[PATCH] v9fs: fix races in fid allocation
Fid management cleanup. The patch attempts to fix the races in dentry's
fid management.
Dentries don't keep the opened fids anymore, they are moved to the file
structs. Ideally there should be no more than one fid with fidcreate equal
to zero in the dentry's list of fids.
v9fs_fid_create initializes the important fields (fid, fidcreated) before
v9fs_fid is added to the list. v9fs_fid_lookup returns only fids that are
not created by v9fs_create. v9fs_fid_get_created returns the fid created
by the same process by v9fs_create (if any) and removes it from dentry's
list
Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index b16322d..2b696ae 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -307,7 +307,7 @@
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
struct super_block *sb = dir->i_sb;
struct v9fs_fid *dirfid =
- v9fs_fid_lookup(file_dentry->d_parent, FID_WALK);
+ v9fs_fid_lookup(file_dentry->d_parent);
struct v9fs_fid *fid = NULL;
struct inode *file_inode = NULL;
struct v9fs_fcall *fcall = NULL;
@@ -317,6 +317,7 @@
long newfid = -1;
int result = 0;
unsigned int iounit = 0;
+ int wfidno = -1;
perm = unixmode2p9mode(v9ses, perm);
@@ -350,7 +351,7 @@
if (result < 0) {
dprintk(DEBUG_ERROR, "clone error: %s\n", FCALL_ERROR(fcall));
v9fs_put_idpool(newfid, &v9ses->fidpool);
- newfid = 0;
+ newfid = -1;
goto CleanUpFid;
}
@@ -369,20 +370,39 @@
qid = fcall->params.rcreate.qid;
kfree(fcall);
- fid = v9fs_fid_create(file_dentry);
+ fid = v9fs_fid_create(file_dentry, v9ses, newfid, 1);
+ dprintk(DEBUG_VFS, "fid %p %d\n", fid, fid->fidcreate);
if (!fid) {
result = -ENOMEM;
goto CleanUpFid;
}
- fid->fid = newfid;
- fid->fidopen = 0;
- fid->fidcreate = 1;
fid->qid = qid;
fid->iounit = iounit;
- fid->rdir_pos = 0;
- fid->rdir_fcall = NULL;
- fid->v9ses = v9ses;
+
+ /* walk to the newly created file and put the fid in the dentry */
+ wfidno = v9fs_get_idpool(&v9ses->fidpool);
+ if (newfid < 0) {
+ eprintk(KERN_WARNING, "no free fids available\n");
+ return -ENOSPC;
+ }
+
+ result = v9fs_t_walk(v9ses, dirfidnum, wfidno,
+ (char *) file_dentry->d_name.name, NULL);
+ if (result < 0) {
+ dprintk(DEBUG_ERROR, "clone error: %s\n", FCALL_ERROR(fcall));
+ v9fs_put_idpool(wfidno, &v9ses->fidpool);
+ wfidno = -1;
+ goto CleanUpFid;
+ }
+
+ if (!v9fs_fid_create(file_dentry, v9ses, wfidno, 0)) {
+ if (!v9fs_t_clunk(v9ses, newfid, &fcall)) {
+ v9fs_put_idpool(wfidno, &v9ses->fidpool);
+ }
+
+ goto CleanUpFid;
+ }
if ((perm & V9FS_DMSYMLINK) || (perm & V9FS_DMLINK) ||
(perm & V9FS_DMNAMEDPIPE) || (perm & V9FS_DMSOCKET) ||
@@ -410,11 +430,11 @@
d_instantiate(file_dentry, file_inode);
if (perm & V9FS_DMDIR) {
- if (v9fs_t_clunk(v9ses, newfid, &fcall))
+ if (!v9fs_t_clunk(v9ses, newfid, &fcall))
+ v9fs_put_idpool(newfid, &v9ses->fidpool);
+ else
dprintk(DEBUG_ERROR, "clunk for mkdir failed: %s\n",
FCALL_ERROR(fcall));
-
- v9fs_put_idpool(newfid, &v9ses->fidpool);
kfree(fcall);
fid->fidopen = 0;
fid->fidcreate = 0;
@@ -426,12 +446,22 @@
CleanUpFid:
kfree(fcall);
- if (newfid) {
- if (v9fs_t_clunk(v9ses, newfid, &fcall))
+ if (newfid >= 0) {
+ if (!v9fs_t_clunk(v9ses, newfid, &fcall))
+ v9fs_put_idpool(newfid, &v9ses->fidpool);
+ else
dprintk(DEBUG_ERROR, "clunk failed: %s\n",
FCALL_ERROR(fcall));
- v9fs_put_idpool(newfid, &v9ses->fidpool);
+ kfree(fcall);
+ }
+ if (wfidno >= 0) {
+ if (!v9fs_t_clunk(v9ses, wfidno, &fcall))
+ v9fs_put_idpool(wfidno, &v9ses->fidpool);
+ else
+ dprintk(DEBUG_ERROR, "clunk failed: %s\n",
+ FCALL_ERROR(fcall));
+
kfree(fcall);
}
return result;
@@ -461,7 +491,7 @@
file_inode = file->d_inode;
sb = file_inode->i_sb;
v9ses = v9fs_inode2v9ses(file_inode);
- v9fid = v9fs_fid_lookup(file, FID_OP);
+ v9fid = v9fs_fid_lookup(file);
if (!v9fid) {
dprintk(DEBUG_ERROR,
@@ -545,7 +575,7 @@
sb = dir->i_sb;
v9ses = v9fs_inode2v9ses(dir);
- dirfid = v9fs_fid_lookup(dentry->d_parent, FID_WALK);
+ dirfid = v9fs_fid_lookup(dentry->d_parent);
if (!dirfid) {
dprintk(DEBUG_ERROR, "no dirfid\n");
@@ -573,7 +603,7 @@
v9fs_put_idpool(newfid, &v9ses->fidpool);
if (result == -ENOENT) {
d_add(dentry, NULL);
- dprintk(DEBUG_ERROR,
+ dprintk(DEBUG_VFS,
"Return negative dentry %p count %d\n",
dentry, atomic_read(&dentry->d_count));
return NULL;
@@ -601,16 +631,13 @@
inode->i_ino = v9fs_qid2ino(&fcall->params.rstat.stat->qid);
- fid = v9fs_fid_create(dentry);
+ fid = v9fs_fid_create(dentry, v9ses, newfid, 0);
if (fid == NULL) {
dprintk(DEBUG_ERROR, "couldn't insert\n");
result = -ENOMEM;
goto FreeFcall;
}
- fid->fid = newfid;
- fid->fidopen = 0;
- fid->v9ses = v9ses;
fid->qid = fcall->params.rstat.stat->qid;
dentry->d_op = &v9fs_dentry_operations;
@@ -665,11 +692,11 @@
{
struct inode *old_inode = old_dentry->d_inode;
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(old_inode);
- struct v9fs_fid *oldfid = v9fs_fid_lookup(old_dentry, FID_WALK);
+ struct v9fs_fid *oldfid = v9fs_fid_lookup(old_dentry);
struct v9fs_fid *olddirfid =
- v9fs_fid_lookup(old_dentry->d_parent, FID_WALK);
+ v9fs_fid_lookup(old_dentry->d_parent);
struct v9fs_fid *newdirfid =
- v9fs_fid_lookup(new_dentry->d_parent, FID_WALK);
+ v9fs_fid_lookup(new_dentry->d_parent);
struct v9fs_stat *mistat = kmalloc(v9ses->maxdata, GFP_KERNEL);
struct v9fs_fcall *fcall = NULL;
int fid = -1;
@@ -744,7 +771,7 @@
{
struct v9fs_fcall *fcall = NULL;
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
- struct v9fs_fid *fid = v9fs_fid_lookup(dentry, FID_OP);
+ struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
int err = -EPERM;
dprintk(DEBUG_VFS, "dentry: %p\n", dentry);
@@ -778,7 +805,7 @@
static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
- struct v9fs_fid *fid = v9fs_fid_lookup(dentry, FID_OP);
+ struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
struct v9fs_fcall *fcall = NULL;
struct v9fs_stat *mistat = kmalloc(v9ses->maxdata, GFP_KERNEL);
int res = -EPERM;
@@ -960,7 +987,7 @@
if (retval != 0)
goto FreeFcall;
- newfid = v9fs_fid_lookup(dentry, FID_OP);
+ newfid = v9fs_fid_lookup(dentry);
/* issue a twstat */
v9fs_blank_mistat(v9ses, mistat);
@@ -1004,7 +1031,7 @@
struct v9fs_fcall *fcall = NULL;
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dentry->d_inode);
- struct v9fs_fid *fid = v9fs_fid_lookup(dentry, FID_OP);
+ struct v9fs_fid *fid = v9fs_fid_lookup(dentry);
if (!fid) {
dprintk(DEBUG_ERROR, "could not resolve fid from dentry\n");
@@ -1148,7 +1175,7 @@
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
struct v9fs_fcall *fcall = NULL;
struct v9fs_stat *mistat = kmalloc(v9ses->maxdata, GFP_KERNEL);
- struct v9fs_fid *oldfid = v9fs_fid_lookup(old_dentry, FID_OP);
+ struct v9fs_fid *oldfid = v9fs_fid_lookup(old_dentry);
struct v9fs_fid *newfid = NULL;
char *symname = __getname();
@@ -1168,7 +1195,7 @@
if (retval != 0)
goto FreeMem;
- newfid = v9fs_fid_lookup(dentry, FID_OP);
+ newfid = v9fs_fid_lookup(dentry);
if (!newfid) {
dprintk(DEBUG_ERROR, "couldn't resolve fid from dentry\n");
goto FreeMem;
@@ -1246,7 +1273,7 @@
if (retval != 0)
goto FreeMem;
- newfid = v9fs_fid_lookup(dentry, FID_OP);
+ newfid = v9fs_fid_lookup(dentry);
if (!newfid) {
dprintk(DEBUG_ERROR, "coudn't resove fid from dentry\n");
retval = -EINVAL;