[PATCH v3 2/3] nilfs2: add nilfs_sufile_set_suinfo to update segment usage

[Andreas Rohner <andreas.rohner-hi6Y0CQ0nG0@public.gmane.org>]

This patch introduces the nilfs_sufile_set_suinfo function, which
expects an array of nilfs_suinfo_update structures and updates the
segment usage information accordingly.

This is basically a helper function for the newly introduced
NILFS_IOCTL_SET_SUINFO ioctl.

Signed-off-by: Andreas Rohner <andreas.rohner-hi6Y0CQ0nG0@public.gmane.org>
---
 fs/nilfs2/sufile.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/nilfs2/sufile.h |   1 +
 2 files changed, 130 insertions(+)

diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index 3127e9f..8922523 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -870,6 +870,135 @@ ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum, void *buf,
 }
 
 /**
+ * nilfs_sufile_set_suinfo - sets segment usage info
+ * @sufile: inode of segment usage file
+ * @buf: array of suinfo_update
+ * @supsz: byte size of suinfo_update
+ * @nsup: size of suinfo_update array
+ *
+ * Description: Takes an array of nilfs_suinfo_update structs and updates
+ * segment usage accordingly. Only the fields indicated by the sup_flags
+ * are updated.
+ *
+ * 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.
+ *
+ * %-EINVAL - Invalid values in input (segment number, flags or nblocks)
+ */
+ssize_t nilfs_sufile_set_suinfo(struct inode *sufile, void *buf,
+				unsigned supsz, size_t nsup)
+{
+	struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
+	struct buffer_head *header_bh, *bh;
+	struct nilfs_suinfo_update *sup, *supend = buf + supsz * nsup;
+	struct nilfs_segment_usage *su;
+	void *kaddr;
+	unsigned long blkoff, prev_blkoff;
+	int ret = 0, ncleansegs, ndirtysegs, cleansi,
+			cleansu, dirtysi, dirtysu;
+
+	if (unlikely(nsup == 0))
+		return ret;
+
+	for (sup = buf; sup < supend; sup = (void *)sup + supsz) {
+		if (sup->sup_segnum >= nilfs->ns_nsegments
+			|| (sup->sup_flags &
+				(~0UL << (NILFS_SUINFO_UPDATE_FLAGS + 1)))
+			|| (nilfs_suinfo_update_nblocks(sup) &&
+				sup->sup_sui.sui_nblocks >
+				nilfs->ns_blocks_per_segment)
+			|| (nilfs_suinfo_update_flags(sup) &&
+				(sup->sup_sui.sui_flags &
+				(~0UL << (NILFS_SEGMENT_USAGE_ERROR + 1)))))
+			return -EINVAL;
+	}
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+
+	ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+	if (ret < 0)
+		goto out_sem;
+
+	sup = buf;
+	blkoff = nilfs_sufile_get_blkoff(sufile, sup->sup_segnum);
+	ret = nilfs_mdt_get_block(sufile, blkoff, 1, NULL, &bh);
+	if (ret < 0)
+		goto out_header;
+
+	for (;;) {
+		kaddr = kmap_atomic(bh->b_page);
+		su = nilfs_sufile_block_get_segment_usage(
+			sufile, sup->sup_segnum, bh, kaddr);
+
+		if (nilfs_suinfo_update_lastmod(sup))
+			su->su_lastmod = cpu_to_le64(sup->sup_sui.sui_lastmod);
+
+		if (nilfs_suinfo_update_nblocks(sup))
+			su->su_nblocks = cpu_to_le32(sup->sup_sui.sui_nblocks);
+
+		if (nilfs_suinfo_update_flags(sup)) {
+			sup->sup_sui.sui_flags &=
+					~(1UL << NILFS_SEGMENT_USAGE_ACTIVE);
+
+			ncleansegs = 0;
+			ndirtysegs = 0;
+			cleansi = nilfs_suinfo_clean(&sup->sup_sui);
+			cleansu = nilfs_segment_usage_clean(su);
+			dirtysi = nilfs_suinfo_dirty(&sup->sup_sui);
+			dirtysu = nilfs_segment_usage_dirty(su);
+
+			if (cleansi && !cleansu)
+				++ncleansegs;
+			else if (!cleansi && cleansu)
+				--ncleansegs;
+
+			if (dirtysi && !dirtysu)
+				++ndirtysegs;
+			else if (!dirtysi && dirtysu)
+				--ndirtysegs;
+
+			su->su_flags = cpu_to_le32(sup->sup_sui.sui_flags);
+
+			nilfs_sufile_mod_counter(header_bh, ncleansegs,
+					ndirtysegs);
+			NILFS_SUI(sufile)->ncleansegs += ncleansegs;
+		}
+
+		kunmap_atomic(kaddr);
+
+		sup = (void *)sup + supsz;
+		if (sup >= supend)
+			break;
+
+		prev_blkoff = blkoff;
+		blkoff = nilfs_sufile_get_blkoff(sufile, sup->sup_segnum);
+		if (blkoff == prev_blkoff)
+			continue;
+
+		/* get different block */
+		mark_buffer_dirty(bh);
+		brelse(bh);
+		ret = nilfs_mdt_get_block(sufile, blkoff, 1, NULL, &bh);
+		if (unlikely(ret < 0))
+			goto out_mark;
+	}
+	mark_buffer_dirty(bh);
+	brelse(bh);
+
+ out_mark:
+	nilfs_mdt_mark_dirty(sufile);
+ out_header:
+	brelse(header_bh);
+ out_sem:
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+/**
  * nilfs_sufile_read - read or get sufile inode
  * @sb: super block instance
  * @susize: size of a segment usage entry
diff --git a/fs/nilfs2/sufile.h b/fs/nilfs2/sufile.h
index e84bc5b..366003c 100644
--- a/fs/nilfs2/sufile.h
+++ b/fs/nilfs2/sufile.h
@@ -44,6 +44,7 @@ int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
 int nilfs_sufile_get_stat(struct inode *, struct nilfs_sustat *);
 ssize_t nilfs_sufile_get_suinfo(struct inode *, __u64, void *, unsigned,
 				size_t);
+ssize_t nilfs_sufile_set_suinfo(struct inode *, void *, unsigned , size_t);
 
 int nilfs_sufile_updatev(struct inode *, __u64 *, size_t, int, size_t *,
 			 void (*dofunc)(struct inode *, __u64,
-- 
1.8.5.3

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