap_mark_dirty(const struct nilfs_bmap *, __u64);
-
-
 __u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
 			      const struct buffer_head *);
 
 __u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
 __u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);
 
-int nilfs_bmap_prepare_update_v(struct nilfs_bmap *,
-				union nilfs_bmap_ptr_req *,
-				union nilfs_bmap_ptr_req *);
-void nilfs_bmap_commit_update_v(struct nilfs_bmap *,
-				union nilfs_bmap_ptr_req *,
-				union nilfs_bmap_ptr_req *);
-void nilfs_bmap_abort_update_v(struct nilfs_bmap *,
-			       union nilfs_bmap_ptr_req *,
-			       union nilfs_bmap_ptr_req *);
-
 void nilfs_bmap_add_blocks(const struct nilfs_bmap *, int);
 void nilfs_bmap_sub_blocks(const struct nilfs_bmap *, int);
 

fs/nilfs2/cpfile.c

@@ -815,8 +815,10 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
 	void *kaddr;
 	int ret;
 
-	if (cno == 0)
-		return -ENOENT; /* checkpoint number 0 is invalid */
+	/* CP number is invalid if it's zero or larger than the
+	largest	exist one.*/
+	if (cno == 0 || cno >= nilfs_mdt_cno(cpfile))
+		return -ENOENT;
 	down_read(&NILFS_MDT(cpfile)->mi_sem);
 
 	ret = nilfs_cpfile_get_checkpoint_block(cpfile, cno, 0, &bh);
@@ -824,6 +826,9 @@ int nilfs_cpfile_is_snapshot(struct inode *cpfile, __u64 cno)
 		goto out;
 	kaddr = kmap_atomic(bh->b_page, KM_USER0);
 	cp = nilfs_cpfile_block_get_checkpoint(cpfile, cno, bh, kaddr);
+	if (nilfs_checkpoint_invalid(cp))
+		ret = -ENOENT;
+	else
 		ret = nilfs_checkpoint_snapshot(cp);
 	kunmap_atomic(kaddr, KM_USER0);
 	brelse(bh);

fs/nilfs2/cpfile.h

@@ -27,8 +27,6 @@
 #include <linux/buffer_head.h>
 #include <linux/nilfs2_fs.h>
 
-#define NILFS_CPFILE_GFP	NILFS_MDT_GFP
-
 
 int nilfs_cpfile_get_checkpoint(struct inode *, __u64, int,
 				struct nilfs_checkpoint **,

fs/nilfs2/dat.c

@@ -109,12 +109,6 @@ void nilfs_dat_commit_free(struct inode *dat, struct nilfs_palloc_req *req)
 	nilfs_palloc_commit_free_entry(dat, req);
 }
 
-void nilfs_dat_abort_free(struct inode *dat, struct nilfs_palloc_req *req)
-{
-	nilfs_dat_abort_entry(dat, req);
-	nilfs_palloc_abort_free_entry(dat, req);
-}
-
 int nilfs_dat_prepare_start(struct inode *dat, struct nilfs_palloc_req *req)
 {
 	int ret;
@@ -140,11 +134,6 @@ void nilfs_dat_commit_start(struct inode *dat, struct nilfs_palloc_req *req,
 	nilfs_dat_commit_entry(dat, req);
 }
 
-void nilfs_dat_abort_start(struct inode *dat, struct nilfs_palloc_req *req)
-{
-	nilfs_dat_abort_entry(dat, req);
-}
-
 int nilfs_dat_prepare_end(struct inode *dat, struct nilfs_palloc_req *req)
 {
 	struct nilfs_dat_entry *entry;
@@ -222,6 +211,37 @@ void nilfs_dat_abort_end(struct inode *dat, struct nilfs_palloc_req *req)
 	nilfs_dat_abort_entry(dat, req);
 }
 
+int nilfs_dat_prepare_update(struct inode *dat,
+			     struct nilfs_palloc_req *oldreq,
+			     struct nilfs_palloc_req *newreq)
+{
+	int ret;
+
+	ret = nilfs_dat_prepare_end(dat, oldreq);
+	if (!ret) {
+		ret = nilfs_dat_prepare_alloc(dat, newreq);
+		if (ret < 0)
+			nilfs_dat_abort_end(dat, oldreq);
+	}
+	return ret;
+}
+
+void nilfs_dat_commit_update(struct inode *dat,
+			     struct nilfs_palloc_req *oldreq,
+			     struct nilfs_palloc_req *newreq, int dead)
+{
+	nilfs_dat_commit_end(dat, oldreq, dead);
+	nilfs_dat_commit_alloc(dat, newreq);
+}
+
+void nilfs_dat_abort_update(struct inode *dat,
+			    struct nilfs_palloc_req *oldreq,
+			    struct nilfs_palloc_req *newreq)
+{
+	nilfs_dat_abort_end(dat, oldreq);
+	nilfs_dat_abort_alloc(dat, newreq);
+}
+
 /**
  * nilfs_dat_mark_dirty -
  * @dat: DAT file inode

fs/nilfs2/dat.h

@@ -27,7 +27,6 @@
 #include <linux/buffer_head.h>
 #include <linux/fs.h>
 
-#define NILFS_DAT_GFP	NILFS_MDT_GFP
 
 struct nilfs_palloc_req;
 
@@ -39,10 +38,15 @@ void nilfs_dat_abort_alloc(struct inode *, struct nilfs_palloc_req *);
 int nilfs_dat_prepare_start(struct inode *, struct nilfs_palloc_req *);
 void nilfs_dat_commit_start(struct inode *, struct nilfs_palloc_req *,
 			    sector_t);
-void nilfs_dat_abort_start(struct inode *, struct nilfs_palloc_req *);
 int nilfs_dat_prepare_end(struct inode *, struct nilfs_palloc_req *);
 void nilfs_dat_commit_end(struct inode *, struct nilfs_palloc_req *, int);
 void nilfs_dat_abort_end(struct inode *, struct nilfs_palloc_req *);
+int nilfs_dat_prepare_update(struct inode *, struct nilfs_palloc_req *,
+			     struct nilfs_palloc_req *);
+void nilfs_dat_commit_update(struct inode *, struct nilfs_palloc_req *,
+			     struct nilfs_palloc_req *, int);
+void nilfs_dat_abort_update(struct inode *, struct nilfs_palloc_req *,
+			    struct nilfs_palloc_req *);
 
 int nilfs_dat_mark_dirty(struct inode *, __u64);
 int nilfs_dat_freev(struct inode *, __u64 *, size_t);

fs/nilfs2/direct.c

@@ -125,106 +125,64 @@ static void nilfs_direct_set_target_v(struct nilfs_direct *direct,
 	direct->d_bmap.b_last_allocated_ptr = ptr;
 }
 
-static int nilfs_direct_prepare_insert(struct nilfs_direct *direct,
-				       __u64 key,
-				       union nilfs_bmap_ptr_req *req,
-				       struct nilfs_bmap_stats *stats)
-{
-	int ret;
-
-	if (NILFS_BMAP_USE_VBN(&direct->d_bmap))
-		req->bpr_ptr = nilfs_direct_find_target_v(direct, key);
-	ret = nilfs_bmap_prepare_alloc_ptr(&direct->d_bmap, req);
-	if (ret < 0)
-		return ret;
-
-	stats->bs_nblocks = 1;
-	return 0;
-}
-
-static void nilfs_direct_commit_insert(struct nilfs_direct *direct,
-				       union nilfs_bmap_ptr_req *req,
-				       __u64 key, __u64 ptr)
-{
-	struct buffer_head *bh;
-
-	/* ptr must be a pointer to a buffer head. */
-	bh = (struct buffer_head *)((unsigned long)ptr);
-	set_buffer_nilfs_volatile(bh);
-
-	nilfs_bmap_commit_alloc_ptr(&direct->d_bmap, req);
-	nilfs_direct_set_ptr(direct, key, req->bpr_ptr);
-
-	if (!nilfs_bmap_dirty(&direct->d_bmap))
-		nilfs_bmap_set_dirty(&direct->d_bmap);
-
-	if (NILFS_BMAP_USE_VBN(&direct->d_bmap))
-		nilfs_direct_set_target_v(direct, key, req->bpr_ptr);
-}
-
 static int nilfs_direct_insert(struct nilfs_bmap *bmap, __u64 key, __u64 ptr)
 {
-	struct nilfs_direct *direct;
+	struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
 	union nilfs_bmap_ptr_req req;
-	struct nilfs_bmap_stats stats;
+	struct inode *dat = NULL;
+	struct buffer_head *bh;
 	int ret;
 
-	direct = (struct nilfs_direct *)bmap;
 	if (key > NILFS_DIRECT_KEY_MAX)
 		return -ENOENT;
 	if (nilfs_direct_get_ptr(direct, key) != NILFS_BMAP_INVALID_PTR)
 		return -EEXIST;
 
-	ret = nilfs_direct_prepare_insert(direct, key, &req, &stats);
-	if (ret < 0)
-		return ret;
-	nilfs_direct_commit_insert(direct, &req, key, ptr);
-	nilfs_bmap_add_blocks(bmap, stats.bs_nblocks);
+	if (NILFS_BMAP_USE_VBN(bmap)) {
+		req.bpr_ptr = nilfs_direct_find_target_v(direct, key);
+		dat = nilfs_bmap_get_dat(bmap);
+	}
+	ret = nilfs_bmap_prepare_alloc_ptr(bmap, &req, dat);
+	if (!ret) {
+		/* ptr must be a pointer to a buffer head. */
+		bh = (struct buffer_head *)((unsigned long)ptr);
+		set_buffer_nilfs_volatile(bh);
 
-	return 0;
-}
+		nilfs_bmap_commit_alloc_ptr(bmap, &req, dat);
+		nilfs_direct_set_ptr(direct, key, req.bpr_ptr);
 
-static int nilfs_direct_prepare_delete(struct nilfs_direct *direct,
-				       union nilfs_bmap_ptr_req *req,
-				       __u64 key,
-				       struct nilfs_bmap_stats *stats)
-{
-	int ret;
+		if (!nilfs_bmap_dirty(bmap))
+			nilfs_bmap_set_dirty(bmap);
 
-	req->bpr_ptr = nilfs_direct_get_ptr(direct, key);
-	ret = nilfs_bmap_prepare_end_ptr(&direct->d_bmap, req);
-	if (!ret)
-		stats->bs_nblocks = 1;
-	return ret;
-}
+		if (NILFS_BMAP_USE_VBN(bmap))
+			nilfs_direct_set_target_v(direct, key, req.bpr_ptr);
 
-static void nilfs_direct_commit_delete(struct nilfs_direct *direct,
-				       union nilfs_bmap_ptr_req *req,
-				       __u64 key)
-{
-	nilfs_bmap_commit_end_ptr(&direct->d_bmap, req);
-	nilfs_direct_set_ptr(direct, key, NILFS_BMAP_INVALID_PTR);
+		nilfs_bmap_add_blocks(bmap, 1);
+	}
+	return ret;
 }
 
 static int nilfs_direct_delete(struct nilfs_bmap *bmap, __u64 key)
 {
-	struct nilfs_direct *direct;
+	struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
 	union nilfs_bmap_ptr_req req;
-	struct nilfs_bmap_stats stats;
+	struct inode *dat;
 	int ret;
 
-	direct = (struct nilfs_direct *)bmap;
-	if ((key > NILFS_DIRECT_KEY_MAX) ||
+	if (key > NILFS_DIRECT_KEY_MAX ||
 	    nilfs_direct_get_ptr(direct, key) == NILFS_BMAP_INVALID_PTR)
 		return -ENOENT;
 
-	ret = nilfs_direct_prepare_delete(direct, &req, key, &stats);
-	if (ret < 0)
-		return ret;
-	nilfs_direct_commit_delete(direct, &req, key);
-	nilfs_bmap_sub_blocks(bmap, stats.bs_nblocks);
+	dat = NILFS_BMAP_USE_VBN(bmap) ? nilfs_bmap_get_dat(bmap) : NULL;
+	req.bpr_ptr = nilfs_direct_get_ptr(direct, key);
 
-	return 0;
+	ret = nilfs_bmap_prepare_end_ptr(bmap, &req, dat);
+	if (!ret) {
+		nilfs_bmap_commit_end_ptr(bmap, &req, dat);
+		nilfs_direct_set_ptr(direct, key, NILFS_BMAP_INVALID_PTR);
+		nilfs_bmap_sub_blocks(bmap, 1);
+	}
+	return ret;
 }
 
 static int nilfs_direct_last_key(const struct nilfs_bmap *bmap, __u64 *keyp)
@@ -310,59 +268,56 @@ int nilfs_direct_delete_and_convert(struct nilfs_bmap *bmap,
 	return 0;
 }
 
-static int nilfs_direct_propagate_v(struct nilfs_direct *direct,
+static int nilfs_direct_propagate(const struct nilfs_bmap *bmap,
 				  struct buffer_head *bh)
 {
-	union nilfs_bmap_ptr_req oldreq, newreq;
+	struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
+	struct nilfs_palloc_req oldreq, newreq;
+	struct inode *dat;
 	__u64 key;
 	__u64 ptr;
 	int ret;
 
-	key = nilfs_bmap_data_get_key(&direct->d_bmap, bh);
+	if (!NILFS_BMAP_USE_VBN(bmap))
+		return 0;
+
+	dat = nilfs_bmap_get_dat(bmap);
+	key = nilfs_bmap_data_get_key(bmap, bh);
 	ptr = nilfs_direct_get_ptr(direct, key);
 	if (!buffer_nilfs_volatile(bh)) {
-		oldreq.bpr_ptr = ptr;
-		newreq.bpr_ptr = ptr;
-		ret = nilfs_bmap_prepare_update_v(&direct->d_bmap, &oldreq,
-						  &newreq);
+		oldreq.pr_entry_nr = ptr;
+		newreq.pr_entry_nr = ptr;
+		ret = nilfs_dat_prepare_update(dat, &oldreq, &newreq);
 		if (ret < 0)
 			return ret;
-		nilfs_bmap_commit_update_v(&direct->d_bmap, &oldreq, &newreq);
+		nilfs_dat_commit_update(dat, &oldreq, &newreq,
+					bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
 		set_buffer_nilfs_volatile(bh);
-		nilfs_direct_set_ptr(direct, key, newreq.bpr_ptr);
+		nilfs_direct_set_ptr(direct, key, newreq.pr_entry_nr);
 	} else
-		ret = nilfs_bmap_mark_dirty(&direct->d_bmap, ptr);
+		ret = nilfs_dat_mark_dirty(dat, ptr);
 
 	return ret;
 }
 
-static int nilfs_direct_propagate(const struct nilfs_bmap *bmap,
-				  struct buffer_head *bh)
-{
-	struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
-
-	return NILFS_BMAP_USE_VBN(bmap) ?
-		nilfs_direct_propagate_v(direct, bh) : 0;
-}
-
 static int nilfs_direct_assign_v(struct nilfs_direct *direct,
 				 __u64 key, __u64 ptr,
 				 struct buffer_head **bh,
 				 sector_t blocknr,
 				 union nilfs_binfo *binfo)
 {
+	struct inode *dat = nilfs_bmap_get_dat(&direct->d_bmap);
 	union nilfs_bmap_ptr_req req;
 	int ret;
 
 	req.bpr_ptr = ptr;
-	ret = nilfs_bmap_start_v(&direct->d_bmap, &req, blocknr);
-	if (unlikely(ret < 0))
-		return ret;
-
+	ret = nilfs_dat_prepare_start(dat, &req.bpr_req);
+	if (!ret) {
+		nilfs_dat_commit_start(dat, &req.bpr_req, blocknr);
 		binfo->bi_v.bi_vblocknr = nilfs_bmap_ptr_to_dptr(ptr);
 		binfo->bi_v.bi_blkoff = nilfs_bmap_key_to_dkey(key);
-
-	return 0;
+	}
+	return ret;
 }
 
 static int nilfs_direct_assign_p(struct nilfs_direct *direct,

fs/nilfs2/ifile.h

@@ -31,7 +31,6 @@
 #include "mdt.h"
 #include "alloc.h"
 
-#define NILFS_IFILE_GFP  NILFS_MDT_GFP
 
 static inline struct nilfs_inode *
 nilfs_ifile_map_inode(struct inode *ifile, ino_t ino, struct buffer_head *ibh)

fs/nilfs2/inode.c

@@ -430,7 +430,8 @@ static int __nilfs_read_inode(struct super_block *sb, unsigned long ino,
 
 	raw_inode = nilfs_ifile_map_inode(sbi->s_ifile, ino, bh);
 
-	if (nilfs_read_inode_common(inode, raw_inode))
+	err = nilfs_read_inode_common(inode, raw_inode);
+	if (err)
 		goto failed_unmap;
 
 	if (S_ISREG(inode->i_mode)) {

fs/nilfs2/ioctl.c

@@ -442,12 +442,6 @@ int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *nilfs,
 	const char *msg;
 	int ret;
 
-	ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]);
-	if (ret < 0) {
-		msg = "cannot read source blocks";
-		goto failed;
-	}
-
 	ret = nilfs_ioctl_delete_checkpoints(nilfs, &argv[1], kbufs[1]);
 	if (ret < 0) {
 		/*
@@ -548,8 +542,26 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 		}
 	}
 
+	/*
+	 * nilfs_ioctl_move_blocks() will call nilfs_gc_iget(),
+	 * which will operates an inode list without blocking.
+	 * To protect the list from concurrent operations,
+	 * nilfs_ioctl_move_blocks should be atomic operation.
+	 */
+	if (test_and_set_bit(THE_NILFS_GC_RUNNING, &nilfs->ns_flags)) {
+		ret = -EBUSY;
+		goto out_free;
+	}
+
+	ret = nilfs_ioctl_move_blocks(nilfs, &argv[0], kbufs[0]);
+	if (ret < 0)
+		printk(KERN_ERR "NILFS: GC failed during preparation: "
+			"cannot read source blocks: err=%d\n", ret);
+	else
 		ret = nilfs_clean_segments(inode->i_sb, argv, kbufs);
 
+	clear_nilfs_gc_running(nilfs);
+
  out_free:
 	while (--n >= 0)
 		vfree(kbufs[n]);

fs/nilfs2/mdt.c

@@ -103,15 +103,12 @@ static int nilfs_mdt_create_block(struct inode *inode, unsigned long block,
 		goto failed_unlock;
 
 	err = -EEXIST;
-	if (buffer_uptodate(bh) || buffer_mapped(bh))
+	if (buffer_uptodate(bh))
 		goto failed_bh;
-#if 0
-	/* The uptodate flag is not protected by the page lock, but
-	   the mapped flag is.  Thus, we don't have to wait the buffer. */
+
 	wait_on_buffer(bh);
 	if (buffer_uptodate(bh))
 		goto failed_bh;
-#endif
 
 	bh->b_bdev = nilfs->ns_bdev;
 	err = nilfs_mdt_insert_new_block(inode, block, bh, init_block);
@@ -139,7 +136,7 @@ nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
 		       int mode, struct buffer_head **out_bh)
 {
 	struct buffer_head *bh;
-	unsigned long blknum = 0;
+	__u64 blknum = 0;
 	int ret = -ENOMEM;
 
 	bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
@@ -162,17 +159,15 @@ nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
 		unlock_buffer(bh);
 		goto out;
 	}
-	if (!buffer_mapped(bh)) { /* unused buffer */
-		ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff,
-					&blknum);
+
+	ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
 	if (unlikely(ret)) {
 		unlock_buffer(bh);
 		goto failed_bh;
 	}
 	bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
-		bh->b_blocknr = blknum;
+	bh->b_blocknr = (sector_t)blknum;
 	set_buffer_mapped(bh);
-	}
 
 	bh->b_end_io = end_buffer_read_sync;
 	get_bh(bh);
@@ -402,6 +397,7 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 	struct inode *inode = container_of(page->mapping,
 					   struct inode, i_data);
 	struct super_block *sb = inode->i_sb;
+	struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
 	struct nilfs_sb_info *writer = NULL;
 	int err = 0;
 
@@ -411,9 +407,10 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 	if (page->mapping->assoc_mapping)
 		return 0; /* Do not request flush for shadow page cache */
 	if (!sb) {
-		writer = nilfs_get_writer(NILFS_MDT(inode)->mi_nilfs);
+		down_read(&nilfs->ns_writer_sem);
+		writer = nilfs->ns_writer;
 		if (!writer) {
-			nilfs_put_writer(NILFS_MDT(inode)->mi_nilfs);
+			up_read(&nilfs->ns_writer_sem);
 			return -EROFS;
 		}
 		sb = writer->s_super;
@@ -425,7 +422,7 @@ nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
 		nilfs_flush_segment(sb, inode->i_ino);
 
 	if (writer)
-		nilfs_put_writer(NILFS_MDT(inode)->mi_nilfs);
+		up_read(&nilfs->ns_writer_sem);
 	return err;
 }
 
@@ -516,9 +513,10 @@ nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb,
 }
 
 struct inode *nilfs_mdt_new(struct the_nilfs *nilfs, struct super_block *sb,
-			    ino_t ino, gfp_t gfp_mask)
+			    ino_t ino)
 {
-	struct inode *inode = nilfs_mdt_new_common(nilfs, sb, ino, gfp_mask);
+	struct inode *inode = nilfs_mdt_new_common(nilfs, sb, ino,
+						   NILFS_MDT_GFP);
 
 	if (!inode)
 		return NULL;

fs/nilfs2/mdt.h

@@ -74,8 +74,7 @@ int nilfs_mdt_forget_block(struct inode *, unsigned long);
 int nilfs_mdt_mark_block_dirty(struct inode *, unsigned long);
 int nilfs_mdt_fetch_dirty(struct inode *);
 
-struct inode *nilfs_mdt_new(struct the_nilfs *, struct super_block *, ino_t,
-			    gfp_t);
+struct inode *nilfs_mdt_new(struct the_nilfs *, struct super_block *, ino_t);
 struct inode *nilfs_mdt_new_common(struct the_nilfs *, struct super_block *,
 				   ino_t, gfp_t);
 void nilfs_mdt_destroy(struct inode *);

fs/nilfs2/recovery.c

@@ -552,7 +552,8 @@ static int recover_dsync_blocks(struct nilfs_sb_info *sbi,
 		printk(KERN_WARNING
 		       "NILFS warning: error recovering data block "
 		       "(err=%d, ino=%lu, block-offset=%llu)\n",
-		       err, rb->ino, (unsigned long long)rb->blkoff);
+		       err, (unsigned long)rb->ino,
+		       (unsigned long long)rb->blkoff);
 		if (!err2)
 			err2 = err;
  next:

fs/nilfs2/segbuf.c

@@ -316,10 +316,10 @@ static struct bio *nilfs_alloc_seg_bio(struct super_block *sb, sector_t start,
 {
 	struct bio *bio;
 
-	bio = bio_alloc(GFP_NOWAIT, nr_vecs);
+	bio = bio_alloc(GFP_NOIO, nr_vecs);
 	if (bio == NULL) {
 		while (!bio && (nr_vecs >>= 1))
-			bio = bio_alloc(GFP_NOWAIT, nr_vecs);
+			bio = bio_alloc(GFP_NOIO, nr_vecs);
 	}
 	if (likely(bio)) {
 		bio->bi_bdev = sb->s_bdev;

fs/nilfs2/segment.c

@@ -2501,7 +2501,8 @@ static int nilfs_segctor_construct(struct nilfs_sc_info *sci,
 		if (test_bit(NILFS_SC_SUPER_ROOT, &sci->sc_flags) &&
 		    nilfs_discontinued(nilfs)) {
 			down_write(&nilfs->ns_sem);
-			req->sb_err = nilfs_commit_super(sbi, 0);
+			req->sb_err = nilfs_commit_super(sbi,
+					nilfs_altsb_need_update(nilfs));
 			up_write(&nilfs->ns_sem);
 		}
 	}
@@ -2689,6 +2690,7 @@ static int nilfs_segctor_thread(void *arg)
 	} else {
 		DEFINE_WAIT(wait);
 		int should_sleep = 1;
+		struct the_nilfs *nilfs;
 
 		prepare_to_wait(&sci->sc_wait_daemon, &wait,
 				TASK_INTERRUPTIBLE);
@@ -2709,6 +2711,9 @@ static int nilfs_segctor_thread(void *arg)
 		finish_wait(&sci->sc_wait_daemon, &wait);
 		timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
 			   time_after_eq(jiffies, sci->sc_timer->expires));
+		nilfs = sci->sc_sbi->s_nilfs;
+		if (sci->sc_super->s_dirt && nilfs_sb_need_update(nilfs))
+			set_nilfs_discontinued(nilfs);
 	}
 	goto loop;
 

fs/nilfs2/sufile.h

@@ -28,7 +28,6 @@
 #include <linux/nilfs2_fs.h>
 #include "mdt.h"
 
-#define NILFS_SUFILE_GFP	NILFS_MDT_GFP
 
 static inline unsigned long nilfs_sufile_get_nsegments(struct inode *sufile)
 {

fs/nilfs2/super.c

@@ -50,6 +50,8 @@
 #include <linux/writeback.h>
 #include <linux/kobject.h>
 #include <linux/exportfs.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
 #include "nilfs.h"
 #include "mdt.h"
 #include "alloc.h"
@@ -65,7 +67,6 @@ MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
 		   "(NILFS)");
 MODULE_LICENSE("GPL");
 
-static void nilfs_write_super(struct super_block *sb);
 static int nilfs_remount(struct super_block *sb, int *flags, char *data);
 
 /**
@@ -311,9 +312,6 @@ static void nilfs_put_super(struct super_block *sb)
 
 	lock_kernel();
 
-	if (sb->s_dirt)
-		nilfs_write_super(sb);
-
 	nilfs_detach_segment_constructor(sbi);
 
 	if (!(sb->s_flags & MS_RDONLY)) {
@@ -336,63 +334,21 @@ static void nilfs_put_super(struct super_block *sb)
 	unlock_kernel();
 }
 
-/**
- * nilfs_write_super - write super block(s) of NILFS
- * @sb: super_block
- *
- * nilfs_write_super() gets a fs-dependent lock, writes super block(s), and
- * clears s_dirt.  This function is called in the section protected by
- * lock_super().
- *
- * The s_dirt flag is managed by each filesystem and we protect it by ns_sem
- * of the struct the_nilfs.  Lock order must be as follows:
- *
- *   1. lock_super()
- *   2.    down_write(&nilfs->ns_sem)
- *
- * Inside NILFS, locking ns_sem is enough to protect s_dirt and the buffer
- * of the super block (nilfs->ns_sbp[]).
- *
- * In most cases, VFS functions call lock_super() before calling these
- * methods.  So we must be careful not to bring on deadlocks when using
- * lock_super();  see generic_shutdown_super(), write_super(), and so on.
- *
- * Note that order of lock_kernel() and lock_super() depends on contexts
- * of VFS.  We should also note that lock_kernel() can be used in its
- * protective section and only the outermost one has an effect.
- */
-static void nilfs_write_super(struct super_block *sb)
+static int nilfs_sync_fs(struct super_block *sb, int wait)
 {
 	struct nilfs_sb_info *sbi = NILFS_SB(sb);
 	struct the_nilfs *nilfs = sbi->s_nilfs;
-
-	down_write(&nilfs->ns_sem);
-	if (!(sb->s_flags & MS_RDONLY)) {
-		struct nilfs_super_block **sbp = nilfs->ns_sbp;
-		u64 t = get_seconds();
-		int dupsb;
-
-		if (!nilfs_discontinued(nilfs) && t >= nilfs->ns_sbwtime[0] &&
-		    t < nilfs->ns_sbwtime[0] + NILFS_SB_FREQ) {
-			up_write(&nilfs->ns_sem);
-			return;
-		}
-		dupsb = sbp[1] && t > nilfs->ns_sbwtime[1] + NILFS_ALTSB_FREQ;
-		nilfs_commit_super(sbi, dupsb);
-	}
-	sb->s_dirt = 0;
-	up_write(&nilfs->ns_sem);
-}
-
-static int nilfs_sync_fs(struct super_block *sb, int wait)
-{
 	int err = 0;
 
-	nilfs_write_super(sb);
-
 	/* This function is called when super block should be written back */
 	if (wait)
 		err = nilfs_construct_segment(sb);
+
+	down_write(&nilfs->ns_sem);
+	if (sb->s_dirt)
+		nilfs_commit_super(sbi, 1);
+	up_write(&nilfs->ns_sem);
+
 	return err;
 }
 
@@ -407,8 +363,7 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
 	list_add(&sbi->s_list, &nilfs->ns_supers);
 	up_write(&nilfs->ns_super_sem);
 
-	sbi->s_ifile = nilfs_mdt_new(
-		nilfs, sbi->s_super, NILFS_IFILE_INO, NILFS_IFILE_GFP);
+	sbi->s_ifile = nilfs_mdt_new(nilfs, sbi->s_super, NILFS_IFILE_INO);
 	if (!sbi->s_ifile)
 		return -ENOMEM;
 
@@ -529,6 +484,26 @@ static int nilfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	return 0;
 }
 
+static int nilfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+	struct super_block *sb = vfs->mnt_sb;
+	struct nilfs_sb_info *sbi = NILFS_SB(sb);
+
+	if (!nilfs_test_opt(sbi, BARRIER))
+		seq_printf(seq, ",barrier=off");
+	if (nilfs_test_opt(sbi, SNAPSHOT))
+		seq_printf(seq, ",cp=%llu",
+			   (unsigned long long int)sbi->s_snapshot_cno);
+	if (nilfs_test_opt(sbi, ERRORS_RO))
+		seq_printf(seq, ",errors=remount-ro");
+	if (nilfs_test_opt(sbi, ERRORS_PANIC))
+		seq_printf(seq, ",errors=panic");
+	if (nilfs_test_opt(sbi, STRICT_ORDER))
+		seq_printf(seq, ",order=strict");
+
+	return 0;
+}
+
 static struct super_operations nilfs_sops = {
 	.alloc_inode    = nilfs_alloc_inode,
 	.destroy_inode  = nilfs_destroy_inode,
@@ -538,7 +513,7 @@ static struct super_operations nilfs_sops = {
 	/* .drop_inode	  = nilfs_drop_inode, */
 	.delete_inode   = nilfs_delete_inode,
 	.put_super      = nilfs_put_super,
-	.write_super    = nilfs_write_super,
+	/* .write_super    = nilfs_write_super, */
 	.sync_fs        = nilfs_sync_fs,
 	/* .write_super_lockfs */
 	/* .unlockfs */
@@ -546,7 +521,7 @@ static struct super_operations nilfs_sops = {
 	.remount_fs     = nilfs_remount,
 	.clear_inode    = nilfs_clear_inode,
 	/* .umount_begin */
-	/* .show_options */
+	.show_options = nilfs_show_options
 };
 
 static struct inode *
@@ -816,10 +791,15 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
 
 	if (sb->s_flags & MS_RDONLY) {
 		if (nilfs_test_opt(sbi, SNAPSHOT)) {
+			down_read(&nilfs->ns_segctor_sem);
 			err = nilfs_cpfile_is_snapshot(nilfs->ns_cpfile,
 						       sbi->s_snapshot_cno);
-			if (err < 0)
+			up_read(&nilfs->ns_segctor_sem);
+			if (err < 0) {
+				if (err == -ENOENT)
+					err = -EINVAL;
 				goto failed_sbi;
+			}
 			if (!err) {
 				printk(KERN_ERR
 				       "NILFS: The specified checkpoint is "
@@ -1127,10 +1107,6 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
 	 */
 	sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno);
 
-	if (!sd.cno)
-		/* trying to get the latest checkpoint.  */
-		sd.cno = nilfs_last_cno(nilfs);
-
 	/*
 	 * Get super block instance holding the nilfs_sb_info struct.
 	 * A new instance is allocated if no existing mount is present or

fs/nilfs2/the_nilfs.c

@@ -68,12 +68,11 @@ static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
 
 	nilfs->ns_bdev = bdev;
 	atomic_set(&nilfs->ns_count, 1);
-	atomic_set(&nilfs->ns_writer_refcount, -1);
 	atomic_set(&nilfs->ns_ndirtyblks, 0);
 	init_rwsem(&nilfs->ns_sem);
 	init_rwsem(&nilfs->ns_super_sem);
 	mutex_init(&nilfs->ns_mount_mutex);
-	mutex_init(&nilfs->ns_writer_mutex);
+	init_rwsem(&nilfs->ns_writer_sem);
 	INIT_LIST_HEAD(&nilfs->ns_list);
 	INIT_LIST_HEAD(&nilfs->ns_supers);
 	spin_lock_init(&nilfs->ns_last_segment_lock);
@@ -188,23 +187,19 @@ static int nilfs_load_super_root(struct the_nilfs *nilfs,
 	inode_size = nilfs->ns_inode_size;
 
 	err = -ENOMEM;
-	nilfs->ns_dat = nilfs_mdt_new(
-		nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
+	nilfs->ns_dat = nilfs_mdt_new(nilfs, NULL, NILFS_DAT_INO);
 	if (unlikely(!nilfs->ns_dat))
 		goto failed;
 
-	nilfs->ns_gc_dat = nilfs_mdt_new(
-		nilfs, NULL, NILFS_DAT_INO, NILFS_DAT_GFP);
+	nilfs->ns_gc_dat = nilfs_mdt_new(nilfs, NULL, NILFS_DAT_INO);
 	if (unlikely(!nilfs->ns_gc_dat))
 		goto failed_dat;
 
-	nilfs->ns_cpfile = nilfs_mdt_new(
-		nilfs, NULL, NILFS_CPFILE_INO, NILFS_CPFILE_GFP);
+	nilfs->ns_cpfile = nilfs_mdt_new(nilfs, NULL, NILFS_CPFILE_INO);
 	if (unlikely(!nilfs->ns_cpfile))
 		goto failed_gc_dat;
 
-	nilfs->ns_sufile = nilfs_mdt_new(
-		nilfs, NULL, NILFS_SUFILE_INO, NILFS_SUFILE_GFP);
+	nilfs->ns_sufile = nilfs_mdt_new(nilfs, NULL, NILFS_SUFILE_INO);
 	if (unlikely(!nilfs->ns_sufile))
 		goto failed_cpfile;
 

fs/nilfs2/the_nilfs.h

@@ -37,6 +37,7 @@ enum {
 	THE_NILFS_LOADED,       /* Roll-back/roll-forward has done and
 				   the latest checkpoint was loaded */
 	THE_NILFS_DISCONTINUED,	/* 'next' pointer chain has broken */
+	THE_NILFS_GC_RUNNING,	/* gc process is running */
 };
 
 /**
@@ -50,8 +51,7 @@ enum {
  * @ns_sem: semaphore for shared states
  * @ns_super_sem: semaphore for global operations across super block instances
  * @ns_mount_mutex: mutex protecting mount process of nilfs
- * @ns_writer_mutex: mutex protecting ns_writer attach/detach
- * @ns_writer_refcount: number of referrers on ns_writer
+ * @ns_writer_sem: semaphore protecting ns_writer attach/detach
  * @ns_current: back pointer to current mount
  * @ns_sbh: buffer heads of on-disk super blocks
  * @ns_sbp: pointers to super block data
@@ -100,8 +100,7 @@ struct the_nilfs {
 	struct rw_semaphore	ns_sem;
 	struct rw_semaphore	ns_super_sem;
 	struct mutex		ns_mount_mutex;
-	struct mutex		ns_writer_mutex;
-	atomic_t		ns_writer_refcount;
+	struct rw_semaphore	ns_writer_sem;
 
 	/*
 	 * components protected by ns_super_sem
@@ -197,11 +196,26 @@ static inline int nilfs_##name(struct the_nilfs *nilfs)			\
 THE_NILFS_FNS(INIT, init)
 THE_NILFS_FNS(LOADED, loaded)
 THE_NILFS_FNS(DISCONTINUED, discontinued)
+THE_NILFS_FNS(GC_RUNNING, gc_running)
 
 /* Minimum interval of periodical update of superblocks (in seconds) */
 #define NILFS_SB_FREQ		10
 #define NILFS_ALTSB_FREQ	60  /* spare superblock */
 
+static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
+{
+	u64 t = get_seconds();
+	return t < nilfs->ns_sbwtime[0] ||
+		 t > nilfs->ns_sbwtime[0] + NILFS_SB_FREQ;
+}
+
+static inline int nilfs_altsb_need_update(struct the_nilfs *nilfs)
+{
+	u64 t = get_seconds();
+	struct nilfs_super_block **sbp = nilfs->ns_sbp;
+	return sbp[1] && t > nilfs->ns_sbwtime[1] + NILFS_ALTSB_FREQ;
+}
+
 void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
 struct the_nilfs *find_or_create_nilfs(struct block_device *);
 void put_nilfs(struct the_nilfs *);
@@ -221,34 +235,21 @@ static inline void get_nilfs(struct the_nilfs *nilfs)
 	atomic_inc(&nilfs->ns_count);
 }
 
-static inline struct nilfs_sb_info *nilfs_get_writer(struct the_nilfs *nilfs)
-{
-	if (atomic_inc_and_test(&nilfs->ns_writer_refcount))
-		mutex_lock(&nilfs->ns_writer_mutex);
-	return nilfs->ns_writer;
-}
-
-static inline void nilfs_put_writer(struct the_nilfs *nilfs)
-{
-	if (atomic_add_negative(-1, &nilfs->ns_writer_refcount))
-		mutex_unlock(&nilfs->ns_writer_mutex);
-}
-
 static inline void
 nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
 {
-	mutex_lock(&nilfs->ns_writer_mutex);
+	down_write(&nilfs->ns_writer_sem);
 	nilfs->ns_writer = sbi;
-	mutex_unlock(&nilfs->ns_writer_mutex);
+	up_write(&nilfs->ns_writer_sem);
 }
 
 static inline void
 nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
 {
-	mutex_lock(&nilfs->ns_writer_mutex);
+	down_write(&nilfs->ns_writer_sem);
 	if (sbi == nilfs->ns_writer)
 		nilfs->ns_writer = NULL;
-	mutex_unlock(&nilfs->ns_writer_mutex);
+	up_write(&nilfs->ns_writer_sem);
 }
 
 static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi)