Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1260 insertions, 0 deletions

diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
new file mode 100644
index 000000000..58ca7c936
--- /dev/null
+++ b/fs/nilfs2/sufile.c
@@ -0,0 +1,1260 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * NILFS segment usage file.
+ *
+ * Copyright (C) 2006-2008 Nippon Telegraph and Telephone Corporation.
+ *
+ * Written by Koji Sato.
+ * Revised by Ryusuke Konishi.
+ */
+
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+#include <linux/errno.h>
+#include "mdt.h"
+#include "sufile.h"
+
+#include <trace/events/nilfs2.h>
+
+/**
+ * struct nilfs_sufile_info - on-memory private data of sufile
+ * @mi: on-memory private data of metadata file
+ * @ncleansegs: number of clean segments
+ * @allocmin: lower limit of allocatable segment range
+ * @allocmax: upper limit of allocatable segment range
+ */
+struct nilfs_sufile_info {
+	struct nilfs_mdt_info mi;
+	unsigned long ncleansegs;/* number of clean segments */
+	__u64 allocmin;		/* lower limit of allocatable segment range */
+	__u64 allocmax;		/* upper limit of allocatable segment range */
+};
+
+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)
+{
+	return NILFS_MDT(sufile)->mi_entries_per_block;
+}
+
+static unsigned long
+nilfs_sufile_get_blkoff(const struct inode *sufile, __u64 segnum)
+{
+	__u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
+
+	do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
+	return (unsigned long)t;
+}
+
+static unsigned long
+nilfs_sufile_get_offset(const struct inode *sufile, __u64 segnum)
+{
+	__u64 t = segnum + NILFS_MDT(sufile)->mi_first_entry_offset;
+
+	return do_div(t, nilfs_sufile_segment_usages_per_block(sufile));
+}
+
+static unsigned long
+nilfs_sufile_segment_usages_in_block(const struct inode *sufile, __u64 curr,
+				     __u64 max)
+{
+	return min_t(unsigned long,
+		     nilfs_sufile_segment_usages_per_block(sufile) -
+		     nilfs_sufile_get_offset(sufile, curr),
+		     max - curr + 1);
+}
+
+static struct nilfs_segment_usage *
+nilfs_sufile_block_get_segment_usage(const struct inode *sufile, __u64 segnum,
+				     struct buffer_head *bh, void *kaddr)
+{
+	return kaddr + bh_offset(bh) +
+		nilfs_sufile_get_offset(sufile, segnum) *
+		NILFS_MDT(sufile)->mi_entry_size;
+}
+
+static inline int nilfs_sufile_get_header_block(struct inode *sufile,
+						struct buffer_head **bhp)
+{
+	return nilfs_mdt_get_block(sufile, 0, 0, NULL, bhp);
+}
+
+static inline int
+nilfs_sufile_get_segment_usage_block(struct inode *sufile, __u64 segnum,
+				     int create, struct buffer_head **bhp)
+{
+	return nilfs_mdt_get_block(sufile,
+				   nilfs_sufile_get_blkoff(sufile, segnum),
+				   create, NULL, bhp);
+}
+
+static int nilfs_sufile_delete_segment_usage_block(struct inode *sufile,
+						   __u64 segnum)
+{
+	return nilfs_mdt_delete_block(sufile,
+				      nilfs_sufile_get_blkoff(sufile, segnum));
+}
+
+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);
+	header = kaddr + bh_offset(header_bh);
+	le64_add_cpu(&header->sh_ncleansegs, ncleanadd);
+	le64_add_cpu(&header->sh_ndirtysegs, ndirtyadd);
+	kunmap_atomic(kaddr);
+
+	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))) {
+			nilfs_warn(sufile->i_sb,
+				   "%s: invalid segment number: %llu",
+				   __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))) {
+		nilfs_warn(sufile->i_sb, "%s: invalid segment number: %llu",
+			   __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_set_alloc_range - limit range of segment to be allocated
+ * @sufile: inode of segment usage file
+ * @start: minimum segment number of allocatable region (inclusive)
+ * @end: maximum segment number of allocatable region (inclusive)
+ *
+ * Return Value: On success, 0 is returned.  On error, one of the
+ * following negative error codes is returned.
+ *
+ * %-ERANGE - invalid segment region
+ */
+int nilfs_sufile_set_alloc_range(struct inode *sufile, __u64 start, __u64 end)
+{
+	struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
+	__u64 nsegs;
+	int ret = -ERANGE;
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+	nsegs = nilfs_sufile_get_nsegments(sufile);
+
+	if (start <= end && end < nsegs) {
+		sui->allocmin = start;
+		sui->allocmax = end;
+		ret = 0;
+	}
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+/**
+ * nilfs_sufile_alloc - allocate a segment
+ * @sufile: inode of segment usage file
+ * @segnump: pointer to segment number
+ *
+ * Description: nilfs_sufile_alloc() allocates a clean segment.
+ *
+ * Return Value: On success, 0 is returned and the segment number of the
+ * allocated segment is stored in the place pointed by @segnump. On error, one
+ * of the following negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ *
+ * %-ENOSPC - No clean segment left.
+ */
+int nilfs_sufile_alloc(struct inode *sufile, __u64 *segnump)
+{
+	struct buffer_head *header_bh, *su_bh;
+	struct nilfs_sufile_header *header;
+	struct nilfs_segment_usage *su;
+	struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
+	size_t susz = NILFS_MDT(sufile)->mi_entry_size;
+	__u64 segnum, maxsegnum, last_alloc;
+	void *kaddr;
+	unsigned long nsegments, nsus, cnt;
+	int ret, j;
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+
+	ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+	if (ret < 0)
+		goto out_sem;
+	kaddr = kmap_atomic(header_bh->b_page);
+	header = kaddr + bh_offset(header_bh);
+	last_alloc = le64_to_cpu(header->sh_last_alloc);
+	kunmap_atomic(kaddr);
+
+	nsegments = nilfs_sufile_get_nsegments(sufile);
+	maxsegnum = sui->allocmax;
+	segnum = last_alloc + 1;
+	if (segnum < sui->allocmin || segnum > sui->allocmax)
+		segnum = sui->allocmin;
+
+	for (cnt = 0; cnt < nsegments; cnt += nsus) {
+		if (segnum > maxsegnum) {
+			if (cnt < sui->allocmax - sui->allocmin + 1) {
+				/*
+				 * wrap around in the limited region.
+				 * if allocation started from
+				 * sui->allocmin, this never happens.
+				 */
+				segnum = sui->allocmin;
+				maxsegnum = last_alloc;
+			} else if (segnum > sui->allocmin &&
+				   sui->allocmax + 1 < nsegments) {
+				segnum = sui->allocmax + 1;
+				maxsegnum = nsegments - 1;
+			} else if (sui->allocmin > 0)  {
+				segnum = 0;
+				maxsegnum = sui->allocmin - 1;
+			} else {
+				break; /* never happens */
+			}
+		}
+		trace_nilfs2_segment_usage_check(sufile, segnum, cnt);
+		ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 1,
+							   &su_bh);
+		if (ret < 0)
+			goto out_header;
+		kaddr = kmap_atomic(su_bh->b_page);
+		su = nilfs_sufile_block_get_segment_usage(
+			sufile, segnum, su_bh, kaddr);
+
+		nsus = nilfs_sufile_segment_usages_in_block(
+			sufile, segnum, maxsegnum);
+		for (j = 0; j < nsus; j++, su = (void *)su + susz, segnum++) {
+			if (!nilfs_segment_usage_clean(su))
+				continue;
+			/* found a clean segment */
+			nilfs_segment_usage_set_dirty(su);
+			kunmap_atomic(kaddr);
+
+			kaddr = kmap_atomic(header_bh->b_page);
+			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);
+
+			sui->ncleansegs--;
+			mark_buffer_dirty(header_bh);
+			mark_buffer_dirty(su_bh);
+			nilfs_mdt_mark_dirty(sufile);
+			brelse(su_bh);
+			*segnump = segnum;
+
+			trace_nilfs2_segment_usage_allocated(sufile, segnum);
+
+			goto out_header;
+		}
+
+		kunmap_atomic(kaddr);
+		brelse(su_bh);
+	}
+
+	/* no segments left */
+	ret = -ENOSPC;
+
+ out_header:
+	brelse(header_bh);
+
+ out_sem:
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+void nilfs_sufile_do_cancel_free(struct inode *sufile, __u64 segnum,
+				 struct buffer_head *header_bh,
+				 struct buffer_head *su_bh)
+{
+	struct nilfs_segment_usage *su;
+	void *kaddr;
+
+	kaddr = kmap_atomic(su_bh->b_page);
+	su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+	if (unlikely(!nilfs_segment_usage_clean(su))) {
+		nilfs_warn(sufile->i_sb, "%s: segment %llu must be clean",
+			   __func__, (unsigned long long)segnum);
+		kunmap_atomic(kaddr);
+		return;
+	}
+	nilfs_segment_usage_set_dirty(su);
+	kunmap_atomic(kaddr);
+
+	nilfs_sufile_mod_counter(header_bh, -1, 1);
+	NILFS_SUI(sufile)->ncleansegs--;
+
+	mark_buffer_dirty(su_bh);
+	nilfs_mdt_mark_dirty(sufile);
+}
+
+void nilfs_sufile_do_scrap(struct inode *sufile, __u64 segnum,
+			   struct buffer_head *header_bh,
+			   struct buffer_head *su_bh)
+{
+	struct nilfs_segment_usage *su;
+	void *kaddr;
+	int clean, dirty;
+
+	kaddr = kmap_atomic(su_bh->b_page);
+	su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+	if (su->su_flags == cpu_to_le32(BIT(NILFS_SEGMENT_USAGE_DIRTY)) &&
+	    su->su_nblocks == cpu_to_le32(0)) {
+		kunmap_atomic(kaddr);
+		return;
+	}
+	clean = nilfs_segment_usage_clean(su);
+	dirty = nilfs_segment_usage_dirty(su);
+
+	/* make the segment garbage */
+	su->su_lastmod = cpu_to_le64(0);
+	su->su_nblocks = cpu_to_le32(0);
+	su->su_flags = cpu_to_le32(BIT(NILFS_SEGMENT_USAGE_DIRTY));
+	kunmap_atomic(kaddr);
+
+	nilfs_sufile_mod_counter(header_bh, clean ? (u64)-1 : 0, dirty ? 0 : 1);
+	NILFS_SUI(sufile)->ncleansegs -= clean;
+
+	mark_buffer_dirty(su_bh);
+	nilfs_mdt_mark_dirty(sufile);
+}
+
+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);
+	su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+	if (nilfs_segment_usage_clean(su)) {
+		nilfs_warn(sufile->i_sb, "%s: segment %llu is already clean",
+			   __func__, (unsigned long long)segnum);
+		kunmap_atomic(kaddr);
+		return;
+	}
+	WARN_ON(nilfs_segment_usage_error(su));
+	WARN_ON(!nilfs_segment_usage_dirty(su));
+
+	sudirty = nilfs_segment_usage_dirty(su);
+	nilfs_segment_usage_set_clean(su);
+	kunmap_atomic(kaddr);
+	mark_buffer_dirty(su_bh);
+
+	nilfs_sufile_mod_counter(header_bh, 1, sudirty ? (u64)-1 : 0);
+	NILFS_SUI(sufile)->ncleansegs++;
+
+	nilfs_mdt_mark_dirty(sufile);
+
+	trace_nilfs2_segment_usage_freed(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_mark_dirty(struct inode *sufile, __u64 segnum)
+{
+	struct buffer_head *bh;
+	void *kaddr;
+	struct nilfs_segment_usage *su;
+	int ret;
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+	ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
+	if (ret)
+		goto out_sem;
+
+	kaddr = kmap_atomic(bh->b_page);
+	su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
+	if (unlikely(nilfs_segment_usage_error(su))) {
+		struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
+
+		kunmap_atomic(kaddr);
+		brelse(bh);
+		if (nilfs_segment_is_active(nilfs, segnum)) {
+			nilfs_error(sufile->i_sb,
+				    "active segment %llu is erroneous",
+				    (unsigned long long)segnum);
+		} else {
+			/*
+			 * Segments marked erroneous are never allocated by
+			 * nilfs_sufile_alloc(); only active segments, ie,
+			 * the segments indexed by ns_segnum or ns_nextnum,
+			 * can be erroneous here.
+			 */
+			WARN_ON_ONCE(1);
+		}
+		ret = -EIO;
+	} else {
+		nilfs_segment_usage_set_dirty(su);
+		kunmap_atomic(kaddr);
+		mark_buffer_dirty(bh);
+		nilfs_mdt_mark_dirty(sufile);
+		brelse(bh);
+	}
+out_sem:
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+/**
+ * nilfs_sufile_set_segment_usage - set usage of a segment
+ * @sufile: inode of segment usage file
+ * @segnum: segment number
+ * @nblocks: number of live blocks in the segment
+ * @modtime: modification time (option)
+ */
+int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
+				   unsigned long nblocks, time64_t modtime)
+{
+	struct buffer_head *bh;
+	struct nilfs_segment_usage *su;
+	void *kaddr;
+	int ret;
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+	ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
+	if (ret < 0)
+		goto out_sem;
+
+	kaddr = kmap_atomic(bh->b_page);
+	su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
+	if (modtime) {
+		/*
+		 * Check segusage error and set su_lastmod only when updating
+		 * this entry with a valid timestamp, not for cancellation.
+		 */
+		WARN_ON_ONCE(nilfs_segment_usage_error(su));
+		su->su_lastmod = cpu_to_le64(modtime);
+	}
+	su->su_nblocks = cpu_to_le32(nblocks);
+	kunmap_atomic(kaddr);
+
+	mark_buffer_dirty(bh);
+	nilfs_mdt_mark_dirty(sufile);
+	brelse(bh);
+
+ out_sem:
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+/**
+ * nilfs_sufile_get_stat - get segment usage statistics
+ * @sufile: inode of segment usage file
+ * @sustat: pointer to a structure of segment usage statistics
+ *
+ * Description: nilfs_sufile_get_stat() returns information about segment
+ * usage.
+ *
+ * Return Value: On success, 0 is returned, and segment usage information is
+ * stored in the place pointed by @sustat. 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_stat(struct inode *sufile, struct nilfs_sustat *sustat)
+{
+	struct buffer_head *header_bh;
+	struct nilfs_sufile_header *header;
+	struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
+	void *kaddr;
+	int ret;
+
+	down_read(&NILFS_MDT(sufile)->mi_sem);
+
+	ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+	if (ret < 0)
+		goto out_sem;
+
+	kaddr = kmap_atomic(header_bh->b_page);
+	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->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);
+	brelse(header_bh);
+
+ out_sem:
+	up_read(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+void nilfs_sufile_do_set_error(struct inode *sufile, __u64 segnum,
+			       struct buffer_head *header_bh,
+			       struct buffer_head *su_bh)
+{
+	struct nilfs_segment_usage *su;
+	void *kaddr;
+	int suclean;
+
+	kaddr = kmap_atomic(su_bh->b_page);
+	su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+	if (nilfs_segment_usage_error(su)) {
+		kunmap_atomic(kaddr);
+		return;
+	}
+	suclean = nilfs_segment_usage_clean(su);
+	nilfs_segment_usage_set_error(su);
+	kunmap_atomic(kaddr);
+
+	if (suclean) {
+		nilfs_sufile_mod_counter(header_bh, -1, 0);
+		NILFS_SUI(sufile)->ncleansegs--;
+	}
+	mark_buffer_dirty(su_bh);
+	nilfs_mdt_mark_dirty(sufile);
+}
+
+/**
+ * nilfs_sufile_truncate_range - truncate range of segment array
+ * @sufile: inode of segment usage file
+ * @start: start segment number (inclusive)
+ * @end: end segment number (inclusive)
+ *
+ * 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 number of segments specified
+ *
+ * %-EBUSY - Dirty or active segments are present in the range
+ */
+static int nilfs_sufile_truncate_range(struct inode *sufile,
+				       __u64 start, __u64 end)
+{
+	struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
+	struct buffer_head *header_bh;
+	struct buffer_head *su_bh;
+	struct nilfs_segment_usage *su, *su2;
+	size_t susz = NILFS_MDT(sufile)->mi_entry_size;
+	unsigned long segusages_per_block;
+	unsigned long nsegs, ncleaned;
+	__u64 segnum;
+	void *kaddr;
+	ssize_t n, nc;
+	int ret;
+	int j;
+
+	nsegs = nilfs_sufile_get_nsegments(sufile);
+
+	ret = -EINVAL;
+	if (start > end || start >= nsegs)
+		goto out;
+
+	ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+	if (ret < 0)
+		goto out;
+
+	segusages_per_block = nilfs_sufile_segment_usages_per_block(sufile);
+	ncleaned = 0;
+
+	for (segnum = start; segnum <= end; segnum += n) {
+		n = min_t(unsigned long,
+			  segusages_per_block -
+				  nilfs_sufile_get_offset(sufile, segnum),
+			  end - segnum + 1);
+		ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
+							   &su_bh);
+		if (ret < 0) {
+			if (ret != -ENOENT)
+				goto out_header;
+			/* hole */
+			continue;
+		}
+		kaddr = kmap_atomic(su_bh->b_page);
+		su = nilfs_sufile_block_get_segment_usage(
+			sufile, segnum, su_bh, kaddr);
+		su2 = su;
+		for (j = 0; j < n; j++, su = (void *)su + susz) {
+			if ((le32_to_cpu(su->su_flags) &
+			     ~BIT(NILFS_SEGMENT_USAGE_ERROR)) ||
+			    nilfs_segment_is_active(nilfs, segnum + j)) {
+				ret = -EBUSY;
+				kunmap_atomic(kaddr);
+				brelse(su_bh);
+				goto out_header;
+			}
+		}
+		nc = 0;
+		for (su = su2, j = 0; j < n; j++, su = (void *)su + susz) {
+			if (nilfs_segment_usage_error(su)) {
+				nilfs_segment_usage_set_clean(su);
+				nc++;
+			}
+		}
+		kunmap_atomic(kaddr);
+		if (nc > 0) {
+			mark_buffer_dirty(su_bh);
+			ncleaned += nc;
+		}
+		brelse(su_bh);
+
+		if (n == segusages_per_block) {
+			/* make hole */
+			nilfs_sufile_delete_segment_usage_block(sufile, segnum);
+		}
+	}
+	ret = 0;
+
+out_header:
+	if (ncleaned > 0) {
+		NILFS_SUI(sufile)->ncleansegs += ncleaned;
+		nilfs_sufile_mod_counter(header_bh, ncleaned, 0);
+		nilfs_mdt_mark_dirty(sufile);
+	}
+	brelse(header_bh);
+out:
+	return ret;
+}
+
+/**
+ * nilfs_sufile_resize - resize segment array
+ * @sufile: inode of segment usage file
+ * @newnsegs: new number of segments
+ *
+ * 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.
+ *
+ * %-ENOSPC - Enough free space is not left for shrinking
+ *
+ * %-EBUSY - Dirty or active segments exist in the region to be truncated
+ */
+int nilfs_sufile_resize(struct inode *sufile, __u64 newnsegs)
+{
+	struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
+	struct buffer_head *header_bh;
+	struct nilfs_sufile_header *header;
+	struct nilfs_sufile_info *sui = NILFS_SUI(sufile);
+	void *kaddr;
+	unsigned long nsegs, nrsvsegs;
+	int ret = 0;
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+
+	nsegs = nilfs_sufile_get_nsegments(sufile);
+	if (nsegs == newnsegs)
+		goto out;
+
+	ret = -ENOSPC;
+	nrsvsegs = nilfs_nrsvsegs(nilfs, newnsegs);
+	if (newnsegs < nsegs && nsegs - newnsegs + nrsvsegs > sui->ncleansegs)
+		goto out;
+
+	ret = nilfs_sufile_get_header_block(sufile, &header_bh);
+	if (ret < 0)
+		goto out;
+
+	if (newnsegs > nsegs) {
+		sui->ncleansegs += newnsegs - nsegs;
+	} else /* newnsegs < nsegs */ {
+		ret = nilfs_sufile_truncate_range(sufile, newnsegs, nsegs - 1);
+		if (ret < 0)
+			goto out_header;
+
+		sui->ncleansegs -= nsegs - newnsegs;
+
+		/*
+		 * If the sufile is successfully truncated, immediately adjust
+		 * the segment allocation space while locking the semaphore
+		 * "mi_sem" so that nilfs_sufile_alloc() never allocates
+		 * segments in the truncated space.
+		 */
+		sui->allocmax = newnsegs - 1;
+		sui->allocmin = 0;
+	}
+
+	kaddr = kmap_atomic(header_bh->b_page);
+	header = kaddr + bh_offset(header_bh);
+	header->sh_ncleansegs = cpu_to_le64(sui->ncleansegs);
+	kunmap_atomic(kaddr);
+
+	mark_buffer_dirty(header_bh);
+	nilfs_mdt_mark_dirty(sufile);
+	nilfs_set_nsegments(nilfs, newnsegs);
+
+out_header:
+	brelse(header_bh);
+out:
+	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
+ * @buf: array of suinfo
+ * @sisz: byte size of suinfo
+ * @nsi: size of suinfo array
+ *
+ * Description:
+ *
+ * Return Value: On success, 0 is returned and .... On error, one of the
+ * following negative error codes is returned.
+ *
+ * %-EIO - I/O error.
+ *
+ * %-ENOMEM - Insufficient amount of memory available.
+ */
+ssize_t nilfs_sufile_get_suinfo(struct inode *sufile, __u64 segnum, void *buf,
+				unsigned int 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 = sufile->i_sb->s_fs_info;
+	void *kaddr;
+	unsigned long nsegs, segusages_per_block;
+	ssize_t n;
+	int ret, i, j;
+
+	down_read(&NILFS_MDT(sufile)->mi_sem);
+
+	segusages_per_block = nilfs_sufile_segment_usages_per_block(sufile);
+	nsegs = min_t(unsigned long,
+		      nilfs_sufile_get_nsegments(sufile) - segnum,
+		      nsi);
+	for (i = 0; i < nsegs; i += n, segnum += n) {
+		n = min_t(unsigned long,
+			  segusages_per_block -
+				  nilfs_sufile_get_offset(sufile, segnum),
+			  nsegs - i);
+		ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
+							   &su_bh);
+		if (ret < 0) {
+			if (ret != -ENOENT)
+				goto out;
+			/* hole */
+			memset(si, 0, sisz * n);
+			si = (void *)si + sisz * n;
+			continue;
+		}
+
+		kaddr = kmap_atomic(su_bh->b_page);
+		su = nilfs_sufile_block_get_segment_usage(
+			sufile, segnum, su_bh, kaddr);
+		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) &
+				~BIT(NILFS_SEGMENT_USAGE_ACTIVE);
+			if (nilfs_segment_is_active(nilfs, segnum + j))
+				si->sui_flags |=
+					BIT(NILFS_SEGMENT_USAGE_ACTIVE);
+		}
+		kunmap_atomic(kaddr);
+		brelse(su_bh);
+	}
+	ret = nsegs;
+
+ out:
+	up_read(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+/**
+ * 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 int 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 cleansi, cleansu, dirtysi, dirtysu;
+	long ncleaned = 0, ndirtied = 0;
+	int ret = 0;
+
+	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 << __NR_NILFS_SUINFO_UPDATE_FIELDS))
+			|| (nilfs_suinfo_update_nblocks(sup) &&
+				sup->sup_sui.sui_nblocks >
+				nilfs->ns_blocks_per_segment))
+			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)) {
+			/*
+			 * Active flag is a virtual flag projected by running
+			 * nilfs kernel code - drop it not to write it to
+			 * disk.
+			 */
+			sup->sup_sui.sui_flags &=
+					~BIT(NILFS_SEGMENT_USAGE_ACTIVE);
+
+			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)
+				++ncleaned;
+			else if (!cleansi && cleansu)
+				--ncleaned;
+
+			if (dirtysi && !dirtysu)
+				++ndirtied;
+			else if (!dirtysi && dirtysu)
+				--ndirtied;
+
+			su->su_flags = cpu_to_le32(sup->sup_sui.sui_flags);
+		}
+
+		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);
+		put_bh(bh);
+		ret = nilfs_mdt_get_block(sufile, blkoff, 1, NULL, &bh);
+		if (unlikely(ret < 0))
+			goto out_mark;
+	}
+	mark_buffer_dirty(bh);
+	put_bh(bh);
+
+ out_mark:
+	if (ncleaned || ndirtied) {
+		nilfs_sufile_mod_counter(header_bh, (u64)ncleaned,
+				(u64)ndirtied);
+		NILFS_SUI(sufile)->ncleansegs += ncleaned;
+	}
+	nilfs_mdt_mark_dirty(sufile);
+ out_header:
+	put_bh(header_bh);
+ out_sem:
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+/**
+ * nilfs_sufile_trim_fs() - trim ioctl handle function
+ * @sufile: inode of segment usage file
+ * @range: fstrim_range structure
+ *
+ * start:	First Byte to trim
+ * len:		number of Bytes to trim from start
+ * minlen:	minimum extent length in Bytes
+ *
+ * Decription: nilfs_sufile_trim_fs goes through all segments containing bytes
+ * from start to start+len. start is rounded up to the next block boundary
+ * and start+len is rounded down. For each clean segment blkdev_issue_discard
+ * function is invoked.
+ *
+ * Return Value: On success, 0 is returned or negative error code, otherwise.
+ */
+int nilfs_sufile_trim_fs(struct inode *sufile, struct fstrim_range *range)
+{
+	struct the_nilfs *nilfs = sufile->i_sb->s_fs_info;
+	struct buffer_head *su_bh;
+	struct nilfs_segment_usage *su;
+	void *kaddr;
+	size_t n, i, susz = NILFS_MDT(sufile)->mi_entry_size;
+	sector_t seg_start, seg_end, start_block, end_block;
+	sector_t start = 0, nblocks = 0;
+	u64 segnum, segnum_end, minlen, len, max_blocks, ndiscarded = 0;
+	int ret = 0;
+	unsigned int sects_per_block;
+
+	sects_per_block = (1 << nilfs->ns_blocksize_bits) /
+			bdev_logical_block_size(nilfs->ns_bdev);
+	len = range->len >> nilfs->ns_blocksize_bits;
+	minlen = range->minlen >> nilfs->ns_blocksize_bits;
+	max_blocks = ((u64)nilfs->ns_nsegments * nilfs->ns_blocks_per_segment);
+
+	if (!len || range->start >= max_blocks << nilfs->ns_blocksize_bits)
+		return -EINVAL;
+
+	start_block = (range->start + nilfs->ns_blocksize - 1) >>
+			nilfs->ns_blocksize_bits;
+
+	/*
+	 * range->len can be very large (actually, it is set to
+	 * ULLONG_MAX by default) - truncate upper end of the range
+	 * carefully so as not to overflow.
+	 */
+	if (max_blocks - start_block < len)
+		end_block = max_blocks - 1;
+	else
+		end_block = start_block + len - 1;
+
+	segnum = nilfs_get_segnum_of_block(nilfs, start_block);
+	segnum_end = nilfs_get_segnum_of_block(nilfs, end_block);
+
+	down_read(&NILFS_MDT(sufile)->mi_sem);
+
+	while (segnum <= segnum_end) {
+		n = nilfs_sufile_segment_usages_in_block(sufile, segnum,
+				segnum_end);
+
+		ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0,
+							   &su_bh);
+		if (ret < 0) {
+			if (ret != -ENOENT)
+				goto out_sem;
+			/* hole */
+			segnum += n;
+			continue;
+		}
+
+		kaddr = kmap_atomic(su_bh->b_page);
+		su = nilfs_sufile_block_get_segment_usage(sufile, segnum,
+				su_bh, kaddr);
+		for (i = 0; i < n; ++i, ++segnum, su = (void *)su + susz) {
+			if (!nilfs_segment_usage_clean(su))
+				continue;
+
+			nilfs_get_segment_range(nilfs, segnum, &seg_start,
+						&seg_end);
+
+			if (!nblocks) {
+				/* start new extent */
+				start = seg_start;
+				nblocks = seg_end - seg_start + 1;
+				continue;
+			}
+
+			if (start + nblocks == seg_start) {
+				/* add to previous extent */
+				nblocks += seg_end - seg_start + 1;
+				continue;
+			}
+
+			/* discard previous extent */
+			if (start < start_block) {
+				nblocks -= start_block - start;
+				start = start_block;
+			}
+
+			if (nblocks >= minlen) {
+				kunmap_atomic(kaddr);
+
+				ret = blkdev_issue_discard(nilfs->ns_bdev,
+						start * sects_per_block,
+						nblocks * sects_per_block,
+						GFP_NOFS);
+				if (ret < 0) {
+					put_bh(su_bh);
+					goto out_sem;
+				}
+
+				ndiscarded += nblocks;
+				kaddr = kmap_atomic(su_bh->b_page);
+				su = nilfs_sufile_block_get_segment_usage(
+					sufile, segnum, su_bh, kaddr);
+			}
+
+			/* start new extent */
+			start = seg_start;
+			nblocks = seg_end - seg_start + 1;
+		}
+		kunmap_atomic(kaddr);
+		put_bh(su_bh);
+	}
+
+
+	if (nblocks) {
+		/* discard last extent */
+		if (start < start_block) {
+			nblocks -= start_block - start;
+			start = start_block;
+		}
+		if (start + nblocks > end_block + 1)
+			nblocks = end_block - start + 1;
+
+		if (nblocks >= minlen) {
+			ret = blkdev_issue_discard(nilfs->ns_bdev,
+					start * sects_per_block,
+					nblocks * sects_per_block,
+					GFP_NOFS);
+			if (!ret)
+				ndiscarded += nblocks;
+		}
+	}
+
+out_sem:
+	up_read(&NILFS_MDT(sufile)->mi_sem);
+
+	range->len = ndiscarded << nilfs->ns_blocksize_bits;
+	return ret;
+}
+
+/**
+ * nilfs_sufile_read - read or get sufile inode
+ * @sb: super block instance
+ * @susize: size of a segment usage entry
+ * @raw_inode: on-disk sufile inode
+ * @inodep: buffer to store the inode
+ */
+int nilfs_sufile_read(struct super_block *sb, size_t susize,
+		      struct nilfs_inode *raw_inode, struct inode **inodep)
+{
+	struct inode *sufile;
+	struct nilfs_sufile_info *sui;
+	struct buffer_head *header_bh;
+	struct nilfs_sufile_header *header;
+	void *kaddr;
+	int err;
+
+	if (susize > sb->s_blocksize) {
+		nilfs_err(sb, "too large segment usage size: %zu bytes",
+			  susize);
+		return -EINVAL;
+	} else if (susize < NILFS_MIN_SEGMENT_USAGE_SIZE) {
+		nilfs_err(sb, "too small segment usage size: %zu bytes",
+			  susize);
+		return -EINVAL;
+	}
+
+	sufile = nilfs_iget_locked(sb, NULL, NILFS_SUFILE_INO);
+	if (unlikely(!sufile))
+		return -ENOMEM;
+	if (!(sufile->i_state & I_NEW))
+		goto out;
+
+	err = nilfs_mdt_init(sufile, NILFS_MDT_GFP, sizeof(*sui));
+	if (err)
+		goto failed;
+
+	nilfs_mdt_set_entry_size(sufile, susize,
+				 sizeof(struct nilfs_sufile_header));
+
+	err = nilfs_read_inode_common(sufile, raw_inode);
+	if (err)
+		goto failed;
+
+	err = nilfs_sufile_get_header_block(sufile, &header_bh);
+	if (err)
+		goto failed;
+
+	sui = NILFS_SUI(sufile);
+	kaddr = kmap_atomic(header_bh->b_page);
+	header = kaddr + bh_offset(header_bh);
+	sui->ncleansegs = le64_to_cpu(header->sh_ncleansegs);
+	kunmap_atomic(kaddr);
+	brelse(header_bh);
+
+	sui->allocmax = nilfs_sufile_get_nsegments(sufile) - 1;
+	sui->allocmin = 0;
+
+	unlock_new_inode(sufile);
+ out:
+	*inodep = sufile;
+	return 0;
+ failed:
+	iget_failed(sufile);
+	return err;
+}