Author: jhb
Date: Tue Feb 1 18:21:45 2011
New Revision: 218175
URL: http://svn.freebsd.org/changeset/base/218175
Log:
- Set the next_alloc fields for an i-node after allocating a new block
so that future allocations start with most recently allocated block
rather than the beginning of the filesystem.
- Fix ext2_alloccg() to properly scan for 8 block chunks that are not
aligned on 8-bit boundaries. Previously this was causing new blocks
to be allocated in a highly fragmented fashion (block 0 of a file at
lbn N, block 1 at lbn N + 8, block 2 at lbn N + 16, etc.).
- Cosmetic tweaks to the currently-disabled fancy realloc sysctls.
PR: kern/153584
Discussed with: bde
Tested by: Pedro F. Giffuni giffunip at yahoo, Zheng Liu (lz)
Modified:
head/sys/fs/ext2fs/ext2_alloc.c
Modified: head/sys/fs/ext2fs/ext2_alloc.c
==============================================================================
--- head/sys/fs/ext2fs/ext2_alloc.c Tue Feb 1 17:42:57 2011
(r218174)
+++ head/sys/fs/ext2fs/ext2_alloc.c Tue Feb 1 18:21:45 2011
(r218175)
@@ -59,6 +59,10 @@ static u_long ext2_hashalloc(struct inod
int));
static daddr_t ext2_nodealloccg(struct inode *, int, daddr_t, int);
static daddr_t ext2_mapsearch(struct m_ext2fs *, char *, daddr_t);
+#ifdef FANCY_REALLOC
+static int ext2_reallocblks(struct vop_reallocblks_args *);
+#endif
+
/*
* Allocate a block in the file system.
*
@@ -108,13 +112,17 @@ ext2_alloc(ip, lbn, bpref, size, cred, b
goto nospace;
if (bpref >= fs->e2fs->e2fs_bcount)
bpref = 0;
- if (bpref == 0)
+ if (bpref == 0)
cg = ino_to_cg(fs, ip->i_number);
else
cg = dtog(fs, bpref);
bno = (daddr_t)ext2_hashalloc(ip, cg, bpref, fs->e2fs_bsize,
ext2_alloccg);
if (bno > 0) {
+ /* set next_alloc fields as done in block_getblk */
+ ip->i_next_alloc_block = lbn;
+ ip->i_next_alloc_goal = bno;
+
ip->i_blocks += btodb(fs->e2fs_bsize);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
*bnp = bno;
@@ -143,13 +151,14 @@ nospace:
*/
#ifdef FANCY_REALLOC
-#include <sys/sysctl.h>
+SYSCTL_NODE(_vfs, OID_AUTO, ext2fs, CTLFLAG_RW, 0, "EXT2FS filesystem");
+
static int doasyncfree = 1;
-static int doreallocblks = 1;
+SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doasyncfree, CTLFLAG_RW, &doasyncfree, 0,
+ "Use asychronous writes to update block pointers when freeing blocks");
-#ifdef OPT_DEBUG
-SYSCTL_INT(_debug, 14, doasyncfree, CTLFLAG_RW, &doasyncfree, 0, "");
-#endif /* OPT_DEBUG */
+static int doreallocblks = 1;
+SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doreallocblks, CTLFLAG_RW, &doreallocblks,
0, "");
#endif
int
@@ -624,7 +633,8 @@ ext2_alloccg(struct inode *ip, int cg, d
struct m_ext2fs *fs;
struct buf *bp;
struct ext2mount *ump;
- int error, bno, start, end, loc;
+ daddr_t bno, runstart, runlen;
+ int bit, loc, end, error, start;
char *bbp;
/* XXX ondisk32 */
fs = ip->i_e2fs;
@@ -665,18 +675,52 @@ ext2_alloccg(struct inode *ip, int cg, d
else
start = 0;
end = howmany(fs->e2fs->e2fs_fpg, NBBY) - start;
+retry:
+ runlen = 0;
+ runstart = 0;
for (loc = start; loc < end; loc++) {
- if (bbp[loc] == 0) {
- bno = loc * NBBY;
- goto gotit;
+ if (bbp[loc] == (char)0xff) {
+ runlen = 0;
+ continue;
}
- }
- for (loc = 0; loc < start; loc++) {
- if (bbp[loc] == 0) {
- bno = loc * NBBY;
+
+ /* Start of a run, find the number of high clear bits. */
+ if (runlen == 0) {
+ bit = fls(bbp[loc]);
+ runlen = NBBY - bit;
+ runstart = loc * NBBY + bit;
+ } else if (bbp[loc] == 0) {
+ /* Continue a run. */
+ runlen += NBBY;
+ } else {
+ /*
+ * Finish the current run. If it isn't long
+ * enough, start a new one.
+ */
+ bit = ffs(bbp[loc]) - 1;
+ runlen += bit;
+ if (runlen >= 8) {
+ bno = runstart;
+ goto gotit;
+ }
+
+ /* Run was too short, start a new one. */
+ bit = fls(bbp[loc]);
+ runlen = NBBY - bit;
+ runstart = loc * NBBY + bit;
+ }
+
+ /* If the current run is long enough, use it. */
+ if (runlen >= 8) {
+ bno = runstart;
goto gotit;
}
}
+ if (start != 0) {
+ end = start;
+ start = 0;
+ goto retry;
+ }
bno = ext2_mapsearch(fs, bbp, bpref);
if (bno < 0){
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
