On Sun, May 19, 2002 at 11:16:33AM +0200, Florian Schaefer wrote:
> today I compiled a new kernel for my new RH7.3 system and suddenly I get
> some oops when accessing coda.
Yeah, there is a race in iget4 that only recently became more noticable
and a change that went into the tree earlier broke mmap in some cases.
Some of the needed fixes have already been sent to Marcello, the iget4
race is something that I just finished cleaning up and I have been
running it only for about a week. I will probably send that one soon.
I'll attach the full diff from 2.4.19-pre8 to what I have right now.
> PS: How do I compile a coda-client from cvs source? The coda module seems
> to be for a server, isn't it?
It builds both the client and the server as a lot of the code is shared
(or at least there are a lot of dependencies) between the two. There are
only different install targets 'client-install' and 'server-install'.
Basically the steps to go through are 'cvs co coda', 'cd coda',
'./bootstrap.sh', './configure --prefix=/usr', 'make', 'make client-install'.
Jan
diff -urN orig/fs/coda/cnode.c coda1/fs/coda/cnode.c
--- orig/fs/coda/cnode.c Fri May 3 13:43:44 2002
+++ coda1/fs/coda/cnode.c Tue May 14 22:11:50 2002
@@ -57,6 +57,7 @@
} else if (S_ISLNK(inode->i_mode)) {
inode->i_op = &coda_symlink_inode_operations;
inode->i_data.a_ops = &coda_symlink_aops;
+ inode->i_mapping = &inode->i_data;
} else
init_special_inode(inode, inode->i_mode, attr->va_rdev);
}
@@ -67,11 +68,14 @@
struct inode *inode;
struct coda_inode_info *cii;
ino_t ino = coda_f2i(fid);
+ struct coda_sb_info *sbi = coda_sbp(sb);
+ down(&sbi->sbi_iget4_mutex);
inode = iget4(sb, ino, coda_inocmp, fid);
if ( !inode ) {
CDEBUG(D_CNODE, "coda_iget: no inode\n");
+ up(&sbi->sbi_iget4_mutex);
return ERR_PTR(-ENOMEM);
}
@@ -80,9 +84,7 @@
if (coda_isnullfid(&cii->c_fid))
/* new, empty inode found... initializing */
cii->c_fid = *fid;
-
- /* we shouldnt see inode collisions anymore */
- if (!coda_fideq(fid, &cii->c_fid)) BUG();
+ up(&sbi->sbi_iget4_mutex);
/* always replace the attributes, type might have changed */
coda_fill_inode(inode, attr);
@@ -147,6 +149,7 @@
ino_t nr;
struct inode *inode;
struct coda_inode_info *cii;
+ struct coda_sb_info *sbi;
if ( !sb ) {
printk("coda_fid_to_inode: no sb!\n");
@@ -155,12 +158,14 @@
CDEBUG(D_INODE, "%s\n", coda_f2s(fid));
+ sbi = coda_sbp(sb);
nr = coda_f2i(fid);
+ down(&sbi->sbi_iget4_mutex);
inode = iget4(sb, nr, coda_inocmp, fid);
if ( !inode ) {
printk("coda_fid_to_inode: null from iget, sb %p, nr %ld.\n",
sb, (long)nr);
- return NULL;
+ goto out_unlock;
}
cii = ITOC(inode);
@@ -169,14 +174,16 @@
if (coda_isnullfid(&cii->c_fid)) {
inode->i_nlink = 0;
iput(inode);
- return NULL;
+ goto out_unlock;
}
- /* we shouldn't see inode collisions anymore */
- if ( !coda_fideq(fid, &cii->c_fid) ) BUG();
-
CDEBUG(D_INODE, "found %ld\n", inode->i_ino);
+ up(&sbi->sbi_iget4_mutex);
return inode;
+
+out_unlock:
+ up(&sbi->sbi_iget4_mutex);
+ return NULL;
}
/* the CONTROL inode is made without asking attributes from Venus */
diff -urN orig/fs/coda/dir.c coda1/fs/coda/dir.c
--- orig/fs/coda/dir.c Fri May 3 13:43:44 2002
+++ coda1/fs/coda/dir.c Fri May 3 13:50:40 2002
@@ -491,6 +491,7 @@
struct dentry *coda_dentry = coda_file->f_dentry;
struct coda_file_info *cfi;
struct file *host_file;
+ int ret;
cfi = CODA_FTOC(coda_file);
if (!cfi || cfi->cfi_magic != CODA_MAGIC) BUG();
@@ -498,12 +499,21 @@
coda_vfs_stat.readdir++;
- if ( host_file->f_op->readdir )
+ down(&host_file->f_dentry->d_inode->i_sem);
+ host_file->f_pos = coda_file->f_pos;
+
+ if ( !host_file->f_op->readdir ) {
+ /* Venus: we must read Venus dirents from the file */
+ ret = coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
+ } else {
/* potemkin case: we were handed a directory inode */
- return vfs_readdir(host_file, filldir, dirent);
+ ret = vfs_readdir(host_file, filldir, dirent);
+ }
+
+ coda_file->f_pos = host_file->f_pos;
+ up(&host_file->f_dentry->d_inode->i_sem);
- /* Venus: we must read Venus dirents from the file */
- return coda_venus_readdir(host_file, filldir, dirent, coda_dentry);
+ return ret;
}
static inline unsigned int CDT2DT(unsigned char cdt)
@@ -736,7 +746,6 @@
return 0;
return_bad_inode:
- make_bad_inode(inode);
unlock_kernel();
return -EIO;
}
diff -urN orig/fs/coda/file.c coda1/fs/coda/file.c
--- orig/fs/coda/file.c Fri May 3 13:43:44 2002
+++ coda1/fs/coda/file.c Tue May 14 23:14:56 2002
@@ -48,7 +48,7 @@
static ssize_t
coda_file_write(struct file *coda_file, const char *buf, size_t count, loff_t *ppos)
{
- struct inode *host_inode, *coda_inode = coda_file->f_dentry->d_inode;
+ struct inode *coda_inode = coda_file->f_dentry->d_inode;
struct coda_file_info *cfi;
struct file *host_file;
ssize_t ret;
@@ -60,12 +60,11 @@
if (!host_file->f_op || !host_file->f_op->write)
return -EINVAL;
- host_inode = host_file->f_dentry->d_inode;
down(&coda_inode->i_sem);
ret = host_file->f_op->write(host_file, buf, count, ppos);
- coda_inode->i_size = host_inode->i_size;
+ coda_inode->i_size = host_file->f_dentry->d_inode->i_size;
coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9;
coda_inode->i_mtime = coda_inode->i_ctime = CURRENT_TIME;
up(&coda_inode->i_sem);
@@ -77,7 +76,9 @@
coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
{
struct coda_file_info *cfi;
+ struct coda_inode_info *cii;
struct file *host_file;
+ struct inode *coda_inode, *host_inode;
cfi = CODA_FTOC(coda_file);
if (!cfi || cfi->cfi_magic != CODA_MAGIC) BUG();
@@ -86,6 +87,21 @@
if (!host_file->f_op || !host_file->f_op->mmap)
return -ENODEV;
+ coda_inode = coda_file->f_dentry->d_inode;
+ host_inode = host_file->f_dentry->d_inode;
+ if (coda_inode->i_mapping == &coda_inode->i_data)
+ coda_inode->i_mapping = host_inode->i_mapping;
+
+ /* only allow additional mmaps as long as userspace isn't changing
+ * the container file on us! */
+ else if (coda_inode->i_mapping != host_inode->i_mapping)
+ return -EBUSY;
+
+ /* keep track of how often the coda_inode/host_file has been mmapped */
+ cii = ITOC(coda_inode);
+ cii->c_mapcount++;
+ cfi->cfi_mapcount++;
+
return host_file->f_op->mmap(host_file, vma);
}
@@ -97,7 +113,6 @@
unsigned short coda_flags = coda_flags_to_cflags(flags);
struct coda_file_info *cfi;
- lock_kernel();
coda_vfs_stat.open++;
cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL);
@@ -106,6 +121,8 @@
return -ENOMEM;
}
+ lock_kernel();
+
error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags,
&host_file);
if (error || !host_file) {
@@ -117,6 +134,7 @@
host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC);
cfi->cfi_magic = CODA_MAGIC;
+ cfi->cfi_mapcount = 0;
cfi->cfi_container = host_file;
coda_load_creds(&cfi->cfi_cred);
@@ -169,6 +187,8 @@
unsigned short flags = (coda_file->f_flags) & (~O_EXCL);
unsigned short coda_flags = coda_flags_to_cflags(flags);
struct coda_file_info *cfi;
+ struct coda_inode_info *cii;
+ struct inode *host_inode;
int err = 0;
lock_kernel();
@@ -189,6 +209,16 @@
if (use_coda_close)
err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode),
coda_flags, &cfi->cfi_cred);
+
+ host_inode = cfi->cfi_container->f_dentry->d_inode;
+ cii = ITOC(coda_inode);
+
+ /* did we mmap this file? */
+ if (coda_inode->i_mapping == &host_inode->i_data) {
+ cii->c_mapcount -= cfi->cfi_mapcount;
+ if (!cii->c_mapcount)
+ coda_inode->i_mapping = &coda_inode->i_data;
+ }
fput(cfi->cfi_container);
kfree(coda_file->private_data);
diff -urN orig/fs/coda/inode.c coda1/fs/coda/inode.c
--- orig/fs/coda/inode.c Fri May 3 13:43:44 2002
+++ coda1/fs/coda/inode.c Tue May 14 22:22:51 2002
@@ -128,6 +128,7 @@
sbi->sbi_sb = sb;
sbi->sbi_vcomm = vc;
INIT_LIST_HEAD(&sbi->sbi_cihead);
+ init_MUTEX(&sbi->sbi_iget4_mutex);
sb->u.generic_sbp = sbi;
sb->s_blocksize = 1024; /* XXXXX what do we put here?? */
@@ -194,6 +195,7 @@
return;
}
+ cii->c_mapcount = 0;
list_add(&cii->c_cilist, &sbi->sbi_cihead);
}
diff -urN orig/include/linux/coda_fs_i.h coda1/include/linux/coda_fs_i.h
--- orig/include/linux/coda_fs_i.h Fri May 3 14:23:33 2002
+++ coda1/include/linux/coda_fs_i.h Tue May 14 23:00:14 2002
@@ -20,6 +20,7 @@
struct ViceFid c_fid; /* Coda identifier */
u_short c_flags; /* flags (see below) */
struct list_head c_cilist; /* list of all coda inodes */
+ int c_mapcount; /* how often is this inode mmapped */
struct coda_cred c_cached_cred; /* credentials of cached perms */
unsigned int c_cached_perm; /* cached access permissions */
};
@@ -30,6 +31,7 @@
#define CODA_MAGIC 0xC0DAC0DA
struct coda_file_info {
int cfi_magic; /* magic number */
+ int cfi_mapcount; /* how often this file is mapped */
struct file *cfi_container; /* container file for this cnode */
struct coda_cred cfi_cred; /* credentials of opener */
};
diff -urN orig/include/linux/coda_psdev.h coda1/include/linux/coda_psdev.h
--- orig/include/linux/coda_psdev.h Wed Apr 25 19:18:54 2001
+++ coda1/include/linux/coda_psdev.h Thu May 9 02:39:34 2002
@@ -11,6 +11,7 @@
struct venus_comm * sbi_vcomm;
struct super_block *sbi_sb;
struct list_head sbi_cihead;
+ struct semaphore sbi_iget4_mutex;
};
/* communication pending/processing queues */
