tfix indirect block reading - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
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---
(DIR) commit 9f4a65a0d84b460b55b1177ed9dc5917bb6d20e9
(DIR) parent 725d9fd7952a63c09f50d5544d0b306177462d43
(HTM) Author: rsc <devnull@localhost>
Date: Thu, 28 Jul 2005 05:16:42 +0000
fix indirect block reading
Diffstat:
M src/libdiskfs/ffs.c | 98 +++++++++++++++++++++++++------
1 file changed, 79 insertions(+), 19 deletions(-)
---
(DIR) diff --git a/src/libdiskfs/ffs.c b/src/libdiskfs/ffs.c
t@@ -15,6 +15,7 @@ static Block *ffsblockread(Fsys*, u64int);
static int ffssync(Fsys*);
static void ffsclose(Fsys*);
+static u64int ffsxfileblock(Fsys *fs, Nfs3Handle *h, u64int offset);
static Nfs3Status ffsroot(Fsys*, Nfs3Handle*);
static Nfs3Status ffsgetattr(Fsys*, SunAuthUnix *au, Nfs3Handle*, Nfs3Attr*);
static Nfs3Status ffslookup(Fsys*, SunAuthUnix *au, Nfs3Handle*, char*, Nfs3Handle*);
t@@ -43,6 +44,7 @@ fsysopenffs(Disk *disk)
fsys->_readfile = ffsreadfile;
fsys->_readlink = ffsreadlink;
fsys->_readdir = ffsreaddir;
+ fsys->fileblock = ffsxfileblock;
if(ffssync(fsys) < 0)
goto error;
t@@ -288,35 +290,60 @@ ffsdatablock(Ffs *fs, u32int bno, int size)
return b;
}
-static Block*
-ffsfileblock(Ffs *fs, Inode *ino, u32int bno, int size)
+static u32int
+ifetch(Ffs *fs, u32int bno, u32int off)
{
- int ppb;
- Block *b;
u32int *a;
+ Block *b;
+
+ if(bno == ~0)
+ return ~0;
+ b = ffsdatablock(fs, bno, fs->blocksize);
+ if(b == nil)
+ return ~0;
+ a = (u32int*)b->data;
+ bno = a[off];
+ blockput(b);
+ return bno;
+}
+
+static u32int
+ffsfileblockno(Ffs *fs, Inode *ino, u32int bno)
+{
+ int ppb;
if(bno < NDADDR){
if(debug) fprint(2, "ffsfileblock %lud: direct %#lux\n", (ulong)bno, (ulong)ino->db[bno]);
- return ffsdatablock(fs, ino->db[bno], size);
+ return ino->db[bno];
}
bno -= NDADDR;
ppb = fs->blocksize/4;
- if(bno/ppb < NIADDR){
- if(debug) fprint(2, "ffsfileblock %lud: indirect %#lux\n", (ulong)(bno+NDADDR),
- (ulong)ino->ib[bno/ppb]);
- b = ffsdatablock(fs, ino->ib[bno/ppb], fs->blocksize);
- if(b == nil)
- return nil;
- a = (u32int*)b->data;
- bno = a[bno%ppb];
- if(debug) fprint(2, "ffsfileblock: indirect fetch %#lux size %d\n", (ulong)bno, size);
- blockput(b);
- return ffsdatablock(fs, bno, size);
- }
+ if(bno < ppb) /* single indirect */
+ return ifetch(fs, ino->ib[0], bno);
+ bno -= ppb;
- fprint(2, "ffsfileblock %lud: too big\n", (ulong)bno+NDADDR);
- return nil;
+ if(bno < ppb*ppb)
+ return ifetch(fs, ifetch(fs, ino->ib[1], bno/ppb), bno%ppb);
+ bno -= ppb*ppb;
+
+ if(bno/ppb/ppb/ppb == 0) /* bno < ppb*ppb*ppb w/o overflow */
+ return ifetch(fs, ifetch(fs, ifetch(fs, ino->ib[2], bno/ppb/ppb), (bno/ppb)%ppb), bno%ppb);
+ bno -= ppb*ppb*ppb;
+
+ fprint(2, "ffsfileblock %lud: way too big\n", (ulong)bno+NDADDR);
+ return ~0;
+}
+
+static Block*
+ffsfileblock(Ffs *fs, Inode *ino, u32int bno, int size)
+{
+ u32int b;
+
+ b = ffsfileblockno(fs, ino, bno);
+ if(b == ~0)
+ return nil;
+ return ffsdatablock(fs, b, size);
}
/*
t@@ -338,6 +365,8 @@ byte2u32(uchar *p)
return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
}
+static u64int iaddr;
+
static Nfs3Status
handle2ino(Ffs *fs, Nfs3Handle *h, u32int *pinum, Inode *ino)
{
t@@ -370,6 +399,8 @@ handle2ino(Ffs *fs, Nfs3Handle *h, u32int *pinum, Inode *ino)
if((b = diskread(fs->disk, fs->blocksize,
(cg->ibno+ioff/fs->inosperblock)*(vlong)fs->blocksize)) == nil)
return Nfs3ErrIo;
+ iaddr = (cg->ibno+ioff/fs->inosperblock)*(vlong)fs->blocksize
+ + (ioff%fs->inosperblock)*sizeof(Inode);
*ino = ((Inode*)b->data)[ioff%fs->inosperblock];
blockput(b);
t@@ -458,6 +489,9 @@ inoperm(Inode *ino, SunAuthUnix *au, int need)
{
int have;
+ if(au == nil)
+ return Nfs3Ok;
+
have = ino->mode&0777;
if(ino->uid == au->uid)
have >>= 6;
t@@ -680,6 +714,32 @@ ffsreaddir(Fsys *fsys, SunAuthUnix *au, Nfs3Handle *h, u32int count, u64int cook
return Nfs3Ok;
}
+static u64int
+ffsxfileblock(Fsys *fsys, Nfs3Handle *h, u64int offset)
+{
+ u32int bno;
+ Inode ino;
+ Nfs3Status ok;
+ Ffs *fs;
+
+ fs = fsys->priv;
+ if((ok = handle2ino(fs, h, nil, &ino)) != Nfs3Ok){
+ nfs3errstr(ok);
+ return 0;
+ }
+ if(offset == 1)
+ return iaddr;
+ if(offset >= ino.size){
+ werrstr("beyond end of file");
+ return 0;
+ }
+ bno = offset/fs->blocksize;
+ bno = ffsfileblockno(fs, &ino, bno);
+ if(bno == ~0)
+ return 0;
+ return bno*(u64int)fs->fragsize;
+}
+
static Nfs3Status
ffsreadfile(Fsys *fsys, SunAuthUnix *au, Nfs3Handle *h, u32int count,
u64int offset, uchar **pdata, u32int *pcount, u1int *peof)