From b0c0ea6338d5018e02d27c5315084fb1a5d099f6 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 10 Nov 2015 18:54:00 +0100 Subject: btrfs: allocate root item at snapshot ioctl time The actual snapshot creation is delayed until transaction commit. If we cannot get enough memory for the root item there, we have to fail the whole transaction commit which is bad. So we'll allocate the memory at the ioctl call and pass it along with the pending_snapshot struct. The potential ENOMEM will be returned to the caller of snapshot ioctl. Signed-off-by: David Sterba --- fs/btrfs/transaction.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'fs/btrfs/transaction.c') diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index be8eae80ff65..2074106122d9 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1325,11 +1325,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, return 0; } - new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); - if (!new_root_item) { - pending->error = -ENOMEM; - goto root_item_alloc_fail; - } + ASSERT(pending->root_item); + new_root_item = pending->root_item; pending->error = btrfs_find_free_objectid(tree_root, &objectid); if (pending->error) @@ -1562,7 +1559,7 @@ clear_skip_qgroup: btrfs_clear_skip_qgroup(trans); no_free_objectid: kfree(new_root_item); -root_item_alloc_fail: + pending->root_item = NULL; btrfs_free_path(path); return ret; } -- cgit v1.2.3 From 8546b570511f428838129c00e701eda481cd7c13 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Tue, 10 Nov 2015 18:54:03 +0100 Subject: btrfs: preallocate path for snapshot creation at ioctl time We can also preallocate btrfs_path that's used during pending snapshot creation and avoid another late ENOMEM failure. Signed-off-by: David Sterba --- fs/btrfs/ioctl.c | 4 +++- fs/btrfs/transaction.c | 9 ++++----- fs/btrfs/transaction.h | 1 + 3 files changed, 8 insertions(+), 6 deletions(-) (limited to 'fs/btrfs/transaction.c') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 27fc660b0ff3..3d9b27d2176e 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -661,7 +661,8 @@ static int create_snapshot(struct btrfs_root *root, struct inode *dir, pending_snapshot->root_item = kzalloc(sizeof(struct btrfs_root_item), GFP_NOFS); - if (!pending_snapshot->root_item) { + pending_snapshot->path = btrfs_alloc_path(); + if (!pending_snapshot->root_item || !pending_snapshot->path) { ret = -ENOMEM; goto free_pending; } @@ -747,6 +748,7 @@ dec_and_free: wake_up_atomic_t(&root->will_be_snapshoted); free_pending: kfree(pending_snapshot->root_item); + btrfs_free_path(pending_snapshot->path); kfree(pending_snapshot); return ret; diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 2074106122d9..be463b7f1f30 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1319,11 +1319,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, u64 root_flags; uuid_le new_uuid; - path = btrfs_alloc_path(); - if (!path) { - pending->error = -ENOMEM; - return 0; - } + ASSERT(pending->path); + path = pending->path; ASSERT(pending->root_item); new_root_item = pending->root_item; @@ -1561,6 +1558,8 @@ no_free_objectid: kfree(new_root_item); pending->root_item = NULL; btrfs_free_path(path); + pending->path = NULL; + return ret; } diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h index b6f9a3c94468..72be51f7ca2f 100644 --- a/fs/btrfs/transaction.h +++ b/fs/btrfs/transaction.h @@ -140,6 +140,7 @@ struct btrfs_pending_snapshot { struct btrfs_root_item *root_item; struct btrfs_root *snap; struct btrfs_qgroup_inherit *inherit; + struct btrfs_path *path; /* block reservation for the operation */ struct btrfs_block_rsv block_rsv; u64 qgroup_reserved; -- cgit v1.2.3