From: Filipe Manana <[email protected]> As of the 4.3 kernel release, the fitrim ioctl can now discard any region of a disk that is not part of a chunk/block group, including the MBR (master boot record). Fix this by not allowing to trim/discard any region in the device starting with an offset not greater than min(alloc_start_mount_option, 1Mb), just as we did for space allocated to chunks/block groups.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109341 Fixes: 499f377f49f0 (btrfs: iterate over unused chunk space in FITRIM) Cc: [email protected] # 4.3+ Signed-off-by: Filipe Manana <[email protected]> --- V2: Fix possiblity of endless loop with fitrim call. fs/btrfs/volumes.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index a114b7b..fd71ee3 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1258,6 +1258,14 @@ int find_free_dev_extent_start(struct btrfs_transaction *transaction, int ret; int slot; struct extent_buffer *l; + u64 min_search_start; + + /* + * we don't want to overwrite the superblock on the drive (nor the MBR + * sector), so we make sure to start at an offset of at least 1MB + */ + min_search_start = max(root->fs_info->alloc_start, 1024ull * 1024); + search_start = max(search_start, min_search_start); path = btrfs_alloc_path(); if (!path) @@ -1398,18 +1406,9 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans, struct btrfs_device *device, u64 num_bytes, u64 *start, u64 *len) { - struct btrfs_root *root = device->dev_root; - u64 search_start; - /* FIXME use last free of some kind */ - - /* - * we don't want to overwrite the superblock on the drive, - * so we make sure to start at an offset of at least 1MB - */ - search_start = max(root->fs_info->alloc_start, 1024ull * 1024); return find_free_dev_extent_start(trans->transaction, device, - num_bytes, search_start, start, len); + num_bytes, 0, start, len); } static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans, -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
