From owner-svn-src-all@FreeBSD.ORG Sun Feb 24 06:44:31 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id ABB4A9C5; Sun, 24 Feb 2013 06:44:31 +0000 (UTC) (envelope-from mckusick@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) by mx1.freebsd.org (Postfix) with ESMTP id 8608F170C; Sun, 24 Feb 2013 06:44:31 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.5/8.14.5) with ESMTP id r1O6iV5f026862; Sun, 24 Feb 2013 06:44:31 GMT (envelope-from mckusick@svn.freebsd.org) Received: (from mckusick@localhost) by svn.freebsd.org (8.14.5/8.14.5/Submit) id r1O6iU12026849; Sun, 24 Feb 2013 06:44:30 GMT (envelope-from mckusick@svn.freebsd.org) Message-Id: <201302240644.r1O6iU12026849@svn.freebsd.org> From: Kirk McKusick Date: Sun, 24 Feb 2013 06:44:30 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r247212 - head/sbin/fsck_ffs X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Feb 2013 06:44:31 -0000 Author: mckusick Date: Sun Feb 24 06:44:29 2013 New Revision: 247212 URL: http://svnweb.freebsd.org/changeset/base/247212 Log: When running with the -d option, instrument fsck_ffs to track the number, data type, and running time of its I/O operations. No functional changes. Modified: head/sbin/fsck_ffs/dir.c head/sbin/fsck_ffs/ea.c head/sbin/fsck_ffs/fsck.h head/sbin/fsck_ffs/fsutil.c head/sbin/fsck_ffs/inode.c head/sbin/fsck_ffs/main.c head/sbin/fsck_ffs/setup.c Modified: head/sbin/fsck_ffs/dir.c ============================================================================== --- head/sbin/fsck_ffs/dir.c Sun Feb 24 05:48:59 2013 (r247211) +++ head/sbin/fsck_ffs/dir.c Sun Feb 24 06:44:29 2013 (r247212) @@ -708,6 +708,6 @@ getdirblk(ufs2_daddr_t blkno, long size) if (pdirbp != 0) pdirbp->b_flags &= ~B_INUSE; - pdirbp = getdatablk(blkno, size); + pdirbp = getdatablk(blkno, size, BT_DIRDATA); return (pdirbp); } Modified: head/sbin/fsck_ffs/ea.c ============================================================================== --- head/sbin/fsck_ffs/ea.c Sun Feb 24 05:48:59 2013 (r247211) +++ head/sbin/fsck_ffs/ea.c Sun Feb 24 06:44:29 2013 (r247212) @@ -73,7 +73,7 @@ eascan(struct inodesc *idesc, struct ufs else blksiz = sblock.fs_bsize; printf("blksiz = %ju\n", (intmax_t)blksiz); - bp = getdatablk(dp->di_extb[0], blksiz); + bp = getdatablk(dp->di_extb[0], blksiz, BT_EXTATTR); cp = (u_char *)bp->b_un.b_buf; for (n = 0; n < blksiz; n++) { printf("%02x", cp[n]); Modified: head/sbin/fsck_ffs/fsck.h ============================================================================== --- head/sbin/fsck_ffs/fsck.h Sun Feb 24 05:48:59 2013 (r247211) +++ head/sbin/fsck_ffs/fsck.h Sun Feb 24 06:44:29 2013 (r247212) @@ -138,6 +138,7 @@ struct bufarea { int b_size; int b_errs; int b_flags; + int b_type; union { char *b_buf; /* buffer space */ ufs1_daddr_t *b_indir1; /* UFS1 indirect block */ @@ -165,6 +166,36 @@ struct bufarea { * Buffer flags */ #define B_INUSE 0x00000001 /* Buffer is in use */ +/* + * Type of data in buffer + */ +#define BT_UNKNOWN 0 /* Buffer holds a superblock */ +#define BT_SUPERBLK 1 /* Buffer holds a superblock */ +#define BT_CYLGRP 2 /* Buffer holds a cylinder group map */ +#define BT_LEVEL1 3 /* Buffer holds single level indirect */ +#define BT_LEVEL2 4 /* Buffer holds double level indirect */ +#define BT_LEVEL3 5 /* Buffer holds triple level indirect */ +#define BT_EXTATTR 6 /* Buffer holds external attribute data */ +#define BT_INODES 7 /* Buffer holds external attribute data */ +#define BT_DIRDATA 8 /* Buffer holds directory data */ +#define BT_DATA 9 /* Buffer holds user data */ +#define BT_NUMBUFTYPES 10 +#define BT_NAMES { \ + "unknown", \ + "Superblock", \ + "Cylinder Group", \ + "Single Level Indirect", \ + "Double Level Indirect", \ + "Triple Level Indirect", \ + "External Attribute", \ + "Inode Block", \ + "Directory Contents", \ + "User Data" } +long readcnt[BT_NUMBUFTYPES]; +long totalreadcnt[BT_NUMBUFTYPES]; +struct timespec readtime[BT_NUMBUFTYPES]; +struct timespec totalreadtime[BT_NUMBUFTYPES]; +struct timespec startprog; struct bufarea sblk; /* file system superblock */ struct bufarea cgblk; /* cylinder group blocks */ @@ -177,10 +208,11 @@ struct bufarea *pbp; /* current inode b else \ (bp)->b_dirty = 1; \ } while (0) -#define initbarea(bp) do { \ +#define initbarea(bp, type) do { \ (bp)->b_dirty = 0; \ (bp)->b_bno = (ufs2_daddr_t)-1; \ (bp)->b_flags = 0; \ + (bp)->b_type = type; \ } while (0) #define sbdirty() dirty(&sblk) @@ -357,6 +389,7 @@ int dirscan(struct inodesc *); int dofix(struct inodesc *, const char *msg); int eascan(struct inodesc *, struct ufs2_dinode *dp); void fileerror(ino_t cwd, ino_t ino, const char *errmesg); +void finalIOstats(void); int findino(struct inodesc *); int findname(struct inodesc *); void flush(int fd, struct bufarea *bp); @@ -365,7 +398,7 @@ void freeino(ino_t ino); void freeinodebuf(void); int ftypeok(union dinode *dp); void getblk(struct bufarea *bp, ufs2_daddr_t blk, long size); -struct bufarea *getdatablk(ufs2_daddr_t blkno, long size); +struct bufarea *getdatablk(ufs2_daddr_t blkno, long size, int type); struct inoinfo *getinoinfo(ino_t inumber); union dinode *getnextinode(ino_t inumber, int rebuildcg); void getpathname(char *namebuf, ino_t curdir, ino_t ino); @@ -375,6 +408,7 @@ void alarmhandler(int sig); void inocleanup(void); void inodirty(void); struct inostat *inoinfo(ino_t inum); +void IOstats(char *what); int linkup(ino_t orphan, ino_t parentdir, char *name); int makeentry(ino_t parent, ino_t ino, const char *name); void panic(const char *fmt, ...) __printflike(1, 2); Modified: head/sbin/fsck_ffs/fsutil.c ============================================================================== --- head/sbin/fsck_ffs/fsutil.c Sun Feb 24 05:48:59 2013 (r247211) +++ head/sbin/fsck_ffs/fsutil.c Sun Feb 24 06:44:29 2013 (r247212) @@ -56,19 +56,23 @@ __FBSDID("$FreeBSD$"); #include #include #include +#include #include #include "fsck.h" static void slowio_start(void); static void slowio_end(void); +static void printIOstats(void); -long diskreads, totalreads; /* Disk cache statistics */ +static long diskreads, totaldiskreads, totalreads; /* Disk cache statistics */ +static struct timespec startpass, finishpass; struct timeval slowio_starttime; int slowio_delay_usec = 10000; /* Initial IO delay for background fsck */ int slowio_pollcnt; static TAILQ_HEAD(buflist, bufarea) bufhead; /* head of buffer cache list */ static int numbufs; /* size of buffer cache */ +static char *buftype[BT_NUMBUFTYPES] = BT_NAMES; int ftypeok(union dinode *dp) @@ -163,7 +167,7 @@ bufinit(void) if (bufp == 0) errx(EEXIT, "cannot allocate buffer pool"); cgblk.b_un.b_buf = bufp; - initbarea(&cgblk); + initbarea(&cgblk, BT_CYLGRP); TAILQ_INIT(&bufhead); bufcnt = MAXBUFS; if (bufcnt < MINBUFS) @@ -178,16 +182,21 @@ bufinit(void) } bp->b_un.b_buf = bufp; TAILQ_INSERT_HEAD(&bufhead, bp, b_list); - initbarea(bp); + initbarea(bp, BT_UNKNOWN); } numbufs = i; /* save number of buffers */ + for (i = 0; i < BT_NUMBUFTYPES; i++) { + readtime[i].tv_sec = totalreadtime[i].tv_sec = 0; + readtime[i].tv_nsec = totalreadtime[i].tv_nsec = 0; + readcnt[i] = totalreadcnt[i] = 0; + } } /* * Manage a cache of directory blocks. */ struct bufarea * -getdatablk(ufs2_daddr_t blkno, long size) +getdatablk(ufs2_daddr_t blkno, long size, int type) { struct bufarea *bp; @@ -199,26 +208,62 @@ getdatablk(ufs2_daddr_t blkno, long size break; if (bp == NULL) errx(EEXIT, "deadlocked buffer pool"); + bp->b_type = type; getblk(bp, blkno, size); /* fall through */ foundit: + if (debug && bp->b_type != type) + printf("Buffer type changed from %s to %s\n", + buftype[bp->b_type], buftype[type]); TAILQ_REMOVE(&bufhead, bp, b_list); TAILQ_INSERT_HEAD(&bufhead, bp, b_list); bp->b_flags |= B_INUSE; return (bp); } +/* + * Timespec operations (from ). + */ +#define timespecsub(vvp, uvp) \ + do { \ + (vvp)->tv_sec -= (uvp)->tv_sec; \ + (vvp)->tv_nsec -= (uvp)->tv_nsec; \ + if ((vvp)->tv_nsec < 0) { \ + (vvp)->tv_sec--; \ + (vvp)->tv_nsec += 1000000000; \ + } \ + } while (0) +#define timespecadd(vvp, uvp) \ + do { \ + (vvp)->tv_sec += (uvp)->tv_sec; \ + (vvp)->tv_nsec += (uvp)->tv_nsec; \ + if ((vvp)->tv_nsec >= 1000000000) { \ + (vvp)->tv_sec++; \ + (vvp)->tv_nsec -= 1000000000; \ + } \ + } while (0) + void getblk(struct bufarea *bp, ufs2_daddr_t blk, long size) { ufs2_daddr_t dblk; + struct timespec start, finish; - totalreads++; dblk = fsbtodb(&sblock, blk); - if (bp->b_bno != dblk) { + if (bp->b_bno == dblk) { + totalreads++; + } else { flush(fswritefd, bp); - diskreads++; + if (debug) { + readcnt[bp->b_type]++; + clock_gettime(CLOCK_REALTIME_PRECISE, &start); + } bp->b_errs = blread(fsreadfd, bp->b_un.b_buf, dblk, size); + if (debug) { + clock_gettime(CLOCK_REALTIME_PRECISE, &finish); + timespecsub(&finish, &start); + timespecadd(&readtime[bp->b_type], &finish); + } bp->b_bno = dblk; bp->b_size = size; } @@ -292,8 +337,8 @@ ckfini(int markclean) } if (debug && totalreads > 0) printf("cache with %d buffers missed %ld of %ld (%d%%)\n", - numbufs, diskreads, totalreads, - (int)(diskreads * 100 / totalreads)); + numbufs, totaldiskreads, totalreads, + (int)(totaldiskreads * 100 / totalreads)); if (fswritefd < 0) { (void)close(fsreadfd); return; @@ -347,6 +392,82 @@ ckfini(int markclean) (void)close(fswritefd); } +/* + * Print out I/O statistics. + */ +void +IOstats(char *what) +{ + int i; + + if (debug == 0) + return; + if (diskreads == 0) { + printf("%s: no I/O\n\n", what); + return; + } + if (startpass.tv_sec == 0) + startpass = startprog; + printf("%s: I/O statistics\n", what); + printIOstats(); + totaldiskreads += diskreads; + diskreads = 0; + for (i = 0; i < BT_NUMBUFTYPES; i++) { + timespecadd(&totalreadtime[i], &readtime[i]); + totalreadcnt[i] += readcnt[i]; + readtime[i].tv_sec = readtime[i].tv_nsec = 0; + readcnt[i] = 0; + } + clock_gettime(CLOCK_REALTIME_PRECISE, &startpass); +} + +void +finalIOstats(void) +{ + int i; + + if (debug == 0) + return; + printf("Final I/O statistics\n"); + totaldiskreads += diskreads; + diskreads = totaldiskreads; + startpass = startprog; + for (i = 0; i < BT_NUMBUFTYPES; i++) { + timespecadd(&totalreadtime[i], &readtime[i]); + totalreadcnt[i] += readcnt[i]; + readtime[i] = totalreadtime[i]; + readcnt[i] = totalreadcnt[i]; + } + printIOstats(); +} + +static void printIOstats(void) +{ + long long msec, totalmsec; + int i; + + clock_gettime(CLOCK_REALTIME_PRECISE, &finishpass); + timespecsub(&finishpass, &startpass); + printf("Running time: %ld msec\n", + finishpass.tv_sec * 1000 + finishpass.tv_nsec / 1000000); + printf("buffer reads by type:\n"); + for (totalmsec = 0, i = 0; i < BT_NUMBUFTYPES; i++) + totalmsec += readtime[i].tv_sec * 1000 + + readtime[i].tv_nsec / 1000000; + if (totalmsec == 0) + totalmsec = 1; + for (i = 0; i < BT_NUMBUFTYPES; i++) { + if (readcnt[i] == 0) + continue; + msec = readtime[i].tv_sec * 1000 + readtime[i].tv_nsec / 1000000; + printf("%21s:%8ld %2ld.%ld%% %8lld msec %2lld.%lld%%\n", + buftype[i], readcnt[i], readcnt[i] * 100 / diskreads, + (readcnt[i] * 1000 / diskreads) % 10, msec, + msec * 100 / totalmsec, (msec * 1000 / totalmsec) % 10); + } + printf("\n"); +} + int blread(int fd, char *buf, ufs2_daddr_t blk, long size) { @@ -358,6 +479,8 @@ blread(int fd, char *buf, ufs2_daddr_t b offset *= dev_bsize; if (bkgrdflag) slowio_start(); + totalreads++; + diskreads++; if (lseek(fd, offset, 0) < 0) rwerror("SEEK BLK", blk); else if (read(fd, buf, (int)size) == size) { Modified: head/sbin/fsck_ffs/inode.c ============================================================================== --- head/sbin/fsck_ffs/inode.c Sun Feb 24 05:48:59 2013 (r247211) +++ head/sbin/fsck_ffs/inode.c Sun Feb 24 06:44:29 2013 (r247212) @@ -52,7 +52,7 @@ __FBSDID("$FreeBSD$"); static ino_t startinum; -static int iblock(struct inodesc *, long ilevel, off_t isize); +static int iblock(struct inodesc *, long ilevel, off_t isize, int type); int ckinode(union dinode *dp, struct inodesc *idesc) @@ -121,7 +121,7 @@ ckinode(union dinode *dp, struct inodesc sizepb *= NINDIR(&sblock); if (DIP(&dino, di_ib[i])) { idesc->id_blkno = DIP(&dino, di_ib[i]); - ret = iblock(idesc, i + 1, remsize); + ret = iblock(idesc, i + 1, remsize, BT_LEVEL1 + i); if (ret & STOP) return (ret); } else { @@ -151,7 +151,7 @@ ckinode(union dinode *dp, struct inodesc } static int -iblock(struct inodesc *idesc, long ilevel, off_t isize) +iblock(struct inodesc *idesc, long ilevel, off_t isize, int type) { struct bufarea *bp; int i, n, (*func)(struct inodesc *), nif; @@ -168,7 +168,7 @@ iblock(struct inodesc *idesc, long ileve func = dirscan; if (chkrange(idesc->id_blkno, idesc->id_numfrags)) return (SKIP); - bp = getdatablk(idesc->id_blkno, sblock.fs_bsize); + bp = getdatablk(idesc->id_blkno, sblock.fs_bsize, type); ilevel--; for (sizepb = sblock.fs_bsize, i = 0; i < ilevel; i++) sizepb *= NINDIR(&sblock); @@ -199,7 +199,7 @@ iblock(struct inodesc *idesc, long ileve if (ilevel == 0) n = (*func)(idesc); else - n = iblock(idesc, ilevel, isize); + n = iblock(idesc, ilevel, isize, type); if (n & STOP) { bp->b_flags &= ~B_INUSE; return (n); @@ -292,7 +292,7 @@ ginode(ino_t inumber) iblk = ino_to_fsba(&sblock, inumber); if (pbp != 0) pbp->b_flags &= ~B_INUSE; - pbp = getdatablk(iblk, sblock.fs_bsize); + pbp = getdatablk(iblk, sblock.fs_bsize, BT_INODES); startinum = (inumber / INOPB(&sblock)) * INOPB(&sblock); } if (sblock.fs_magic == FS_UFS1_MAGIC) @@ -306,8 +306,8 @@ ginode(ino_t inumber) * over all the inodes in numerical order. */ static ino_t nextino, lastinum, lastvalidinum; -static long readcnt, readpercg, fullcnt, inobufsize, partialcnt, partialsize; -static caddr_t inodebuf; +static long readcount, readpercg, fullcnt, inobufsize, partialcnt, partialsize; +static struct bufarea inobuf; union dinode * getnextinode(ino_t inumber, int rebuildcg) @@ -315,7 +315,7 @@ getnextinode(ino_t inumber, int rebuildc int j; long size; mode_t mode; - ufs2_daddr_t ndb, dblk; + ufs2_daddr_t ndb, blk; union dinode *dp; static caddr_t nextinop; @@ -323,9 +323,9 @@ getnextinode(ino_t inumber, int rebuildc errx(EEXIT, "bad inode number %ju to nextinode", (uintmax_t)inumber); if (inumber >= lastinum) { - readcnt++; - dblk = fsbtodb(&sblock, ino_to_fsba(&sblock, lastinum)); - if (readcnt % readpercg == 0) { + readcount++; + blk = ino_to_fsba(&sblock, lastinum); + if (readcount % readpercg == 0) { size = partialsize; lastinum += partialcnt; } else { @@ -333,14 +333,14 @@ getnextinode(ino_t inumber, int rebuildc lastinum += fullcnt; } /* - * If blread returns an error, it will already have zeroed + * If getblk encounters an error, it will already have zeroed * out the buffer, so we do not need to do so here. */ - (void)blread(fsreadfd, inodebuf, dblk, size); - nextinop = inodebuf; + getblk(&inobuf, blk, size); + nextinop = inobuf.b_un.b_buf; } dp = (union dinode *)nextinop; - if (rebuildcg && nextinop == inodebuf) { + if (rebuildcg && nextinop == inobuf.b_un.b_buf) { /* * Try to determine if we have reached the end of the * allocated inodes. @@ -406,8 +406,8 @@ setinodebuf(ino_t inum) startinum = 0; nextino = inum; lastinum = inum; - readcnt = 0; - if (inodebuf != NULL) + readcount = 0; + if (inobuf.b_un.b_buf != NULL) return; inobufsize = blkroundup(&sblock, INOBUFSIZE); fullcnt = inobufsize / ((sblock.fs_magic == FS_UFS1_MAGIC) ? @@ -422,7 +422,8 @@ setinodebuf(ino_t inum) partialcnt = fullcnt; partialsize = inobufsize; } - if ((inodebuf = malloc((unsigned)inobufsize)) == NULL) + initbarea(&inobuf, BT_INODES); + if ((inobuf.b_un.b_buf = malloc((unsigned)inobufsize)) == NULL) errx(EEXIT, "cannot allocate space for inode buffer"); } @@ -430,9 +431,9 @@ void freeinodebuf(void) { - if (inodebuf != NULL) - free((char *)inodebuf); - inodebuf = NULL; + if (inobuf.b_un.b_buf != NULL) + free((char *)inobuf.b_un.b_buf); + inobuf.b_un.b_buf = NULL; } /* Modified: head/sbin/fsck_ffs/main.c ============================================================================== --- head/sbin/fsck_ffs/main.c Sun Feb 24 05:48:59 2013 (r247211) +++ head/sbin/fsck_ffs/main.c Sun Feb 24 06:44:29 2013 (r247212) @@ -424,7 +424,9 @@ checkfilesys(char *filesys) printf("** Root file system\n"); printf("** Phase 1 - Check Blocks and Sizes\n"); } + clock_gettime(CLOCK_REALTIME_PRECISE, &startprog); pass1(); + IOstats("Pass1"); /* * 1b: locate first references to duplicates, if any @@ -437,6 +439,7 @@ checkfilesys(char *filesys) usedsoftdep ? "softupdates" : ""); printf("** Phase 1b - Rescan For More DUPS\n"); pass1b(); + IOstats("Pass1b"); } /* @@ -445,6 +448,7 @@ checkfilesys(char *filesys) if (preen == 0) printf("** Phase 2 - Check Pathnames\n"); pass2(); + IOstats("Pass2"); /* * 3: scan inodes looking for disconnected directories @@ -452,6 +456,7 @@ checkfilesys(char *filesys) if (preen == 0) printf("** Phase 3 - Check Connectivity\n"); pass3(); + IOstats("Pass3"); /* * 4: scan inodes looking for disconnected files; check reference counts @@ -459,6 +464,7 @@ checkfilesys(char *filesys) if (preen == 0) printf("** Phase 4 - Check Reference Counts\n"); pass4(); + IOstats("Pass4"); /* * 5: check and repair resource counts in cylinder groups @@ -466,6 +472,7 @@ checkfilesys(char *filesys) if (preen == 0) printf("** Phase 5 - Check Cyl groups\n"); pass5(); + IOstats("Pass5"); /* * print out summary statistics @@ -519,6 +526,7 @@ checkfilesys(char *filesys) } if (rerun) resolved = 0; + finalIOstats(); /* * Check to see if the file system is mounted read-write. Modified: head/sbin/fsck_ffs/setup.c ============================================================================== --- head/sbin/fsck_ffs/setup.c Sun Feb 24 05:48:59 2013 (r247211) +++ head/sbin/fsck_ffs/setup.c Sun Feb 24 06:44:29 2013 (r247212) @@ -249,6 +249,7 @@ setup(char *dev) for (i = 0, j = 0; i < sblock.fs_cssize; i += sblock.fs_bsize, j++) { size = sblock.fs_cssize - i < sblock.fs_bsize ? sblock.fs_cssize - i : sblock.fs_bsize; + readcnt[sblk.b_type]++; if (blread(fsreadfd, (char *)sblock.fs_csp + i, fsbtodb(&sblock, sblock.fs_csaddr + j * sblock.fs_frag), size) != 0 && !asked) { @@ -322,6 +323,7 @@ readsb(int listerr) if (bflag) { super = bflag; + readcnt[sblk.b_type]++; if ((blread(fsreadfd, (char *)&sblock, super, (long)SBLOCKSIZE))) return (0); if (sblock.fs_magic == FS_BAD_MAGIC) { @@ -337,6 +339,7 @@ readsb(int listerr) } else { for (i = 0; sblock_try[i] != -1; i++) { super = sblock_try[i] / dev_bsize; + readcnt[sblk.b_type]++; if ((blread(fsreadfd, (char *)&sblock, super, (long)SBLOCKSIZE))) return (0); @@ -439,8 +442,8 @@ sblock_init(void) fswritefd = -1; fsmodified = 0; lfdir = 0; - initbarea(&sblk); - initbarea(&asblk); + initbarea(&sblk, BT_SUPERBLK); + initbarea(&asblk, BT_SUPERBLK); sblk.b_un.b_buf = malloc(SBLOCKSIZE); asblk.b_un.b_buf = malloc(SBLOCKSIZE); if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL)