return ret;
}
+ /*
+ * Defrag specific helper to get an extent map.
+ *
+ * Differences between this and btrfs_get_extent() are:
+ *
+ * - No extent_map will be added to inode->extent_tree
+ * To reduce memory usage in the long run.
+ *
+ * - Extra optimization to skip file extents older than @newer_than
+ * By using btrfs_search_forward() we can skip entire file ranges that
+ * have extents created in past transactions, because btrfs_search_forward()
+ * will not visit leaves and nodes with a generation smaller than given
+ * minimal generation threshold (@newer_than).
+ *
+ * Return valid em if we find a file extent matching the requirement.
+ * Return NULL if we can not find a file extent matching the requirement.
+ *
+ * Return ERR_PTR() for error.
+ */
+ static struct extent_map *defrag_get_extent(struct btrfs_inode *inode,
+ u64 start, u64 newer_than)
+ {
+ struct btrfs_root *root = inode->root;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_path path = { 0 };
+ struct extent_map *em;
+ struct btrfs_key key;
+ u64 ino = btrfs_ino(inode);
+ int ret;
+
+ em = alloc_extent_map();
+ if (!em) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ key.objectid = ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = start;
+
+ if (newer_than) {
+ ret = btrfs_search_forward(root, &key, &path, newer_than);
+ if (ret < 0)
+ goto err;
+ /* Can't find anything newer */
+ if (ret > 0)
+ goto not_found;
+ } else {
+ ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
+ if (ret < 0)
+ goto err;
+ }
+ if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
+ /*
+ * If btrfs_search_slot() makes path to point beyond nritems,
+ * we should not have an empty leaf, as this inode must at
+ * least have its INODE_ITEM.
+ */
+ ASSERT(btrfs_header_nritems(path.nodes[0]));
+ path.slots[0] = btrfs_header_nritems(path.nodes[0]) - 1;
+ }
+ btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+ /* Perfect match, no need to go one slot back */
+ if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY &&
+ key.offset == start)
+ goto iterate;
+
+ /* We didn't find a perfect match, needs to go one slot back */
+ if (path.slots[0] > 0) {
+ btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+ if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY)
+ path.slots[0]--;
+ }
+
+ iterate:
+ /* Iterate through the path to find a file extent covering @start */
+ while (true) {
+ u64 extent_end;
+
+ if (path.slots[0] >= btrfs_header_nritems(path.nodes[0]))
+ goto next;
+
+ btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
+
+ /*
+ * We may go one slot back to INODE_REF/XATTR item, then
+ * need to go forward until we reach an EXTENT_DATA.
+ * But we should still has the correct ino as key.objectid.
+ */
+ if (WARN_ON(key.objectid < ino) || key.type < BTRFS_EXTENT_DATA_KEY)
+ goto next;
+
+ /* It's beyond our target range, definitely not extent found */
+ if (key.objectid > ino || key.type > BTRFS_EXTENT_DATA_KEY)
+ goto not_found;
+
+ /*
+ * | |<- File extent ->|
+ * \- start
+ *
+ * This means there is a hole between start and key.offset.
+ */
+ if (key.offset > start) {
+ em->start = start;
+ em->orig_start = start;
+ em->block_start = EXTENT_MAP_HOLE;
+ em->len = key.offset - start;
+ break;
+ }
+
+ fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
+ struct btrfs_file_extent_item);
+ extent_end = btrfs_file_extent_end(&path);
+
+ /*
+ * |<- file extent ->| |
+ * \- start
+ *
+ * We haven't reached start, search next slot.
+ */
+ if (extent_end <= start)
+ goto next;
+
+ /* Now this extent covers @start, convert it to em */
+ btrfs_extent_item_to_extent_map(inode, &path, fi, false, em);
+ break;
+ next:
+ ret = btrfs_next_item(root, &path);
+ if (ret < 0)
+ goto err;
+ if (ret > 0)
+ goto not_found;
+ }
+ btrfs_release_path(&path);
+ return em;
+
+ not_found:
+ btrfs_release_path(&path);
+ free_extent_map(em);
+ return NULL;
+
+ err:
+ btrfs_release_path(&path);
+ free_extent_map(em);
+ return ERR_PTR(ret);
+ }
+
static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start,
- bool locked)
+ u64 newer_than, bool locked)
{
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
em = lookup_extent_mapping(em_tree, start, sectorsize);
read_unlock(&em_tree->lock);
+ /*
+ * We can get a merged extent, in that case, we need to re-search
+ * tree to get the original em for defrag.
+ *
+ * If @newer_than is 0 or em::generation < newer_than, we can trust
+ * this em, as either we don't care about the generation, or the
+ * merged extent map will be rejected anyway.
+ */
+ if (em && test_bit(EXTENT_FLAG_MERGED, &em->flags) &&
+ newer_than && em->generation >= newer_than) {
+ free_extent_map(em);
+ em = NULL;
+ }
+
if (!em) {
struct extent_state *cached = NULL;
u64 end = start + sectorsize - 1;
/* get the big lock and read metadata off disk */
if (!locked)
lock_extent_bits(io_tree, start, end, &cached);
- em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, sectorsize);
+ em = defrag_get_extent(BTRFS_I(inode), start, newer_than);
if (!locked)
unlock_extent_cached(io_tree, start, end, &cached);
return em;
}
+ static u32 get_extent_max_capacity(const struct extent_map *em)
+ {
+ if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
+ return BTRFS_MAX_COMPRESSED;
+ return BTRFS_MAX_EXTENT_SIZE;
+ }
+
static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em,
bool locked)
{
struct extent_map *next;
- bool ret = true;
+ bool ret = false;
/* this is the last extent */
if (em->start + em->len >= i_size_read(inode))
return false;
- next = defrag_lookup_extent(inode, em->start + em->len, locked);
+ /*
+ * We want to check if the next extent can be merged with the current
+ * one, which can be an extent created in a past generation, so we pass
+ * a minimum generation of 0 to defrag_lookup_extent().
+ */
+ next = defrag_lookup_extent(inode, em->start + em->len, 0, locked);
+ /* No more em or hole */
if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
- ret = false;
- else if ((em->block_start + em->block_len == next->block_start) &&
- (em->block_len > SZ_128K && next->block_len > SZ_128K))
- ret = false;
-
+ goto out;
+ if (test_bit(EXTENT_FLAG_PREALLOC, &next->flags))
+ goto out;
+ /*
+ * If the next extent is at its max capacity, defragging current extent
+ * makes no sense, as the total number of extents won't change.
+ */
+ if (next->len >= get_extent_max_capacity(em))
+ goto out;
+ ret = true;
+ out:
free_extent_map(next);
return ret;
}
static int defrag_collect_targets(struct btrfs_inode *inode,
u64 start, u64 len, u32 extent_thresh,
u64 newer_than, bool do_compress,
- bool locked, struct list_head *target_list)
+ bool locked, struct list_head *target_list,
+ u64 *last_scanned_ret)
{
+ bool last_is_target = false;
u64 cur = start;
int ret = 0;
bool next_mergeable = true;
u64 range_len;
- em = defrag_lookup_extent(&inode->vfs_inode, cur, locked);
+ last_is_target = false;
+ em = defrag_lookup_extent(&inode->vfs_inode, cur,
+ newer_than, locked);
if (!em)
break;
if (range_len >= extent_thresh)
goto next;
+ /*
+ * Skip extents already at its max capacity, this is mostly for
+ * compressed extents, which max cap is only 128K.
+ */
+ if (em->len >= get_extent_max_capacity(em))
+ goto next;
+
next_mergeable = defrag_check_next_extent(&inode->vfs_inode, em,
locked);
if (!next_mergeable) {
}
add:
+ last_is_target = true;
range_len = min(extent_map_end(em), start + len) - cur;
/*
* This one is a good target, check if it can be merged into
kfree(entry);
}
}
+ if (!ret && last_scanned_ret) {
+ /*
+ * If the last extent is not a target, the caller can skip to
+ * the end of that extent.
+ * Otherwise, we can only go the end of the specified range.
+ */
+ if (!last_is_target)
+ *last_scanned_ret = max(cur, *last_scanned_ret);
+ else
+ *last_scanned_ret = max(start + len, *last_scanned_ret);
+ }
return ret;
}
}
static int defrag_one_range(struct btrfs_inode *inode, u64 start, u32 len,
- u32 extent_thresh, u64 newer_than, bool do_compress)
+ u32 extent_thresh, u64 newer_than, bool do_compress,
+ u64 *last_scanned_ret)
{
struct extent_state *cached_state = NULL;
struct defrag_target_range *entry;
*/
ret = defrag_collect_targets(inode, start, len, extent_thresh,
newer_than, do_compress, true,
- &target_list);
+ &target_list, last_scanned_ret);
if (ret < 0)
goto unlock_extent;
u64 start, u32 len, u32 extent_thresh,
u64 newer_than, bool do_compress,
unsigned long *sectors_defragged,
- unsigned long max_sectors)
+ unsigned long max_sectors,
+ u64 *last_scanned_ret)
{
const u32 sectorsize = inode->root->fs_info->sectorsize;
struct defrag_target_range *entry;
BUILD_BUG_ON(!IS_ALIGNED(CLUSTER_SIZE, PAGE_SIZE));
ret = defrag_collect_targets(inode, start, len, extent_thresh,
newer_than, do_compress, false,
- &target_list);
+ &target_list, NULL);
if (ret < 0)
goto out;
range_len = min_t(u32, range_len,
(max_sectors - *sectors_defragged) * sectorsize);
+ /*
+ * If defrag_one_range() has updated last_scanned_ret,
+ * our range may already be invalid (e.g. hole punched).
+ * Skip if our range is before last_scanned_ret, as there is
+ * no need to defrag the range anymore.
+ */
+ if (entry->start + range_len <= *last_scanned_ret)
+ continue;
+
if (ra)
page_cache_sync_readahead(inode->vfs_inode.i_mapping,
ra, NULL, entry->start >> PAGE_SHIFT,
* accounting.
*/
ret = defrag_one_range(inode, entry->start, range_len,
- extent_thresh, newer_than, do_compress);
+ extent_thresh, newer_than, do_compress,
+ last_scanned_ret);
if (ret < 0)
break;
*sectors_defragged += range_len >>
list_del_init(&entry->list);
kfree(entry);
}
+ if (ret >= 0)
+ *last_scanned_ret = max(*last_scanned_ret, start + len);
return ret;
}
while (cur < last_byte) {
const unsigned long prev_sectors_defragged = sectors_defragged;
+ u64 last_scanned = cur;
u64 cluster_end;
/* The cluster size 256K should always be page aligned */
BTRFS_I(inode)->defrag_compress = compress_type;
ret = defrag_one_cluster(BTRFS_I(inode), ra, cur,
cluster_end + 1 - cur, extent_thresh,
- newer_than, do_compress,
- §ors_defragged, max_to_defrag);
+ newer_than, do_compress, §ors_defragged,
+ max_to_defrag, &last_scanned);
if (sectors_defragged > prev_sectors_defragged)
balance_dirty_pages_ratelimited(inode->i_mapping);
btrfs_inode_unlock(inode, 0);
if (ret < 0)
break;
- cur = cluster_end + 1;
+ cur = max(cluster_end + 1, last_scanned);
if (ret > 0) {
ret = 0;
break;
btrfs_inode_lock(inode, 0);
err = btrfs_delete_subvolume(dir, dentry);
btrfs_inode_unlock(inode, 0);
- if (!err) {
- fsnotify_rmdir(dir, dentry);
- d_delete(dentry);
- }
+ if (!err)
+ d_delete_notify(dir, dentry);
out_dput:
dput(dentry);
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