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VFS: improve crashed FS resource cleanup

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When VFS detects that an FS has crashed and tries to clean up
resources, it marks fairly late in the process that a vmnt is not
to be used again (to send requests to). This allows a thread to
become blocked on a vmnt after all blocked threads were stopped, but
before it finds out it shouldn't try to send to that vmnt.
This commit is contained in:
Thomas Veerman 2012-02-22 13:54:35 +00:00
parent 04eb5d326a
commit 1efb51b1de
3 changed files with 23 additions and 10 deletions
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9
servers/vfs/mount.c
View file

@ -273,8 +273,7 @@ char mount_label[LABEL_MAX] )
new_vmp->m_flags &= ~VMNT_MOUNTING;
if (r != OK) {
new_vmp->m_fs_e = NONE;
new_vmp->m_dev = NO_DEV;
mark_vmnt_free(new_vmp);
unlock_vnode(root_node);
if (vp != NULL) {
unlock_vnode(vp);
@ -349,11 +348,10 @@ char mount_label[LABEL_MAX] )
if (r != OK) {
unlock_vnode(vp);
unlock_vnode(root_node);
mark_vmnt_free(new_vmp);
unlock_vmnt(new_vmp);
put_vnode(vp);
put_vnode(root_node);
new_vmp->m_dev = NO_DEV;
new_vmp->m_flags = 0;
unlock_bsf();
return(r);
}
@ -505,8 +503,7 @@ PUBLIC int unmount(
vmp->m_root_node->v_sdev = NO_DEV;
vmp->m_root_node = NULL;
}
vmp->m_dev = NO_DEV;
vmp->m_fs_e = NONE;
mark_vmnt_free(vmp);
unlock_vmnt(vmp);

1
servers/vfs/proto.h
View file

@ -331,6 +331,7 @@ _PROTOTYPE( int in_group, (struct fproc *rfp, gid_t grp) );
/* vmnt.c */
_PROTOTYPE( void check_vmnt_locks, (void) );
_PROTOTYPE( void check_vmnt_locks_by_me, (struct fproc *rfp) );
_PROTOTYPE( void mark_vmnt_free, (struct vmnt *vmp) );
_PROTOTYPE( struct vmnt *get_free_vmnt, (void) );
_PROTOTYPE( struct vmnt *find_vmnt, (endpoint_t fs_e) );
_PROTOTYPE( struct vmnt *get_locked_vmnt, (struct fproc *rfp) );

23
servers/vfs/vmnt.c
View file

@ -59,6 +59,17 @@ PUBLIC void check_vmnt_locks()
#endif
}
/*===========================================================================*
* mark_vmnt_free *
*===========================================================================*/
PUBLIC void mark_vmnt_free(struct vmnt *vmp)
{
ASSERTVMP(vmp);
vmp->m_fs_e = NONE;
vmp->m_dev = NO_DEV;
}
/*===========================================================================*
* clear_vmnt *
*===========================================================================*/
@ -83,10 +94,14 @@ PRIVATE void clear_vmnt(struct vmnt *vmp)
*===========================================================================*/
PUBLIC struct vmnt *get_free_vmnt(void)
{
struct vmnt *vp;
struct vmnt *vmp;
for (vp = &vmnt[0]; vp < &vmnt[NR_MNTS]; ++vp)
if (vp->m_dev == NO_DEV) return(vp);
for (vmp = &vmnt[0]; vmp < &vmnt[NR_MNTS]; ++vmp) {
if (vmp->m_dev == NO_DEV) {
clear_vmnt(vmp);
return(vmp);
}
}
return(NULL);
}
@ -167,6 +182,7 @@ PUBLIC void vmnt_unmap_by_endpt(endpoint_t proc_e)
struct vmnt *vmp;
if ((vmp = find_vmnt(proc_e)) != NULL) {
mark_vmnt_free(vmp);
fs_cancel(vmp);
invalidate_filp_by_endpt(proc_e);
if (vmp->m_mounted_on) {
@ -174,7 +190,6 @@ PUBLIC void vmnt_unmap_by_endpt(endpoint_t proc_e)
* point. That is, the mount was succesful. */
put_vnode(vmp->m_mounted_on);
}
clear_vmnt(vmp);
}
}