diff options
| -rw-r--r-- | fs/xfs/xfs_inode.c | 68 | ||||
| -rw-r--r-- | fs/xfs/xfs_inode.h | 85 |
2 files changed, 110 insertions, 43 deletions
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 3e343c7f347a..657f6123b445 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -164,7 +164,7 @@ xfs_ilock( (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL)); ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) != (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); - ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0); + ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0); if (lock_flags & XFS_IOLOCK_EXCL) mrupdate_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags)); @@ -212,7 +212,7 @@ xfs_ilock_nowait( (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL)); ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) != (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); - ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0); + ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0); if (lock_flags & XFS_IOLOCK_EXCL) { if (!mrtryupdate(&ip->i_iolock)) @@ -281,7 +281,7 @@ xfs_iunlock( (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL)); ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) != (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)); - ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0); + ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0); ASSERT(lock_flags != 0); if (lock_flags & XFS_IOLOCK_EXCL) @@ -364,30 +364,38 @@ int xfs_lock_delays; /* * Bump the subclass so xfs_lock_inodes() acquires each lock with a different - * value. This shouldn't be called for page fault locking, but we also need to - * ensure we don't overrun the number of lockdep subclasses for the iolock or - * mmaplock as that is limited to 12 by the mmap lock lockdep annotations. + * value. This can be called for any type of inode lock combination, including + * parent locking. Care must be taken to ensure we don't overrun the subclass + * storage fields in the class mask we build. */ static inline int xfs_lock_inumorder(int lock_mode, int subclass) { + int class = 0; + + ASSERT(!(lock_mode & (XFS_ILOCK_PARENT | XFS_ILOCK_RTBITMAP | + XFS_ILOCK_RTSUM))); + if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)) { - ASSERT(subclass + XFS_LOCK_INUMORDER < - (1 << (XFS_MMAPLOCK_SHIFT - XFS_IOLOCK_SHIFT))); - lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_IOLOCK_SHIFT; + ASSERT(subclass <= XFS_IOLOCK_MAX_SUBCLASS); + ASSERT(subclass + XFS_IOLOCK_PARENT_VAL < + MAX_LOCKDEP_SUBCLASSES); + class += subclass << XFS_IOLOCK_SHIFT; + if (lock_mode & XFS_IOLOCK_PARENT) + class += XFS_IOLOCK_PARENT_VAL << XFS_IOLOCK_SHIFT; } if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) { - ASSERT(subclass + XFS_LOCK_INUMORDER < - (1 << (XFS_ILOCK_SHIFT - XFS_MMAPLOCK_SHIFT))); - lock_mode |= (subclass + XFS_LOCK_INUMORDER) << - XFS_MMAPLOCK_SHIFT; + ASSERT(subclass <= XFS_MMAPLOCK_MAX_SUBCLASS); + class += subclass << XFS_MMAPLOCK_SHIFT; } - if (lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)) - lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_ILOCK_SHIFT; + if (lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)) { + ASSERT(subclass <= XFS_ILOCK_MAX_SUBCLASS); + class += subclass << XFS_ILOCK_SHIFT; + } - return lock_mode; + return (lock_mode & ~XFS_LOCK_SUBCLASS_MASK) | class; } /* @@ -399,6 +407,11 @@ xfs_lock_inumorder(int lock_mode, int subclass) * transaction (such as truncate). This can result in deadlock since the long * running trans might need to wait for the inode we just locked in order to * push the tail and free space in the log. + * + * xfs_lock_inodes() can only be used to lock one type of lock at a time - + * the iolock, the mmaplock or the ilock, but not more than one at a time. If we + * lock more than one at a time, lockdep will report false positives saying we + * have violated locking orders. */ void xfs_lock_inodes( @@ -409,8 +422,29 @@ xfs_lock_inodes( int attempts = 0, i, j, try_lock; xfs_log_item_t *lp; - /* currently supports between 2 and 5 inodes */ + /* + * Currently supports between 2 and 5 inodes with exclusive locking. We + * support an arbitrary depth of locking here, but absolute limits on + * inodes depend on the the type of locking and the limits placed by + * lockdep annotations in xfs_lock_inumorder. These are all checked by + * the asserts. + */ ASSERT(ips && inodes >= 2 && inodes <= 5); + ASSERT(lock_mode & (XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL | + XFS_ILOCK_EXCL)); + ASSERT(!(lock_mode & (XFS_IOLOCK_SHARED | XFS_MMAPLOCK_SHARED | + XFS_ILOCK_SHARED))); + ASSERT(!(lock_mode & XFS_IOLOCK_EXCL) || + inodes <= XFS_IOLOCK_MAX_SUBCLASS + 1); + ASSERT(!(lock_mode & XFS_MMAPLOCK_EXCL) || + inodes <= XFS_MMAPLOCK_MAX_SUBCLASS + 1); + ASSERT(!(lock_mode & XFS_ILOCK_EXCL) || + inodes <= XFS_ILOCK_MAX_SUBCLASS + 1); + + if (lock_mode & XFS_IOLOCK_EXCL) { + ASSERT(!(lock_mode & (XFS_MMAPLOCK_EXCL | XFS_ILOCK_EXCL))); + } else if (lock_mode & XFS_MMAPLOCK_EXCL) + ASSERT(!(lock_mode & XFS_ILOCK_EXCL)); try_lock = 0; i = 0; 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) |