[0/3] Btrfs: fix free space tree bitmaps+tests on big-endian systems

Message ID	20160818203327.GA7696@vader.DHCP.thefacebook.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-btrfs-owner@kernel.org> Date: Thu, 18 Aug 2016 13:33:27 -0700 From: Omar Sandoval <osandov@osandov.com> To: Chris Mason <clm@fb.com> Cc: Chandan Rajendra <chandan@linux.vnet.ibm.com>, linux-btrfs@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 0/3] Btrfs: fix free space tree bitmaps+tests on big-endian systems Message-ID: <20160818203327.GA7696@vader.DHCP.thefacebook.com> References: <cover.1468538030.git.osandov@fb.com> <399ec92c-9905-0ede-d5b0-ea3b0bf922e4@fb.com> <20160718223104.GA6681@vader.DHCP.thefacebook.com> <2544227.upOtQjWuiQ@localhost.localdomain> <83e50f77-ae10-4c8d-4a03-3c9af298d9c7@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <83e50f77-ae10-4c8d-4a03-3c9af298d9c7@fb.com> User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 2fe8f89..f50b3e0 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -246,7 +246,8 @@ struct btrfs_super_block { * Compat flags that we support. If any incompat flags are set other than the * ones specified below then we will fail to mount */ -#define BTRFS_FEATURE_COMPAT_SUPP 0ULL +#define BTRFS_FEATURE_COMPAT_SUPP \ + (BTRFS_FEATURE_COMPAT_FREE_SPACE_TREE_LE) #define BTRFS_FEATURE_COMPAT_SAFE_SET 0ULL #define BTRFS_FEATURE_COMPAT_SAFE_CLEAR 0ULL @@ -3538,6 +3539,62 @@ static inline int __btrfs_fs_compat_ro(struct btrfs_fs_info *fs_info, u64 flag) return !!(btrfs_super_compat_ro_flags(disk_super) & flag); } +#define btrfs_set_fs_compat(__fs_info, opt) \ + __btrfs_set_fs_compat((__fs_info), BTRFS_FEATURE_COMPAT_##opt) + +static inline void __btrfs_set_fs_compat(struct btrfs_fs_info *fs_info, + u64 flag) +{ + struct btrfs_super_block *disk_super; + u64 features; + + disk_super = fs_info->super_copy; + features = btrfs_super_compat_flags(disk_super); + if (!(features & flag)) { + spin_lock(&fs_info->super_lock); + features = btrfs_super_compat_flags(disk_super); + if (!(features & flag)) { + features |= flag; + btrfs_set_super_compat_flags(disk_super, features); + btrfs_info(fs_info, "setting %llu feature flag", flag); + } + spin_unlock(&fs_info->super_lock); + } +} + +#define btrfs_clear_fs_compat(__fs_info, opt) \ + __btrfs_clear_fs_compat((__fs_info), BTRFS_FEATURE_COMPAT_##opt) + +static inline void __btrfs_clear_fs_compat(struct btrfs_fs_info *fs_info, + u64 flag) +{ + struct btrfs_super_block *disk_super; + u64 features; + + disk_super = fs_info->super_copy; + features = btrfs_super_compat_flags(disk_super); + if (features & flag) { + spin_lock(&fs_info->super_lock); + features = btrfs_super_compat_flags(disk_super); + if (features & flag) { + features &= ~flag; + btrfs_set_super_compat_flags(disk_super, features); + btrfs_info(fs_info, "clearing %llu feature flag", flag); + } + spin_unlock(&fs_info->super_lock); + } +} + +#define btrfs_fs_compat(fs_info, opt) \ + __btrfs_fs_compat((fs_info), BTRFS_FEATURE_COMPAT_##opt) + +static inline int __btrfs_fs_compat(struct btrfs_fs_info *fs_info, u64 flag) +{ + struct btrfs_super_block *disk_super; + disk_super = fs_info->super_copy; + return !!(btrfs_super_compat_flags(disk_super) & flag); +} + /* acl.c */ #ifdef CONFIG_BTRFS_FS_POSIX_ACL struct posix_acl *btrfs_get_acl(struct inode *inode, int type); diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 59febfb..467c364 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3090,6 +3090,15 @@ retry_root_backup: if (sb->s_flags & MS_RDONLY) return 0; + if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) && + !btrfs_test_opt(fs_info, CLEAR_CACHE)) { + ret = btrfs_check_free_space_tree_le(fs_info); + if (ret) { + close_ctree(tree_root); + return ret; + } + } + if (btrfs_test_opt(tree_root->fs_info, FREE_SPACE_TREE) && !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) { btrfs_info(fs_info, "creating free space tree"); diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c index 8fd85bf..ef84c1d 100644 --- a/fs/btrfs/free-space-tree.c +++ b/fs/btrfs/free-space-tree.c @@ -1182,6 +1182,7 @@ int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info) } btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); + btrfs_set_fs_compat(fs_info, FREE_SPACE_TREE_LE); fs_info->creating_free_space_tree = 0; ret = btrfs_commit_transaction(trans, tree_root); @@ -1250,6 +1251,7 @@ int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info) return PTR_ERR(trans); btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE); + btrfs_clear_fs_compat(fs_info, FREE_SPACE_TREE_LE); fs_info->free_space_root = NULL; ret = clear_free_space_tree(trans, free_space_root); @@ -1284,6 +1286,40 @@ abort: return ret; } +#ifdef __LITTLE_ENDIAN +static int __btrfs_set_free_space_tree_le(struct btrfs_fs_info *fs_info) +{ + struct btrfs_trans_handle *trans; + struct btrfs_root *tree_root = fs_info->tree_root; + + trans = btrfs_start_transaction(tree_root, 0); + if (IS_ERR(trans)) + return PTR_ERR(trans); + btrfs_set_fs_compat(fs_info, FREE_SPACE_TREE_LE); + return btrfs_commit_transaction(trans, tree_root); +} +#endif + +/* + * The free space tree was broken on big-endian systems when it was introduced. + * This attempts to catch that with the FREE_SPACE_TREE_LE compat bit. If it's + * not set, then we assume that the filesystem being mounted was created/used on + * the same endianness, which kind of sucks. + */ +int btrfs_check_free_space_tree_le(struct btrfs_fs_info *fs_info) +{ + if (btrfs_fs_compat(fs_info, FREE_SPACE_TREE_LE)) + return 0; + +#ifdef __LITTLE_ENDIAN + return __btrfs_set_free_space_tree_le(fs_info); +#else + btrfs_err(fs_info, "free space tree created with broken big-endian kernel"); + btrfs_err(fs_info, "please remount once with nospace_cache,clear_cache and then remount with space_cache=v2"); + return -EINVAL; +#endif +} + static int __add_block_group_free_space(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, struct btrfs_block_group_cache *block_group, diff --git a/fs/btrfs/free-space-tree.h b/fs/btrfs/free-space-tree.h index 54ffced..505b13e 100644 --- a/fs/btrfs/free-space-tree.h +++ b/fs/btrfs/free-space-tree.h @@ -30,6 +30,7 @@ void set_free_space_tree_thresholds(struct btrfs_block_group_cache *block_group); int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info); int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info); +int btrfs_check_free_space_tree_le(struct btrfs_fs_info *fs_info); int load_free_space_tree(struct btrfs_caching_control *caching_ctl); int add_block_group_free_space(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index ac5eacd..2695b3d 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -239,6 +239,8 @@ struct btrfs_ioctl_fs_info_args { * Used by: * struct btrfs_ioctl_feature_flags */ +#define BTRFS_FEATURE_COMPAT_FREE_SPACE_TREE_LE (1ULL << 0) + #define BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE (1ULL << 0) #define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF (1ULL << 0)

[0/3] Btrfs: fix free space tree bitmaps+tests on big-endian systems

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