The branch stable/13 has been updated by rmacklem:
URL:
https://cgit.FreeBSD.org/src/commit/?id=7a074c8449943eb9fd156987cdb3a36a4de0dd8d
commit 7a074c8449943eb9fd156987cdb3a36a4de0dd8d
Author: Rick Macklem <rmack...@freebsd.org>
AuthorDate: 2022-11-17 01:37:22 +0000
Commit: Rick Macklem <rmack...@freebsd.org>
CommitDate: 2022-12-02 21:04:46 +0000
vfs_vnops.c: Fix blksize for ZFS
Since ZFS reports _PC_MIN_HOLE_SIZE as 512 (although it
appears that an unwritten region must be at least f_iosize
to remain unallocated), vn_generic_copy_file_range()
uses 4096 for the copy blksize for ZFS, reulting in slow copies.
For most other file systems, _PC_MIN_HOLE_SIZE and f_iosize
are the same value, so this patch modifies the code to
use f_iosize for most cases. It also documents in comments
why the blksize is being set a certain way, so that the code
does not appear to be doing "magic math".
(cherry picked from commit 4ee16246f97825e893e0a4a4499d1bbe5bc07b6a)
---
sys/kern/vfs_vnops.c | 51 +++++++++++++++++++++++++++++----------------------
1 file changed, 29 insertions(+), 22 deletions(-)
diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index b71d37820b0c..a54d2c463dc7 100644
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -3241,7 +3241,7 @@ vn_generic_copy_file_range(struct vnode *invp, off_t
*inoffp,
int error, interrupted;
bool cantseek, readzeros, eof, lastblock, holetoeof;
ssize_t aresid, r = 0;
- size_t copylen, len, rem, savlen;
+ size_t copylen, len, savlen;
char *dat;
long holein, holeout;
struct timespec curts, endts;
@@ -3313,31 +3313,38 @@ vn_generic_copy_file_range(struct vnode *invp, off_t
*inoffp,
if (error != 0)
goto out;
- /*
- * Set the blksize to the larger of the hole sizes for invp and outvp.
- * If hole sizes aren't available, set the blksize to the larger
- * f_iosize of invp and outvp.
- * This code expects the hole sizes and f_iosizes to be powers of 2.
- * This value is clipped at 4Kbytes and 1Mbyte.
- */
- blksize = MAX(holein, holeout);
-
- /* Clip len to end at an exact multiple of hole size. */
- if (blksize > 1) {
- rem = *inoffp % blksize;
- if (rem > 0)
- rem = blksize - rem;
- if (len > rem && len - rem > blksize)
- len = savlen = rounddown(len - rem, blksize) + rem;
- }
-
- if (blksize <= 1)
+ if (holein == 0 && holeout > 0) {
+ /*
+ * For this special case, the input data will be scanned
+ * for blocks of all 0 bytes. For these blocks, the
+ * write can be skipped for the output file to create
+ * an unallocated region.
+ * Therefore, use the appropriate size for the output file.
+ */
+ blksize = holeout;
+ if (blksize <= 512) {
+ /*
+ * Use f_iosize, since ZFS reports a _PC_MIN_HOLE_SIZE
+ * of 512, although it actually only creates
+ * unallocated regions for blocks >= f_iosize.
+ */
+ blksize = outvp->v_mount->mnt_stat.f_iosize;
+ }
+ } else {
+ /*
+ * Use the larger of the two f_iosize values. If they are
+ * not the same size, one will normally be an exact multiple of
+ * the other, since they are both likely to be a power of 2.
+ */
blksize = MAX(invp->v_mount->mnt_stat.f_iosize,
outvp->v_mount->mnt_stat.f_iosize);
+ }
+
+ /* Clip to sane limits. */
if (blksize < 4096)
blksize = 4096;
- else if (blksize > 1024 * 1024)
- blksize = 1024 * 1024;
+ else if (blksize > maxphys)
+ blksize = maxphys;
dat = malloc(blksize, M_TEMP, M_WAITOK);
/*
