Author: rmacklem Date: Thu Oct 1 00:33:44 2020 New Revision: 366302 URL: https://svnweb.freebsd.org/changeset/base/366302
Log: Clip the "len" argument to vn_generic_copy_file_range() at a hole size boundary. By clipping the len argument of vn_generic_copy_file_range() to end at an exact multiple of hole size, holes are more likely to be maintained during the copy. A hole can still straddle the boundary at the end of the copy range, resulting in a block being allocated in the output file as it is being grown in size, but this will reduce the likelyhood of this happening. While here, also modify setting of blksize to better handle the case where _PC_MIN_HOLE_SIZE is returned as 1. Reviewed by: asomers Differential Revision: https://reviews.freebsd.org/D26570 Modified: head/sys/kern/vfs_vnops.c Modified: head/sys/kern/vfs_vnops.c ============================================================================== --- head/sys/kern/vfs_vnops.c Wed Sep 30 22:41:24 2020 (r366301) +++ head/sys/kern/vfs_vnops.c Thu Oct 1 00:33:44 2020 (r366302) @@ -3020,7 +3020,7 @@ vn_generic_copy_file_range(struct vnode *invp, off_t * int error; bool cantseek, readzeros, eof, lastblock; ssize_t aresid; - size_t copylen, len, savlen; + size_t copylen, len, rem, savlen; char *dat; long holein, holeout; @@ -3089,7 +3089,17 @@ vn_generic_copy_file_range(struct vnode *invp, off_t * * This value is clipped at 4Kbytes and 1Mbyte. */ blksize = MAX(holein, holeout); - if (blksize == 0) + + /* 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 > blksize) + len = savlen = rounddown(len - rem, blksize) + rem; + } + + if (blksize <= 1) blksize = MAX(invp->v_mount->mnt_stat.f_iosize, outvp->v_mount->mnt_stat.f_iosize); if (blksize < 4096) _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
