| Message ID | 20170921041016.14752-3-ce3g8jdj@umail.furryterror.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Sep 21, 2017 at 12:10:15AM -0400, Zygo Blaxell wrote: > Now that check_extent_in_eb()'s extent offset filter can be turned off, > we need a way to do it from userspace. > > Add a 'flags' field to the btrfs_logical_ino_args structure to disable extent > offset filtering, taking the place of one of the reserved[] fields. > > Previous versions of LOGICAL_INO neglected to check whether any of the > reserved fields have non-zero values. Assigning meaning to those fields > now may change the behavior of existing programs that left these fields > uninitialized. > > To avoid any surprises, define a new ioctl LOGICAL_INO_V2 which uses > the same argument layout as LOGICAL_INO, but uses one of the reserved > fields for flags. The V2 ioctl explicitly checks that unsupported flag > bits are zero so that userspace can probe for future feature bits as > they are defined. If the other reserved fields are used in the future, > one of the remaining flag bits could specify that the other reserved > fields are valid, so we don't need to check those for now. > > Since the memory layouts and behavior of the two ioctls' arguments > are almost identical, there is no need for a separate function for > logical_to_ino_v2 (contrast with tree_search_v2 vs tree_search). > A version parameter and an 'if' statement will suffice. > > Now that we have a flags field in logical_ino_args, add a flag > BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET to get the behavior we want, > and pass it down the stack to iterate_inodes_from_logical. > > Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> > --- > fs/btrfs/ioctl.c | 21 ++++++++++++++++++--- > include/uapi/linux/btrfs.h | 8 +++++++- > 2 files changed, 25 insertions(+), 4 deletions(-) > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index b7de32568082..2bc3a9588d1d 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -4536,13 +4536,14 @@ static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx) > } > > static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > - void __user *arg) > + void __user *arg, int version) > { > int ret = 0; > int size; > struct btrfs_ioctl_logical_ino_args *loi; > struct btrfs_data_container *inodes = NULL; > struct btrfs_path *path = NULL; > + bool ignore_offset; > > if (!capable(CAP_SYS_ADMIN)) > return -EPERM; > @@ -4551,6 +4552,17 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > if (IS_ERR(loi)) > return PTR_ERR(loi); > > + if (version == 1) { > + ignore_offset = false; > + } else { > + /* Only accept flags we have defined so far */ > + if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) { > + ret = -EINVAL; > + goto out_loi; > + } > + ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET; Please check loi->reserved[3] for zeroness so that the next person who wants to add a field to btrfs_ioctl_logical_ino_args doesn't have to create LOGICAL_INO_V3 for the same reason you're creating V2. --D > + } > + > path = btrfs_alloc_path(); > if (!path) { > ret = -ENOMEM; > @@ -4566,7 +4578,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > } > > ret = iterate_inodes_from_logical(loi->logical, fs_info, path, > - build_ino_list, inodes, false); > + build_ino_list, inodes, ignore_offset); > if (ret == -EINVAL) > ret = -ENOENT; > if (ret < 0) > @@ -4580,6 +4592,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > out: > btrfs_free_path(path); > kvfree(inodes); > +out_loi: > kfree(loi); > > return ret; > @@ -5550,7 +5563,9 @@ long btrfs_ioctl(struct file *file, unsigned int > case BTRFS_IOC_INO_PATHS: > return btrfs_ioctl_ino_to_path(root, argp); > case BTRFS_IOC_LOGICAL_INO: > - return btrfs_ioctl_logical_to_ino(fs_info, argp); > + return btrfs_ioctl_logical_to_ino(fs_info, argp, 1); > + case BTRFS_IOC_LOGICAL_INO_V2: > + return btrfs_ioctl_logical_to_ino(fs_info, argp, 2); > case BTRFS_IOC_SPACE_INFO: > return btrfs_ioctl_space_info(fs_info, argp); > case BTRFS_IOC_SYNC: { > diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h > index 378230c163d5..0b3de597e04f 100644 > --- a/include/uapi/linux/btrfs.h > +++ b/include/uapi/linux/btrfs.h > @@ -608,10 +608,14 @@ struct btrfs_ioctl_ino_path_args { > struct btrfs_ioctl_logical_ino_args { > __u64 logical; /* in */ > __u64 size; /* in */ > - __u64 reserved[4]; > + __u64 flags; /* in, v2 only */ > + __u64 reserved[3]; > /* struct btrfs_data_container *inodes; out */ > __u64 inodes; > }; > +/* Return every ref to the extent, not just those containing logical block. > + * Requires logical == extent bytenr. */ > +#define BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET (1ULL << 0) > > enum btrfs_dev_stat_values { > /* disk I/O failure stats */ > @@ -835,5 +839,7 @@ enum btrfs_err_code { > struct btrfs_ioctl_feature_flags[3]) > #define BTRFS_IOC_RM_DEV_V2 _IOW(BTRFS_IOCTL_MAGIC, 58, \ > struct btrfs_ioctl_vol_args_v2) > +#define BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ > + struct btrfs_ioctl_logical_ino_args) > > #endif /* _UAPI_LINUX_BTRFS_H */ > -- > 2.11.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Sep 21, 2017 at 12:59:42PM -0700, Darrick J. Wong wrote: > On Thu, Sep 21, 2017 at 12:10:15AM -0400, Zygo Blaxell wrote: > > Now that check_extent_in_eb()'s extent offset filter can be turned off, > > we need a way to do it from userspace. > > > > Add a 'flags' field to the btrfs_logical_ino_args structure to disable extent > > offset filtering, taking the place of one of the reserved[] fields. > > > > Previous versions of LOGICAL_INO neglected to check whether any of the > > reserved fields have non-zero values. Assigning meaning to those fields > > now may change the behavior of existing programs that left these fields > > uninitialized. > > > > To avoid any surprises, define a new ioctl LOGICAL_INO_V2 which uses > > the same argument layout as LOGICAL_INO, but uses one of the reserved > > fields for flags. The V2 ioctl explicitly checks that unsupported flag > > bits are zero so that userspace can probe for future feature bits as > > they are defined. If the other reserved fields are used in the future, > > one of the remaining flag bits could specify that the other reserved > > fields are valid, so we don't need to check those for now. > > > > Since the memory layouts and behavior of the two ioctls' arguments > > are almost identical, there is no need for a separate function for > > logical_to_ino_v2 (contrast with tree_search_v2 vs tree_search). > > A version parameter and an 'if' statement will suffice. > > > > Now that we have a flags field in logical_ino_args, add a flag > > BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET to get the behavior we want, > > and pass it down the stack to iterate_inodes_from_logical. > > > > Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> > > --- > > fs/btrfs/ioctl.c | 21 ++++++++++++++++++--- > > include/uapi/linux/btrfs.h | 8 +++++++- > > 2 files changed, 25 insertions(+), 4 deletions(-) > > > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > > index b7de32568082..2bc3a9588d1d 100644 > > --- a/fs/btrfs/ioctl.c > > +++ b/fs/btrfs/ioctl.c > > @@ -4536,13 +4536,14 @@ static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx) > > } > > > > static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > - void __user *arg) > > + void __user *arg, int version) > > { > > int ret = 0; > > int size; > > struct btrfs_ioctl_logical_ino_args *loi; > > struct btrfs_data_container *inodes = NULL; > > struct btrfs_path *path = NULL; > > + bool ignore_offset; > > > > if (!capable(CAP_SYS_ADMIN)) > > return -EPERM; > > @@ -4551,6 +4552,17 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > if (IS_ERR(loi)) > > return PTR_ERR(loi); > > > > + if (version == 1) { > > + ignore_offset = false; > > + } else { > > + /* Only accept flags we have defined so far */ > > + if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) { > > + ret = -EINVAL; > > + goto out_loi; > > + } > > + ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET; > > Please check loi->reserved[3] for zeroness so that the next person who > wants to add a field to btrfs_ioctl_logical_ino_args doesn't have to > create LOGICAL_INO_V3 for the same reason you're creating V2. OK now I'm confused, in several distinct ways. I wonder if you meant reserved[1] and reserved[2] there, since I'm not checking them (for reasons stated in the commit log--we can use flags to indicate whether and what values are present there). But that's not the bigger problem. Maybe you did mean reserved[3], but there's no "reserved[3]" any more. I shortened the reserved array from 4 elements to 3, so "reserved[3]" is no longer a valid memory reference. Also "reserved[0]" no longer refers to the same thing it once did. > --D > > > + } > > + > > path = btrfs_alloc_path(); > > if (!path) { > > ret = -ENOMEM; > > @@ -4566,7 +4578,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > } > > > > ret = iterate_inodes_from_logical(loi->logical, fs_info, path, > > - build_ino_list, inodes, false); > > + build_ino_list, inodes, ignore_offset); > > if (ret == -EINVAL) > > ret = -ENOENT; > > if (ret < 0) > > @@ -4580,6 +4592,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > out: > > btrfs_free_path(path); > > kvfree(inodes); > > +out_loi: > > kfree(loi); > > > > return ret; > > @@ -5550,7 +5563,9 @@ long btrfs_ioctl(struct file *file, unsigned int > > case BTRFS_IOC_INO_PATHS: > > return btrfs_ioctl_ino_to_path(root, argp); > > case BTRFS_IOC_LOGICAL_INO: > > - return btrfs_ioctl_logical_to_ino(fs_info, argp); > > + return btrfs_ioctl_logical_to_ino(fs_info, argp, 1); > > + case BTRFS_IOC_LOGICAL_INO_V2: > > + return btrfs_ioctl_logical_to_ino(fs_info, argp, 2); > > case BTRFS_IOC_SPACE_INFO: > > return btrfs_ioctl_space_info(fs_info, argp); > > case BTRFS_IOC_SYNC: { > > diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h > > index 378230c163d5..0b3de597e04f 100644 > > --- a/include/uapi/linux/btrfs.h > > +++ b/include/uapi/linux/btrfs.h > > @@ -608,10 +608,14 @@ struct btrfs_ioctl_ino_path_args { > > struct btrfs_ioctl_logical_ino_args { > > __u64 logical; /* in */ > > __u64 size; /* in */ > > - __u64 reserved[4]; > > + __u64 flags; /* in, v2 only */ > > + __u64 reserved[3]; Should I rename 'reserved' here, e.g. __u64 logical; /* in */ __u64 size; /* in */ __u64 flags; /* in, v2 only */ __u64 reserved1; __u64 reserved2; __u64 reserved3; /* struct btrfs_data_container *inodes; out */ __u64 inodes; That way any existing code that happened to use reserved[3] now fails to compile instead of clobbering the first u64 of inodes, and there's no silent rearrangement of reserved[0..2]. Another option is I just put flags where reserved[3] is: __u64 logical; /* in */ __u64 size; /* in */ __u64 reserved[3]; __u64 flags; /* in, v2 only */ /* struct btrfs_data_container *inodes; out */ __u64 inodes; This means code that has reserved[3] still works (maybe it just prints the value for a human to read), and it just happens to land where the new flags field is. > > /* struct btrfs_data_container *inodes; out */ > > __u64 inodes; > > }; > > +/* Return every ref to the extent, not just those containing logical block. > > + * Requires logical == extent bytenr. */ > > +#define BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET (1ULL << 0) > > > > enum btrfs_dev_stat_values { > > /* disk I/O failure stats */ > > @@ -835,5 +839,7 @@ enum btrfs_err_code { > > struct btrfs_ioctl_feature_flags[3]) > > #define BTRFS_IOC_RM_DEV_V2 _IOW(BTRFS_IOCTL_MAGIC, 58, \ > > struct btrfs_ioctl_vol_args_v2) > > +#define BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ > > + struct btrfs_ioctl_logical_ino_args) > > > > #endif /* _UAPI_LINUX_BTRFS_H */ > > -- > > 2.11.0 > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
On Thu, Sep 21, 2017 at 04:16:35PM -0400, Zygo Blaxell wrote: > On Thu, Sep 21, 2017 at 12:59:42PM -0700, Darrick J. Wong wrote: > > On Thu, Sep 21, 2017 at 12:10:15AM -0400, Zygo Blaxell wrote: > > > Now that check_extent_in_eb()'s extent offset filter can be turned off, > > > we need a way to do it from userspace. > > > > > > Add a 'flags' field to the btrfs_logical_ino_args structure to disable extent > > > offset filtering, taking the place of one of the reserved[] fields. > > > > > > Previous versions of LOGICAL_INO neglected to check whether any of the > > > reserved fields have non-zero values. Assigning meaning to those fields > > > now may change the behavior of existing programs that left these fields > > > uninitialized. > > > > > > To avoid any surprises, define a new ioctl LOGICAL_INO_V2 which uses > > > the same argument layout as LOGICAL_INO, but uses one of the reserved > > > fields for flags. The V2 ioctl explicitly checks that unsupported flag > > > bits are zero so that userspace can probe for future feature bits as > > > they are defined. If the other reserved fields are used in the future, > > > one of the remaining flag bits could specify that the other reserved > > > fields are valid, so we don't need to check those for now. > > > > > > Since the memory layouts and behavior of the two ioctls' arguments > > > are almost identical, there is no need for a separate function for > > > logical_to_ino_v2 (contrast with tree_search_v2 vs tree_search). > > > A version parameter and an 'if' statement will suffice. > > > > > > Now that we have a flags field in logical_ino_args, add a flag > > > BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET to get the behavior we want, > > > and pass it down the stack to iterate_inodes_from_logical. > > > > > > Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> > > > --- > > > fs/btrfs/ioctl.c | 21 ++++++++++++++++++--- > > > include/uapi/linux/btrfs.h | 8 +++++++- > > > 2 files changed, 25 insertions(+), 4 deletions(-) > > > > > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > > > index b7de32568082..2bc3a9588d1d 100644 > > > --- a/fs/btrfs/ioctl.c > > > +++ b/fs/btrfs/ioctl.c > > > @@ -4536,13 +4536,14 @@ static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx) > > > } > > > > > > static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > > - void __user *arg) > > > + void __user *arg, int version) > > > { > > > int ret = 0; > > > int size; > > > struct btrfs_ioctl_logical_ino_args *loi; > > > struct btrfs_data_container *inodes = NULL; > > > struct btrfs_path *path = NULL; > > > + bool ignore_offset; > > > > > > if (!capable(CAP_SYS_ADMIN)) > > > return -EPERM; > > > @@ -4551,6 +4552,17 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > > if (IS_ERR(loi)) > > > return PTR_ERR(loi); > > > > > > + if (version == 1) { > > > + ignore_offset = false; > > > + } else { > > > + /* Only accept flags we have defined so far */ > > > + if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) { > > > + ret = -EINVAL; > > > + goto out_loi; > > > + } > > > + ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET; > > > > Please check loi->reserved[3] for zeroness so that the next person who > > wants to add a field to btrfs_ioctl_logical_ino_args doesn't have to > > create LOGICAL_INO_V3 for the same reason you're creating V2. > > OK now I'm confused, in several distinct ways. > > I wonder if you meant reserved[1] and reserved[2] there, since I'm not > checking them (for reasons stated in the commit log--we can use flags > to indicate whether and what values are present there). You can do that, though that means you have to burn flag bits to light up the remaining reserved area, which means you can't in the future decide that a non-zero field value will turn on some new feature. You retain the ability to use flag bits to turn on the new field, if it's the case that zero has a meaning. > But that's not the bigger problem. Maybe you did mean reserved[3], but > there's no "reserved[3]" any more. I shortened the reserved array from > 4 elements to 3, so "reserved[3]" is no longer a valid memory reference. > Also "reserved[0]" no longer refers to the same thing it once did. Oops, sorry, that was a typo, I meant reserved[], as in 'check the whole array via memchr_inv'. --D > > > --D > > > > > + } > > > + > > > path = btrfs_alloc_path(); > > > if (!path) { > > > ret = -ENOMEM; > > > @@ -4566,7 +4578,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > > } > > > > > > ret = iterate_inodes_from_logical(loi->logical, fs_info, path, > > > - build_ino_list, inodes, false); > > > + build_ino_list, inodes, ignore_offset); > > > if (ret == -EINVAL) > > > ret = -ENOENT; > > > if (ret < 0) > > > @@ -4580,6 +4592,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, > > > out: > > > btrfs_free_path(path); > > > kvfree(inodes); > > > +out_loi: > > > kfree(loi); > > > > > > return ret; > > > @@ -5550,7 +5563,9 @@ long btrfs_ioctl(struct file *file, unsigned int > > > case BTRFS_IOC_INO_PATHS: > > > return btrfs_ioctl_ino_to_path(root, argp); > > > case BTRFS_IOC_LOGICAL_INO: > > > - return btrfs_ioctl_logical_to_ino(fs_info, argp); > > > + return btrfs_ioctl_logical_to_ino(fs_info, argp, 1); > > > + case BTRFS_IOC_LOGICAL_INO_V2: > > > + return btrfs_ioctl_logical_to_ino(fs_info, argp, 2); > > > case BTRFS_IOC_SPACE_INFO: > > > return btrfs_ioctl_space_info(fs_info, argp); > > > case BTRFS_IOC_SYNC: { > > > diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h > > > index 378230c163d5..0b3de597e04f 100644 > > > --- a/include/uapi/linux/btrfs.h > > > +++ b/include/uapi/linux/btrfs.h > > > @@ -608,10 +608,14 @@ struct btrfs_ioctl_ino_path_args { > > > struct btrfs_ioctl_logical_ino_args { > > > __u64 logical; /* in */ > > > __u64 size; /* in */ > > > - __u64 reserved[4]; > > > + __u64 flags; /* in, v2 only */ > > > + __u64 reserved[3]; > > Should I rename 'reserved' here, e.g. > > __u64 logical; /* in */ > __u64 size; /* in */ > __u64 flags; /* in, v2 only */ > __u64 reserved1; > __u64 reserved2; > __u64 reserved3; > /* struct btrfs_data_container *inodes; out */ > __u64 inodes; > > That way any existing code that happened to use reserved[3] now > fails to compile instead of clobbering the first u64 of inodes, > and there's no silent rearrangement of reserved[0..2]. > > Another option is I just put flags where reserved[3] is: > > __u64 logical; /* in */ > __u64 size; /* in */ > __u64 reserved[3]; > __u64 flags; /* in, v2 only */ > /* struct btrfs_data_container *inodes; out */ > __u64 inodes; > > This means code that has reserved[3] still works (maybe it just prints > the value for a human to read), and it just happens to land where the > new flags field is. > > > > /* struct btrfs_data_container *inodes; out */ > > > __u64 inodes; > > > }; > > > +/* Return every ref to the extent, not just those containing logical block. > > > + * Requires logical == extent bytenr. */ > > > +#define BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET (1ULL << 0) > > > > > > enum btrfs_dev_stat_values { > > > /* disk I/O failure stats */ > > > @@ -835,5 +839,7 @@ enum btrfs_err_code { > > > struct btrfs_ioctl_feature_flags[3]) > > > #define BTRFS_IOC_RM_DEV_V2 _IOW(BTRFS_IOCTL_MAGIC, 58, \ > > > struct btrfs_ioctl_vol_args_v2) > > > +#define BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ > > > + struct btrfs_ioctl_logical_ino_args) > > > > > > #endif /* _UAPI_LINUX_BTRFS_H */ > > > -- > > > 2.11.0 > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index b7de32568082..2bc3a9588d1d 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4536,13 +4536,14 @@ static int build_ino_list(u64 inum, u64 offset, u64 root, void *ctx) } static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, - void __user *arg) + void __user *arg, int version) { int ret = 0; int size; struct btrfs_ioctl_logical_ino_args *loi; struct btrfs_data_container *inodes = NULL; struct btrfs_path *path = NULL; + bool ignore_offset; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -4551,6 +4552,17 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, if (IS_ERR(loi)) return PTR_ERR(loi); + if (version == 1) { + ignore_offset = false; + } else { + /* Only accept flags we have defined so far */ + if (loi->flags & ~(BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET)) { + ret = -EINVAL; + goto out_loi; + } + ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET; + } + path = btrfs_alloc_path(); if (!path) { ret = -ENOMEM; @@ -4566,7 +4578,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, } ret = iterate_inodes_from_logical(loi->logical, fs_info, path, - build_ino_list, inodes, false); + build_ino_list, inodes, ignore_offset); if (ret == -EINVAL) ret = -ENOENT; if (ret < 0) @@ -4580,6 +4592,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info, out: btrfs_free_path(path); kvfree(inodes); +out_loi: kfree(loi); return ret; @@ -5550,7 +5563,9 @@ long btrfs_ioctl(struct file *file, unsigned int case BTRFS_IOC_INO_PATHS: return btrfs_ioctl_ino_to_path(root, argp); case BTRFS_IOC_LOGICAL_INO: - return btrfs_ioctl_logical_to_ino(fs_info, argp); + return btrfs_ioctl_logical_to_ino(fs_info, argp, 1); + case BTRFS_IOC_LOGICAL_INO_V2: + return btrfs_ioctl_logical_to_ino(fs_info, argp, 2); case BTRFS_IOC_SPACE_INFO: return btrfs_ioctl_space_info(fs_info, argp); case BTRFS_IOC_SYNC: { diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index 378230c163d5..0b3de597e04f 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -608,10 +608,14 @@ struct btrfs_ioctl_ino_path_args { struct btrfs_ioctl_logical_ino_args { __u64 logical; /* in */ __u64 size; /* in */ - __u64 reserved[4]; + __u64 flags; /* in, v2 only */ + __u64 reserved[3]; /* struct btrfs_data_container *inodes; out */ __u64 inodes; }; +/* Return every ref to the extent, not just those containing logical block. + * Requires logical == extent bytenr. */ +#define BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET (1ULL << 0) enum btrfs_dev_stat_values { /* disk I/O failure stats */ @@ -835,5 +839,7 @@ enum btrfs_err_code { struct btrfs_ioctl_feature_flags[3]) #define BTRFS_IOC_RM_DEV_V2 _IOW(BTRFS_IOCTL_MAGIC, 58, \ struct btrfs_ioctl_vol_args_v2) +#define BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ + struct btrfs_ioctl_logical_ino_args) #endif /* _UAPI_LINUX_BTRFS_H */
Now that check_extent_in_eb()'s extent offset filter can be turned off, we need a way to do it from userspace. Add a 'flags' field to the btrfs_logical_ino_args structure to disable extent offset filtering, taking the place of one of the reserved[] fields. Previous versions of LOGICAL_INO neglected to check whether any of the reserved fields have non-zero values. Assigning meaning to those fields now may change the behavior of existing programs that left these fields uninitialized. To avoid any surprises, define a new ioctl LOGICAL_INO_V2 which uses the same argument layout as LOGICAL_INO, but uses one of the reserved fields for flags. The V2 ioctl explicitly checks that unsupported flag bits are zero so that userspace can probe for future feature bits as they are defined. If the other reserved fields are used in the future, one of the remaining flag bits could specify that the other reserved fields are valid, so we don't need to check those for now. Since the memory layouts and behavior of the two ioctls' arguments are almost identical, there is no need for a separate function for logical_to_ino_v2 (contrast with tree_search_v2 vs tree_search). A version parameter and an 'if' statement will suffice. Now that we have a flags field in logical_ino_args, add a flag BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET to get the behavior we want, and pass it down the stack to iterate_inodes_from_logical. Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org> --- fs/btrfs/ioctl.c | 21 ++++++++++++++++++--- include/uapi/linux/btrfs.h | 8 +++++++- 2 files changed, 25 insertions(+), 4 deletions(-)