From b30757178dad19a0388d958ff9eea66e674d39ed Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Tue, 22 Apr 2008 09:22:07 -0400 Subject: [PATCH] Btrfs: Add a special device list for chunk allocations This allows other code that needs to walk every device in the FS to do so without locking against allocations. Signed-off-by: Chris Mason --- fs/btrfs/volumes.c | 15 ++++++++++----- fs/btrfs/volumes.h | 7 +++++++ 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 107fc74c3ab8..5619e50583e3 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -111,6 +111,7 @@ static int device_list_add(const char *path, if (!fs_devices) return -ENOMEM; INIT_LIST_HEAD(&fs_devices->devices); + INIT_LIST_HEAD(&fs_devices->alloc_list); list_add(&fs_devices->list, &fs_uuids); memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE); fs_devices->latest_devid = devid; @@ -139,6 +140,7 @@ static int device_list_add(const char *path, return -ENOMEM; } list_add(&device->dev_list, &fs_devices->devices); + list_add(&device->dev_alloc_list, &fs_devices->alloc_list); fs_devices->num_devices++; } @@ -660,7 +662,7 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, struct btrfs_device *device = NULL; struct btrfs_chunk *chunk; struct list_head private_devs; - struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices; + struct list_head *dev_list; struct list_head *cur; struct extent_map_tree *em_tree; struct map_lookup *map; @@ -682,6 +684,7 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, int stripe_len = 64 * 1024; struct btrfs_key key; + dev_list = &extent_root->fs_info->fs_devices->alloc_list; if (list_empty(dev_list)) return -ENOSPC; @@ -752,12 +755,12 @@ int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, /* build a private list of devices we will allocate from */ while(index < num_stripes) { - device = list_entry(cur, struct btrfs_device, dev_list); + device = list_entry(cur, struct btrfs_device, dev_alloc_list); avail = device->total_bytes - device->bytes_used; cur = cur->next; if (avail >= min_free) { - list_move_tail(&device->dev_list, &private_devs); + list_move_tail(&device->dev_alloc_list, &private_devs); index++; if (type & BTRFS_BLOCK_GROUP_DUP) index++; @@ -812,12 +815,12 @@ printk("new chunk type %Lu start %Lu size %Lu\n", type, key.offset, *num_bytes); struct btrfs_stripe *stripe; BUG_ON(list_empty(&private_devs)); cur = private_devs.next; - device = list_entry(cur, struct btrfs_device, dev_list); + device = list_entry(cur, struct btrfs_device, dev_alloc_list); /* loop over this device again if we're doing a dup group */ if (!(type & BTRFS_BLOCK_GROUP_DUP) || (index == num_stripes - 1)) - list_move_tail(&device->dev_list, dev_list); + list_move_tail(&device->dev_alloc_list, dev_list); ret = btrfs_alloc_dev_extent(trans, device, info->chunk_root->root_key.objectid, @@ -1329,6 +1332,8 @@ static int read_one_dev(struct btrfs_root *root, return -ENOMEM; list_add(&device->dev_list, &root->fs_info->fs_devices->devices); + list_add(&device->dev_alloc_list, + &root->fs_info->fs_devices->alloc_list); device->barriers = 1; spin_lock_init(&device->io_lock); } diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index dfe7e8a9507c..a2660d2b6b34 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -24,9 +24,12 @@ struct buffer_head; struct btrfs_device { struct list_head dev_list; + struct list_head dev_alloc_list; struct btrfs_root *dev_root; struct buffer_head *pending_io; + int barriers; + spinlock_t io_lock; struct block_device *bdev; @@ -70,7 +73,11 @@ struct btrfs_fs_devices { u64 num_devices; struct block_device *latest_bdev; struct block_device *lowest_bdev; + /* all of the devices in the FS */ struct list_head devices; + + /* devices not currently being allocated */ + struct list_head alloc_list; struct list_head list; }; -- GitLab