On 11/21/13, 8:07 AM, Filipe David Manana wrote:
> On Wed, Nov 20, 2013 at 9:59 PM, Jeff Mahoney <jeffm@suse.com> wrote:
>> Filipe noticed that we were leaking the features attribute group
>> after umount. His fix of just calling sysfs_remove_group() wasn't enough
>> since that removes just the supported features and not the unknown
>> features (but a regular test wouldn't show that).
>>
>> This patch changes the unknown feature handling to add them individually
>> so we can skip the kmalloc and uses the same iteration to tear them down
>> later.
>>
>> We also fix the error handling during mount so that we catch the
>> failing creation of the per-super kobject, and handle proper teardown
>> of a half-setup sysfs context.
>>
>> Reported-by: Filipe David Borba Manana <fdmanana@gmail.com>
>> Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> 
> Hi Jeff, I tested this patch (reverted my patch and applied yours) and
> after about 20 minutes of running xfstests I had 169 kmemleak
> warnings, see below some of the stack traces. Thanks.

*sigh*

I missed the original sysfs_remove_group that was the point of all this.
(Well done, Jeff.)

-Jeff

> unreferenced object 0xffff8807424bdb90 (size 64):
>   comm "mount", pid 20697, jiffies 4295160287 (age 1117.544s)
>   hex dump (first 32 bytes):
>     64 36 61 34 61 30 64 30 2d 39 62 31 63 2d 34 31  d6a4a0d0-9b1c-41
>     37 62 2d 38 31 30 37 2d 34 36 66 32 39 63 30 39  7b-8107-46f29c09
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8119061b>] __kmalloc_track_caller+0x1cb/0x240
>     [<ffffffff81157102>] kstrdup+0x42/0x70
>     [<ffffffff81219271>] sysfs_new_dirent+0x31/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219aa9>] sysfs_create_dir+0x89/0xe0
>     [<ffffffff813e3416>] kobject_add_internal+0x96/0x210
>     [<ffffffff813e37a3>] kobject_init_and_add+0x63/0x90
>     [<ffffffffa06adadd>] btrfs_sysfs_add_one+0x7d/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
> unreferenced object 0xffff8800968254f8 (size 160):
>   comm "mount", pid 20697, jiffies 4295160287 (age 1117.544s)
>   hex dump (first 32 bytes):
>     01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8118f294>] kmem_cache_alloc+0x114/0x200
>     [<ffffffff81219291>] sysfs_new_dirent+0x51/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219aa9>] sysfs_create_dir+0x89/0xe0
>     [<ffffffff813e3416>] kobject_add_internal+0x96/0x210
>     [<ffffffff813e37a3>] kobject_init_and_add+0x63/0x90
>     [<ffffffffa06adadd>] btrfs_sysfs_add_one+0x7d/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff8806b3cf22b0 (size 16):
>   comm "mount", pid 20697, jiffies 4295160287 (age 1117.544s)
>   hex dump (first 16 bytes):
>     66 65 61 74 75 72 65 73 00 6b 6b 6b 6b 6b 6b a5  features.kkkkkk.
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8119061b>] __kmalloc_track_caller+0x1cb/0x240
>     [<ffffffff81157102>] kstrdup+0x42/0x70
>     [<ffffffff81219271>] sysfs_new_dirent+0x31/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219a0f>] sysfs_create_subdir+0x1f/0x30
>     [<ffffffff8121b51e>] internal_create_group+0x5e/0x270
>     [<ffffffff8121b763>] sysfs_create_group+0x13/0x20
>     [<ffffffffa06adb07>] btrfs_sysfs_add_one+0xa7/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
> unreferenced object 0xffff880096825310 (size 160):
>   comm "mount", pid 20697, jiffies 4295160287 (age 1117.648s)
>   hex dump (first 32 bytes):
>     03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8118f294>] kmem_cache_alloc+0x114/0x200
>     [<ffffffff81219291>] sysfs_new_dirent+0x51/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219a0f>] sysfs_create_subdir+0x1f/0x30
>     [<ffffffff8121b51e>] internal_create_group+0x5e/0x270
>     [<ffffffff8121b763>] sysfs_create_group+0x13/0x20
>     [<ffffffffa06adb07>] btrfs_sysfs_add_one+0xa7/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff880096824b70 (size 160):
>   comm "mount", pid 20697, jiffies 4295160287 (age 1117.648s)
>   hex dump (first 32 bytes):
>     01 00 00 00 00 00 00 00 b8 4d 72 a0 ff ff ff ff  .........Mr.....
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8118f294>] kmem_cache_alloc+0x114/0x200
>     [<ffffffff81219291>] sysfs_new_dirent+0x51/0x130
>     [<ffffffff8121847a>] sysfs_add_file_mode+0x6a/0x110
>     [<ffffffff8121b5a1>] internal_create_group+0xe1/0x270
>     [<ffffffff8121b763>] sysfs_create_group+0x13/0x20
>     [<ffffffffa06adb07>] btrfs_sysfs_add_one+0xa7/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff880096825128 (size 160):
>   comm "mount", pid 20697, jiffies 4295160287 (age 1117.648s)
>   hex dump (first 32 bytes):
>     01 00 00 00 00 00 00 00 38 4f 72 a0 ff ff ff ff  ........8Or.....
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8118f294>] kmem_cache_alloc+0x114/0x200
>     [<ffffffff81219291>] sysfs_new_dirent+0x51/0x130
>     [<ffffffff8121847a>] sysfs_add_file_mode+0x6a/0x110
>     [<ffffffff8121b5a1>] internal_create_group+0xe1/0x270
>     [<ffffffff8121b763>] sysfs_create_group+0x13/0x20
>     [<ffffffffa06adb07>] btrfs_sysfs_add_one+0xa7/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff880758bbb6f8 (size 64):
>   comm "mount", pid 20762, jiffies 4295160425 (age 1117.192s)
>   hex dump (first 32 bytes):
>     34 62 31 39 39 65 37 35 2d 30 62 31 32 2d 34 34  4b199e75-0b12-44
>     64 39 2d 61 31 61 34 2d 31 32 39 31 66 37 63 30  d9-a1a4-1291f7c0
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8119061b>] __kmalloc_track_caller+0x1cb/0x240
>     [<ffffffff81157102>] kstrdup+0x42/0x70
>     [<ffffffff81219271>] sysfs_new_dirent+0x31/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219aa9>] sysfs_create_dir+0x89/0xe0
>     [<ffffffff813e3416>] kobject_add_internal+0x96/0x210
>     [<ffffffff813e37a3>] kobject_init_and_add+0x63/0x90
>     [<ffffffffa06adadd>] btrfs_sysfs_add_one+0x7d/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
> unreferenced object 0xffff8806649361e8 (size 160):
>   comm "mount", pid 20762, jiffies 4295160425 (age 1117.192s)
>   hex dump (first 32 bytes):
>     01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8118f294>] kmem_cache_alloc+0x114/0x200
>     [<ffffffff81219291>] sysfs_new_dirent+0x51/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219aa9>] sysfs_create_dir+0x89/0xe0
>     [<ffffffff813e3416>] kobject_add_internal+0x96/0x210
>     [<ffffffff813e37a3>] kobject_init_and_add+0x63/0x90
>     [<ffffffffa06adadd>] btrfs_sysfs_add_one+0x7d/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff8806b3cf32d0 (size 16):
>   comm "mount", pid 20762, jiffies 4295160425 (age 1117.192s)
>   hex dump (first 16 bytes):
>     66 65 61 74 75 72 65 73 00 6b 6b 6b 6b 6b 6b a5  features.kkkkkk.
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8119061b>] __kmalloc_track_caller+0x1cb/0x240
>     [<ffffffff81157102>] kstrdup+0x42/0x70
>     [<ffffffff81219271>] sysfs_new_dirent+0x31/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219a0f>] sysfs_create_subdir+0x1f/0x30
>     [<ffffffff8121b51e>] internal_create_group+0x5e/0x270
>     [<ffffffff8121b763>] sysfs_create_group+0x13/0x20
>     [<ffffffffa06adb07>] btrfs_sysfs_add_one+0xa7/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
> unreferenced object 0xffff8806649363d0 (size 160):
>   comm "mount", pid 20762, jiffies 4295160425 (age 1117.272s)
>   hex dump (first 32 bytes):
>     03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8118f294>] kmem_cache_alloc+0x114/0x200
>     [<ffffffff81219291>] sysfs_new_dirent+0x51/0x130
>     [<ffffffff812196e2>] create_dir+0x42/0xd0
>     [<ffffffff81219a0f>] sysfs_create_subdir+0x1f/0x30
>     [<ffffffff8121b51e>] internal_create_group+0x5e/0x270
>     [<ffffffff8121b763>] sysfs_create_group+0x13/0x20
>     [<ffffffffa06adb07>] btrfs_sysfs_add_one+0xa7/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> unreferenced object 0xffff8806649378c8 (size 160):
>   comm "mount", pid 20762, jiffies 4295160425 (age 1117.272s)
>   hex dump (first 32 bytes):
>     01 00 00 00 00 00 00 00 b8 4d 72 a0 ff ff ff ff  .........Mr.....
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace:
>     [<ffffffff8175f606>] kmemleak_alloc+0x26/0x50
>     [<ffffffff8118f294>] kmem_cache_alloc+0x114/0x200
>     [<ffffffff81219291>] sysfs_new_dirent+0x51/0x130
>     [<ffffffff8121847a>] sysfs_add_file_mode+0x6a/0x110
>     [<ffffffff8121b5a1>] internal_create_group+0xe1/0x270
>     [<ffffffff8121b763>] sysfs_create_group+0x13/0x20
>     [<ffffffffa06adb07>] btrfs_sysfs_add_one+0xa7/0x1b0 [btrfs]
>     [<ffffffffa0693792>] open_ctree+0x17d2/0x21f0 [btrfs]
>     [<ffffffffa066983a>] btrfs_mount+0x53a/0x7d0 [btrfs]
>     [<ffffffff811a3ae3>] mount_fs+0x43/0x1b0
>     [<ffffffff811bfa66>] vfs_kern_mount+0x76/0x120
>     [<ffffffff811c1d87>] do_mount+0x237/0xa70
>     [<ffffffff811c2650>] SyS_mount+0x90/0xe0
>     [<ffffffff8177ef12>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> 
> 
> 
>> ---
>>  fs/btrfs/sysfs.c |  132 ++++++++++++++++++++++++++++++-------------------------
>>  1 file changed, 72 insertions(+), 60 deletions(-)
>>
>> --- a/fs/btrfs/sysfs.c  2013-11-20 14:58:40.907456459 -0500
>> +++ b/fs/btrfs/sysfs.c  2013-11-20 16:59:02.359951682 -0500
>> @@ -417,28 +417,83 @@ static inline struct btrfs_fs_info *to_f
>>         return container_of(kobj, struct btrfs_fs_info, super_kobj);
>>  }
>>
>> -void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
>> +#define NUM_FEATURE_BITS 64
>> +static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
>> +static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
>> +
>> +static u64 supported_feature_masks[3] = {
>> +       [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
>> +       [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
>> +       [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
>> +};
>> +
>> +static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add)
>> +{
>> +       int set;
>> +
>> +       for (set = 0; set < FEAT_MAX; set++) {
>> +               int i;
>> +               struct attribute *attrs[2];
>> +               struct attribute_group agroup = {
>> +                       .name = "features",
>> +                       .attrs = attrs,
>> +               };
>> +               u64 features = get_features(fs_info, set);
>> +               features &= ~supported_feature_masks[set];
>> +
>> +               if (!features)
>> +                       continue;
>> +
>> +               attrs[1] = NULL;
>> +               for (i = 0; i < NUM_FEATURE_BITS; i++) {
>> +                       struct btrfs_feature_attr *fa;
>> +
>> +                       if (!(features & (1ULL << i)))
>> +                               continue;
>> +
>> +                       fa = &btrfs_feature_attrs[set][i];
>> +                       attrs[0] = &fa->kobj_attr.attr;
>> +                       if (add) {
>> +                               int ret;
>> +                               ret = sysfs_merge_group(&fs_info->super_kobj,
>> +                                                       &agroup);
>> +                               if (ret)
>> +                                       return ret;
>> +                       } else
>> +                               sysfs_unmerge_group(&fs_info->super_kobj,
>> +                                                   &agroup);
>> +               }
>> +
>> +       }
>> +       return 0;
>> +}
>> +
>> +static void __btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
>>  {
>> -       sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
>> -       kobject_del(fs_info->device_dir_kobj);
>> -       kobject_put(fs_info->device_dir_kobj);
>> -       kobject_del(fs_info->space_info_kobj);
>> -       kobject_put(fs_info->space_info_kobj);
>>         kobject_del(&fs_info->super_kobj);
>>         kobject_put(&fs_info->super_kobj);
>>         wait_for_completion(&fs_info->kobj_unregister);
>>  }
>>
>> +void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
>> +{
>> +       if (fs_info->space_info_kobj) {
>> +               sysfs_remove_files(fs_info->space_info_kobj, allocation_attrs);
>> +               kobject_del(fs_info->space_info_kobj);
>> +               kobject_put(fs_info->space_info_kobj);
>> +       }
>> +       kobject_del(fs_info->device_dir_kobj);
>> +       kobject_put(fs_info->device_dir_kobj);
>> +       addrm_unknown_feature_attrs(fs_info, false);
>> +       __btrfs_sysfs_remove_one(fs_info);
>> +}
>> +
>>  const char * const btrfs_feature_set_names[3] = {
>>         [FEAT_COMPAT]    = "compat",
>>         [FEAT_COMPAT_RO] = "compat_ro",
>>         [FEAT_INCOMPAT]  = "incompat",
>>  };
>>
>> -#define NUM_FEATURE_BITS 64
>> -static char btrfs_unknown_feature_names[3][NUM_FEATURE_BITS][13];
>> -static struct btrfs_feature_attr btrfs_feature_attrs[3][NUM_FEATURE_BITS];
>> -
>>  char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
>>  {
>>         size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
>> @@ -508,53 +563,6 @@ static void init_feature_attrs(void)
>>         }
>>  }
>>
>> -static u64 supported_feature_masks[3] = {
>> -       [FEAT_COMPAT]    = BTRFS_FEATURE_COMPAT_SUPP,
>> -       [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP,
>> -       [FEAT_INCOMPAT]  = BTRFS_FEATURE_INCOMPAT_SUPP,
>> -};
>> -
>> -static int add_unknown_feature_attrs(struct btrfs_fs_info *fs_info)
>> -{
>> -       int set;
>> -
>> -       for (set = 0; set < FEAT_MAX; set++) {
>> -               int i, count, ret, index = 0;
>> -               struct attribute **attrs;
>> -               struct attribute_group agroup = {
>> -                       .name = "features",
>> -               };
>> -               u64 features = get_features(fs_info, set);
>> -               features &= ~supported_feature_masks[set];
>> -
>> -               count = hweight64(features);
>> -
>> -               if (!count)
>> -                       continue;
>> -
>> -               attrs = kcalloc(count + 1, sizeof(void *), GFP_KERNEL);
>> -
>> -               for (i = 0; i < NUM_FEATURE_BITS; i++) {
>> -                       struct btrfs_feature_attr *fa;
>> -
>> -                       if (!(features & (1ULL << i)))
>> -                               continue;
>> -
>> -                       fa = &btrfs_feature_attrs[set][i];
>> -                       attrs[index++] = &fa->kobj_attr.attr;
>> -               }
>> -
>> -               attrs[index] = NULL;
>> -               agroup.attrs = attrs;
>> -
>> -               ret = sysfs_merge_group(&fs_info->super_kobj, &agroup);
>> -               kfree(attrs);
>> -               if (ret)
>> -                       return ret;
>> -       }
>> -       return 0;
>> -}
>> -
>>  static int add_device_membership(struct btrfs_fs_info *fs_info)
>>  {
>>         int error = 0;
>> @@ -590,13 +598,17 @@ int btrfs_sysfs_add_one(struct btrfs_fs_
>>         fs_info->super_kobj.kset = btrfs_kset;
>>         error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
>>                                      "%pU", fs_info->fsid);
>> +       if (error)
>> +               return error;
>>
>>         error = sysfs_create_group(&fs_info->super_kobj,
>>                                    &btrfs_feature_attr_group);
>> -       if (error)
>> -               goto failure;
>> +       if (error) {
>> +               __btrfs_sysfs_remove_one(fs_info);
>> +               return error;
>> +       }
>>
>> -       error = add_unknown_feature_attrs(fs_info);
>> +       error = addrm_unknown_feature_attrs(fs_info, true);
>>         if (error)
>>                 goto failure;
>>
>>
>>
>> --
>> Jeff Mahoney
>> SUSE Labs
> 
> 
> 


-- 
Jeff Mahoney
SUSE Labs