* [PATCH] Btrfs: implement support for fallocate collapse range
@ 2014-06-23 10:25 Filipe David Borba Manana
2014-07-02 15:11 ` Filipe David Manana
2014-07-03 4:46 ` Chandan Rajendra
0 siblings, 2 replies; 4+ messages in thread
From: Filipe David Borba Manana @ 2014-06-23 10:25 UTC (permalink / raw)
To: linux-btrfs; +Cc: Filipe David Borba Manana
This implements fallocate's FALLOC_FL_COLLAPSE_RANGE operation for
BTRFS. This fallocate operation was introduced in the linux kernel
version 3.15.
Existing tests in xfstests already test this operation explicitly
and implicitly via fsstress.
Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
---
fs/btrfs/ctree.c | 42 ++++-
fs/btrfs/ctree.h | 2 +
fs/btrfs/extent-tree.c | 30 +--
fs/btrfs/file.c | 486 +++++++++++++++++++++++++++++++++++++++++--------
4 files changed, 453 insertions(+), 107 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index aeab453..8f1a371 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2825,12 +2825,12 @@ cow_done:
* It is safe to drop the lock on our parent before we
* go through the expensive btree search on b.
*
- * If we're inserting or deleting (ins_len != 0), then we might
- * be changing slot zero, which may require changing the parent.
- * So, we can't drop the lock until after we know which slot
- * we're operating on.
+ * If we're inserting, deleting or updating a key (cow != 0),
+ * then we might be changing slot zero, which may require
+ * changing the parent. So, we can't drop the lock until after
+ * we know which slot we're operating on.
*/
- if (!ins_len && !p->keep_locks) {
+ if (!cow && !p->keep_locks) {
int u = level + 1;
if (u < BTRFS_MAX_LEVEL && p->locks[u]) {
@@ -2865,7 +2865,7 @@ cow_done:
* which means we must have a write lock
* on the parent
*/
- if (slot == 0 && ins_len &&
+ if (slot == 0 && cow &&
write_lock_level < level + 1) {
write_lock_level = level + 1;
btrfs_release_path(p);
@@ -5660,6 +5660,36 @@ next:
}
/*
+ * This differs from btrfs_find_next_key in that it ignores leaf/node
+ * generations and it doesn't unlock and re-lock nodes/leaves nor does
+ * any subsequent searches (calls to btrfs_search_slot), preserving the
+ * locks in the given path.
+ *
+ * Returns 0 if a next key exists, 1 otherwise.
+ */
+int btrfs_find_next_current_key(struct btrfs_path *path, int level,
+ struct btrfs_key *key)
+
+{
+ for (; level < BTRFS_MAX_LEVEL; level++) {
+ if (!path->nodes[level])
+ break;
+ if (path->slots[level] + 1 >=
+ btrfs_header_nritems(path->nodes[level]))
+ continue;
+ if (level == 0)
+ btrfs_item_key_to_cpu(path->nodes[level], key,
+ path->slots[level] + 1);
+ else
+ btrfs_node_key_to_cpu(path->nodes[level], key,
+ path->slots[level] + 1);
+ return 0;
+ }
+ return 1;
+}
+
+
+/*
* search the tree again to find a leaf with greater keys
* returns 0 if it found something or 1 if there are no greater leaves.
* returns < 0 on io errors.
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index b7e2c1c..166a35f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3446,6 +3446,8 @@ struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *key, int lowest_level,
u64 min_trans);
+int btrfs_find_next_current_key(struct btrfs_path *path, int level,
+ struct btrfs_key *key);
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
struct btrfs_path *path,
u64 min_trans);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fafb3e5..a6d0ec7 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -100,8 +100,6 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
static int do_chunk_alloc(struct btrfs_trans_handle *trans,
struct btrfs_root *extent_root, u64 flags,
int force);
-static int find_next_key(struct btrfs_path *path, int level,
- struct btrfs_key *key);
static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
int dump_block_groups);
static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
@@ -440,7 +438,7 @@ next:
if (path->slots[0] < nritems) {
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
} else {
- ret = find_next_key(path, 0, &key);
+ ret = btrfs_find_next_current_key(path, 0, &key);
if (ret)
break;
@@ -1443,27 +1441,6 @@ static inline int extent_ref_type(u64 parent, u64 owner)
return type;
}
-static int find_next_key(struct btrfs_path *path, int level,
- struct btrfs_key *key)
-
-{
- for (; level < BTRFS_MAX_LEVEL; level++) {
- if (!path->nodes[level])
- break;
- if (path->slots[level] + 1 >=
- btrfs_header_nritems(path->nodes[level]))
- continue;
- if (level == 0)
- btrfs_item_key_to_cpu(path->nodes[level], key,
- path->slots[level] + 1);
- else
- btrfs_node_key_to_cpu(path->nodes[level], key,
- path->slots[level] + 1);
- return 0;
- }
- return 1;
-}
-
/*
* look for inline back ref. if back ref is found, *ref_ret is set
* to the address of inline back ref, and 0 is returned.
@@ -1651,7 +1628,7 @@ again:
* For simplicity, we just do not add new inline back
* ref if there is any kind of item for this block
*/
- if (find_next_key(path, 0, &key) == 0 &&
+ if (btrfs_find_next_current_key(path, 0, &key) == 0 &&
key.objectid == bytenr &&
key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
err = -EAGAIN;
@@ -7649,7 +7626,8 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
if (level < wc->shared_level)
goto out;
- ret = find_next_key(path, level + 1, &wc->update_progress);
+ ret = btrfs_find_next_current_key(path, level + 1,
+ &wc->update_progress);
if (ret > 0)
wc->update_ref = 0;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index ad7c059..c306ce4 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -2087,6 +2087,44 @@ static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
return 0;
}
+static void fill_hole_em(struct extent_map *em,
+ struct btrfs_trans_handle *trans,
+ struct inode *inode,
+ const u64 start,
+ const u64 len)
+{
+ em->start = start;
+ em->len = len;
+ em->ram_bytes = em->len;
+ em->orig_start = start;
+ em->block_start = EXTENT_MAP_HOLE;
+ em->block_len = 0;
+ em->orig_block_len = 0;
+ em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
+ em->compress_type = BTRFS_COMPRESS_NONE;
+ em->generation = trans->transid;
+}
+
+static void replace_inode_em(struct extent_map *em, struct inode *inode)
+{
+ struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+ int ret;
+
+ while (1) {
+ write_lock(&em_tree->lock);
+ ret = add_extent_mapping(em_tree, em, 1);
+ write_unlock(&em_tree->lock);
+ if (ret != -EEXIST)
+ break;
+ btrfs_drop_extent_cache(inode, em->start,
+ em->start + em->len - 1, 0);
+ };
+ free_extent_map(em);
+ if (ret)
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+ &BTRFS_I(inode)->runtime_flags);
+}
+
static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
struct btrfs_path *path, u64 offset, u64 end)
{
@@ -2094,7 +2132,6 @@ static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct extent_map *hole_em;
- struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct btrfs_key key;
int ret;
@@ -2159,28 +2196,8 @@ out:
set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
} else {
- hole_em->start = offset;
- hole_em->len = end - offset;
- hole_em->ram_bytes = hole_em->len;
- hole_em->orig_start = offset;
-
- hole_em->block_start = EXTENT_MAP_HOLE;
- hole_em->block_len = 0;
- hole_em->orig_block_len = 0;
- hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
- hole_em->compress_type = BTRFS_COMPRESS_NONE;
- hole_em->generation = trans->transid;
-
- do {
- btrfs_drop_extent_cache(inode, offset, end - 1, 0);
- write_lock(&em_tree->lock);
- ret = add_extent_mapping(em_tree, hole_em, 1);
- write_unlock(&em_tree->lock);
- } while (ret == -EEXIST);
- free_extent_map(hole_em);
- if (ret)
- set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
- &BTRFS_I(inode)->runtime_flags);
+ fill_hole_em(hole_em, trans, inode, offset, end - offset);
+ replace_inode_em(hole_em, inode);
}
return 0;
@@ -2217,6 +2234,80 @@ static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len)
return ret;
}
+static int wait_lock_ordered_range(struct inode *inode,
+ const u64 lockstart,
+ const u64 lockend,
+ struct extent_state **cached_state)
+{
+ while (1) {
+ struct btrfs_ordered_extent *ordered;
+ int ret;
+
+ truncate_pagecache_range(inode, lockstart, lockend);
+
+ lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+ 0, cached_state);
+ ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
+
+ /*
+ * We need to make sure we have no ordered extents in this range
+ * and nobody raced in and read a page in this range, if we did
+ * we need to try again.
+ */
+ if ((!ordered ||
+ (ordered->file_offset + ordered->len <= lockstart ||
+ ordered->file_offset > lockend)) &&
+ !btrfs_page_exists_in_range(inode, lockstart, lockend)) {
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+ break;
+ }
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
+ lockend, cached_state, GFP_NOFS);
+ ret = btrfs_wait_ordered_range(inode, lockstart,
+ lockend - lockstart + 1);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int fallocate_restart_transaction(struct btrfs_trans_handle **trans,
+ struct inode *inode,
+ const int trans_units,
+ const int min_size)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_block_rsv *rsv = (*trans)->block_rsv;
+ int ret;
+
+ (*trans)->block_rsv = &root->fs_info->trans_block_rsv;
+ ret = btrfs_update_inode(*trans, root, inode);
+ if (ret)
+ return ret;
+
+ btrfs_end_transaction(*trans, root);
+ btrfs_btree_balance_dirty(root);
+
+ *trans = btrfs_start_transaction(root, trans_units);
+ if (IS_ERR(*trans)) {
+ ret = PTR_ERR(*trans);
+ *trans = NULL;
+ return ret;
+ }
+
+ ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
+ rsv, min_size);
+ if (unlikely(ret))
+ return ret;
+ (*trans)->block_rsv = rsv;
+
+ return 0;
+}
+
static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -2324,38 +2415,10 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
return 0;
}
- while (1) {
- struct btrfs_ordered_extent *ordered;
-
- truncate_pagecache_range(inode, lockstart, lockend);
-
- lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
- 0, &cached_state);
- ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
-
- /*
- * We need to make sure we have no ordered extents in this range
- * and nobody raced in and read a page in this range, if we did
- * we need to try again.
- */
- if ((!ordered ||
- (ordered->file_offset + ordered->len <= lockstart ||
- ordered->file_offset > lockend)) &&
- !btrfs_page_exists_in_range(inode, lockstart, lockend)) {
- if (ordered)
- btrfs_put_ordered_extent(ordered);
- break;
- }
- if (ordered)
- btrfs_put_ordered_extent(ordered);
- unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
- lockend, &cached_state, GFP_NOFS);
- ret = btrfs_wait_ordered_range(inode, lockstart,
- lockend - lockstart + 1);
- if (ret) {
- mutex_unlock(&inode->i_mutex);
- return ret;
- }
+ ret = wait_lock_ordered_range(inode, lockstart, lockend, &cached_state);
+ if (ret) {
+ mutex_unlock(&inode->i_mutex);
+ return ret;
}
path = btrfs_alloc_path();
@@ -2411,26 +2474,11 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
cur_offset = drop_end;
- ret = btrfs_update_inode(trans, root, inode);
- if (ret) {
- err = ret;
- break;
- }
-
- btrfs_end_transaction(trans, root);
- btrfs_btree_balance_dirty(root);
-
- trans = btrfs_start_transaction(root, rsv_count);
- if (IS_ERR(trans)) {
- ret = PTR_ERR(trans);
- trans = NULL;
- break;
- }
-
- ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
- rsv, min_size);
- BUG_ON(ret); /* shouldn't happen */
trans->block_rsv = rsv;
+ ret = fallocate_restart_transaction(&trans, inode, rsv_count,
+ min_size);
+ if (ret)
+ break;
ret = find_first_non_hole(inode, &cur_offset, &len);
if (unlikely(ret < 0))
@@ -2484,6 +2532,291 @@ out_only_mutex:
return err;
}
+static int collapse_file_extents(struct inode *inode,
+ struct btrfs_trans_handle **trans,
+ struct btrfs_path *path,
+ const u64 start,
+ const u64 len)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ struct btrfs_file_extent_item *fi;
+ struct extent_map *em;
+ const u64 ino = btrfs_ino(inode);
+ bool last_leaf = false;
+ bool retry_on_enospc = true;
+ u64 last_extent_end = start - len;
+ int slot;
+ int ret;
+ const u64 new_file_size = i_size_read(inode) - len;
+ const u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
+
+ /*
+ * Start tree search from left (lower file offsets) to right (higher
+ * file offsets), to avoid leaving duplicated keys in the tree at
+ * any time.
+ */
+ key.objectid = ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ key.offset = start;
+again:
+ if (key.objectid > ino || key.type != BTRFS_EXTENT_DATA_KEY)
+ goto done;
+ path->keep_locks = 1;
+ ret = btrfs_search_slot(*trans, root, &key, path, 0, 1);
+ if (ret == -ENOSPC && retry_on_enospc) {
+ ret = fallocate_restart_transaction(trans, inode, 2, min_size);
+ if (ret)
+ goto out;
+ retry_on_enospc = false;
+ goto again;
+ } else if (ret < 0) {
+ goto out;
+ }
+
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+ path->slots[0] = btrfs_header_nritems(leaf);
+ /*
+ * Get smallest key of the next leaf to use to get into the next leaf.
+ * This is to avoid ending up in the same leaf again and over again
+ * after processing a full leaf, which is more likely to happen in
+ * the case of implicit holes (NO_HOLES feature).
+ */
+ ret = btrfs_find_next_current_key(path, 0, &key);
+ if (ret > 0)
+ last_leaf = true;
+ path->slots[0] = slot;
+ retry_on_enospc = true;
+
+ while (1) {
+ u64 extent_len, disk_bytenr, num_bytes, extent_offset;
+ int extent_type;
+ struct btrfs_key found_key, new_key;
+
+ if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+ btrfs_release_path(path);
+ if (last_leaf)
+ break;
+ else
+ goto again;
+ }
+
+ if (path->slots[0] > 0) {
+ path->keep_locks = 0;
+ btrfs_unlock_up_safe(path, 1);
+ }
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.objectid != ino)
+ break;
+ if (found_key.type != BTRFS_EXTENT_DATA_KEY)
+ break;
+ ASSERT(found_key.offset >= start);
+
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ extent_type = btrfs_file_extent_type(leaf, fi);
+ /* Inline extents are always at file offset 0. */
+ ASSERT(extent_type != BTRFS_FILE_EXTENT_INLINE);
+
+ extent_len = btrfs_file_extent_num_bytes(leaf, fi);
+ disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+ num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+ extent_offset = btrfs_file_extent_offset(leaf, fi);
+
+ memcpy(&new_key, &found_key, sizeof(new_key));
+ new_key.offset -= len;
+ btrfs_set_item_key_safe(root, path, &new_key);
+
+ if (disk_bytenr == 0)
+ goto setup_ems;
+
+ ret = btrfs_inc_extent_ref(*trans, root, disk_bytenr, num_bytes,
+ 0, root->root_key.objectid, ino,
+ new_key.offset - extent_offset, 1);
+ if (ret)
+ goto out;
+ ret = btrfs_free_extent(*trans, root, disk_bytenr, num_bytes, 0,
+ root->root_key.objectid, ino,
+ found_key.offset - extent_offset, 1);
+ if (ret)
+ goto out;
+setup_ems:
+ em = alloc_extent_map();
+ if (!em) {
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+ &BTRFS_I(inode)->runtime_flags);
+ goto next;
+ }
+
+ /* Implicit hole, NO_HOLES feature. */
+ if (new_key.offset != last_extent_end) {
+ ASSERT(new_key.offset > last_extent_end);
+ fill_hole_em(em, *trans, inode, last_extent_end,
+ new_key.offset - last_extent_end);
+ replace_inode_em(em, inode);
+ em = alloc_extent_map();
+ if (!em) {
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+ &BTRFS_I(inode)->runtime_flags);
+ goto next;
+ }
+ }
+
+ btrfs_extent_item_to_extent_map(inode, path, fi, false, em);
+ replace_inode_em(em, inode);
+next:
+ last_extent_end = new_key.offset + extent_len;
+ path->slots[0]++;
+ }
+
+done:
+ ret = 0;
+
+ /* Implicit trailing hole, NO_HOLES feature. */
+ if (last_extent_end < new_file_size) {
+ em = alloc_extent_map();
+ if (!em) {
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
+ &BTRFS_I(inode)->runtime_flags);
+ } else {
+ fill_hole_em(em, *trans, inode, last_extent_end,
+ new_file_size - last_extent_end);
+ replace_inode_em(em, inode);
+ }
+ }
+
+out:
+ path->keep_locks = 0;
+ btrfs_release_path(path);
+ if (ret)
+ btrfs_abort_transaction(*trans, root, ret);
+
+ return ret;
+}
+
+static int btrfs_collapse_range(struct inode *inode,
+ const loff_t offset,
+ const loff_t len)
+{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct extent_state *cached_state = NULL;
+ struct btrfs_path *path = NULL;
+ struct btrfs_block_rsv *rsv = NULL;
+ struct btrfs_trans_handle *trans = NULL;
+ const u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
+ const u64 lockstart = round_up(offset, root->sectorsize);
+ const u64 lockend = OFFSET_MAX;
+ u64 cur_offset = lockstart;
+ const u64 drop_end = round_down(offset + len, root->sectorsize) - 1;
+ loff_t new_size;
+ int ret = 0;
+
+ if (!S_ISREG(inode->i_mode))
+ return -EINVAL;
+
+ if (offset & (root->sectorsize - 1) || len & (root->sectorsize - 1))
+ return -EINVAL;
+
+ if (!len)
+ return 0;
+
+ ret = btrfs_wait_ordered_range(inode, offset, lockend);
+ if (ret)
+ return ret;
+
+ mutex_lock(&inode->i_mutex);
+
+ if (offset + len >= i_size_read(inode)) {
+ ret = -EINVAL;
+ goto out_only_mutex;
+ }
+ new_size = i_size_read(inode) - len;
+
+ /* Lock the range we're modifying and remove data from page cache. */
+ ret = wait_lock_ordered_range(inode, lockstart, lockend, &cached_state);
+ if (ret)
+ goto out_only_mutex;
+ btrfs_drop_extent_cache(inode, lockstart, lockend, 0);
+
+ path = btrfs_alloc_path();
+ if (!path) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
+ if (!rsv) {
+ ret = -ENOMEM;
+ goto out_free;
+ }
+ rsv->size = min_size;
+ rsv->failfast = 1;
+
+ /*
+ * 1 - update the inode
+ * 1 - removing the extents in the range
+ */
+ trans = btrfs_start_transaction(root, 2);
+ if (IS_ERR(trans)) {
+ ret = PTR_ERR(trans);
+ goto out_free;
+ }
+
+ ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
+ min_size);
+ if (ret) {
+ btrfs_end_transaction(trans, root);
+ goto out_free;
+ }
+ trans->block_rsv = rsv;
+
+ while (cur_offset < drop_end) {
+ ret = __btrfs_drop_extents(trans, root, inode, path,
+ cur_offset, drop_end + 1,
+ &cur_offset, 1, 0, 0, NULL);
+ if (!ret)
+ break;
+ else if (ret != -ENOSPC)
+ goto out_trans;
+
+ ret = fallocate_restart_transaction(&trans, inode, 2, min_size);
+ if (ret)
+ goto out_trans;
+ }
+
+ ret = collapse_file_extents(inode, &trans, path, drop_end + 1, len);
+ if (ret)
+ goto out_trans;
+ btrfs_i_size_write(inode, new_size);
+
+out_trans:
+ set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
+ if (!trans)
+ goto out_free;
+ inode_inc_iversion(inode);
+ inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ trans->block_rsv = &root->fs_info->trans_block_rsv;
+ if (!ret)
+ ret = btrfs_update_inode(trans, root, inode);
+ else
+ btrfs_update_inode(trans, root, inode);
+ btrfs_end_transaction(trans, root);
+ btrfs_btree_balance_dirty(root);
+out_free:
+ btrfs_free_path(path);
+ btrfs_free_block_rsv(root, rsv);
+out:
+ unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+ &cached_state, GFP_NOFS);
+out_only_mutex:
+ mutex_unlock(&inode->i_mutex);
+
+ return ret;
+}
+
static long btrfs_fallocate(struct file *file, int mode,
loff_t offset, loff_t len)
{
@@ -2504,11 +2837,14 @@ static long btrfs_fallocate(struct file *file, int mode,
alloc_end = round_up(offset + len, blocksize);
/* Make sure we aren't being give some crap mode */
- if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
+ FALLOC_FL_COLLAPSE_RANGE))
return -EOPNOTSUPP;
if (mode & FALLOC_FL_PUNCH_HOLE)
return btrfs_punch_hole(inode, offset, len);
+ if (mode & FALLOC_FL_COLLAPSE_RANGE)
+ return btrfs_collapse_range(inode, offset, len);
/*
* Make sure we have enough space before we do the
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] Btrfs: implement support for fallocate collapse range
2014-06-23 10:25 [PATCH] Btrfs: implement support for fallocate collapse range Filipe David Borba Manana
@ 2014-07-02 15:11 ` Filipe David Manana
2014-07-03 4:46 ` Chandan Rajendra
1 sibling, 0 replies; 4+ messages in thread
From: Filipe David Manana @ 2014-07-02 15:11 UTC (permalink / raw)
To: linux-btrfs@vger.kernel.org; +Cc: Filipe David Borba Manana
On Mon, Jun 23, 2014 at 11:25 AM, Filipe David Borba Manana
<fdmanana@gmail.com> wrote:
> This implements fallocate's FALLOC_FL_COLLAPSE_RANGE operation for
> BTRFS. This fallocate operation was introduced in the linux kernel
> version 3.15.
>
> Existing tests in xfstests already test this operation explicitly
> and implicitly via fsstress.
>
> Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
> ---
> fs/btrfs/ctree.c | 42 ++++-
> fs/btrfs/ctree.h | 2 +
> fs/btrfs/extent-tree.c | 30 +--
> fs/btrfs/file.c | 486 +++++++++++++++++++++++++++++++++++++++++--------
> 4 files changed, 453 insertions(+), 107 deletions(-)
>
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index aeab453..8f1a371 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -2825,12 +2825,12 @@ cow_done:
> * It is safe to drop the lock on our parent before we
> * go through the expensive btree search on b.
> *
> - * If we're inserting or deleting (ins_len != 0), then we might
> - * be changing slot zero, which may require changing the parent.
> - * So, we can't drop the lock until after we know which slot
> - * we're operating on.
> + * If we're inserting, deleting or updating a key (cow != 0),
> + * then we might be changing slot zero, which may require
> + * changing the parent. So, we can't drop the lock until after
> + * we know which slot we're operating on.
> */
> - if (!ins_len && !p->keep_locks) {
> + if (!cow && !p->keep_locks) {
> int u = level + 1;
>
> if (u < BTRFS_MAX_LEVEL && p->locks[u]) {
> @@ -2865,7 +2865,7 @@ cow_done:
> * which means we must have a write lock
> * on the parent
> */
> - if (slot == 0 && ins_len &&
> + if (slot == 0 && cow &&
> write_lock_level < level + 1) {
> write_lock_level = level + 1;
> btrfs_release_path(p);
> @@ -5660,6 +5660,36 @@ next:
> }
>
> /*
> + * This differs from btrfs_find_next_key in that it ignores leaf/node
> + * generations and it doesn't unlock and re-lock nodes/leaves nor does
> + * any subsequent searches (calls to btrfs_search_slot), preserving the
> + * locks in the given path.
> + *
> + * Returns 0 if a next key exists, 1 otherwise.
> + */
> +int btrfs_find_next_current_key(struct btrfs_path *path, int level,
> + struct btrfs_key *key)
> +
> +{
> + for (; level < BTRFS_MAX_LEVEL; level++) {
> + if (!path->nodes[level])
> + break;
> + if (path->slots[level] + 1 >=
> + btrfs_header_nritems(path->nodes[level]))
> + continue;
> + if (level == 0)
> + btrfs_item_key_to_cpu(path->nodes[level], key,
> + path->slots[level] + 1);
> + else
> + btrfs_node_key_to_cpu(path->nodes[level], key,
> + path->slots[level] + 1);
> + return 0;
> + }
> + return 1;
> +}
> +
> +
> +/*
> * search the tree again to find a leaf with greater keys
> * returns 0 if it found something or 1 if there are no greater leaves.
> * returns < 0 on io errors.
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index b7e2c1c..166a35f 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -3446,6 +3446,8 @@ struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
> int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
> struct btrfs_key *key, int lowest_level,
> u64 min_trans);
> +int btrfs_find_next_current_key(struct btrfs_path *path, int level,
> + struct btrfs_key *key);
> int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
> struct btrfs_path *path,
> u64 min_trans);
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index fafb3e5..a6d0ec7 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -100,8 +100,6 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
> static int do_chunk_alloc(struct btrfs_trans_handle *trans,
> struct btrfs_root *extent_root, u64 flags,
> int force);
> -static int find_next_key(struct btrfs_path *path, int level,
> - struct btrfs_key *key);
> static void dump_space_info(struct btrfs_space_info *info, u64 bytes,
> int dump_block_groups);
> static int btrfs_update_reserved_bytes(struct btrfs_block_group_cache *cache,
> @@ -440,7 +438,7 @@ next:
> if (path->slots[0] < nritems) {
> btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
> } else {
> - ret = find_next_key(path, 0, &key);
> + ret = btrfs_find_next_current_key(path, 0, &key);
> if (ret)
> break;
>
> @@ -1443,27 +1441,6 @@ static inline int extent_ref_type(u64 parent, u64 owner)
> return type;
> }
>
> -static int find_next_key(struct btrfs_path *path, int level,
> - struct btrfs_key *key)
> -
> -{
> - for (; level < BTRFS_MAX_LEVEL; level++) {
> - if (!path->nodes[level])
> - break;
> - if (path->slots[level] + 1 >=
> - btrfs_header_nritems(path->nodes[level]))
> - continue;
> - if (level == 0)
> - btrfs_item_key_to_cpu(path->nodes[level], key,
> - path->slots[level] + 1);
> - else
> - btrfs_node_key_to_cpu(path->nodes[level], key,
> - path->slots[level] + 1);
> - return 0;
> - }
> - return 1;
> -}
> -
> /*
> * look for inline back ref. if back ref is found, *ref_ret is set
> * to the address of inline back ref, and 0 is returned.
> @@ -1651,7 +1628,7 @@ again:
> * For simplicity, we just do not add new inline back
> * ref if there is any kind of item for this block
> */
> - if (find_next_key(path, 0, &key) == 0 &&
> + if (btrfs_find_next_current_key(path, 0, &key) == 0 &&
> key.objectid == bytenr &&
> key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
> err = -EAGAIN;
> @@ -7649,7 +7626,8 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
> if (level < wc->shared_level)
> goto out;
>
> - ret = find_next_key(path, level + 1, &wc->update_progress);
> + ret = btrfs_find_next_current_key(path, level + 1,
> + &wc->update_progress);
> if (ret > 0)
> wc->update_ref = 0;
>
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index ad7c059..c306ce4 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -2087,6 +2087,44 @@ static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
> return 0;
> }
>
> +static void fill_hole_em(struct extent_map *em,
> + struct btrfs_trans_handle *trans,
> + struct inode *inode,
> + const u64 start,
> + const u64 len)
> +{
> + em->start = start;
> + em->len = len;
> + em->ram_bytes = em->len;
> + em->orig_start = start;
> + em->block_start = EXTENT_MAP_HOLE;
> + em->block_len = 0;
> + em->orig_block_len = 0;
> + em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
> + em->compress_type = BTRFS_COMPRESS_NONE;
> + em->generation = trans->transid;
> +}
> +
> +static void replace_inode_em(struct extent_map *em, struct inode *inode)
> +{
> + struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
> + int ret;
> +
> + while (1) {
> + write_lock(&em_tree->lock);
> + ret = add_extent_mapping(em_tree, em, 1);
> + write_unlock(&em_tree->lock);
> + if (ret != -EEXIST)
> + break;
> + btrfs_drop_extent_cache(inode, em->start,
> + em->start + em->len - 1, 0);
> + };
> + free_extent_map(em);
> + if (ret)
> + set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
> + &BTRFS_I(inode)->runtime_flags);
> +}
> +
> static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
> struct btrfs_path *path, u64 offset, u64 end)
> {
> @@ -2094,7 +2132,6 @@ static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
> struct extent_buffer *leaf;
> struct btrfs_file_extent_item *fi;
> struct extent_map *hole_em;
> - struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
> struct btrfs_key key;
> int ret;
>
> @@ -2159,28 +2196,8 @@ out:
> set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
> &BTRFS_I(inode)->runtime_flags);
> } else {
> - hole_em->start = offset;
> - hole_em->len = end - offset;
> - hole_em->ram_bytes = hole_em->len;
> - hole_em->orig_start = offset;
> -
> - hole_em->block_start = EXTENT_MAP_HOLE;
> - hole_em->block_len = 0;
> - hole_em->orig_block_len = 0;
> - hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
> - hole_em->compress_type = BTRFS_COMPRESS_NONE;
> - hole_em->generation = trans->transid;
> -
> - do {
> - btrfs_drop_extent_cache(inode, offset, end - 1, 0);
> - write_lock(&em_tree->lock);
> - ret = add_extent_mapping(em_tree, hole_em, 1);
> - write_unlock(&em_tree->lock);
> - } while (ret == -EEXIST);
> - free_extent_map(hole_em);
> - if (ret)
> - set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
> - &BTRFS_I(inode)->runtime_flags);
> + fill_hole_em(hole_em, trans, inode, offset, end - offset);
> + replace_inode_em(hole_em, inode);
> }
>
> return 0;
> @@ -2217,6 +2234,80 @@ static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len)
> return ret;
> }
>
> +static int wait_lock_ordered_range(struct inode *inode,
> + const u64 lockstart,
> + const u64 lockend,
> + struct extent_state **cached_state)
> +{
> + while (1) {
> + struct btrfs_ordered_extent *ordered;
> + int ret;
> +
> + truncate_pagecache_range(inode, lockstart, lockend);
> +
> + lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
> + 0, cached_state);
> + ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
> +
> + /*
> + * We need to make sure we have no ordered extents in this range
> + * and nobody raced in and read a page in this range, if we did
> + * we need to try again.
> + */
> + if ((!ordered ||
> + (ordered->file_offset + ordered->len <= lockstart ||
> + ordered->file_offset > lockend)) &&
> + !btrfs_page_exists_in_range(inode, lockstart, lockend)) {
> + if (ordered)
> + btrfs_put_ordered_extent(ordered);
> + break;
> + }
> + if (ordered)
> + btrfs_put_ordered_extent(ordered);
> + unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
> + lockend, cached_state, GFP_NOFS);
> + ret = btrfs_wait_ordered_range(inode, lockstart,
> + lockend - lockstart + 1);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int fallocate_restart_transaction(struct btrfs_trans_handle **trans,
> + struct inode *inode,
> + const int trans_units,
> + const int min_size)
> +{
> + struct btrfs_root *root = BTRFS_I(inode)->root;
> + struct btrfs_block_rsv *rsv = (*trans)->block_rsv;
> + int ret;
> +
> + (*trans)->block_rsv = &root->fs_info->trans_block_rsv;
> + ret = btrfs_update_inode(*trans, root, inode);
> + if (ret)
> + return ret;
> +
> + btrfs_end_transaction(*trans, root);
> + btrfs_btree_balance_dirty(root);
> +
> + *trans = btrfs_start_transaction(root, trans_units);
> + if (IS_ERR(*trans)) {
> + ret = PTR_ERR(*trans);
> + *trans = NULL;
> + return ret;
> + }
> +
> + ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
> + rsv, min_size);
> + if (unlikely(ret))
> + return ret;
> + (*trans)->block_rsv = rsv;
> +
> + return 0;
> +}
> +
> static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
> {
> struct btrfs_root *root = BTRFS_I(inode)->root;
> @@ -2324,38 +2415,10 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
> return 0;
> }
>
> - while (1) {
> - struct btrfs_ordered_extent *ordered;
> -
> - truncate_pagecache_range(inode, lockstart, lockend);
> -
> - lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
> - 0, &cached_state);
> - ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
> -
> - /*
> - * We need to make sure we have no ordered extents in this range
> - * and nobody raced in and read a page in this range, if we did
> - * we need to try again.
> - */
> - if ((!ordered ||
> - (ordered->file_offset + ordered->len <= lockstart ||
> - ordered->file_offset > lockend)) &&
> - !btrfs_page_exists_in_range(inode, lockstart, lockend)) {
> - if (ordered)
> - btrfs_put_ordered_extent(ordered);
> - break;
> - }
> - if (ordered)
> - btrfs_put_ordered_extent(ordered);
> - unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
> - lockend, &cached_state, GFP_NOFS);
> - ret = btrfs_wait_ordered_range(inode, lockstart,
> - lockend - lockstart + 1);
> - if (ret) {
> - mutex_unlock(&inode->i_mutex);
> - return ret;
> - }
> + ret = wait_lock_ordered_range(inode, lockstart, lockend, &cached_state);
> + if (ret) {
> + mutex_unlock(&inode->i_mutex);
> + return ret;
> }
>
> path = btrfs_alloc_path();
> @@ -2411,26 +2474,11 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
>
> cur_offset = drop_end;
>
> - ret = btrfs_update_inode(trans, root, inode);
> - if (ret) {
> - err = ret;
> - break;
> - }
> -
> - btrfs_end_transaction(trans, root);
> - btrfs_btree_balance_dirty(root);
> -
> - trans = btrfs_start_transaction(root, rsv_count);
> - if (IS_ERR(trans)) {
> - ret = PTR_ERR(trans);
> - trans = NULL;
> - break;
> - }
> -
> - ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
> - rsv, min_size);
> - BUG_ON(ret); /* shouldn't happen */
> trans->block_rsv = rsv;
> + ret = fallocate_restart_transaction(&trans, inode, rsv_count,
> + min_size);
> + if (ret)
> + break;
>
> ret = find_first_non_hole(inode, &cur_offset, &len);
> if (unlikely(ret < 0))
> @@ -2484,6 +2532,291 @@ out_only_mutex:
> return err;
> }
>
> +static int collapse_file_extents(struct inode *inode,
> + struct btrfs_trans_handle **trans,
> + struct btrfs_path *path,
> + const u64 start,
> + const u64 len)
> +{
> + struct btrfs_root *root = BTRFS_I(inode)->root;
> + struct btrfs_key key;
> + struct extent_buffer *leaf;
> + struct btrfs_file_extent_item *fi;
> + struct extent_map *em;
> + const u64 ino = btrfs_ino(inode);
> + bool last_leaf = false;
> + bool retry_on_enospc = true;
> + u64 last_extent_end = start - len;
> + int slot;
> + int ret;
> + const u64 new_file_size = i_size_read(inode) - len;
> + const u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
> +
> + /*
> + * Start tree search from left (lower file offsets) to right (higher
> + * file offsets), to avoid leaving duplicated keys in the tree at
> + * any time.
> + */
> + key.objectid = ino;
> + key.type = BTRFS_EXTENT_DATA_KEY;
> + key.offset = start;
> +again:
> + if (key.objectid > ino || key.type != BTRFS_EXTENT_DATA_KEY)
> + goto done;
> + path->keep_locks = 1;
> + ret = btrfs_search_slot(*trans, root, &key, path, 0, 1);
> + if (ret == -ENOSPC && retry_on_enospc) {
> + ret = fallocate_restart_transaction(trans, inode, 2, min_size);
> + if (ret)
> + goto out;
> + retry_on_enospc = false;
> + goto again;
> + } else if (ret < 0) {
> + goto out;
> + }
> +
> + leaf = path->nodes[0];
> + slot = path->slots[0];
> + path->slots[0] = btrfs_header_nritems(leaf);
> + /*
> + * Get smallest key of the next leaf to use to get into the next leaf.
> + * This is to avoid ending up in the same leaf again and over again
> + * after processing a full leaf, which is more likely to happen in
> + * the case of implicit holes (NO_HOLES feature).
> + */
> + ret = btrfs_find_next_current_key(path, 0, &key);
> + if (ret > 0)
> + last_leaf = true;
> + path->slots[0] = slot;
> + retry_on_enospc = true;
> +
> + while (1) {
> + u64 extent_len, disk_bytenr, num_bytes, extent_offset;
> + int extent_type;
> + struct btrfs_key found_key, new_key;
> +
> + if (path->slots[0] >= btrfs_header_nritems(leaf)) {
> + btrfs_release_path(path);
> + if (last_leaf)
> + break;
> + else
> + goto again;
> + }
> +
> + if (path->slots[0] > 0) {
> + path->keep_locks = 0;
> + btrfs_unlock_up_safe(path, 1);
> + }
> +
> + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
> + if (found_key.objectid != ino)
> + break;
> + if (found_key.type != BTRFS_EXTENT_DATA_KEY)
> + break;
> + ASSERT(found_key.offset >= start);
> +
> + fi = btrfs_item_ptr(leaf, path->slots[0],
> + struct btrfs_file_extent_item);
> + extent_type = btrfs_file_extent_type(leaf, fi);
> + /* Inline extents are always at file offset 0. */
> + ASSERT(extent_type != BTRFS_FILE_EXTENT_INLINE);
> +
> + extent_len = btrfs_file_extent_num_bytes(leaf, fi);
> + disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
> + num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
> + extent_offset = btrfs_file_extent_offset(leaf, fi);
> +
> + memcpy(&new_key, &found_key, sizeof(new_key));
> + new_key.offset -= len;
> + btrfs_set_item_key_safe(root, path, &new_key);
> +
> + if (disk_bytenr == 0)
> + goto setup_ems;
> +
> + ret = btrfs_inc_extent_ref(*trans, root, disk_bytenr, num_bytes,
> + 0, root->root_key.objectid, ino,
> + new_key.offset - extent_offset, 1);
Note to self and nack.
Due to the left shifting of file extent offsets, new_key.offset -
extent_offset can now often be negative, resulting in data backrefs
with a wrong offset value (a very large u64 value) that causes
confusion in the backref walking and management code.
Need some more thought and work around this.
Thanks
> + if (ret)
> + goto out;
> + ret = btrfs_free_extent(*trans, root, disk_bytenr, num_bytes, 0,
> + root->root_key.objectid, ino,
> + found_key.offset - extent_offset, 1);
> + if (ret)
> + goto out;
> +setup_ems:
> + em = alloc_extent_map();
> + if (!em) {
> + set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
> + &BTRFS_I(inode)->runtime_flags);
> + goto next;
> + }
> +
> + /* Implicit hole, NO_HOLES feature. */
> + if (new_key.offset != last_extent_end) {
> + ASSERT(new_key.offset > last_extent_end);
> + fill_hole_em(em, *trans, inode, last_extent_end,
> + new_key.offset - last_extent_end);
> + replace_inode_em(em, inode);
> + em = alloc_extent_map();
> + if (!em) {
> + set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
> + &BTRFS_I(inode)->runtime_flags);
> + goto next;
> + }
> + }
> +
> + btrfs_extent_item_to_extent_map(inode, path, fi, false, em);
> + replace_inode_em(em, inode);
> +next:
> + last_extent_end = new_key.offset + extent_len;
> + path->slots[0]++;
> + }
> +
> +done:
> + ret = 0;
> +
> + /* Implicit trailing hole, NO_HOLES feature. */
> + if (last_extent_end < new_file_size) {
> + em = alloc_extent_map();
> + if (!em) {
> + set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
> + &BTRFS_I(inode)->runtime_flags);
> + } else {
> + fill_hole_em(em, *trans, inode, last_extent_end,
> + new_file_size - last_extent_end);
> + replace_inode_em(em, inode);
> + }
> + }
> +
> +out:
> + path->keep_locks = 0;
> + btrfs_release_path(path);
> + if (ret)
> + btrfs_abort_transaction(*trans, root, ret);
> +
> + return ret;
> +}
> +
> +static int btrfs_collapse_range(struct inode *inode,
> + const loff_t offset,
> + const loff_t len)
> +{
> + struct btrfs_root *root = BTRFS_I(inode)->root;
> + struct extent_state *cached_state = NULL;
> + struct btrfs_path *path = NULL;
> + struct btrfs_block_rsv *rsv = NULL;
> + struct btrfs_trans_handle *trans = NULL;
> + const u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
> + const u64 lockstart = round_up(offset, root->sectorsize);
> + const u64 lockend = OFFSET_MAX;
> + u64 cur_offset = lockstart;
> + const u64 drop_end = round_down(offset + len, root->sectorsize) - 1;
> + loff_t new_size;
> + int ret = 0;
> +
> + if (!S_ISREG(inode->i_mode))
> + return -EINVAL;
> +
> + if (offset & (root->sectorsize - 1) || len & (root->sectorsize - 1))
> + return -EINVAL;
> +
> + if (!len)
> + return 0;
> +
> + ret = btrfs_wait_ordered_range(inode, offset, lockend);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&inode->i_mutex);
> +
> + if (offset + len >= i_size_read(inode)) {
> + ret = -EINVAL;
> + goto out_only_mutex;
> + }
> + new_size = i_size_read(inode) - len;
> +
> + /* Lock the range we're modifying and remove data from page cache. */
> + ret = wait_lock_ordered_range(inode, lockstart, lockend, &cached_state);
> + if (ret)
> + goto out_only_mutex;
> + btrfs_drop_extent_cache(inode, lockstart, lockend, 0);
> +
> + path = btrfs_alloc_path();
> + if (!path) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
> + if (!rsv) {
> + ret = -ENOMEM;
> + goto out_free;
> + }
> + rsv->size = min_size;
> + rsv->failfast = 1;
> +
> + /*
> + * 1 - update the inode
> + * 1 - removing the extents in the range
> + */
> + trans = btrfs_start_transaction(root, 2);
> + if (IS_ERR(trans)) {
> + ret = PTR_ERR(trans);
> + goto out_free;
> + }
> +
> + ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
> + min_size);
> + if (ret) {
> + btrfs_end_transaction(trans, root);
> + goto out_free;
> + }
> + trans->block_rsv = rsv;
> +
> + while (cur_offset < drop_end) {
> + ret = __btrfs_drop_extents(trans, root, inode, path,
> + cur_offset, drop_end + 1,
> + &cur_offset, 1, 0, 0, NULL);
> + if (!ret)
> + break;
> + else if (ret != -ENOSPC)
> + goto out_trans;
> +
> + ret = fallocate_restart_transaction(&trans, inode, 2, min_size);
> + if (ret)
> + goto out_trans;
> + }
> +
> + ret = collapse_file_extents(inode, &trans, path, drop_end + 1, len);
> + if (ret)
> + goto out_trans;
> + btrfs_i_size_write(inode, new_size);
> +
> +out_trans:
> + set_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags);
> + if (!trans)
> + goto out_free;
> + inode_inc_iversion(inode);
> + inode->i_mtime = inode->i_ctime = CURRENT_TIME;
> + trans->block_rsv = &root->fs_info->trans_block_rsv;
> + if (!ret)
> + ret = btrfs_update_inode(trans, root, inode);
> + else
> + btrfs_update_inode(trans, root, inode);
> + btrfs_end_transaction(trans, root);
> + btrfs_btree_balance_dirty(root);
> +out_free:
> + btrfs_free_path(path);
> + btrfs_free_block_rsv(root, rsv);
> +out:
> + unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
> + &cached_state, GFP_NOFS);
> +out_only_mutex:
> + mutex_unlock(&inode->i_mutex);
> +
> + return ret;
> +}
> +
> static long btrfs_fallocate(struct file *file, int mode,
> loff_t offset, loff_t len)
> {
> @@ -2504,11 +2837,14 @@ static long btrfs_fallocate(struct file *file, int mode,
> alloc_end = round_up(offset + len, blocksize);
>
> /* Make sure we aren't being give some crap mode */
> - if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
> + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
> + FALLOC_FL_COLLAPSE_RANGE))
> return -EOPNOTSUPP;
>
> if (mode & FALLOC_FL_PUNCH_HOLE)
> return btrfs_punch_hole(inode, offset, len);
> + if (mode & FALLOC_FL_COLLAPSE_RANGE)
> + return btrfs_collapse_range(inode, offset, len);
>
> /*
> * Make sure we have enough space before we do the
> --
> 1.9.1
>
--
Filipe David Manana,
"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Btrfs: implement support for fallocate collapse range
2014-06-23 10:25 [PATCH] Btrfs: implement support for fallocate collapse range Filipe David Borba Manana
2014-07-02 15:11 ` Filipe David Manana
@ 2014-07-03 4:46 ` Chandan Rajendra
2014-07-03 11:28 ` Filipe David Manana
1 sibling, 1 reply; 4+ messages in thread
From: Chandan Rajendra @ 2014-07-03 4:46 UTC (permalink / raw)
To: linux-btrfs, Filipe David Borba Manana
On Monday 23 Jun 2014 11:25:47 Filipe David Borba Manana wrote:
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index aeab453..8f1a371 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -2825,12 +2825,12 @@ cow_done:
> * It is safe to drop the lock on our parent before we
> * go through the expensive btree search on b.
> *
> - * If we're inserting or deleting (ins_len != 0), then we might
> - * be changing slot zero, which may require changing the parent.
> - * So, we can't drop the lock until after we know which slot
> - * we're operating on.
> + * If we're inserting, deleting or updating a key (cow != 0),
> + * then we might be changing slot zero, which may require
> + * changing the parent. So, we can't drop the lock until after
> + * we know which slot we're operating on.
> */
> - if (!ins_len && !p->keep_locks) {
> + if (!cow && !p->keep_locks) {
> int u = level + 1;
For the "key update" case (i.e. (ins_len == 0) and (cow == 1)), maybe
we could optimize by having a variable to hold the return value of
should_cow_block(), i.e. it keeps track of whether the current
metadata block was COWed. If the variable indicates that the block was
*not* COWed, then we could release the lock on the parent block since
the update operation (even on slot 0) isn't going to change the
corresponding entry in the parent block.
Thanks,
chandan
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Btrfs: implement support for fallocate collapse range
2014-07-03 4:46 ` Chandan Rajendra
@ 2014-07-03 11:28 ` Filipe David Manana
0 siblings, 0 replies; 4+ messages in thread
From: Filipe David Manana @ 2014-07-03 11:28 UTC (permalink / raw)
To: Chandan Rajendra; +Cc: linux-btrfs@vger.kernel.org
On Thu, Jul 3, 2014 at 5:46 AM, Chandan Rajendra
<chandan@linux.vnet.ibm.com> wrote:
> On Monday 23 Jun 2014 11:25:47 Filipe David Borba Manana wrote:
>> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
>> index aeab453..8f1a371 100644
>> --- a/fs/btrfs/ctree.c
>> +++ b/fs/btrfs/ctree.c
>> @@ -2825,12 +2825,12 @@ cow_done:
>> * It is safe to drop the lock on our parent before we
>> * go through the expensive btree search on b.
>> *
>> - * If we're inserting or deleting (ins_len != 0), then we might
>> - * be changing slot zero, which may require changing the parent.
>> - * So, we can't drop the lock until after we know which slot
>> - * we're operating on.
>> + * If we're inserting, deleting or updating a key (cow != 0),
>> + * then we might be changing slot zero, which may require
>> + * changing the parent. So, we can't drop the lock until after
>> + * we know which slot we're operating on.
>> */
>> - if (!ins_len && !p->keep_locks) {
>> + if (!cow && !p->keep_locks) {
>> int u = level + 1;
>
> For the "key update" case (i.e. (ins_len == 0) and (cow == 1)), maybe
> we could optimize by having a variable to hold the return value of
> should_cow_block(), i.e. it keeps track of whether the current
> metadata block was COWed. If the variable indicates that the block was
> *not* COWed, then we could release the lock on the parent block since
> the update operation (even on slot 0) isn't going to change the
> corresponding entry in the parent block.
Hi Chandan,
Just because a node wasn't cowed it doesn't mean it isn't going to be
updated. Further updating the key works bottom-up - we don't know
during btrfs_search_slot() if our caller intends to update a key in
the leaf or just update the item, so we need to return a path here
with all nodes with slot == 0 having a write lock on them. I'm
actually for now basically just undoing this
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=eb653de15987612444b6cde3b0e67b1edd94625f
Anyway right now I have a functional issue to tackle first.
Thanks.
>
> Thanks,
> chandan
>
--
Filipe David Manana,
"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-07-03 11:28 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2014-06-23 10:25 [PATCH] Btrfs: implement support for fallocate collapse range Filipe David Borba Manana
2014-07-02 15:11 ` Filipe David Manana
2014-07-03 4:46 ` Chandan Rajendra
2014-07-03 11:28 ` Filipe David Manana
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