From: "Darrick J. Wong" djwong@kernel.org
[ Upstream commit 9d720a5a658f5135861773f26e927449bef93d61 ]
Hoist these multiline conditionals into separate static inline helpers to improve readability and set the stage for corruption fixes that will be introduced in the next patch.
Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Dave Chinner dchinner@redhat.com Reviewed-by: Xiao Yang yangx.jy@fujitsu.com Signed-off-by: Leah Rumancik leah.rumancik@gmail.com Acked-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/libxfs/xfs_refcount.c | 129 ++++++++++++++++++++++++++++++----- 1 file changed, 113 insertions(+), 16 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_refcount.c b/fs/xfs/libxfs/xfs_refcount.c index 3f34bafe18dd..4408893333a6 100644 --- a/fs/xfs/libxfs/xfs_refcount.c +++ b/fs/xfs/libxfs/xfs_refcount.c @@ -815,11 +815,119 @@ xfs_refcount_find_right_extents( /* Is this extent valid? */ static inline bool xfs_refc_valid( - struct xfs_refcount_irec *rc) + const struct xfs_refcount_irec *rc) { return rc->rc_startblock != NULLAGBLOCK; }
+static inline bool +xfs_refc_want_merge_center( + const struct xfs_refcount_irec *left, + const struct xfs_refcount_irec *cleft, + const struct xfs_refcount_irec *cright, + const struct xfs_refcount_irec *right, + bool cleft_is_cright, + enum xfs_refc_adjust_op adjust, + unsigned long long *ulenp) +{ + unsigned long long ulen = left->rc_blockcount; + + /* + * To merge with a center record, both shoulder records must be + * adjacent to the record we want to adjust. This is only true if + * find_left and find_right made all four records valid. + */ + if (!xfs_refc_valid(left) || !xfs_refc_valid(right) || + !xfs_refc_valid(cleft) || !xfs_refc_valid(cright)) + return false; + + /* There must only be one record for the entire range. */ + if (!cleft_is_cright) + return false; + + /* The shoulder record refcounts must match the new refcount. */ + if (left->rc_refcount != cleft->rc_refcount + adjust) + return false; + if (right->rc_refcount != cleft->rc_refcount + adjust) + return false; + + /* + * The new record cannot exceed the max length. ulen is a ULL as the + * individual record block counts can be up to (u32 - 1) in length + * hence we need to catch u32 addition overflows here. + */ + ulen += cleft->rc_blockcount + right->rc_blockcount; + if (ulen >= MAXREFCEXTLEN) + return false; + + *ulenp = ulen; + return true; +} + +static inline bool +xfs_refc_want_merge_left( + const struct xfs_refcount_irec *left, + const struct xfs_refcount_irec *cleft, + enum xfs_refc_adjust_op adjust) +{ + unsigned long long ulen = left->rc_blockcount; + + /* + * For a left merge, the left shoulder record must be adjacent to the + * start of the range. If this is true, find_left made left and cleft + * contain valid contents. + */ + if (!xfs_refc_valid(left) || !xfs_refc_valid(cleft)) + return false; + + /* Left shoulder record refcount must match the new refcount. */ + if (left->rc_refcount != cleft->rc_refcount + adjust) + return false; + + /* + * The new record cannot exceed the max length. ulen is a ULL as the + * individual record block counts can be up to (u32 - 1) in length + * hence we need to catch u32 addition overflows here. + */ + ulen += cleft->rc_blockcount; + if (ulen >= MAXREFCEXTLEN) + return false; + + return true; +} + +static inline bool +xfs_refc_want_merge_right( + const struct xfs_refcount_irec *cright, + const struct xfs_refcount_irec *right, + enum xfs_refc_adjust_op adjust) +{ + unsigned long long ulen = right->rc_blockcount; + + /* + * For a right merge, the right shoulder record must be adjacent to the + * end of the range. If this is true, find_right made cright and right + * contain valid contents. + */ + if (!xfs_refc_valid(right) || !xfs_refc_valid(cright)) + return false; + + /* Right shoulder record refcount must match the new refcount. */ + if (right->rc_refcount != cright->rc_refcount + adjust) + return false; + + /* + * The new record cannot exceed the max length. ulen is a ULL as the + * individual record block counts can be up to (u32 - 1) in length + * hence we need to catch u32 addition overflows here. + */ + ulen += cright->rc_blockcount; + if (ulen >= MAXREFCEXTLEN) + return false; + + return true; +} + /* * Try to merge with any extents on the boundaries of the adjustment range. */ @@ -861,23 +969,15 @@ xfs_refcount_merge_extents( (cleft.rc_blockcount == cright.rc_blockcount);
/* Try to merge left, cleft, and right. cleft must == cright. */ - ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount + - right.rc_blockcount; - if (xfs_refc_valid(&left) && xfs_refc_valid(&right) && - xfs_refc_valid(&cleft) && xfs_refc_valid(&cright) && cequal && - left.rc_refcount == cleft.rc_refcount + adjust && - right.rc_refcount == cleft.rc_refcount + adjust && - ulen < MAXREFCEXTLEN) { + if (xfs_refc_want_merge_center(&left, &cleft, &cright, &right, cequal, + adjust, &ulen)) { *shape_changed = true; return xfs_refcount_merge_center_extents(cur, &left, &cleft, &right, ulen, aglen); }
/* Try to merge left and cleft. */ - ulen = (unsigned long long)left.rc_blockcount + cleft.rc_blockcount; - if (xfs_refc_valid(&left) && xfs_refc_valid(&cleft) && - left.rc_refcount == cleft.rc_refcount + adjust && - ulen < MAXREFCEXTLEN) { + if (xfs_refc_want_merge_left(&left, &cleft, adjust)) { *shape_changed = true; error = xfs_refcount_merge_left_extent(cur, &left, &cleft, agbno, aglen); @@ -893,10 +993,7 @@ xfs_refcount_merge_extents( }
/* Try to merge cright and right. */ - ulen = (unsigned long long)right.rc_blockcount + cright.rc_blockcount; - if (xfs_refc_valid(&right) && xfs_refc_valid(&cright) && - right.rc_refcount == cright.rc_refcount + adjust && - ulen < MAXREFCEXTLEN) { + if (xfs_refc_want_merge_right(&cright, &right, adjust)) { *shape_changed = true; return xfs_refcount_merge_right_extent(cur, &right, &cright, aglen);