Date: Thu, 15 Aug 2019 02:30:44 +0000 (UTC) From: Doug Moore <dougm@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r351064 - in head: sbin/swapon share/man/man5 sys/vm Message-ID: <201908150230.x7F2Ui4Y088925@repo.freebsd.org>
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Author: dougm Date: Thu Aug 15 02:30:44 2019 New Revision: 351064 URL: https://svnweb.freebsd.org/changeset/base/351064 Log: swap_pager.c reserves 2 blocks for a bsd label. Change that 2 to the expression howmany(BBSIZE, PAGE_SIZE), where BBSIZE is the size of the boot block area. That can be less than 2 if PAGE_SIZE is big. swapon(8) has an option to trim (delete) all the blocks of a device at startup. However, if the first of those blocks is a bsd label, then trimming those blocks is destructive. Change swapon to leave the first BBSIZE bytes untrimmed. Update manual pages to reflect changes in how swapon and how it may be used, espeically in association with savecore. Reviewed by: alc Approved by: markj (mentor) MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D21191 Modified: head/sbin/swapon/swapon.8 head/sbin/swapon/swapon.c head/share/man/man5/fstab.5 head/sys/vm/swap_pager.c Modified: head/sbin/swapon/swapon.8 ============================================================================== --- head/sbin/swapon/swapon.8 Thu Aug 15 02:14:44 2019 (r351063) +++ head/sbin/swapon/swapon.8 Thu Aug 15 02:30:44 2019 (r351064) @@ -90,7 +90,17 @@ The .Fl E option causes each of following devices to receive a .Dv BIO_DELETE -command to mark all blocks as unused. +command. +This command marks the device's blocks as unused, except those that +might store a disk label. +This marking can erase a crash dump. +To delay +.Nm swapon +for a device until after +.Nm savecore +has copied the crash dump to another location, use the +.Dq late +option. .Pp The .Nm swapoff Modified: head/sbin/swapon/swapon.c ============================================================================== --- head/sbin/swapon/swapon.c Thu Aug 15 02:14:44 2019 (r351063) +++ head/sbin/swapon/swapon.c Thu Aug 15 02:30:44 2019 (r351064) @@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/disk.h> +#include <sys/disklabel.h> #include <sys/mdioctl.h> #include <sys/stat.h> #include <sys/sysctl.h> @@ -761,8 +762,8 @@ swapon_trim(const char *name) } else errx(1, "%s has an invalid file type", name); /* Trim the device. */ - ioarg[0] = 0; - ioarg[1] = sz; + ioarg[0] = BBSIZE; + ioarg[1] = sz - BBSIZE; if (ioctl(fd, DIOCGDELETE, ioarg) != 0) warn("ioctl(DIOCGDELETE)"); Modified: head/share/man/man5/fstab.5 ============================================================================== --- head/share/man/man5/fstab.5 Thu Aug 15 02:14:44 2019 (r351063) +++ head/share/man/man5/fstab.5 Thu Aug 15 02:30:44 2019 (r351064) @@ -246,8 +246,17 @@ For swap devices, the keyword .Dq trimonce triggers the delivery of a .Dv BIO_DELETE -command to the device to mark -all blocks as unused. +command to the device. +This command marks the device's blocks as unused, except those that +might store a disk label. +This marking can erase a crash dump. +To delay +.Nm swapon +for a device until after +.Nm savecore +has copied the crash dump to another location, use the +.Dq late +option. For vnode-backed swap spaces, .Dq file is supported in the Modified: head/sys/vm/swap_pager.c ============================================================================== --- head/sys/vm/swap_pager.c Thu Aug 15 02:14:44 2019 (r351063) +++ head/sys/vm/swap_pager.c Thu Aug 15 02:30:44 2019 (r351064) @@ -79,6 +79,7 @@ __FBSDID("$FreeBSD$"); #include <sys/buf.h> #include <sys/conf.h> #include <sys/disk.h> +#include <sys/disklabel.h> #include <sys/eventhandler.h> #include <sys/fcntl.h> #include <sys/lock.h> @@ -2298,10 +2299,11 @@ swaponsomething(struct vnode *vp, void *id, u_long nbl sp->sw_blist = blist_create(nblks, M_WAITOK); /* - * Do not free the first two block in order to avoid overwriting + * Do not free the first blocks in order to avoid overwriting * any bsd label at the front of the partition */ - blist_free(sp->sw_blist, 2, nblks - 2); + blist_free(sp->sw_blist, howmany(BBSIZE, PAGE_SIZE), + nblks - howmany(BBSIZE, PAGE_SIZE)); dvbase = 0; mtx_lock(&sw_dev_mtx); @@ -2319,7 +2321,7 @@ swaponsomething(struct vnode *vp, void *id, u_long nbl sp->sw_end = dvbase + nblks; TAILQ_INSERT_TAIL(&swtailq, sp, sw_list); nswapdev++; - swap_pager_avail += nblks - 2; + swap_pager_avail += nblks - howmany(BBSIZE, PAGE_SIZE); swap_total += nblks; swapon_check_swzone(); swp_sizecheck();
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