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-rw-r--r--fs/btrfs/ioctl.c150
1 files changed, 140 insertions, 10 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7875a75315d0..3a89cd77f307 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -475,6 +475,73 @@ out_unlock:
return error;
}
+static int should_defrag_range(struct inode *inode, u64 start, u64 len,
+ u64 *last_len, u64 *skip, u64 *defrag_end)
+{
+ struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+ struct extent_map *em = NULL;
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+ int ret = 1;
+
+ /*
+ * make sure that once we start defragging and extent, we keep on
+ * defragging it
+ */
+ if (start < *defrag_end)
+ return 1;
+
+ *skip = 0;
+
+ /*
+ * hopefully we have this extent in the tree already, try without
+ * the full extent lock
+ */
+ read_lock(&em_tree->lock);
+ em = lookup_extent_mapping(em_tree, start, len);
+ read_unlock(&em_tree->lock);
+
+ if (!em) {
+ /* get the big lock and read metadata off disk */
+ lock_extent(io_tree, start, start + len - 1, GFP_NOFS);
+ em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
+ unlock_extent(io_tree, start, start + len - 1, GFP_NOFS);
+
+ if (!em)
+ return 0;
+ }
+
+ /* this will cover holes, and inline extents */
+ if (em->block_start >= EXTENT_MAP_LAST_BYTE)
+ ret = 0;
+
+ /*
+ * we hit a real extent, if it is big don't bother defragging it again
+ */
+ if ((*last_len == 0 || *last_len >= 256 * 1024) &&
+ em->len >= 256 * 1024)
+ ret = 0;
+
+ /*
+ * last_len ends up being a counter of how many bytes we've defragged.
+ * every time we choose not to defrag an extent, we reset *last_len
+ * so that the next tiny extent will force a defrag.
+ *
+ * The end result of this is that tiny extents before a single big
+ * extent will force at least part of that big extent to be defragged.
+ */
+ if (ret) {
+ *last_len += len;
+ *defrag_end = extent_map_end(em);
+ } else {
+ *last_len = 0;
+ *skip = extent_map_end(em);
+ *defrag_end = 0;
+ }
+
+ free_extent_map(em);
+ return ret;
+}
+
static int btrfs_defrag_file(struct file *file)
{
struct inode *inode = fdentry(file)->d_inode;
@@ -487,37 +554,86 @@ static int btrfs_defrag_file(struct file *file)
unsigned long total_read = 0;
u64 page_start;
u64 page_end;
+ u64 last_len = 0;
+ u64 skip = 0;
+ u64 defrag_end = 0;
unsigned long i;
int ret;
- ret = btrfs_check_data_free_space(root, inode, inode->i_size);
- if (ret)
- return -ENOSPC;
+ if (inode->i_size == 0)
+ return 0;
+
+ last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
+ i = 0;
+ while (i <= last_index) {
+ if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
+ PAGE_CACHE_SIZE, &last_len, &skip,
+ &defrag_end)) {
+ unsigned long next;
+ /*
+ * the should_defrag function tells us how much to skip
+ * bump our counter by the suggested amount
+ */
+ next = (skip + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ i = max(i + 1, next);
+ continue;
+ }
- mutex_lock(&inode->i_mutex);
- last_index = inode->i_size >> PAGE_CACHE_SHIFT;
- for (i = 0; i <= last_index; i++) {
if (total_read % ra_pages == 0) {
btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
min(last_index, i + ra_pages - 1));
}
total_read++;
+ mutex_lock(&inode->i_mutex);
+
+ ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
+ if (ret) {
+ ret = -ENOSPC;
+ break;
+ }
+
+ ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
+ if (ret) {
+ btrfs_free_reserved_data_space(root, inode,
+ PAGE_CACHE_SIZE);
+ ret = -ENOSPC;
+ break;
+ }
again:
+ if (inode->i_size == 0 ||
+ i > ((inode->i_size - 1) >> PAGE_CACHE_SHIFT)) {
+ ret = 0;
+ goto err_reservations;
+ }
+
page = grab_cache_page(inode->i_mapping, i);
if (!page)
- goto out_unlock;
+ goto err_reservations;
+
if (!PageUptodate(page)) {
btrfs_readpage(NULL, page);
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
page_cache_release(page);
- goto out_unlock;
+ goto err_reservations;
}
}
+ if (page->mapping != inode->i_mapping) {
+ unlock_page(page);
+ page_cache_release(page);
+ goto again;
+ }
+
wait_on_page_writeback(page);
+ if (PageDirty(page)) {
+ btrfs_free_reserved_data_space(root, inode,
+ PAGE_CACHE_SIZE);
+ goto loop_unlock;
+ }
+
page_start = (u64)page->index << PAGE_CACHE_SHIFT;
page_end = page_start + PAGE_CACHE_SIZE - 1;
lock_extent(io_tree, page_start, page_end, GFP_NOFS);
@@ -538,18 +654,32 @@ again:
* page if it is dirtied again later
*/
clear_page_dirty_for_io(page);
+ clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start,
+ page_end, EXTENT_DIRTY | EXTENT_DELALLOC |
+ EXTENT_DO_ACCOUNTING, GFP_NOFS);
btrfs_set_extent_delalloc(inode, page_start, page_end);
+ ClearPageChecked(page);
set_page_dirty(page);
unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
+
+loop_unlock:
unlock_page(page);
page_cache_release(page);
+ mutex_unlock(&inode->i_mutex);
+
+ btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
+ i++;
}
-out_unlock:
- mutex_unlock(&inode->i_mutex);
return 0;
+
+err_reservations:
+ mutex_unlock(&inode->i_mutex);
+ btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
+ btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
+ return ret;
}
static noinline int btrfs_ioctl_resize(struct btrfs_root *root,