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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2011-05-05 01:23:58 +0900
committerRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2011-05-10 22:21:45 +0900
commit78eb64c2479e0f408b725c3c8e1cdf557857af48 (patch)
tree0aaee16c95e7a1a6ca4b1c7136bebf9dcea48a1b
parentcfb0a4bfd8736418cbe5cbc115cabc84b527111e (diff)
downloadop-kernel-dev-78eb64c2479e0f408b725c3c8e1cdf557857af48.zip
op-kernel-dev-78eb64c2479e0f408b725c3c8e1cdf557857af48.tar.gz
nilfs2: add truncation routine of segment usage file
When shrinking the filesystem, segments to be truncated must be test if they are busy or not, and unneeded sufile block should be deleted. This adds routines for the truncation. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
-rw-r--r--fs/nilfs2/sufile.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index f4374df..22f2e6e 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -98,6 +98,13 @@ nilfs_sufile_get_segment_usage_block(struct inode *sufile, __u64 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)
{
@@ -610,6 +617,111 @@ void nilfs_sufile_do_set_error(struct inode *sufile, __u64 segnum,
}
/**
+ * 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, KM_USER0);
+ 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) &
+ ~(1UL << NILFS_SEGMENT_USAGE_ERROR)) ||
+ nilfs_segment_is_active(nilfs, segnum + j)) {
+ ret = -EBUSY;
+ kunmap_atomic(kaddr, KM_USER0);
+ 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, KM_USER0);
+ if (nc > 0) {
+ nilfs_mdt_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_get_suinfo -
* @sufile: inode of segment usage file
* @segnum: segment number to start looking
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