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Add support for O_TMPFILE

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Linux 3.11 add O_TMPFILE to open(2), which allow creating an unlinked file on
supported filesystem. It's basically doing open(2) and unlink(2) atomically.

The filesystem support is added through i_op->tmpfile. We basically copy the
create operation except we get rid of the link and name related stuff and add
the new node to unlinked set.

We also add support for linkat(2) to link tmpfile. However, since all previous
file operation will skip ZIL, we force a txg_wait_synced to make sure we are
sync safe.

Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
This commit is contained in:
Chunwei Chen
2016-01-26 12:29:46 -08:00
committed by Brian Behlendorf
parent 987014903f
commit ace1eae84c
18 changed files with 644 additions and 8 deletions
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module/zfs/zfs_vnops.c
+151 -7
View File
@@ -1509,6 +1509,123 @@ out:
}
EXPORT_SYMBOL(zfs_create);
/* ARGSUSED */
int
zfs_tmpfile(struct inode *dip, vattr_t *vap, int excl,
int mode, struct inode **ipp, cred_t *cr, int flag, vsecattr_t *vsecp)
{
znode_t *zp = NULL, *dzp = ITOZ(dip);
zfs_sb_t *zsb = ITOZSB(dip);
objset_t *os;
dmu_tx_t *tx;
int error;
uid_t uid;
gid_t gid;
zfs_acl_ids_t acl_ids;
boolean_t fuid_dirtied;
boolean_t have_acl = B_FALSE;
boolean_t waited = B_FALSE;
/*
* If we have an ephemeral id, ACL, or XVATTR then
* make sure file system is at proper version
*/
gid = crgetgid(cr);
uid = crgetuid(cr);
if (zsb->z_use_fuids == B_FALSE &&
(vsecp || IS_EPHEMERAL(uid) || IS_EPHEMERAL(gid)))
return (SET_ERROR(EINVAL));
ZFS_ENTER(zsb);
ZFS_VERIFY_ZP(dzp);
os = zsb->z_os;
if (vap->va_mask & ATTR_XVATTR) {
if ((error = secpolicy_xvattr((xvattr_t *)vap,
crgetuid(cr), cr, vap->va_mode)) != 0) {
ZFS_EXIT(zsb);
return (error);
}
}
top:
*ipp = NULL;
/*
* Create a new file object and update the directory
* to reference it.
*/
if ((error = zfs_zaccess(dzp, ACE_ADD_FILE, 0, B_FALSE, cr))) {
if (have_acl)
zfs_acl_ids_free(&acl_ids);
goto out;
}
if (!have_acl && (error = zfs_acl_ids_create(dzp, 0, vap,
cr, vsecp, &acl_ids)) != 0)
goto out;
have_acl = B_TRUE;
if (zfs_acl_ids_overquota(zsb, &acl_ids)) {
zfs_acl_ids_free(&acl_ids);
error = SET_ERROR(EDQUOT);
goto out;
}
tx = dmu_tx_create(os);
dmu_tx_hold_sa_create(tx, acl_ids.z_aclp->z_acl_bytes +
ZFS_SA_BASE_ATTR_SIZE);
dmu_tx_hold_zap(tx, zsb->z_unlinkedobj, FALSE, NULL);
fuid_dirtied = zsb->z_fuid_dirty;
if (fuid_dirtied)
zfs_fuid_txhold(zsb, tx);
if (!zsb->z_use_sa &&
acl_ids.z_aclp->z_acl_bytes > ZFS_ACE_SPACE) {
dmu_tx_hold_write(tx, DMU_NEW_OBJECT,
0, acl_ids.z_aclp->z_acl_bytes);
}
error = dmu_tx_assign(tx, waited ? TXG_WAITED : TXG_NOWAIT);
if (error) {
if (error == ERESTART) {
waited = B_TRUE;
dmu_tx_wait(tx);
dmu_tx_abort(tx);
goto top;
}
zfs_acl_ids_free(&acl_ids);
dmu_tx_abort(tx);
ZFS_EXIT(zsb);
return (error);
}
zfs_mknode(dzp, vap, tx, cr, IS_TMPFILE, &zp, &acl_ids);
if (fuid_dirtied)
zfs_fuid_sync(zsb, tx);
/* Add to unlinked set */
zp->z_unlinked = 1;
zfs_unlinked_add(zp, tx);
zfs_acl_ids_free(&acl_ids);
dmu_tx_commit(tx);
out:
if (error) {
if (zp)
iput(ZTOI(zp));
} else {
zfs_inode_update(dzp);
zfs_inode_update(zp);
*ipp = ZTOI(zp);
}
ZFS_EXIT(zsb);
return (error);
}
/*
* Remove an entry from a directory.
*
@@ -3802,7 +3919,11 @@ zfs_link(struct inode *tdip, struct inode *sip, char *name, cred_t *cr,
uint64_t parent;
uid_t owner;
boolean_t waited = B_FALSE;
boolean_t is_tmpfile = 0;
uint64_t txg;
#ifdef HAVE_TMPFILE
is_tmpfile = (sip->i_nlink == 0 && (sip->i_state & I_LINKABLE));
#endif
ASSERT(S_ISDIR(tdip->i_mode));
ZFS_ENTER(zsb);
@@ -3885,6 +4006,9 @@ top:
tx = dmu_tx_create(zsb->z_os);
dmu_tx_hold_sa(tx, szp->z_sa_hdl, B_FALSE);
dmu_tx_hold_zap(tx, dzp->z_id, TRUE, name);
if (is_tmpfile)
dmu_tx_hold_zap(tx, zsb->z_unlinkedobj, FALSE, NULL);
zfs_sa_upgrade_txholds(tx, szp);
zfs_sa_upgrade_txholds(tx, dzp);
error = dmu_tx_assign(tx, waited ? TXG_WAITED : TXG_NOWAIT);
@@ -3900,23 +4024,43 @@ top:
ZFS_EXIT(zsb);
return (error);
}
/* unmark z_unlinked so zfs_link_create will not reject */
if (is_tmpfile)
szp->z_unlinked = 0;
error = zfs_link_create(dl, szp, tx, 0);
if (error == 0) {
uint64_t txtype = TX_LINK;
if (flags & FIGNORECASE)
txtype |= TX_CI;
zfs_log_link(zilog, tx, txtype, dzp, szp, name);
/*
* tmpfile is created to be in z_unlinkedobj, so remove it.
* Also, we don't log in ZIL, be cause all previous file
* operation on the tmpfile are ignored by ZIL. Instead we
* always wait for txg to sync to make sure all previous
* operation are sync safe.
*/
if (is_tmpfile) {
VERIFY(zap_remove_int(zsb->z_os, zsb->z_unlinkedobj,
szp->z_id, tx) == 0);
} else {
if (flags & FIGNORECASE)
txtype |= TX_CI;
zfs_log_link(zilog, tx, txtype, dzp, szp, name);
}
} else if (is_tmpfile) {
/* restore z_unlinked since when linking failed */
szp->z_unlinked = 1;
}
txg = dmu_tx_get_txg(tx);
dmu_tx_commit(tx);
zfs_dirent_unlock(dl);
if (zsb->z_os->os_sync == ZFS_SYNC_ALWAYS)
if (!is_tmpfile && zsb->z_os->os_sync == ZFS_SYNC_ALWAYS)
zil_commit(zilog, 0);
if (is_tmpfile)
txg_wait_synced(dmu_objset_pool(zsb->z_os), txg);
zfs_inode_update(dzp);
zfs_inode_update(szp);
ZFS_EXIT(zsb);
module/zfs/zfs_znode.c
+1 -1
View File
@@ -764,7 +764,7 @@ zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
links = 2;
} else {
size = 0;
links = 1;
links = (flag & IS_TMPFILE) ? 0 : 1;
}
if (S_ISBLK(vap->va_mode) || S_ISCHR(vap->va_mode))
module/zfs/zpl_inode.c
+42
View File
@@ -214,6 +214,45 @@ zpl_mknod(struct inode *dir, struct dentry *dentry, zpl_umode_t mode,
return (error);
}
#ifdef HAVE_TMPFILE
static int
zpl_tmpfile(struct inode *dir, struct dentry *dentry, zpl_umode_t mode)
{
cred_t *cr = CRED();
struct inode *ip;
vattr_t *vap;
int error;
fstrans_cookie_t cookie;
crhold(cr);
vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
zpl_vap_init(vap, dir, mode, cr);
cookie = spl_fstrans_mark();
error = -zfs_tmpfile(dir, vap, 0, mode, &ip, cr, 0, NULL);
if (error == 0) {
/* d_tmpfile will do drop_nlink, so we should set it first */
set_nlink(ip, 1);
d_tmpfile(dentry, ip);
error = zpl_xattr_security_init(ip, dir, &dentry->d_name);
if (error == 0)
error = zpl_init_acl(ip, dir);
/*
* don't need to handle error here, file is already in
* unlinked set.
*/
}
spl_fstrans_unmark(cookie);
kmem_free(vap, sizeof (vattr_t));
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
#endif
static int
zpl_unlink(struct inode *dir, struct dentry *dentry)
{
@@ -700,6 +739,9 @@ const struct inode_operations zpl_dir_inode_operations = {
.rename = zpl_rename2,
#else
.rename = zpl_rename,
#endif
#ifdef HAVE_TMPFILE
.tmpfile = zpl_tmpfile,
#endif
.setattr = zpl_setattr,
.getattr = zpl_getattr,