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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2015-11-06 16:31:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-06 17:50:42 -0800
commitd0c14a9ee79467cd6a04b281577e1e6f74806ab2 (patch)
treea757000613b5d690b972ead91eb5a5adefc8c4b5 /fs/nilfs2/alloc.c
parentda019954dd821682d6b2a8330c9c90acb943c456 (diff)
downloadlinux-d0c14a9ee79467cd6a04b281577e1e6f74806ab2.tar.bz2
nilfs2: free unused dat file blocks during garbage collection
As a nilfs2 volume ages, the amount of available disk space decreases little by little due to bloat of DAT (disk address translation) metadata file. Even if we delete all files in a file system and free their block addresses from the DAT file through a garbage collection, empty DAT blocks are not freed. This fixes the issue by extending the deallocator of block addresses so that empty data blocks and empty bitmap blocks of DAT are deleted. The following comparison shows the effect of this patch. Each shows disk amount information of a nilfs2 volume that we cleaned out by deleting all files and running gc after having filled 90% of its capacity. Before: Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 500105212 3022844 472072192 1% /test After: Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 500105212 16380 475078656 1% /test Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/nilfs2/alloc.c')
-rw-r--r--fs/nilfs2/alloc.c91
1 files changed, 74 insertions, 17 deletions
diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index 225b79768865..b335a32e9561 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -154,13 +154,17 @@ nilfs_palloc_group_desc_nfrees(const struct nilfs_palloc_group_desc *desc,
* @lock: spin lock protecting @desc
* @n: delta to be added
*/
-static void
+static u32
nilfs_palloc_group_desc_add_entries(struct nilfs_palloc_group_desc *desc,
spinlock_t *lock, u32 n)
{
+ u32 nfree;
+
spin_lock(lock);
le32_add_cpu(&desc->pg_nfrees, n);
+ nfree = le32_to_cpu(desc->pg_nfrees);
spin_unlock(lock);
+ return nfree;
}
/**
@@ -735,12 +739,18 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
unsigned char *bitmap;
void *desc_kaddr, *bitmap_kaddr;
unsigned long group, group_offset;
- __u64 group_min_nr;
+ __u64 group_min_nr, last_nrs[8];
const unsigned long epg = nilfs_palloc_entries_per_group(inode);
+ const unsigned epb = NILFS_MDT(inode)->mi_entries_per_block;
+ unsigned entry_start, end, pos;
spinlock_t *lock;
- int i, j, n, ret;
+ int i, j, k, ret;
+ u32 nfree;
for (i = 0; i < nitems; i = j) {
+ int change_group = false;
+ int nempties = 0, n = 0;
+
group = nilfs_palloc_group(inode, entry_nrs[i], &group_offset);
ret = nilfs_palloc_get_desc_block(inode, group, 0, &desc_bh);
if (ret < 0)
@@ -755,17 +765,13 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
/* Get the first entry number of the group */
group_min_nr = (__u64)group * epg;
- desc_kaddr = kmap(desc_bh->b_page);
- desc = nilfs_palloc_block_get_group_desc(
- inode, group, desc_bh, desc_kaddr);
bitmap_kaddr = kmap(bitmap_bh->b_page);
bitmap = bitmap_kaddr + bh_offset(bitmap_bh);
lock = nilfs_mdt_bgl_lock(inode, group);
- for (j = i, n = 0;
- j < nitems && entry_nrs[j] >= group_min_nr &&
- entry_nrs[j] < group_min_nr + epg;
- j++) {
- group_offset = entry_nrs[j] - group_min_nr;
+
+ j = i;
+ entry_start = rounddown(group_offset, epb);
+ do {
if (!nilfs_clear_bit_atomic(lock, group_offset,
bitmap)) {
nilfs_warning(inode->i_sb, __func__,
@@ -775,18 +781,69 @@ int nilfs_palloc_freev(struct inode *inode, __u64 *entry_nrs, size_t nitems)
} else {
n++;
}
- }
- nilfs_palloc_group_desc_add_entries(desc, lock, n);
+
+ j++;
+ if (j >= nitems || entry_nrs[j] < group_min_nr ||
+ entry_nrs[j] >= group_min_nr + epg) {
+ change_group = true;
+ } else {
+ group_offset = entry_nrs[j] - group_min_nr;
+ if (group_offset >= entry_start &&
+ group_offset < entry_start + epb) {
+ /* This entry is in the same block */
+ continue;
+ }
+ }
+
+ /* Test if the entry block is empty or not */
+ end = entry_start + epb;
+ pos = nilfs_find_next_bit(bitmap, end, entry_start);
+ if (pos >= end) {
+ last_nrs[nempties++] = entry_nrs[j - 1];
+ if (nempties >= ARRAY_SIZE(last_nrs))
+ break;
+ }
+
+ if (change_group)
+ break;
+
+ /* Go on to the next entry block */
+ entry_start = rounddown(group_offset, epb);
+ } while (true);
kunmap(bitmap_bh->b_page);
- kunmap(desc_bh->b_page);
+ mark_buffer_dirty(bitmap_bh);
+ brelse(bitmap_bh);
+ for (k = 0; k < nempties; k++) {
+ ret = nilfs_palloc_delete_entry_block(inode,
+ last_nrs[k]);
+ if (ret && ret != -ENOENT) {
+ nilfs_warning(inode->i_sb, __func__,
+ "failed to delete block of entry %llu: ino=%lu, err=%d\n",
+ (unsigned long long)last_nrs[k],
+ (unsigned long)inode->i_ino, ret);
+ }
+ }
+
+ desc_kaddr = kmap_atomic(desc_bh->b_page);
+ desc = nilfs_palloc_block_get_group_desc(
+ inode, group, desc_bh, desc_kaddr);
+ nfree = nilfs_palloc_group_desc_add_entries(desc, lock, n);
+ kunmap_atomic(desc_kaddr);
mark_buffer_dirty(desc_bh);
- mark_buffer_dirty(bitmap_bh);
nilfs_mdt_mark_dirty(inode);
-
- brelse(bitmap_bh);
brelse(desc_bh);
+
+ if (nfree == nilfs_palloc_entries_per_group(inode)) {
+ ret = nilfs_palloc_delete_bitmap_block(inode, group);
+ if (ret && ret != -ENOENT) {
+ nilfs_warning(inode->i_sb, __func__,
+ "failed to delete bitmap block of group %lu: ino=%lu, err=%d\n",
+ group,
+ (unsigned long)inode->i_ino, ret);
+ }
+ }
}
return 0;
}