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Kill zp->z_xattr_parent to prevent pinning
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zp->z_xattr_parent will pin the parent. This will cause huge issue
when unlink a file with xattr. Because the unlinked file is pinned, it
will never get purged immediately. And because of that, the xattr
stuff will never be marked as unlinked. So the whole unlinked stuff
will stay there until shrink cache or umount.

This change partially reverts e89260a.  This is safe because only the
zp->z_xattr_parent optimization is removed, zpl_xattr_security_init()
is still called from the zpl outside the inode lock.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Issue #4359
Issue #3508
Issue #4413
Issue #4827
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@behlendorf
Chunwei Chen authored and behlendorf committed Jul 12, 2016
1 parent ddae16a commit 31b6111
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Showing 3 changed files with 26 additions and 63 deletions.
1 change: 0 additions & 1 deletion include/sys/zfs_znode.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -197,7 +197,6 @@ typedef struct znode {
zfs_acl_t *z_acl_cached; /* cached acl */
krwlock_t z_xattr_lock; /* xattr data lock */
nvlist_t *z_xattr_cached; /* cached xattrs */
struct znode *z_xattr_parent; /* xattr parent znode */
list_node_t z_link_node; /* all znodes in fs link */
sa_handle_t *z_sa_hdl; /* handle to sa data */
boolean_t z_is_sa; /* are we native sa? */
Expand Down
59 changes: 23 additions & 36 deletions module/zfs/zfs_acl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2471,53 +2471,33 @@ zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr)
{
uint32_t working_mode;
int error;
boolean_t check_privs;
znode_t *check_zp = zp;
int is_attr;
boolean_t check_privs;
znode_t *xzp;
znode_t *check_zp = zp;
mode_t needed_bits;
uid_t owner;

is_attr = ((zp->z_pflags & ZFS_XATTR) && S_ISDIR(ZTOI(zp)->i_mode));

/*
* If attribute then validate against base file
*/
if ((zp->z_pflags & ZFS_XATTR) && S_ISDIR(ZTOI(zp)->i_mode)) {
if (is_attr) {
uint64_t parent;

rw_enter(&zp->z_xattr_lock, RW_READER);
if (zp->z_xattr_parent) {
check_zp = zp->z_xattr_parent;
rw_exit(&zp->z_xattr_lock);

/*
* Verify a lookup yields the same znode.
*/
ASSERT3S(sa_lookup(zp->z_sa_hdl, SA_ZPL_PARENT(
ZTOZSB(zp)), &parent, sizeof (parent)), ==, 0);
ASSERT3U(check_zp->z_id, ==, parent);
} else {
rw_exit(&zp->z_xattr_lock);

error = sa_lookup(zp->z_sa_hdl, SA_ZPL_PARENT(
ZTOZSB(zp)), &parent, sizeof (parent));
if (error)
return (error);
if ((error = sa_lookup(zp->z_sa_hdl,
SA_ZPL_PARENT(ZTOZSB(zp)), &parent,
sizeof (parent))) != 0)
return (error);

/*
* Cache the lookup on the parent file znode as
* zp->z_xattr_parent and hold a reference. This
* effectively pins the parent in memory until all
* child xattr znodes have been destroyed and
* release their references in zfs_inode_destroy().
*/
error = zfs_zget(ZTOZSB(zp), parent, &check_zp);
if (error)
return (error);

rw_enter(&zp->z_xattr_lock, RW_WRITER);
if (zp->z_xattr_parent == NULL)
zp->z_xattr_parent = check_zp;
rw_exit(&zp->z_xattr_lock);
if ((error = zfs_zget(ZTOZSB(zp),
parent, &xzp)) != 0) {
return (error);
}

check_zp = xzp;

/*
* fixup mode to map to xattr perms
*/
Expand Down Expand Up @@ -2559,11 +2539,15 @@ zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr)

if ((error = zfs_zaccess_common(check_zp, mode, &working_mode,
&check_privs, skipaclchk, cr)) == 0) {
if (is_attr)
iput(ZTOI(xzp));
return (secpolicy_vnode_access2(cr, ZTOI(zp), owner,
needed_bits, needed_bits));
}

if (error && !check_privs) {
if (is_attr)
iput(ZTOI(xzp));
return (error);
}

Expand Down Expand Up @@ -2624,6 +2608,9 @@ zfs_zaccess(znode_t *zp, int mode, int flags, boolean_t skipaclchk, cred_t *cr)
needed_bits, needed_bits);
}

if (is_attr)
iput(ZTOI(xzp));

return (error);
}

Expand Down
29 changes: 3 additions & 26 deletions module/zfs/zfs_znode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -119,7 +119,6 @@ zfs_znode_cache_constructor(void *buf, void *arg, int kmflags)
zp->z_dirlocks = NULL;
zp->z_acl_cached = NULL;
zp->z_xattr_cached = NULL;
zp->z_xattr_parent = NULL;
zp->z_moved = 0;
return (0);
}
Expand All @@ -141,7 +140,6 @@ zfs_znode_cache_destructor(void *buf, void *arg)
ASSERT(zp->z_dirlocks == NULL);
ASSERT(zp->z_acl_cached == NULL);
ASSERT(zp->z_xattr_cached == NULL);
ASSERT(zp->z_xattr_parent == NULL);
}

static int
Expand Down Expand Up @@ -433,11 +431,6 @@ zfs_inode_destroy(struct inode *ip)
zp->z_xattr_cached = NULL;
}

if (zp->z_xattr_parent) {
zfs_iput_async(ZTOI(zp->z_xattr_parent));
zp->z_xattr_parent = NULL;
}

kmem_cache_free(znode_cache, zp);
}

Expand Down Expand Up @@ -582,8 +575,7 @@ zfs_inode_update(znode_t *zp)
*/
static znode_t *
zfs_znode_alloc(zfs_sb_t *zsb, dmu_buf_t *db, int blksz,
dmu_object_type_t obj_type, uint64_t obj, sa_handle_t *hdl,
struct inode *dip)
dmu_object_type_t obj_type, uint64_t obj, sa_handle_t *hdl)
{
znode_t *zp;
struct inode *ip;
Expand All @@ -603,7 +595,6 @@ zfs_znode_alloc(zfs_sb_t *zsb, dmu_buf_t *db, int blksz,
ASSERT(zp->z_dirlocks == NULL);
ASSERT3P(zp->z_acl_cached, ==, NULL);
ASSERT3P(zp->z_xattr_cached, ==, NULL);
ASSERT3P(zp->z_xattr_parent, ==, NULL);
zp->z_moved = 0;
zp->z_sa_hdl = NULL;
zp->z_unlinked = 0;
Expand Down Expand Up @@ -645,14 +636,6 @@ zfs_znode_alloc(zfs_sb_t *zsb, dmu_buf_t *db, int blksz,
zp->z_mode = mode;
ip->i_generation = (uint32_t)tmp_gen;

/*
* xattr znodes hold a reference on their unique parent
*/
if (dip && zp->z_pflags & ZFS_XATTR) {
igrab(dip);
zp->z_xattr_parent = ITOZ(dip);
}

ip->i_ino = obj;
zfs_inode_update_new(zp);
zfs_inode_set_ops(zsb, ip);
Expand Down Expand Up @@ -940,8 +923,7 @@ zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
VERIFY(sa_replace_all_by_template(sa_hdl, sa_attrs, cnt, tx) == 0);

if (!(flag & IS_ROOT_NODE)) {
*zpp = zfs_znode_alloc(zsb, db, 0, obj_type, obj, sa_hdl,
ZTOI(dzp));
*zpp = zfs_znode_alloc(zsb, db, 0, obj_type, obj, sa_hdl);
VERIFY(*zpp != NULL);
VERIFY(dzp != NULL);
} else {
Expand Down Expand Up @@ -1152,7 +1134,7 @@ zfs_zget(zfs_sb_t *zsb, uint64_t obj_num, znode_t **zpp)
* bonus buffer.
*/
zp = zfs_znode_alloc(zsb, db, doi.doi_data_block_size,
doi.doi_bonus_type, obj_num, NULL, NULL);
doi.doi_bonus_type, obj_num, NULL);
if (zp == NULL) {
err = SET_ERROR(ENOENT);
} else {
Expand Down Expand Up @@ -1200,11 +1182,6 @@ zfs_rezget(znode_t *zp)
nvlist_free(zp->z_xattr_cached);
zp->z_xattr_cached = NULL;
}

if (zp->z_xattr_parent) {
zfs_iput_async(ZTOI(zp->z_xattr_parent));
zp->z_xattr_parent = NULL;
}
rw_exit(&zp->z_xattr_lock);

ASSERT(zp->z_sa_hdl == NULL);
Expand Down

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