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Resolve a deadlock when fs_nodealloccg() initializes more inodes on

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an UFS2 file system.  With the current cylinder group buffer busy it
calls ffs_getblk().  This runs through copy-on-write and may need the
current cylinder group buffer to allocate a new block for the snapshot.

While here write the cylinder group buffer synchronously after
cg_initediblk was changed because fsck_ffs will trust it.

Reviewed by: Jason Thorpe <thorpej@netbsd.org>
This commit is contained in:
hannken 2008-07-31 09:35:09 +00:00
parent 0800f2fb9f
commit fb6f2c9b30
1 changed files with 47 additions and 14 deletions
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61
sys/ufs/ffs/ffs_alloc.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: ffs_alloc.c,v 1.111 2008/07/31 05:38:06 simonb Exp $ */
/* $NetBSD: ffs_alloc.c,v 1.112 2008/07/31 09:35:09 hannken Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@ -70,7 +70,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ffs_alloc.c,v 1.111 2008/07/31 05:38:06 simonb Exp $");
__KERNEL_RCSID(0, "$NetBSD: ffs_alloc.c,v 1.112 2008/07/31 09:35:09 hannken Exp $");
#if defined(_KERNEL_OPT)
#include "opt_ffs.h"
@ -1612,6 +1612,7 @@ ffs_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode, int flags)
u_int8_t *inosused;
int error, start, len, loc, map, i;
int32_t initediblk;
daddr_t nalloc;
struct ufs2_dinode *dp2;
#ifdef FFS_EI
const int needswap = UFS_FSNEEDSWAP(fs);
@ -1623,6 +1624,9 @@ ffs_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode, int flags)
if (fs->fs_cs(fs, cg).cs_nifree == 0)
return (0);
mutex_exit(&ump->um_lock);
ibp = NULL;
initediblk = -1;
retry:
error = bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
(int)fs->fs_cgsize, NOCRED, B_MODIFY, &bp);
if (error)
@ -1630,6 +1634,37 @@ ffs_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode, int flags)
cgp = (struct cg *)bp->b_data;
if (!cg_chkmagic(cgp, needswap) || cgp->cg_cs.cs_nifree == 0)
goto fail;
if (ibp != NULL &&
initediblk != ufs_rw32(cgp->cg_initediblk, needswap)) {
/* Another thread allocated more inodes so we retry the test. */
brelse(ibp, BC_INVAL);
ibp = NULL;
}
/*
* Check to see if we need to initialize more inodes.
*/
if (fs->fs_magic == FS_UFS2_MAGIC && ibp == NULL) {
initediblk = ufs_rw32(cgp->cg_initediblk, needswap);
nalloc = fs->fs_ipg - ufs_rw32(cgp->cg_cs.cs_nifree, needswap);
if (nalloc + INOPB(fs) > initediblk &&
initediblk < ufs_rw32(cgp->cg_niblk, needswap)) {
/*
* We have to release the cg buffer here to prevent
* a deadlock when reading the inode block will
* run a copy-on-write that might use this cg.
*/
brelse(bp, 0);
bp = NULL;
error = ffs_getblk(ip->i_devvp, fsbtodb(fs,
ino_to_fsba(fs, cg * fs->fs_ipg + initediblk)),
FFS_NOBLK, fs->fs_bsize, false, &ibp);
if (error)
goto fail;
goto retry;
}
}
cgp->cg_old_time = ufs_rw32(time_second, needswap);
if ((fs->fs_magic != FS_UFS1_MAGIC) ||
(fs->fs_old_flags & FS_FLAGS_UPDATED))
@ -1674,15 +1709,8 @@ gotit:
/*
* Check to see if we need to initialize more inodes.
*/
initediblk = ufs_rw32(cgp->cg_initediblk, needswap);
ibp = NULL;
if (fs->fs_magic == FS_UFS2_MAGIC &&
ipref + INOPB(fs) > initediblk &&
initediblk < ufs_rw32(cgp->cg_niblk, needswap)) {
if (ffs_getblk(ip->i_devvp, fsbtodb(fs,
ino_to_fsba(fs, cg * fs->fs_ipg + initediblk)),
FFS_NOBLK, fs->fs_bsize, false, &ibp) != 0)
goto fail;
if (ibp != NULL) {
KASSERT(initediblk == ufs_rw32(cgp->cg_initediblk, needswap));
memset(ibp->b_data, 0, fs->fs_bsize);
dp2 = (struct ufs2_dinode *)(ibp->b_data);
for (i = 0; i < INOPB(fs); i++) {
@ -1712,12 +1740,17 @@ gotit:
mutex_exit(&ump->um_lock);
if (DOINGSOFTDEP(ITOV(ip)))
softdep_setup_inomapdep(bp, ip, cg * fs->fs_ipg + ipref);
bdwrite(bp);
if (ibp != NULL)
if (ibp != NULL) {
bwrite(bp);
bawrite(ibp);
} else
bdwrite(bp);
return (cg * fs->fs_ipg + ipref);
fail:
brelse(bp, 0);
if (bp != NULL)
brelse(bp, 0);
if (ibp != NULL)
brelse(ibp, BC_INVAL);
mutex_enter(&ump->um_lock);
return (0);
}