xfs: remove duplicated #include
[safe/jmp/linux-2.6] / fs / nilfs2 / sufile.c
index b3674a8..3c6cc60 100644 (file)
@@ -18,6 +18,7 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  *
  * Written by Koji Sato <koji@osrg.net>.
+ * Revised by Ryusuke Konishi <ryusuke@osrg.net>.
  */
 
 #include <linux/kernel.h>
 #include "sufile.h"
 
 
+struct nilfs_sufile_info {
+       struct nilfs_mdt_info mi;
+       unsigned long ncleansegs;
+};
+
+static inline struct nilfs_sufile_info *NILFS_SUI(struct inode *sufile)
+{
+       return (struct nilfs_sufile_info *)NILFS_MDT(sufile);
+}
+
 static inline unsigned long
 nilfs_sufile_segment_usages_per_block(const struct inode *sufile)
 {
@@ -61,14 +72,6 @@ nilfs_sufile_segment_usages_in_block(const struct inode *sufile, __u64 curr,
                     max - curr + 1);
 }
 
-static inline struct nilfs_sufile_header *
-nilfs_sufile_block_get_header(const struct inode *sufile,
-                             struct buffer_head *bh,
-                             void *kaddr)
-{
-       return kaddr + bh_offset(bh);
-}
-
 static struct nilfs_segment_usage *
 nilfs_sufile_block_get_segment_usage(const struct inode *sufile, __u64 segnum,
                                     struct buffer_head *bh, void *kaddr)
@@ -93,6 +96,157 @@ nilfs_sufile_get_segment_usage_block(struct inode *sufile, __u64 segnum,
                                   create, NULL, bhp);
 }
 
+static void nilfs_sufile_mod_counter(struct buffer_head *header_bh,
+                                    u64 ncleanadd, u64 ndirtyadd)
+{
+       struct nilfs_sufile_header *header;
+       void *kaddr;
+
+       kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
+       header = kaddr + bh_offset(header_bh);
+       le64_add_cpu(&header->sh_ncleansegs, ncleanadd);
+       le64_add_cpu(&header->sh_ndirtysegs, ndirtyadd);
+       kunmap_atomic(kaddr, KM_USER0);
+
+       nilfs_mdt_mark_buffer_dirty(header_bh);
+}
+
+/**
+ * nilfs_sufile_get_ncleansegs - return the number of clean segments
+ * @sufile: inode of segment usage file
+ */
+unsigned long nilfs_sufile_get_ncleansegs(struct inode *sufile)
+{
+       return NILFS_SUI(sufile)->ncleansegs;
+}
+
+/**
+ * nilfs_sufile_updatev - modify multiple segment usages at a time
+ * @sufile: inode of segment usage file
+ * @segnumv: array of segment numbers
+ * @nsegs: size of @segnumv array
+ * @create: creation flag
+ * @ndone: place to store number of modified segments on @segnumv
+ * @dofunc: primitive operation for the update
+ *
+ * Description: nilfs_sufile_updatev() repeatedly calls @dofunc
+ * against the given array of segments.  The @dofunc is called with
+ * buffers of a header block and the sufile block in which the target
+ * segment usage entry is contained.  If @ndone is given, the number
+ * of successfully modified segments from the head is stored in the
+ * place @ndone points to.
+ *
+ * Return Value: On success, zero is returned.  On error, one of the
+ * following negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOENT - Given segment usage is in hole block (may be returned if
+ *            @create is zero)
+ *
+ * %-EINVAL - Invalid segment usage number
+ */
+int nilfs_sufile_updatev(struct inode *sufile, __u64 *segnumv, size_t nsegs,
+                        int create, size_t *ndone,
+                        void (*dofunc)(struct inode *, __u64,
+                                       struct buffer_head *,
+                                       struct buffer_head *))
+{
+       struct buffer_head *header_bh, *bh;
+       unsigned long blkoff, prev_blkoff;
+       __u64 *seg;
+       size_t nerr = 0, n = 0;
+       int ret = 0;
+
+       if (unlikely(nsegs == 0))
+               goto out;
+
+       down_write(&NILFS_MDT(sufile)->mi_sem);
+       for (seg = segnumv; seg < segnumv + nsegs; seg++) {
+               if (unlikely(*seg >= nilfs_sufile_get_nsegments(sufile))) {
+                       printk(KERN_WARNING
+                              "%s: invalid segment number: %llu\n", __func__,
+                              (unsigned long long)*seg);
+                       nerr++;
+               }
+       }
+       if (nerr > 0) {
+               ret = -EINVAL;
+               goto out_sem;
+       }
+
+       ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+       if (ret < 0)
+               goto out_sem;
+
+       seg = segnumv;
+       blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
+       ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
+       if (ret < 0)
+               goto out_header;
+
+       for (;;) {
+               dofunc(sufile, *seg, header_bh, bh);
+
+               if (++seg >= segnumv + nsegs)
+                       break;
+               prev_blkoff = blkoff;
+               blkoff = nilfs_sufile_get_blkoff(sufile, *seg);
+               if (blkoff == prev_blkoff)
+                       continue;
+
+               /* get different block */
+               brelse(bh);
+               ret = nilfs_mdt_get_block(sufile, blkoff, create, NULL, &bh);
+               if (unlikely(ret < 0))
+                       goto out_header;
+       }
+       brelse(bh);
+
+ out_header:
+       n = seg - segnumv;
+       brelse(header_bh);
+ out_sem:
+       up_write(&NILFS_MDT(sufile)->mi_sem);
+ out:
+       if (ndone)
+               *ndone = n;
+       return ret;
+}
+
+int nilfs_sufile_update(struct inode *sufile, __u64 segnum, int create,
+                       void (*dofunc)(struct inode *, __u64,
+                                      struct buffer_head *,
+                                      struct buffer_head *))
+{
+       struct buffer_head *header_bh, *bh;
+       int ret;
+
+       if (unlikely(segnum >= nilfs_sufile_get_nsegments(sufile))) {
+               printk(KERN_WARNING "%s: invalid segment number: %llu\n",
+                      __func__, (unsigned long long)segnum);
+               return -EINVAL;
+       }
+       down_write(&NILFS_MDT(sufile)->mi_sem);
+
+       ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+       if (ret < 0)
+               goto out_sem;
+
+       ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, create, &bh);
+       if (!ret) {
+               dofunc(sufile, segnum, header_bh, bh);
+               brelse(bh);
+       }
+       brelse(header_bh);
+
+ out_sem:
+       up_write(&NILFS_MDT(sufile)->mi_sem);
+       return ret;
+}
+
 /**
  * nilfs_sufile_alloc - allocate a segment
  * @sufile: inode of segment usage file
@@ -113,7 +267,6 @@ nilfs_sufile_get_segment_usage_block(struct inode *sufile, __u64 segnum,
 int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 {
        struct buffer_head *header_bh, *su_bh;
-       struct the_nilfs *nilfs;
        struct nilfs_sufile_header *header;
        struct nilfs_segment_usage *su;
        size_t susz = NILFS_MDT(sufile)->mi_entry_size;
@@ -124,13 +277,11 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
 
        down_write(&NILFS_MDT(sufile)->mi_sem);
 
-       nilfs = NILFS_MDT(sufile)->mi_nilfs;
-
        ret = nilfs_sufile_get_header_block(sufile, &header_bh);
        if (ret < 0)
                goto out_sem;
        kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
-       header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
+       header = kaddr + bh_offset(header_bh);
        ncleansegs = le64_to_cpu(header->sh_ncleansegs);
        last_alloc = le64_to_cpu(header->sh_last_alloc);
        kunmap_atomic(kaddr, KM_USER0);
@@ -158,18 +309,17 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
                        if (!nilfs_segment_usage_clean(su))
                                continue;
                        /* found a clean segment */
-                       nilfs_segment_usage_set_active(su);
                        nilfs_segment_usage_set_dirty(su);
                        kunmap_atomic(kaddr, KM_USER0);
 
                        kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
-                       header = nilfs_sufile_block_get_header(
-                               sufile, header_bh, kaddr);
+                       header = kaddr + bh_offset(header_bh);
                        le64_add_cpu(&header->sh_ncleansegs, -1);
                        le64_add_cpu(&header->sh_ndirtysegs, 1);
                        header->sh_last_alloc = cpu_to_le64(segnum);
                        kunmap_atomic(kaddr, KM_USER0);
 
+                       NILFS_SUI(sufile)->ncleansegs--;
                        nilfs_mdt_mark_buffer_dirty(header_bh);
                        nilfs_mdt_mark_buffer_dirty(su_bh);
                        nilfs_mdt_mark_dirty(sufile);
@@ -193,216 +343,142 @@ int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
        return ret;
 }
 
-/**
- * nilfs_sufile_cancel_free -
- * @sufile: inode of segment usage file
- * @segnum: segment number
- *
- * Description:
- *
- * Return Value: On success, 0 is returned. On error, one of the following
- * negative error codes is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- */
-int nilfs_sufile_cancel_free(struct inode *sufile, __u64 segnum)
+void nilfs_sufile_do_cancel_free(struct inode *sufile, __u64 segnum,
+                                struct buffer_head *header_bh,
+                                struct buffer_head *su_bh)
 {
-       struct buffer_head *header_bh, *su_bh;
-       struct the_nilfs *nilfs;
-       struct nilfs_sufile_header *header;
        struct nilfs_segment_usage *su;
        void *kaddr;
-       int ret;
-
-       down_write(&NILFS_MDT(sufile)->mi_sem);
-
-       nilfs = NILFS_MDT(sufile)->mi_nilfs;
-
-       ret = nilfs_sufile_get_header_block(sufile, &header_bh);
-       if (ret < 0)
-               goto out_sem;
-
-       ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &su_bh);
-       if (ret < 0)
-               goto out_header;
 
        kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
-       su = nilfs_sufile_block_get_segment_usage(
-               sufile, segnum, su_bh, kaddr);
-       if (!nilfs_segment_usage_clean(su)) {
-               printk(KERN_CRIT "%s: segment %llu must be clean\n",
+       su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+       if (unlikely(!nilfs_segment_usage_clean(su))) {
+               printk(KERN_WARNING "%s: segment %llu must be clean\n",
                       __func__, (unsigned long long)segnum);
-               BUG();
+               kunmap_atomic(kaddr, KM_USER0);
+               return;
        }
        nilfs_segment_usage_set_dirty(su);
        kunmap_atomic(kaddr, KM_USER0);
 
-       kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
-       header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
-       le64_add_cpu(&header->sh_ncleansegs, -1);
-       le64_add_cpu(&header->sh_ndirtysegs, 1);
-       kunmap_atomic(kaddr, KM_USER0);
+       nilfs_sufile_mod_counter(header_bh, -1, 1);
+       NILFS_SUI(sufile)->ncleansegs--;
 
-       nilfs_mdt_mark_buffer_dirty(header_bh);
        nilfs_mdt_mark_buffer_dirty(su_bh);
        nilfs_mdt_mark_dirty(sufile);
-
-       brelse(su_bh);
-
- out_header:
-       brelse(header_bh);
-
- out_sem:
-       up_write(&NILFS_MDT(sufile)->mi_sem);
-       return ret;
 }
 
-/**
- * nilfs_sufile_freev - free segments
- * @sufile: inode of segment usage file
- * @segnum: array of segment numbers
- * @nsegs: number of segments
- *
- * Description: nilfs_sufile_freev() frees segments specified by @segnum and
- * @nsegs, which must have been returned by a previous call to
- * nilfs_sufile_alloc().
- *
- * Return Value: On success, 0 is returned. On error, one of the following
- * negative error codes is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- */
-#define NILFS_SUFILE_FREEV_PREALLOC    16
-int nilfs_sufile_freev(struct inode *sufile, __u64 *segnum, size_t nsegs)
+void nilfs_sufile_do_scrap(struct inode *sufile, __u64 segnum,
+                          struct buffer_head *header_bh,
+                          struct buffer_head *su_bh)
 {
-       struct buffer_head *header_bh, **su_bh,
-               *su_bh_prealloc[NILFS_SUFILE_FREEV_PREALLOC];
-       struct the_nilfs *nilfs;
-       struct nilfs_sufile_header *header;
        struct nilfs_segment_usage *su;
        void *kaddr;
-       int ret, i;
+       int clean, dirty;
 
-       down_write(&NILFS_MDT(sufile)->mi_sem);
+       kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
+       su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+       if (su->su_flags == cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY) &&
+           su->su_nblocks == cpu_to_le32(0)) {
+               kunmap_atomic(kaddr, KM_USER0);
+               return;
+       }
+       clean = nilfs_segment_usage_clean(su);
+       dirty = nilfs_segment_usage_dirty(su);
 
-       nilfs = NILFS_MDT(sufile)->mi_nilfs;
+       /* make the segment garbage */
+       su->su_lastmod = cpu_to_le64(0);
+       su->su_nblocks = cpu_to_le32(0);
+       su->su_flags = cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY);
+       kunmap_atomic(kaddr, KM_USER0);
 
-       /* prepare resources */
-       if (nsegs <= NILFS_SUFILE_FREEV_PREALLOC)
-               su_bh = su_bh_prealloc;
-       else {
-               su_bh = kmalloc(sizeof(*su_bh) * nsegs, GFP_NOFS);
-               if (su_bh == NULL) {
-                       ret = -ENOMEM;
-                       goto out_sem;
-               }
-       }
+       nilfs_sufile_mod_counter(header_bh, clean ? (u64)-1 : 0, dirty ? 0 : 1);
+       NILFS_SUI(sufile)->ncleansegs -= clean;
 
-       ret = nilfs_sufile_get_header_block(sufile, &header_bh);
-       if (ret < 0)
-               goto out_su_bh;
-       for (i = 0; i < nsegs; i++) {
-               ret = nilfs_sufile_get_segment_usage_block(sufile, segnum[i],
-                                                          0, &su_bh[i]);
-               if (ret < 0)
-                       goto out_bh;
-       }
+       nilfs_mdt_mark_buffer_dirty(su_bh);
+       nilfs_mdt_mark_dirty(sufile);
+}
 
-       /* free segments */
-       for (i = 0; i < nsegs; i++) {
-               kaddr = kmap_atomic(su_bh[i]->b_page, KM_USER0);
-               su = nilfs_sufile_block_get_segment_usage(
-                       sufile, segnum[i], su_bh[i], kaddr);
-               BUG_ON(nilfs_segment_usage_error(su));
-               nilfs_segment_usage_set_clean(su);
+void nilfs_sufile_do_free(struct inode *sufile, __u64 segnum,
+                         struct buffer_head *header_bh,
+                         struct buffer_head *su_bh)
+{
+       struct nilfs_segment_usage *su;
+       void *kaddr;
+       int sudirty;
+
+       kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
+       su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+       if (nilfs_segment_usage_clean(su)) {
+               printk(KERN_WARNING "%s: segment %llu is already clean\n",
+                      __func__, (unsigned long long)segnum);
                kunmap_atomic(kaddr, KM_USER0);
-               nilfs_mdt_mark_buffer_dirty(su_bh[i]);
+               return;
        }
-       kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
-       header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
-       le64_add_cpu(&header->sh_ncleansegs, nsegs);
-       le64_add_cpu(&header->sh_ndirtysegs, -(u64)nsegs);
-       kunmap_atomic(kaddr, KM_USER0);
-       nilfs_mdt_mark_buffer_dirty(header_bh);
-       nilfs_mdt_mark_dirty(sufile);
+       WARN_ON(nilfs_segment_usage_error(su));
+       WARN_ON(!nilfs_segment_usage_dirty(su));
 
- out_bh:
-       for (i--; i >= 0; i--)
-               brelse(su_bh[i]);
-       brelse(header_bh);
+       sudirty = nilfs_segment_usage_dirty(su);
+       nilfs_segment_usage_set_clean(su);
+       kunmap_atomic(kaddr, KM_USER0);
+       nilfs_mdt_mark_buffer_dirty(su_bh);
 
- out_su_bh:
-       if (su_bh != su_bh_prealloc)
-               kfree(su_bh);
+       nilfs_sufile_mod_counter(header_bh, 1, sudirty ? (u64)-1 : 0);
+       NILFS_SUI(sufile)->ncleansegs++;
 
- out_sem:
-       up_write(&NILFS_MDT(sufile)->mi_sem);
-       return ret;
+       nilfs_mdt_mark_dirty(sufile);
 }
 
 /**
- * nilfs_sufile_free -
- * @sufile:
- * @segnum:
+ * nilfs_sufile_mark_dirty - mark the buffer having a segment usage dirty
+ * @sufile: inode of segment usage file
+ * @segnum: segment number
  */
-int nilfs_sufile_free(struct inode *sufile, __u64 segnum)
+int nilfs_sufile_mark_dirty(struct inode *sufile, __u64 segnum)
 {
-       return nilfs_sufile_freev(sufile, &segnum, 1);
+       struct buffer_head *bh;
+       int ret;
+
+       ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
+       if (!ret) {
+               nilfs_mdt_mark_buffer_dirty(bh);
+               nilfs_mdt_mark_dirty(sufile);
+               brelse(bh);
+       }
+       return ret;
 }
 
 /**
- * nilfs_sufile_get_segment_usage - get a segment usage
+ * nilfs_sufile_set_segment_usage - set usage of a segment
  * @sufile: inode of segment usage file
  * @segnum: segment number
- * @sup: pointer to segment usage
- * @bhp: pointer to buffer head
- *
- * Description: nilfs_sufile_get_segment_usage() acquires the segment usage
- * specified by @segnum.
- *
- * Return Value: On success, 0 is returned, and the segment usage and the
- * buffer head of the buffer on which the segment usage is located are stored
- * in the place pointed by @sup and @bhp, respectively. On error, one of the
- * following negative error codes is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- *
- * %-EINVAL - Invalid segment usage number.
+ * @nblocks: number of live blocks in the segment
+ * @modtime: modification time (option)
  */
-int nilfs_sufile_get_segment_usage(struct inode *sufile, __u64 segnum,
-                                  struct nilfs_segment_usage **sup,
-                                  struct buffer_head **bhp)
+int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
+                                  unsigned long nblocks, time_t modtime)
 {
        struct buffer_head *bh;
        struct nilfs_segment_usage *su;
        void *kaddr;
        int ret;
 
-       /* segnum is 0 origin */
-       BUG_ON(segnum >= nilfs_sufile_get_nsegments(sufile));
-
        down_write(&NILFS_MDT(sufile)->mi_sem);
-       ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1, &bh);
+       ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
        if (ret < 0)
                goto out_sem;
-       kaddr = kmap(bh->b_page);
+
+       kaddr = kmap_atomic(bh->b_page, KM_USER0);
        su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
-       if (nilfs_segment_usage_error(su)) {
-               kunmap(bh->b_page);
-               brelse(bh);
-               ret = -EINVAL;
-               goto out_sem;
-       }
+       WARN_ON(nilfs_segment_usage_error(su));
+       if (modtime)
+               su->su_lastmod = cpu_to_le64(modtime);
+       su->su_nblocks = cpu_to_le32(nblocks);
+       kunmap_atomic(kaddr, KM_USER0);
 
-       if (sup != NULL)
-               *sup = su;
-       *bhp = bh;
+       nilfs_mdt_mark_buffer_dirty(bh);
+       nilfs_mdt_mark_dirty(sufile);
+       brelse(bh);
 
  out_sem:
        up_write(&NILFS_MDT(sufile)->mi_sem);
@@ -410,23 +486,6 @@ int nilfs_sufile_get_segment_usage(struct inode *sufile, __u64 segnum,
 }
 
 /**
- * nilfs_sufile_put_segment_usage - put a segment usage
- * @sufile: inode of segment usage file
- * @segnum: segment number
- * @bh: buffer head
- *
- * Description: nilfs_sufile_put_segment_usage() releases the segment usage
- * specified by @segnum. @bh must be the buffer head which have been returned
- * by a previous call to nilfs_sufile_get_segment_usage() with @segnum.
- */
-void nilfs_sufile_put_segment_usage(struct inode *sufile, __u64 segnum,
-                                   struct buffer_head *bh)
-{
-       kunmap(bh->b_page);
-       brelse(bh);
-}
-
-/**
  * nilfs_sufile_get_stat - get segment usage statistics
  * @sufile: inode of segment usage file
  * @stat: pointer to a structure of segment usage statistics
@@ -446,6 +505,7 @@ int nilfs_sufile_get_stat(struct inode *sufile, struct nilfs_sustat *sustat)
 {
        struct buffer_head *header_bh;
        struct nilfs_sufile_header *header;
+       struct the_nilfs *nilfs = NILFS_MDT(sufile)->mi_nilfs;
        void *kaddr;
        int ret;
 
@@ -456,12 +516,15 @@ int nilfs_sufile_get_stat(struct inode *sufile, struct nilfs_sustat *sustat)
                goto out_sem;
 
        kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
-       header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
+       header = kaddr + bh_offset(header_bh);
        sustat->ss_nsegs = nilfs_sufile_get_nsegments(sufile);
        sustat->ss_ncleansegs = le64_to_cpu(header->sh_ncleansegs);
        sustat->ss_ndirtysegs = le64_to_cpu(header->sh_ndirtysegs);
-       sustat->ss_ctime = NILFS_MDT(sufile)->mi_nilfs->ns_ctime;
-       sustat->ss_nongc_ctime = NILFS_MDT(sufile)->mi_nilfs->ns_nongc_ctime;
+       sustat->ss_ctime = nilfs->ns_ctime;
+       sustat->ss_nongc_ctime = nilfs->ns_nongc_ctime;
+       spin_lock(&nilfs->ns_last_segment_lock);
+       sustat->ss_prot_seq = nilfs->ns_prot_seq;
+       spin_unlock(&nilfs->ns_last_segment_lock);
        kunmap_atomic(kaddr, KM_USER0);
        brelse(header_bh);
 
@@ -470,101 +533,38 @@ int nilfs_sufile_get_stat(struct inode *sufile, struct nilfs_sustat *sustat)
        return ret;
 }
 
-/**
- * nilfs_sufile_get_ncleansegs - get the number of clean segments
- * @sufile: inode of segment usage file
- * @nsegsp: pointer to the number of clean segments
- *
- * Description: nilfs_sufile_get_ncleansegs() acquires the number of clean
- * segments.
- *
- * Return Value: On success, 0 is returned and the number of clean segments is
- * stored in the place pointed by @nsegsp. On error, one of the following
- * negative error codes is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- */
-int nilfs_sufile_get_ncleansegs(struct inode *sufile, unsigned long *nsegsp)
+void nilfs_sufile_do_set_error(struct inode *sufile, __u64 segnum,
+                              struct buffer_head *header_bh,
+                              struct buffer_head *su_bh)
 {
-       struct nilfs_sustat sustat;
-       int ret;
-
-       ret = nilfs_sufile_get_stat(sufile, &sustat);
-       if (ret == 0)
-               *nsegsp = sustat.ss_ncleansegs;
-       return ret;
-}
-
-/**
- * nilfs_sufile_set_error - mark a segment as erroneous
- * @sufile: inode of segment usage file
- * @segnum: segment number
- *
- * Description: nilfs_sufile_set_error() marks the segment specified by
- * @segnum as erroneous. The error segment will never be used again.
- *
- * Return Value: On success, 0 is returned. On error, one of the following
- * negative error codes is returned.
- *
- * %-EIO - I/O error.
- *
- * %-ENOMEM - Insufficient amount of memory available.
- */
-int nilfs_sufile_set_error(struct inode *sufile, __u64 segnum)
-{
-       struct buffer_head *header_bh, *su_bh;
        struct nilfs_segment_usage *su;
-       struct nilfs_sufile_header *header;
        void *kaddr;
-       int ret;
-
-       BUG_ON(segnum >= nilfs_sufile_get_nsegments(sufile));
-
-       down_write(&NILFS_MDT(sufile)->mi_sem);
-
-       ret = nilfs_sufile_get_header_block(sufile, &header_bh);
-       if (ret < 0)
-               goto out_sem;
-       ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &su_bh);
-       if (ret < 0)
-               goto out_header;
+       int suclean;
 
        kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
        su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
        if (nilfs_segment_usage_error(su)) {
                kunmap_atomic(kaddr, KM_USER0);
-               brelse(su_bh);
-               goto out_header;
+               return;
        }
-
+       suclean = nilfs_segment_usage_clean(su);
        nilfs_segment_usage_set_error(su);
        kunmap_atomic(kaddr, KM_USER0);
-       brelse(su_bh);
 
-       kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
-       header = nilfs_sufile_block_get_header(sufile, header_bh, kaddr);
-       le64_add_cpu(&header->sh_ndirtysegs, -1);
-       kunmap_atomic(kaddr, KM_USER0);
-       nilfs_mdt_mark_buffer_dirty(header_bh);
+       if (suclean) {
+               nilfs_sufile_mod_counter(header_bh, -1, 0);
+               NILFS_SUI(sufile)->ncleansegs--;
+       }
        nilfs_mdt_mark_buffer_dirty(su_bh);
        nilfs_mdt_mark_dirty(sufile);
-       brelse(su_bh);
-
- out_header:
-       brelse(header_bh);
-
- out_sem:
-       up_write(&NILFS_MDT(sufile)->mi_sem);
-       return ret;
 }
 
 /**
  * nilfs_sufile_get_suinfo -
  * @sufile: inode of segment usage file
  * @segnum: segment number to start looking
- * @si: array of suinfo
+ * @buf: array of suinfo
+ * @sisz: byte size of suinfo
  * @nsi: size of suinfo array
  *
  * Description:
@@ -576,12 +576,14 @@ int nilfs_sufile_set_error(struct inode *sufile, __u64 segnum)
  *
  * %-ENOMEM - Insufficient amount of memory available.
  */
-ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum,
-                               struct nilfs_suinfo *si, size_t nsi)
+ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum, void *buf,
+                               unsigned sisz, size_t nsi)
 {
        struct buffer_head *su_bh;
        struct nilfs_segment_usage *su;
+       struct nilfs_suinfo *si = buf;
        size_t susz = NILFS_MDT(sufile)->mi_entry_size;
+       struct the_nilfs *nilfs = NILFS_MDT(sufile)->mi_nilfs;
        void *kaddr;
        unsigned long nsegs, segusages_per_block;
        ssize_t n;
@@ -604,17 +606,23 @@ ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum,
                        if (ret != -ENOENT)
                                goto out;
                        /* hole */
-                       memset(&si[i], 0, sizeof(struct nilfs_suinfo) * n);
+                       memset(si, 0, sisz * n);
+                       si = (void *)si + sisz * n;
                        continue;
                }
 
                kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
                su = nilfs_sufile_block_get_segment_usage(
                        sufile, segnum, su_bh, kaddr);
-               for (j = 0; j < n; j++, su = (void *)su + susz) {
-                       si[i + j].sui_lastmod = le64_to_cpu(su->su_lastmod);
-                       si[i + j].sui_nblocks = le32_to_cpu(su->su_nblocks);
-                       si[i + j].sui_flags = le32_to_cpu(su->su_flags);
+               for (j = 0; j < n;
+                    j++, su = (void *)su + susz, si = (void *)si + sisz) {
+                       si->sui_lastmod = le64_to_cpu(su->su_lastmod);
+                       si->sui_nblocks = le32_to_cpu(su->su_nblocks);
+                       si->sui_flags = le32_to_cpu(su->su_flags) &
+                               ~(1UL << NILFS_SEGMENT_USAGE_ACTIVE);
+                       if (nilfs_segment_is_active(nilfs, segnum + j))
+                               si->sui_flags |=
+                                       (1UL << NILFS_SEGMENT_USAGE_ACTIVE);
                }
                kunmap_atomic(kaddr, KM_USER0);
                brelse(su_bh);
@@ -625,3 +633,48 @@ ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum,
        up_read(&NILFS_MDT(sufile)->mi_sem);
        return ret;
 }
+
+/**
+ * nilfs_sufile_read - read sufile inode
+ * @sufile: sufile inode
+ * @raw_inode: on-disk sufile inode
+ */
+int nilfs_sufile_read(struct inode *sufile, struct nilfs_inode *raw_inode)
+{
+       struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
+       struct buffer_head *header_bh;
+       struct nilfs_sufile_header *header;
+       void *kaddr;
+       int ret;
+
+       ret = nilfs_read_inode_common(sufile, raw_inode);
+       if (ret < 0)
+               return ret;
+
+       ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+       if (!ret) {
+               kaddr = kmap_atomic(header_bh->b_page, KM_USER0);
+               header = kaddr + bh_offset(header_bh);
+               sui->ncleansegs = le64_to_cpu(header->sh_ncleansegs);
+               kunmap_atomic(kaddr, KM_USER0);
+               brelse(header_bh);
+       }
+       return ret;
+}
+
+/**
+ * nilfs_sufile_new - create sufile
+ * @nilfs: nilfs object
+ * @susize: size of a segment usage entry
+ */
+struct inode *nilfs_sufile_new(struct the_nilfs *nilfs, size_t susize)
+{
+       struct inode *sufile;
+
+       sufile = nilfs_mdt_new(nilfs, NULL, NILFS_SUFILE_INO,
+                              sizeof(struct nilfs_sufile_info));
+       if (sufile)
+               nilfs_mdt_set_entry_size(sufile, susize,
+                                        sizeof(struct nilfs_sufile_header));
+       return sufile;
+}