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VFS: fix locking bug in clone_opcl

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When VFS runs out of vnodes after closing a vnode in opcl, common_open
will try to unlock a vnode through unlock_filp that has already been
unlocked in clone_opcl. By first obtaining and locking a new vnode this
situation is prevented; if there are no free vnodes, common_open will
unlock a still locked vnode.
This commit is contained in:
Thomas Veerman 2012-07-26 12:28:03 +00:00
parent f6b0d662b5
commit 66dbf73049
1 changed files with 14 additions and 16 deletions
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30
servers/vfs/device.c
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@ -881,35 +881,33 @@ int clone_opcl(
if (op == DEV_OPEN && dev_mess.REP_STATUS >= 0) { if (op == DEV_OPEN && dev_mess.REP_STATUS >= 0) {
if (dev_mess.REP_STATUS != minor_dev) { if (dev_mess.REP_STATUS != minor_dev) {
struct vnode *vp; struct vnode *vp;
struct node_details res; struct node_details res;
/* A new minor device number has been returned. /* A new minor device number has been returned.
* Request PFS to create a temporary device file to hold it. * Request PFS to create a temporary device file to hold it.
*/ */
/* Device number of the new device. */ /* Device number of the new device. */
dev = (dev & ~(BYTE << MINOR)) | (dev_mess.REP_STATUS << MINOR); dev = (dev & ~(BYTE << MINOR)) | (dev_mess.REP_STATUS << MINOR);
/* Issue request */ /* Issue request */
r = req_newnode(PFS_PROC_NR, fp->fp_effuid, fp->fp_effgid, r = req_newnode(PFS_PROC_NR, fp->fp_effuid, fp->fp_effgid,
ALL_MODES | I_CHAR_SPECIAL, dev, &res); ALL_MODES | I_CHAR_SPECIAL, dev, &res);
if (r != OK) { if (r != OK) {
(void) clone_opcl(DEV_CLOSE, dev, proc_e, 0); (void) clone_opcl(DEV_CLOSE, dev, proc_e, 0);
return r; return r;
} }
/* Drop old node and use the new values */ /* Drop old node and use the new values */
assert(FD_ISSET(scratch(fp).file.fd_nr, &fp->fp_filp_inuse));
vp = fp->fp_filp[scratch(fp).file.fd_nr]->filp_vno;
unlock_vnode(vp);
put_vnode(vp);
if ((vp = get_free_vnode()) == NULL) if ((vp = get_free_vnode()) == NULL)
return(err_code); return(err_code);
lock_vnode(vp, VNODE_OPCL); lock_vnode(vp, VNODE_OPCL);
assert(FD_ISSET(scratch(fp).file.fd_nr, &fp->fp_filp_inuse));
unlock_vnode(fp->fp_filp[scratch(fp).file.fd_nr]->filp_vno);
put_vnode(fp->fp_filp[scratch(fp).file.fd_nr]->filp_vno);
vp->v_fs_e = res.fs_e; vp->v_fs_e = res.fs_e;
vp->v_vmnt = NULL; vp->v_vmnt = NULL;
vp->v_dev = NO_DEV; vp->v_dev = NO_DEV;