diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index a5bd6926f7ffe9741eeddcbd5ce246019728423e..eef5b300b9a9db9b9179115eb17e29f10fc1c4c8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1213,6 +1213,35 @@ static int defrag_collect_targets(struct btrfs_inode *inode,
if (em->generation < newer_than)
goto next;
+ /*
+ * Our start offset might be in the middle of an existing extent
+ * map, so take that into account.
+ */
+ range_len = em->len - (cur - em->start);
+ /*
+ * If this range of the extent map is already flagged for delalloc,
+ * skip it, because:
+ *
+ * 1) We could deadlock later, when trying to reserve space for
+ * delalloc, because in case we can't immediately reserve space
+ * the flusher can start delalloc and wait for the respective
+ * ordered extents to complete. The deadlock would happen
+ * because we do the space reservation while holding the range
+ * locked, and starting writeback, or finishing an ordered
+ * extent, requires locking the range;
+ *
+ * 2) If there's delalloc there, it means there's dirty pages for
+ * which writeback has not started yet (we clean the delalloc
+ * flag when starting writeback and after creating an ordered
+ * extent). If we mark pages in an adjacent range for defrag,
+ * then we will have a larger contiguous range for delalloc,
+ * very likely resulting in a larger extent after writeback is
+ * triggered (except in a case of free space fragmentation).
+ */
+ if (test_range_bit(&inode->io_tree, cur, cur + range_len - 1,
+ EXTENT_DELALLOC, 0, NULL))
+ goto next;
+
/*
* For do_compress case, we want to compress all valid file
* extents, thus no @extent_thresh or mergeable check.
@@ -1221,7 +1250,7 @@ static int defrag_collect_targets(struct btrfs_inode *inode,
goto add;
/* Skip too large extent */
- if (em->len >= extent_thresh)
+ if (range_len >= extent_thresh)
goto next;
next_mergeable = defrag_check_next_extent(&inode->vfs_inode, em,
@@ -1442,9 +1471,11 @@ static int defrag_one_cluster(struct btrfs_inode *inode,
list_for_each_entry(entry, &target_list, list) {
u32 range_len = entry->len;
- /* Reached the limit */
- if (max_sectors && max_sectors == *sectors_defragged)
+ /* Reached or beyond the limit */
+ if (max_sectors && *sectors_defragged >= max_sectors) {
+ ret = 1;
break;
+ }
if (max_sectors)
range_len = min_t(u32, range_len,
@@ -1465,7 +1496,8 @@ static int defrag_one_cluster(struct btrfs_inode *inode,
extent_thresh, newer_than, do_compress);
if (ret < 0)
break;
- *sectors_defragged += range_len;
+ *sectors_defragged += range_len >>
+ inode->root->fs_info->sectorsize_bits;
}
out:
list_for_each_entry_safe(entry, tmp, &target_list, list) {
@@ -1484,6 +1516,12 @@ static int defrag_one_cluster(struct btrfs_inode *inode,
* @newer_than: minimum transid to defrag
* @max_to_defrag: max number of sectors to be defragged, if 0, the whole inode
* will be defragged.
+ *
+ * Return <0 for error.
+ * Return >=0 for the number of sectors defragged, and range->start will be updated
+ * to indicate the file offset where next defrag should be started at.
+ * (Mostly for autodefrag, which sets @max_to_defrag thus we may exit early without
+ * defragging all the range).
*/
int btrfs_defrag_file(struct inode *inode, struct file_ra_state *ra,
struct btrfs_ioctl_defrag_range_args *range,
@@ -1499,6 +1537,7 @@ int btrfs_defrag_file(struct inode *inode, struct file_ra_state *ra,
int compress_type = BTRFS_COMPRESS_ZLIB;
int ret = 0;
u32 extent_thresh = range->extent_thresh;
+ pgoff_t start_index;
if (isize == 0)
return 0;
@@ -1518,12 +1557,16 @@ int btrfs_defrag_file(struct inode *inode, struct file_ra_state *ra,
if (range->start + range->len > range->start) {
/* Got a specific range */
- last_byte = min(isize, range->start + range->len) - 1;
+ last_byte = min(isize, range->start + range->len);
} else {
/* Defrag until file end */
- last_byte = isize - 1;
+ last_byte = isize;
}
+ /* Align the range */
+ cur = round_down(range->start, fs_info->sectorsize);
+ last_byte = round_up(last_byte, fs_info->sectorsize) - 1;
+
/*
* If we were not given a ra, allocate a readahead context. As
* readahead is just an optimization, defrag will work without it so
@@ -1536,16 +1579,26 @@ int btrfs_defrag_file(struct inode *inode, struct file_ra_state *ra,
file_ra_state_init(ra, inode->i_mapping);
}
- /* Align the range */
- cur = round_down(range->start, fs_info->sectorsize);
- last_byte = round_up(last_byte, fs_info->sectorsize) - 1;
+ /*
+ * Make writeback start from the beginning of the range, so that the
+ * defrag range can be written sequentially.
+ */
+ start_index = cur >> PAGE_SHIFT;
+ if (start_index < inode->i_mapping->writeback_index)
+ inode->i_mapping->writeback_index = start_index;
while (cur < last_byte) {
+ const unsigned long prev_sectors_defragged = sectors_defragged;
u64 cluster_end;
/* The cluster size 256K should always be page aligned */
BUILD_BUG_ON(!IS_ALIGNED(CLUSTER_SIZE, PAGE_SIZE));
+ if (btrfs_defrag_cancelled(fs_info)) {
+ ret = -EAGAIN;
+ break;
+ }
+
/* We want the cluster end at page boundary when possible */
cluster_end = (((cur >> PAGE_SHIFT) +
(SZ_256K >> PAGE_SHIFT)) << PAGE_SHIFT) - 1;
@@ -1567,14 +1620,27 @@ int btrfs_defrag_file(struct inode *inode, struct file_ra_state *ra,
cluster_end + 1 - cur, extent_thresh,
newer_than, do_compress,
§ors_defragged, max_to_defrag);
+
+ 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;
+ if (ret > 0) {
+ ret = 0;
+ break;
+ }
}
if (ra_allocated)
kfree(ra);
+ /*
+ * Update range.start for autodefrag, this will indicate where to start
+ * in next run.
+ */
+ range->start = cur;
if (sectors_defragged) {
/*
* We have defragged some sectors, for compression case they