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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: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
alistair/sunxi64-5.4-dsi
David Sterba 2019-05-15 15:31:04 +02:00
parent 9b4e675a99
commit 5911c8fe05
3 changed files with 23 additions and 14 deletions
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17
fs/btrfs/backref.c
View File

@ -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;
}

3
fs/btrfs/backref.h
View File

@ -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);

17
fs/btrfs/extent_io.c
View File

@ -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 @@ out:
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;
}