Author: kib
Date: Sun Feb 17 20:35:54 2013
New Revision: 246921
URL: http://svnweb.freebsd.org/changeset/base/246921
Log:
Do not update the fsinfo block on each update of any fat block, this
is excessive. Postpone the flush of the fsinfo to VFS_SYNC(),
remembering the need for update with the flag MSDOSFS_FSIMOD, stored
in pm_flags.
FAT32 specification describes both FSI_Free_Count and FSI_Nxt_Free as
the advisory hints, not requiring them to be correct.
Based on the patch from bde, modified by me.
Reviewed by: bde
MFC after: 2 weeks
Modified:
head/sys/fs/msdosfs/msdosfs_fat.c
head/sys/fs/msdosfs/msdosfs_vfsops.c
head/sys/fs/msdosfs/msdosfsmount.h
Modified: head/sys/fs/msdosfs/msdosfs_fat.c
==============================================================================
--- head/sys/fs/msdosfs/msdosfs_fat.c Sun Feb 17 19:49:59 2013
(r246920)
+++ head/sys/fs/msdosfs/msdosfs_fat.c Sun Feb 17 20:35:54 2013
(r246921)
@@ -328,29 +328,6 @@ updatefats(pmp, bp, fatbn)
printf("updatefats(pmp %p, bp %p, fatbn %lu)\n", pmp, bp, fatbn);
#endif
- /*
- * If we have an FSInfo block, update it.
- */
- if (pmp->pm_fsinfo) {
- if (bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
- NOCRED, &bpn) != 0) {
- /*
- * Ignore the error, but turn off FSInfo update for the
future.
- */
- pmp->pm_fsinfo = 0;
- brelse(bpn);
- } else {
- struct fsinfo *fp = (struct fsinfo *)bpn->b_data;
-
- putulong(fp->fsinfree, pmp->pm_freeclustercount);
- putulong(fp->fsinxtfree, pmp->pm_nxtfree);
- if (pmp->pm_flags & MSDOSFSMNT_WAITONFAT)
- bwrite(bpn);
- else
- bdwrite(bpn);
- }
- }
-
if (pmp->pm_flags & MSDOSFS_FATMIRROR) {
/*
* Now copy the block(s) of the modified fat to the other
copies of
@@ -393,9 +370,6 @@ updatefats(pmp, bp, fatbn)
bwrite(bp);
else
bdwrite(bp);
- /*
- * Maybe update fsinfo sector here?
- */
}
/*
@@ -431,6 +405,7 @@ usemap_alloc(pmp, cn)
pmp->pm_inusemap[cn / N_INUSEBITS] |= 1 << (cn % N_INUSEBITS);
KASSERT(pmp->pm_freeclustercount > 0, ("usemap_alloc: too little"));
pmp->pm_freeclustercount--;
+ pmp->pm_flags |= MSDOSFS_FSIMOD;
}
static __inline void
@@ -441,6 +416,7 @@ usemap_free(pmp, cn)
MSDOSFS_ASSERT_MP_LOCKED(pmp);
pmp->pm_freeclustercount++;
+ pmp->pm_flags |= MSDOSFS_FSIMOD;
KASSERT((pmp->pm_inusemap[cn / N_INUSEBITS] & (1 << (cn % N_INUSEBITS)))
!= 0, ("Freeing unused sector %ld %ld %x", cn, cn % N_INUSEBITS,
(unsigned)pmp->pm_inusemap[cn / N_INUSEBITS]));
@@ -742,7 +718,10 @@ chainalloc(pmp, start, count, fillwith,
for (cl = start, n = count; n-- > 0;)
usemap_alloc(pmp, cl++);
-
+ pmp->pm_nxtfree = start + count;
+ if (pmp->pm_nxtfree > pmp->pm_maxcluster)
+ pmp->pm_nxtfree = CLUST_FIRST;
+ pmp->pm_flags |= MSDOSFS_FSIMOD;
error = fatchain(pmp, start, count, fillwith);
if (error != 0)
return (error);
@@ -754,9 +733,6 @@ chainalloc(pmp, start, count, fillwith,
*retcluster = start;
if (got)
*got = count;
- pmp->pm_nxtfree = start + count;
- if (pmp->pm_nxtfree > pmp->pm_maxcluster)
- pmp->pm_nxtfree = CLUST_FIRST;
return (0);
}
Modified: head/sys/fs/msdosfs/msdosfs_vfsops.c
==============================================================================
--- head/sys/fs/msdosfs/msdosfs_vfsops.c Sun Feb 17 19:49:59 2013
(r246920)
+++ head/sys/fs/msdosfs/msdosfs_vfsops.c Sun Feb 17 20:35:54 2013
(r246921)
@@ -896,6 +896,40 @@ msdosfs_statfs(struct mount *mp, struct
return (0);
}
+/*
+ * If we have an FSInfo block, update it.
+ */
+static int
+msdosfs_fsiflush(struct msdosfsmount *pmp, int waitfor)
+{
+ struct fsinfo *fp;
+ struct buf *bp;
+ int error;
+
+ MSDOSFS_LOCK_MP(pmp);
+ if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
+ error = 0;
+ goto unlock;
+ }
+ error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
+ NOCRED, &bp);
+ if (error != 0) {
+ brelse(bp);
+ goto unlock;
+ }
+ fp = (struct fsinfo *)bp->b_data;
+ putulong(fp->fsinfree, pmp->pm_freeclustercount);
+ putulong(fp->fsinxtfree, pmp->pm_nxtfree);
+ pmp->pm_flags &= ~MSDOSFS_FSIMOD;
+ if (waitfor == MNT_WAIT)
+ error = bwrite(bp);
+ else
+ bawrite(bp);
+unlock:
+ MSDOSFS_UNLOCK_MP(pmp);
+ return (error);
+}
+
static int
msdosfs_sync(struct mount *mp, int waitfor)
{
@@ -958,6 +992,10 @@ loop:
allerror = error;
VOP_UNLOCK(pmp->pm_devvp, 0);
}
+
+ error = msdosfs_fsiflush(pmp, waitfor);
+ if (error != 0)
+ allerror = error;
return (allerror);
}
Modified: head/sys/fs/msdosfs/msdosfsmount.h
==============================================================================
--- head/sys/fs/msdosfs/msdosfsmount.h Sun Feb 17 19:49:59 2013
(r246920)
+++ head/sys/fs/msdosfs/msdosfsmount.h Sun Feb 17 20:35:54 2013
(r246921)
@@ -262,6 +262,7 @@ struct msdosfs_args {
#define MSDOSFSMNT_WAITONFAT 0x40000000 /* mounted synchronous
*/
#define MSDOSFS_FATMIRROR 0x20000000 /* FAT is mirrored */
#define MSDOSFS_LARGEFS 0x10000000 /* perform fileno
mapping */
+#define MSDOSFS_FSIMOD 0x01000000
#define MSDOSFS_ARGSMAGIC 0xe4eff300
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