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The non-modifying EA VOPs are executed with only shared vnode lock taken.

Browse Source 
Provide a custom lock around initializing and tearing down EA area,
to prevent both memory leaks and double-free of it. Count the number
of EA area accessors.

Lock protocol requires either holding exclusive vnode lock to modify
i_ea_area, or shared vnode lock and owning IN_EA_LOCKED flag in i_flag.

Noted by:	YAMAMOTO, Taku <taku tackymt homeip net>
Tested by:	pho (previous version)
MFC after:	2 weeks
This commit is contained in:
kib 2009-03-12 12:43:56 +00:00
parent 33b0309eb2
commit 9e27cf574d
3 changed files with 94 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/ufs/ffs/ffs_vfsops.c
View File

@ -1451,6 +1451,7 @@ ffs_vgetf(mp, ino, flags, vpp, ffs_flags)
ip->i_fs = fs;
ip->i_dev = dev;
ip->i_number = ino;
ip->i_ea_refs = 0;
#ifdef QUOTA
{
int i;

153
sys/ufs/ffs/ffs_vnops.c
View File

@ -1225,6 +1225,35 @@ ffs_rdextattr(u_char **p, struct vnode *vp, struct thread *td, int extra)
return (0);
}
static void
ffs_lock_ea(struct vnode *vp)
{
struct inode *ip;
ip = VTOI(vp);
VI_LOCK(vp);
while (ip->i_flag & IN_EA_LOCKED) {
ip->i_flag |= IN_EA_LOCKWAIT;
msleep(&ip->i_ea_refs, &vp->v_interlock, PINOD + 2, "ufs_ea",
0);
}
ip->i_flag |= IN_EA_LOCKED;
VI_UNLOCK(vp);
}
static void
ffs_unlock_ea(struct vnode *vp)
{
struct inode *ip;
ip = VTOI(vp);
VI_LOCK(vp);
if (ip->i_flag & IN_EA_LOCKWAIT)
wakeup(&ip->i_ea_refs);
ip->i_flag &= ~(IN_EA_LOCKED | IN_EA_LOCKWAIT);
VI_UNLOCK(vp);
}
static int
ffs_open_ea(struct vnode *vp, struct ucred *cred, struct thread *td)
{
@ -1234,14 +1263,22 @@ ffs_open_ea(struct vnode *vp, struct ucred *cred, struct thread *td)
ip = VTOI(vp);
if (ip->i_ea_area != NULL)
return (EBUSY);
ffs_lock_ea(vp);
if (ip->i_ea_area != NULL) {
ip->i_ea_refs++;
ffs_unlock_ea(vp);
return (0);
}
dp = ip->i_din2;
error = ffs_rdextattr(&ip->i_ea_area, vp, td, 0);
if (error)
if (error) {
ffs_unlock_ea(vp);
return (error);
}
ip->i_ea_len = dp->di_extsize;
ip->i_ea_error = 0;
ip->i_ea_refs++;
ffs_unlock_ea(vp);
return (0);
}
@ -1258,11 +1295,16 @@ ffs_close_ea(struct vnode *vp, int commit, struct ucred *cred, struct thread *td
struct ufs2_dinode *dp;
ip = VTOI(vp);
if (ip->i_ea_area == NULL)
ffs_lock_ea(vp);
if (ip->i_ea_area == NULL) {
ffs_unlock_ea(vp);
return (EINVAL);
}
dp = ip->i_din2;
error = ip->i_ea_error;
if (commit && error == 0) {
ASSERT_VOP_ELOCKED(vp, "ffs_close_ea commit");
if (cred == NOCRED)
cred = vp->v_mount->mnt_cred;
liovec.iov_base = ip->i_ea_area;
@ -1279,10 +1321,13 @@ ffs_close_ea(struct vnode *vp, int commit, struct ucred *cred, struct thread *td
error = ffs_truncate(vp, 0, IO_EXT, cred, td);
error = ffs_extwrite(vp, &luio, IO_EXT | IO_SYNC, cred);
}
free(ip->i_ea_area, M_TEMP);
ip->i_ea_area = NULL;
ip->i_ea_len = 0;
ip->i_ea_error = 0;
if (--ip->i_ea_refs == 0) {
free(ip->i_ea_area, M_TEMP);
ip->i_ea_area = NULL;
ip->i_ea_len = 0;
ip->i_ea_error = 0;
}
ffs_unlock_ea(vp);
return (error);
}
@ -1392,7 +1437,6 @@ vop_deleteextattr {
uint32_t ealength, ul;
int ealen, olen, eapad1, eapad2, error, i, easize;
u_char *eae, *p;
int stand_alone;
ip = VTOI(ap->a_vp);
fs = ip->i_fs;
@ -1409,19 +1453,19 @@ vop_deleteextattr {
error = extattr_check_cred(ap->a_vp, ap->a_attrnamespace,
ap->a_cred, ap->a_td, VWRITE);
if (error) {
/*
* ffs_lock_ea is not needed there, because the vnode
* must be exlusively locked.
*/
if (ip->i_ea_area != NULL && ip->i_ea_error == 0)
ip->i_ea_error = error;
return (error);
}
if (ip->i_ea_area == NULL) {
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
stand_alone = 1;
} else {
stand_alone = 0;
}
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
ealength = eapad1 = ealen = eapad2 = 0;
@ -1434,8 +1478,7 @@ vop_deleteextattr {
if (olen == -1) {
/* delete but nonexistent */
free(eae, M_TEMP);
if (stand_alone)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
return(ENOATTR);
}
bcopy(p, &ul, sizeof ul);
@ -1446,9 +1489,8 @@ vop_deleteextattr {
}
if (easize > NXADDR * fs->fs_bsize) {
free(eae, M_TEMP);
if (stand_alone)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
else if (ip->i_ea_error == 0)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
if (ip->i_ea_area != NULL && ip->i_ea_error == 0)
ip->i_ea_error = ENOSPC;
return(ENOSPC);
}
@ -1456,8 +1498,7 @@ vop_deleteextattr {
ip->i_ea_area = eae;
ip->i_ea_len = easize;
free(p, M_TEMP);
if (stand_alone)
error = ffs_close_ea(ap->a_vp, 1, ap->a_cred, ap->a_td);
error = ffs_close_ea(ap->a_vp, 1, ap->a_cred, ap->a_td);
return(error);
}
@ -1482,7 +1523,7 @@ vop_getextattr {
struct fs *fs;
u_char *eae, *p;
unsigned easize;
int error, ealen, stand_alone;
int error, ealen;
ip = VTOI(ap->a_vp);
fs = ip->i_fs;
@ -1495,14 +1536,10 @@ vop_getextattr {
if (error)
return (error);
if (ip->i_ea_area == NULL) {
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
stand_alone = 1;
} else {
stand_alone = 0;
}
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
eae = ip->i_ea_area;
easize = ip->i_ea_len;
@ -1516,8 +1553,8 @@ vop_getextattr {
error = uiomove(p, ealen, ap->a_uio);
} else
error = ENOATTR;
if (stand_alone)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
return(error);
}
@ -1542,7 +1579,7 @@ vop_listextattr {
u_char *eae, *p, *pe, *pn;
unsigned easize;
uint32_t ul;
int error, ealen, stand_alone;
int error, ealen;
ip = VTOI(ap->a_vp);
fs = ip->i_fs;
@ -1555,14 +1592,9 @@ vop_listextattr {
if (error)
return (error);
if (ip->i_ea_area == NULL) {
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
stand_alone = 1;
} else {
stand_alone = 0;
}
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
eae = ip->i_ea_area;
easize = ip->i_ea_len;
@ -1586,8 +1618,7 @@ vop_listextattr {
error = uiomove(p, ealen + 1, ap->a_uio);
}
}
if (stand_alone)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
return(error);
}
@ -1612,7 +1643,6 @@ vop_setextattr {
uint32_t ealength, ul;
int ealen, olen, eapad1, eapad2, error, i, easize;
u_char *eae, *p;
int stand_alone;
ip = VTOI(ap->a_vp);
fs = ip->i_fs;
@ -1633,19 +1663,19 @@ vop_setextattr {
error = extattr_check_cred(ap->a_vp, ap->a_attrnamespace,
ap->a_cred, ap->a_td, VWRITE);
if (error) {
/*
* ffs_lock_ea is not needed there, because the vnode
* must be exlusively locked.
*/
if (ip->i_ea_area != NULL && ip->i_ea_error == 0)
ip->i_ea_error = error;
return (error);
}
if (ip->i_ea_area == NULL) {
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
stand_alone = 1;
} else {
stand_alone = 0;
}
error = ffs_open_ea(ap->a_vp, ap->a_cred, ap->a_td);
if (error)
return (error);
ealen = ap->a_uio->uio_resid;
ealength = sizeof(uint32_t) + 3 + strlen(ap->a_name);
@ -1677,9 +1707,8 @@ vop_setextattr {
}
if (easize > NXADDR * fs->fs_bsize) {
free(eae, M_TEMP);
if (stand_alone)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
else if (ip->i_ea_error == 0)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
if (ip->i_ea_area != NULL && ip->i_ea_error == 0)
ip->i_ea_error = ENOSPC;
return(ENOSPC);
}
@ -1695,9 +1724,8 @@ vop_setextattr {
error = uiomove(p, ealen, ap->a_uio);
if (error) {
free(eae, M_TEMP);
if (stand_alone)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
else if (ip->i_ea_error == 0)
ffs_close_ea(ap->a_vp, 0, ap->a_cred, ap->a_td);
if (ip->i_ea_area != NULL && ip->i_ea_error == 0)
ip->i_ea_error = error;
return(error);
}
@ -1708,8 +1736,7 @@ vop_setextattr {
ip->i_ea_area = eae;
ip->i_ea_len = easize;
free(p, M_TEMP);
if (stand_alone)
error = ffs_close_ea(ap->a_vp, 1, ap->a_cred, ap->a_td);
error = ffs_close_ea(ap->a_vp, 1, ap->a_cred, ap->a_td);
return(error);
}

3
sys/ufs/ufs/inode.h
View File

@ -94,6 +94,7 @@ struct inode {
u_char *i_ea_area; /* Pointer to malloced copy of EA area */
unsigned i_ea_len; /* Length of i_ea_area */
int i_ea_error; /* First errno in transaction */
int i_ea_refs; /* Number of users of EA area */
/*
* Copies from the on-disk dinode itself.
@ -125,6 +126,8 @@ struct inode {
#define IN_SPACECOUNTED 0x0080 /* Blocks to be freed in free count. */
#define IN_LAZYACCESS 0x0100 /* Process IN_ACCESS after the
suspension finished */
#define IN_EA_LOCKED 0x0200
#define IN_EA_LOCKWAIT 0x0400
#define i_devvp i_ump->um_devvp
#define i_umbufobj i_ump->um_bo