[PATCH v6.1 02/12] xfs: add helpers to compute log item overhead

Darrick J. Wong
2025-04-09T02:25:21Z

From: Darrick J. Wong <djwong@kernel.org>

Add selected helpers to estimate the transaction reservation required to
write various log intent and buffer items to the log. These helpers
will be used by the online repair code for more precise estimations of
how much work can be done in a single transaction.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
6.1: ripped out the transaction reservation bits
---
fs/xfs/xfs_bmap_item.h | 3 +++
fs/xfs/xfs_buf_item.h | 3 +++
fs/xfs/xfs_extfree_item.h | 3 +++
fs/xfs/xfs_log_priv.h | 13 +++++++++++++
fs/xfs/xfs_refcount_item.h | 3 +++
fs/xfs/xfs_rmap_item.h | 3 +++
fs/xfs/xfs_bmap_item.c | 10 ++++++++++
fs/xfs/xfs_buf_item.c | 19 +++++++++++++++++++
fs/xfs/xfs_extfree_item.c | 10 ++++++++++
fs/xfs/xfs_log_cil.c | 4 +---
fs/xfs/xfs_refcount_item.c | 10 ++++++++++
fs/xfs/xfs_rmap_item.c | 10 ++++++++++
12 files changed, 88 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_bmap_item.h b/fs/xfs/xfs_bmap_item.h
index 6fee6a5083436b..b42fee06899df6 100644
--- a/fs/xfs/xfs_bmap_item.h
+++ b/fs/xfs/xfs_bmap_item.h
@@ -72,4 +72,7 @@ struct xfs_bmap_intent;

void xfs_bmap_defer_add(struct xfs_trans *tp, struct xfs_bmap_intent *bi);

+unsigned int xfs_bui_log_space(unsigned int nr);
+unsigned int xfs_bud_log_space(void);
+
#endif /* __XFS_BMAP_ITEM_H__ */
diff --git a/fs/xfs/xfs_buf_item.h b/fs/xfs/xfs_buf_item.h
index 8cde85259a586d..e10e324cd24504 100644
--- a/fs/xfs/xfs_buf_item.h
+++ b/fs/xfs/xfs_buf_item.h
@@ -64,6 +64,9 @@ static inline void xfs_buf_dquot_iodone(struct xfs_buf *bp)
void xfs_buf_iodone(struct xfs_buf *);
bool xfs_buf_log_check_iovec(struct xfs_log_iovec *iovec);

+unsigned int xfs_buf_inval_log_space(unsigned int map_count,
+ unsigned int blocksize);
+
extern struct kmem_cache *xfs_buf_item_cache;

#endif /* __XFS_BUF_ITEM_H__ */
diff --git a/fs/xfs/xfs_extfree_item.h b/fs/xfs/xfs_extfree_item.h
index 41b7c43060799b..c8402040410b54 100644
--- a/fs/xfs/xfs_extfree_item.h
+++ b/fs/xfs/xfs_extfree_item.h
@@ -94,4 +94,7 @@ void xfs_extent_free_defer_add(struct xfs_trans *tp,
struct xfs_extent_free_item *xefi,
struct xfs_defer_pending **dfpp);

+unsigned int xfs_efi_log_space(unsigned int nr);
+unsigned int xfs_efd_log_space(unsigned int nr);
+
#endif /* __XFS_EXTFREE_ITEM_H__ */
diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index f3d78869e5e5a3..39a102cc1b43e6 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -698,4 +698,17 @@ xlog_kvmalloc(
return p;
}

+/*
+ * Given a count of iovecs and space for a log item, compute the space we need
+ * in the log to store that data plus the log headers.
+ */
+static inline unsigned int
+xlog_item_space(
+ unsigned int niovecs,
+ unsigned int nbytes)
+{
+ nbytes += niovecs * (sizeof(uint64_t) + sizeof(struct xlog_op_header));
+ return round_up(nbytes, sizeof(uint64_t));
+}
+
#endif /* __XFS_LOG_PRIV_H__ */
diff --git a/fs/xfs/xfs_refcount_item.h b/fs/xfs/xfs_refcount_item.h
index bfee8f30c63ce9..0fc3f493342bbd 100644
--- a/fs/xfs/xfs_refcount_item.h
+++ b/fs/xfs/xfs_refcount_item.h
@@ -76,4 +76,7 @@ struct xfs_refcount_intent;
void xfs_refcount_defer_add(struct xfs_trans *tp,
struct xfs_refcount_intent *ri);

+unsigned int xfs_cui_log_space(unsigned int nr);
+unsigned int xfs_cud_log_space(void);
+
#endif /* __XFS_REFCOUNT_ITEM_H__ */
diff --git a/fs/xfs/xfs_rmap_item.h b/fs/xfs/xfs_rmap_item.h
index 40d331555675ba..3a99f0117f2d8a 100644
--- a/fs/xfs/xfs_rmap_item.h
+++ b/fs/xfs/xfs_rmap_item.h
@@ -75,4 +75,7 @@ struct xfs_rmap_intent;

void xfs_rmap_defer_add(struct xfs_trans *tp, struct xfs_rmap_intent *ri);

+unsigned int xfs_rui_log_space(unsigned int nr);
+unsigned int xfs_rud_log_space(void);
+
#endif /* __XFS_RMAP_ITEM_H__ */
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 3d52e9d7ad571a..646c515ee35518 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -77,6 +77,11 @@ xfs_bui_item_size(
*nbytes += xfs_bui_log_format_sizeof(buip->bui_format.bui_nextents);
}

+unsigned int xfs_bui_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_bui_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given bui log item. We use only 1 iovec, and we point that
@@ -168,6 +173,11 @@ xfs_bud_item_size(
*nbytes += sizeof(struct xfs_bud_log_format);
}

+unsigned int xfs_bud_log_space(void)
+{
+ return xlog_item_space(1, sizeof(struct xfs_bud_log_format));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given bud log item. We use only 1 iovec, and we point that
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 47549cfa61cd82..254d0a072f983b 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -167,6 +167,25 @@ xfs_buf_item_size_segment(
}
}

+/*
+ * Compute the worst case log item overhead for an invalidated buffer with the
+ * given map count and block size.
+ */
+unsigned int
+xfs_buf_inval_log_space(
+ unsigned int map_count,
+ unsigned int blocksize)
+{
+ unsigned int chunks = DIV_ROUND_UP(blocksize, XFS_BLF_CHUNK);
+ unsigned int bitmap_size = DIV_ROUND_UP(chunks, NBWORD);
+ unsigned int ret =
+ offsetof(struct xfs_buf_log_format, blf_data_map) +
+ (bitmap_size * sizeof_field(struct xfs_buf_log_format,
+ blf_data_map[0]));
+
+ return ret * map_count;
+}
+
/*
* Return the number of log iovecs and space needed to log the given buf log
* item.
diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
index a25c713ff888c7..0163dd6426661d 100644
--- a/fs/xfs/xfs_extfree_item.c
+++ b/fs/xfs/xfs_extfree_item.c
@@ -82,6 +82,11 @@ xfs_efi_item_size(
*nbytes += xfs_efi_log_format_sizeof(efip->efi_format.efi_nextents);
}

+unsigned int xfs_efi_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_efi_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given efi log item. We use only 1 iovec, and we point that
@@ -253,6 +258,11 @@ xfs_efd_item_size(
*nbytes += xfs_efd_log_format_sizeof(efdp->efd_format.efd_nextents);
}

+unsigned int xfs_efd_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_efd_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given efd log item. We use only 1 iovec, and we point that
diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index 1ca406ec1b40b3..f66d2d430e4f37 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -309,9 +309,7 @@ xlog_cil_alloc_shadow_bufs(
* Then round nbytes up to 64-bit alignment so that the initial
* buffer alignment is easy to calculate and verify.
*/
- nbytes += niovecs *
- (sizeof(uint64_t) + sizeof(struct xlog_op_header));
- nbytes = round_up(nbytes, sizeof(uint64_t));
+ nbytes = xlog_item_space(niovecs, nbytes);

/*
* The data buffer needs to start 64-bit aligned, so round up
diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
index fe2d7aab8554fc..076501123d89f0 100644
--- a/fs/xfs/xfs_refcount_item.c
+++ b/fs/xfs/xfs_refcount_item.c
@@ -78,6 +78,11 @@ xfs_cui_item_size(
*nbytes += xfs_cui_log_format_sizeof(cuip->cui_format.cui_nextents);
}

+unsigned int xfs_cui_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_cui_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given cui log item. We use only 1 iovec, and we point that
@@ -179,6 +184,11 @@ xfs_cud_item_size(
*nbytes += sizeof(struct xfs_cud_log_format);
}

+unsigned int xfs_cud_log_space(void)
+{
+ return xlog_item_space(1, sizeof(struct xfs_cud_log_format));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given cud log item. We use only 1 iovec, and we point that
diff --git a/fs/xfs/xfs_rmap_item.c b/fs/xfs/xfs_rmap_item.c
index 89decffe76c8b5..c99700318ec24b 100644
--- a/fs/xfs/xfs_rmap_item.c
+++ b/fs/xfs/xfs_rmap_item.c
@@ -77,6 +77,11 @@ xfs_rui_item_size(
*nbytes += xfs_rui_log_format_sizeof(ruip->rui_format.rui_nextents);
}

+unsigned int xfs_rui_log_space(unsigned int nr)
+{
+ return xlog_item_space(1, xfs_rui_log_format_sizeof(nr));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given rui log item. We use only 1 iovec, and we point that
@@ -180,6 +185,11 @@ xfs_rud_item_size(
*nbytes += sizeof(struct xfs_rud_log_format);
}

+unsigned int xfs_rud_log_space(void)
+{
+ return xlog_item_space(1, sizeof(struct xfs_rud_log_format));
+}
+
/*
* This is called to fill in the vector of log iovecs for the
* given rud log item. We use only 1 iovec, and we point that