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Commit 5911c8fe authored by David Sterba's avatar David Sterba
Browse files

btrfs: fiemap: preallocate ulists for btrfs_check_shared 



btrfs_check_shared looks up parents of a given extent and uses ulists
for that. These are allocated and freed repeatedly. Preallocation in the
caller will avoid the overhead and also allow us to use the GFP_KERNEL
as it is happens before the extent locks are taken.

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 9b4e675a

fs/btrfs/backref.c

+6 −11
Original line number Diff line number Diff line
@@ -1465,12 +1465,11 @@ int btrfs_find_all_roots(struct btrfs_trans_handle *trans, 
 *

 * Return: 0 if extent is not shared, 1 if it is shared, < 0 on error.

 */

int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr)

int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,

		struct ulist *roots, struct ulist *tmp)

{

	struct btrfs_fs_info *fs_info = root->fs_info;

	struct btrfs_trans_handle *trans;

	struct ulist *tmp = NULL;

	struct ulist *roots = NULL;

	struct ulist_iterator uiter;

	struct ulist_node *node;

	struct seq_list elem = SEQ_LIST_INIT(elem);
@@ -1481,12 +1480,8 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr) 
		.share_count = 0,

	};



	tmp = ulist_alloc(GFP_NOFS);

	roots = ulist_alloc(GFP_NOFS);

	if (!tmp || !roots) {

		ret = -ENOMEM;

		goto out;

	}

	ulist_init(roots);

	ulist_init(tmp);



	trans = btrfs_attach_transaction(root);

	if (IS_ERR(trans)) {
@@ -1527,8 +1522,8 @@ int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr) 
		up_read(&fs_info->commit_root_sem);

	}

out:

	ulist_free(tmp);

	ulist_free(roots);

	ulist_release(roots);

	ulist_release(tmp);

	return ret;

}

fs/btrfs/backref.h

+2 −1
Original line number Diff line number Diff line
@@ -57,7 +57,8 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid, 
			  u64 start_off, struct btrfs_path *path,

			  struct btrfs_inode_extref **ret_extref,

			  u64 *found_off);

int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr);

int btrfs_check_shared(struct btrfs_root *root, u64 inum, u64 bytenr,

		struct ulist *roots, struct ulist *tmp_ulist);



int __init btrfs_prelim_ref_init(void);

void __cold btrfs_prelim_ref_exit(void);

fs/btrfs/extent_io.c

+15 −2
Original line number Diff line number Diff line
@@ -4542,6 +4542,8 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
	struct btrfs_path *path;

	struct btrfs_root *root = BTRFS_I(inode)->root;

	struct fiemap_cache cache = { 0 };

	struct ulist *roots;

	struct ulist *tmp_ulist;

	int end = 0;

	u64 em_start = 0;

	u64 em_len = 0;
@@ -4555,6 +4557,13 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
		return -ENOMEM;

	path->leave_spinning = 1;



	roots = ulist_alloc(GFP_KERNEL);

	tmp_ulist = ulist_alloc(GFP_KERNEL);

	if (!roots || !tmp_ulist) {

		ret = -ENOMEM;

		goto out_free_ulist;

	}



	start = round_down(start, btrfs_inode_sectorsize(inode));

	len = round_up(max, btrfs_inode_sectorsize(inode)) - start;
@@ -4566,7 +4575,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
			btrfs_ino(BTRFS_I(inode)), -1, 0);

	if (ret < 0) {

		btrfs_free_path(path);

		return ret;

		goto out_free_ulist;

	} else {

		WARN_ON(!ret);

		if (ret == 1)
@@ -4675,7 +4684,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
			 */

			ret = btrfs_check_shared(root,

						 btrfs_ino(BTRFS_I(inode)),

						 bytenr);

						 bytenr, roots, tmp_ulist);

			if (ret < 0)

				goto out_free;

			if (ret)
@@ -4721,6 +4730,10 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 
	btrfs_free_path(path);

	unlock_extent_cached(&BTRFS_I(inode)->io_tree, start, start + len - 1,

			     &cached_state);



out_free_ulist:

	ulist_free(roots);

	ulist_free(tmp_ulist);

	return ret;

}