diff options
Diffstat (limited to 'fs/xfs/xfs_inode.h')
| -rw-r--r-- | fs/xfs/xfs_inode.h | 85 |
1 files changed, 59 insertions, 26 deletions
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index 8f22d20368d8..ca9e11989cbd 100644 --- a/fs/xfs/xfs_inode.h +++ b/fs/xfs/xfs_inode.h @@ -284,9 +284,9 @@ static inline int xfs_isiflocked(struct xfs_inode *ip) * Flags for lockdep annotations. * * XFS_LOCK_PARENT - for directory operations that require locking a - * parent directory inode and a child entry inode. The parent gets locked - * with this flag so it gets a lockdep subclass of 1 and the child entry - * lock will have a lockdep subclass of 0. + * parent directory inode and a child entry inode. IOLOCK requires nesting, + * MMAPLOCK does not support this class, ILOCK requires a single subclass + * to differentiate parent from child. * * XFS_LOCK_RTBITMAP/XFS_LOCK_RTSUM - the realtime device bitmap and summary * inodes do not participate in the normal lock order, and thus have their @@ -295,30 +295,63 @@ static inline int xfs_isiflocked(struct xfs_inode *ip) * XFS_LOCK_INUMORDER - for locking several inodes at the some time * with xfs_lock_inodes(). This flag is used as the starting subclass * and each subsequent lock acquired will increment the subclass by one. - * So the first lock acquired will have a lockdep subclass of 4, the - * second lock will have a lockdep subclass of 5, and so on. It is - * the responsibility of the class builder to shift this to the correct - * portion of the lock_mode lockdep mask. + * However, MAX_LOCKDEP_SUBCLASSES == 8, which means we are greatly + * limited to the subclasses we can represent via nesting. We need at least + * 5 inodes nest depth for the ILOCK through rename, and we also have to support + * XFS_ILOCK_PARENT, which gives 6 subclasses. Then we have XFS_ILOCK_RTBITMAP + * and XFS_ILOCK_RTSUM, which are another 2 unique subclasses, so that's all + * 8 subclasses supported by lockdep. + * + * This also means we have to number the sub-classes in the lowest bits of + * the mask we keep, and we have to ensure we never exceed 3 bits of lockdep + * mask and we can't use bit-masking to build the subclasses. What a mess. + * + * Bit layout: + * + * Bit Lock Region + * 16-19 XFS_IOLOCK_SHIFT dependencies + * 20-23 XFS_MMAPLOCK_SHIFT dependencies + * 24-31 XFS_ILOCK_SHIFT dependencies + * + * IOLOCK values + * + * 0-3 subclass value + * 4-7 PARENT subclass values + * + * MMAPLOCK values + * + * 0-3 subclass value + * 4-7 unused + * + * ILOCK values + * 0-4 subclass values + * 5 PARENT subclass (not nestable) + * 6 RTBITMAP subclass (not nestable) + * 7 RTSUM subclass (not nestable) + * */ -#define XFS_LOCK_PARENT 1 -#define XFS_LOCK_RTBITMAP 2 -#define XFS_LOCK_RTSUM 3 -#define XFS_LOCK_INUMORDER 4 - -#define XFS_IOLOCK_SHIFT 16 -#define XFS_IOLOCK_PARENT (XFS_LOCK_PARENT << XFS_IOLOCK_SHIFT) - -#define XFS_MMAPLOCK_SHIFT 20 - -#define XFS_ILOCK_SHIFT 24 -#define XFS_ILOCK_PARENT (XFS_LOCK_PARENT << XFS_ILOCK_SHIFT) -#define XFS_ILOCK_RTBITMAP (XFS_LOCK_RTBITMAP << XFS_ILOCK_SHIFT) -#define XFS_ILOCK_RTSUM (XFS_LOCK_RTSUM << XFS_ILOCK_SHIFT) - -#define XFS_IOLOCK_DEP_MASK 0x000f0000 -#define XFS_MMAPLOCK_DEP_MASK 0x00f00000 -#define XFS_ILOCK_DEP_MASK 0xff000000 -#define XFS_LOCK_DEP_MASK (XFS_IOLOCK_DEP_MASK | \ +#define XFS_IOLOCK_SHIFT 16 +#define XFS_IOLOCK_PARENT_VAL 4 +#define XFS_IOLOCK_MAX_SUBCLASS (XFS_IOLOCK_PARENT_VAL - 1) +#define XFS_IOLOCK_DEP_MASK 0x000f0000 +#define XFS_IOLOCK_PARENT (XFS_IOLOCK_PARENT_VAL << XFS_IOLOCK_SHIFT) + +#define XFS_MMAPLOCK_SHIFT 20 +#define XFS_MMAPLOCK_NUMORDER 0 +#define XFS_MMAPLOCK_MAX_SUBCLASS 3 +#define XFS_MMAPLOCK_DEP_MASK 0x00f00000 + +#define XFS_ILOCK_SHIFT 24 +#define XFS_ILOCK_PARENT_VAL 5 +#define XFS_ILOCK_MAX_SUBCLASS (XFS_ILOCK_PARENT_VAL - 1) +#define XFS_ILOCK_RTBITMAP_VAL 6 +#define XFS_ILOCK_RTSUM_VAL 7 +#define XFS_ILOCK_DEP_MASK 0xff000000 +#define XFS_ILOCK_PARENT (XFS_ILOCK_PARENT_VAL << XFS_ILOCK_SHIFT) +#define XFS_ILOCK_RTBITMAP (XFS_ILOCK_RTBITMAP_VAL << XFS_ILOCK_SHIFT) +#define XFS_ILOCK_RTSUM (XFS_ILOCK_RTSUM_VAL << XFS_ILOCK_SHIFT) + +#define XFS_LOCK_SUBCLASS_MASK (XFS_IOLOCK_DEP_MASK | \ XFS_MMAPLOCK_DEP_MASK | \ XFS_ILOCK_DEP_MASK) |