/*
* HAMMER2 inode locks
*
* HAMMER2 offers shared locks and exclusive locks on inodes.
*
* An inode's ip->chain pointer is resolved and stable while an inode is
* locked, and can be cleaned out at any time (become NULL) when an inode
* is not locked.
*
* This function handles duplication races and hardlink replacement races
* which can cause ip's cached chain to become stale.
*
* The underlying chain is also locked and returned.
*
* NOTE: We don't combine the inode/chain lock because putting away an
* inode would otherwise confuse multiple lock holders of the inode.
*/
hammer2_chain_t *
hammer2_inode_lock_ex(hammer2_inode_t *ip)
{
hammer2_chain_t *chain;
hammer2_chain_t *ochain;
hammer2_chain_core_t *core;
int error;
hammer2_inode_ref(ip);
ccms_thread_lock(&ip->topo_cst, CCMS_STATE_EXCLUSIVE);
chain = ip->chain;
core = chain->core;
for (;;) {
if (chain->flags & HAMMER2_CHAIN_DUPLICATED) {
spin_lock(&core->cst.spin);
while (chain->flags & HAMMER2_CHAIN_DUPLICATED)
chain = TAILQ_NEXT(chain, core_entry);
hammer2_chain_ref(chain);
spin_unlock(&core->cst.spin);
hammer2_inode_repoint(ip, NULL, chain);
hammer2_chain_drop(chain);
}
hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
if ((chain->flags & HAMMER2_CHAIN_DUPLICATED) == 0)
break;
hammer2_chain_unlock(chain);
}
if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK &&
(chain->flags & HAMMER2_CHAIN_DELETED) == 0) {
error = hammer2_hardlink_find(ip->pip, &chain, &ochain);
hammer2_chain_drop(ochain);
KKASSERT(error == 0);
/* XXX error handling */
}
return (chain);
}
/*
* Unlink the file from the specified directory inode. The directory inode
* does not need to be locked.
*
* isdir determines whether a directory/non-directory check should be made.
* No check is made if isdir is set to -1.
*
* NOTE! This function does not prevent the underlying file from still
* being used if it has other refs (such as from an inode, or if it's
* chain is manually held). However, the caller is responsible for
* fixing up ip->chain if e.g. a rename occurs (see chain_duplicate()).
*/
int
hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip,
const uint8_t *name, size_t name_len,
int isdir, int *hlinkp)
{
hammer2_inode_data_t *ipdata;
hammer2_chain_t *parent;
hammer2_chain_t *ochain;
hammer2_chain_t *chain;
hammer2_chain_t *dparent;
hammer2_chain_t *dchain;
hammer2_key_t lhc;
int error;
uint8_t type;
error = 0;
ochain = NULL;
lhc = hammer2_dirhash(name, name_len);
/*
* Search for the filename in the directory
*/
if (hlinkp)
*hlinkp = 0;
parent = hammer2_inode_lock_ex(dip);
chain = hammer2_chain_lookup(&parent,
lhc, lhc + HAMMER2_DIRHASH_LOMASK,
0);
while (chain) {
if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
name_len == chain->data->ipdata.name_len &&
bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
break;
}
chain = hammer2_chain_next(&parent, chain,
lhc, lhc + HAMMER2_DIRHASH_LOMASK,
0);
}
hammer2_inode_unlock_ex(dip, NULL); /* retain parent */
/*
* Not found or wrong type (isdir < 0 disables the type check).
* If a hardlink pointer, type checks use the hardlink target.
*/
if (chain == NULL) {
error = ENOENT;
goto done;
}
if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) {
if (hlinkp)
*hlinkp = 1;
type = chain->data->ipdata.target_type;
}
if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
error = ENOTDIR;
goto done;
}
if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir >= 1) {
error = EISDIR;
goto done;
}
/*
* Hardlink must be resolved. We can't hold parent locked while we
* do this or we could deadlock.
*
* On success chain will be adjusted to point at the hardlink target
* and ochain will point to the hardlink pointer in the original
* directory. Otherwise chain remains pointing to the original.
*/
if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
hammer2_chain_unlock(parent);
parent = NULL;
error = hammer2_hardlink_find(dip, &chain, &ochain);
}
/*
* If this is a directory the directory must be empty. However, if
* isdir < 0 we are doing a rename and the directory does not have
* to be empty, and if isdir > 1 we are deleting a PFS/snapshot
* and the directory does not have to be empty.
*
* NOTE: We check the full key range here which covers both visible
* and invisible entries. Theoretically there should be no
* invisible (hardlink target) entries if there are no visible
* entries.
*/
if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
dparent = hammer2_chain_lookup_init(chain, 0);
dchain = hammer2_chain_lookup(&dparent,
0, (hammer2_key_t)-1,
HAMMER2_LOOKUP_NODATA);
if (dchain) {
hammer2_chain_unlock(dchain);
hammer2_chain_lookup_done(dparent);
error = ENOTEMPTY;
goto done;
}
hammer2_chain_lookup_done(dparent);
dparent = NULL;
/* dchain NULL */
}
/*
* Ok, we can now unlink the chain. We always decrement nlinks even
* if the entry can be deleted in case someone has the file open and
* does an fstat().
*
* The chain itself will no longer be in the on-media topology but
* can still be flushed to the media (e.g. if an open descriptor
* remains). When the last vnode/ip ref goes away the chain will
* be marked unmodified, avoiding any further (now unnecesary) I/O.
*
* A non-NULL ochain indicates a hardlink.
*/
if (ochain) {
/*
* Delete the original hardlink pointer.
*
* NOTE: parent from above is NULL when ochain != NULL
* so we can reuse it.
*/
hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
hammer2_chain_delete(trans, ochain);
hammer2_chain_unlock(ochain);
/*
* Then decrement nlinks on hardlink target, deleting
* the target when nlinks drops to 0.
*/
hammer2_chain_modify(trans, &chain, 0);
--chain->data->ipdata.nlinks;
if (chain->data->ipdata.nlinks == 0)
hammer2_chain_delete(trans, chain);
} else {
/*
* Otherwise this was not a hardlink and we can just
* remove the entry and decrement nlinks.
*
* NOTE: *_get() integrates chain's lock into the inode lock.
*/
hammer2_chain_modify(trans, &chain, 0);
ipdata = &chain->data->ipdata;
--ipdata->nlinks;
hammer2_chain_delete(trans, chain);
}
error = 0;
done:
if (chain)
hammer2_chain_unlock(chain);
if (parent)
hammer2_chain_lookup_done(parent);
if (ochain)
hammer2_chain_drop(ochain);
return error;
}
/*
* Unlink the file from the specified directory inode. The directory inode
* does not need to be locked.
*
* isdir determines whether a directory/non-directory check should be made.
* No check is made if isdir is set to -1.
*
* isopen specifies whether special unlink-with-open-descriptor handling
* must be performed. If set to -1 the caller is deleting a PFS and we
* check whether the chain is mounted or not (chain->pmp != NULL). 1 is
* implied if it is mounted.
*
* If isopen is 1 and nlinks drops to 0 this function must move the chain
* to a special hidden directory until last-close occurs on the file.
*
* NOTE! The underlying file can still be active with open descriptors
* or if the chain is being manually held (e.g. for rename).
*
* The caller is responsible for fixing up ip->chain if e.g. a
* rename occurs (see chain_duplicate()).
*/
int
hammer2_unlink_file(hammer2_trans_t *trans, hammer2_inode_t *dip,
const uint8_t *name, size_t name_len,
int isdir, int *hlinkp, struct nchandle *nch)
{
hammer2_inode_data_t *ipdata;
hammer2_chain_t *parent;
hammer2_chain_t *ochain;
hammer2_chain_t *chain;
hammer2_chain_t *dparent;
hammer2_chain_t *dchain;
hammer2_key_t key_dummy;
hammer2_key_t key_next;
hammer2_key_t lhc;
int error;
int cache_index = -1;
uint8_t type;
error = 0;
ochain = NULL;
lhc = hammer2_dirhash(name, name_len);
/*
* Search for the filename in the directory
*/
if (hlinkp)
*hlinkp = 0;
parent = hammer2_inode_lock_ex(dip);
chain = hammer2_chain_lookup(&parent, &key_next,
lhc, lhc + HAMMER2_DIRHASH_LOMASK,
&cache_index, 0);
while (chain) {
if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
name_len == chain->data->ipdata.name_len &&
bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
break;
}
chain = hammer2_chain_next(&parent, chain, &key_next,
key_next,
lhc + HAMMER2_DIRHASH_LOMASK,
&cache_index, 0);
}
hammer2_inode_unlock_ex(dip, NULL); /* retain parent */
/*
* Not found or wrong type (isdir < 0 disables the type check).
* If a hardlink pointer, type checks use the hardlink target.
*/
if (chain == NULL) {
error = ENOENT;
goto done;
}
if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK) {
if (hlinkp)
*hlinkp = 1;
type = chain->data->ipdata.target_type;
}
if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
error = ENOTDIR;
goto done;
}
if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir >= 1) {
error = EISDIR;
goto done;
}
/*
* Hardlink must be resolved. We can't hold the parent locked
* while we do this or we could deadlock.
*
* On success chain will be adjusted to point at the hardlink target
* and ochain will point to the hardlink pointer in the original
* directory. Otherwise chain remains pointing to the original.
*/
if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
hammer2_chain_unlock(parent);
parent = NULL;
error = hammer2_hardlink_find(dip, &chain, &ochain);
}
/*
* If this is a directory the directory must be empty. However, if
* isdir < 0 we are doing a rename and the directory does not have
* to be empty, and if isdir > 1 we are deleting a PFS/snapshot
* and the directory does not have to be empty.
*
* NOTE: We check the full key range here which covers both visible
* and invisible entries. Theoretically there should be no
* invisible (hardlink target) entries if there are no visible
* entries.
*/
if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
dparent = hammer2_chain_lookup_init(chain, 0);
dchain = hammer2_chain_lookup(&dparent, &key_dummy,
0, (hammer2_key_t)-1,
&cache_index,
HAMMER2_LOOKUP_NODATA);
if (dchain) {
hammer2_chain_unlock(dchain);
hammer2_chain_lookup_done(dparent);
error = ENOTEMPTY;
goto done;
}
hammer2_chain_lookup_done(dparent);
dparent = NULL;
/* dchain NULL */
}
/*
* Ok, we can now unlink the chain. We always decrement nlinks even
* if the entry can be deleted in case someone has the file open and
* does an fstat().
*
* The chain itself will no longer be in the on-media topology but
* can still be flushed to the media (e.g. if an open descriptor
* remains). When the last vnode/ip ref goes away the chain will
* be marked unmodified, avoiding any further (now unnecesary) I/O.
*
* A non-NULL ochain indicates a hardlink.
*/
if (ochain) {
/*
* Delete the original hardlink pointer unconditionally.
* (any open descriptors will migrate to the hardlink
* target and have no affect on this operation).
*
* NOTE: parent from above is NULL when ochain != NULL
* so we can reuse it.
*/
hammer2_chain_lock(ochain, HAMMER2_RESOLVE_ALWAYS);
hammer2_chain_delete(trans, ochain, 0);
hammer2_chain_unlock(ochain);
}
/*
* Decrement nlinks on the hardlink target (or original file if
* there it was not hardlinked). Delete the target when nlinks
* reaches 0 with special handling if (isopen) is set.
*
* NOTE! In DragonFly the vnops function calls cache_unlink() after
* calling us here to clean out the namecache association,
* (which does not represent a ref for the open-test), and to
* force finalization of the vnode if/when the last ref gets
* dropped.
*
* NOTE! Files are unlinked by rename and then relinked. nch will be
* passed as NULL in this situation. hammer2_inode_connect()
* will bump nlinks.
*/
KKASSERT(chain != NULL);
hammer2_chain_modify(trans, &chain, 0);
ipdata = &chain->data->ipdata;
--ipdata->nlinks;
if ((int64_t)ipdata->nlinks < 0) /* XXX debugging */
ipdata->nlinks = 0;
if (ipdata->nlinks == 0) {
if ((chain->flags & HAMMER2_CHAIN_PFSROOT) && chain->pmp) {
error = EINVAL;
kprintf("hammer2: PFS \"%s\" cannot be deleted "
"while still mounted\n",
ipdata->filename);
goto done;
}
if (nch && cache_isopen(nch)) {
kprintf("WARNING: unlinking open file\n");
atomic_set_int(&chain->flags, HAMMER2_CHAIN_UNLINKED);
hammer2_inode_move_to_hidden(trans, &chain,
ipdata->inum);
} else {
hammer2_chain_delete(trans, chain, 0);
}
}
error = 0;
done:
if (chain)
hammer2_chain_unlock(chain);
if (parent)
hammer2_chain_lookup_done(parent);
if (ochain)
hammer2_chain_drop(ochain);
return error;
}
/*
* Unlink the file from the specified directory inode. The directory inode
* does not need to be locked.
*
* isdir determines whether a directory/non-directory check should be made.
* No check is made if isdir is set to -1.
*/
int
hammer2_unlink_file(hammer2_inode_t *dip,
const uint8_t *name, size_t name_len,
int isdir, hammer2_inode_t *retain_ip)
{
hammer2_mount_t *hmp;
hammer2_chain_t *parent;
hammer2_chain_t *chain;
hammer2_chain_t *dparent;
hammer2_chain_t *dchain;
hammer2_key_t lhc;
hammer2_inode_t *ip;
hammer2_inode_t *oip;
int error;
uint8_t type;
error = 0;
oip = NULL;
hmp = dip->hmp;
lhc = hammer2_dirhash(name, name_len);
/*
* Search for the filename in the directory
*/
parent = &dip->chain;
hammer2_chain_lock(hmp, parent, HAMMER2_RESOLVE_ALWAYS);
chain = hammer2_chain_lookup(hmp, &parent,
lhc, lhc + HAMMER2_DIRHASH_LOMASK,
0);
while (chain) {
if (chain->bref.type == HAMMER2_BREF_TYPE_INODE &&
chain->u.ip &&
name_len == chain->data->ipdata.name_len &&
bcmp(name, chain->data->ipdata.filename, name_len) == 0) {
break;
}
chain = hammer2_chain_next(hmp, &parent, chain,
lhc, lhc + HAMMER2_DIRHASH_LOMASK,
0);
}
/*
* Not found or wrong type (isdir < 0 disables the type check).
*/
if (chain == NULL) {
hammer2_chain_unlock(hmp, parent);
return ENOENT;
}
if ((type = chain->data->ipdata.type) == HAMMER2_OBJTYPE_HARDLINK)
type = chain->data->ipdata.target_type;
if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir == 0) {
error = ENOTDIR;
goto done;
}
if (type != HAMMER2_OBJTYPE_DIRECTORY && isdir == 1) {
error = EISDIR;
goto done;
}
/*
* Hardlink must be resolved. We can't hold parent locked while we
* do this or we could deadlock.
*/
if (chain->data->ipdata.type == HAMMER2_OBJTYPE_HARDLINK) {
hammer2_chain_unlock(hmp, parent);
parent = NULL;
error = hammer2_hardlink_find(dip, &chain, &oip);
}
/*
* If this is a directory the directory must be empty. However, if
* isdir < 0 we are doing a rename and the directory does not have
* to be empty.
*
* NOTE: We check the full key range here which covers both visible
* and invisible entries. Theoretically there should be no
* invisible (hardlink target) entries if there are no visible
* entries.
*/
if (type == HAMMER2_OBJTYPE_DIRECTORY && isdir >= 0) {
dparent = chain;
hammer2_chain_lock(hmp, dparent, HAMMER2_RESOLVE_ALWAYS);
dchain = hammer2_chain_lookup(hmp, &dparent,
0, (hammer2_key_t)-1,
HAMMER2_LOOKUP_NODATA);
if (dchain) {
hammer2_chain_unlock(hmp, dchain);
hammer2_chain_unlock(hmp, dparent);
error = ENOTEMPTY;
goto done;
}
hammer2_chain_unlock(hmp, dparent);
dparent = NULL;
/* dchain NULL */
}
/*
* Ok, we can now unlink the chain. We always decrement nlinks even
* if the entry can be deleted in case someone has the file open and
* does an fstat().
*
* The chain itself will no longer be in the on-media topology but
* can still be flushed to the media (e.g. if an open descriptor
* remains). When the last vnode/ip ref goes away the chain will
* be marked unmodified, avoiding any further (now unnecesary) I/O.
*/
if (oip) {
/*
* If this was a hardlink we first delete the hardlink
* pointer entry.
*/
parent = oip->chain.parent;
hammer2_chain_lock(hmp, parent, HAMMER2_RESOLVE_ALWAYS);
hammer2_chain_lock(hmp, &oip->chain, HAMMER2_RESOLVE_ALWAYS);
hammer2_chain_delete(hmp, parent, &oip->chain,
(retain_ip == oip));
hammer2_chain_unlock(hmp, &oip->chain);
hammer2_chain_unlock(hmp, parent);
parent = NULL;
/*
* Then decrement nlinks on hardlink target.
*/
ip = chain->u.ip;
if (ip->ip_data.nlinks == 1) {
dparent = chain->parent;
hammer2_chain_ref(hmp, chain);
hammer2_chain_unlock(hmp, chain);
hammer2_chain_lock(hmp, dparent,
HAMMER2_RESOLVE_ALWAYS);
hammer2_chain_lock(hmp, chain, HAMMER2_RESOLVE_ALWAYS);
hammer2_chain_drop(hmp, chain);
hammer2_chain_modify(hmp, chain, 0);
--ip->ip_data.nlinks;
hammer2_chain_delete(hmp, dparent, chain, 0);
hammer2_chain_unlock(hmp, dparent);
} else {
hammer2_chain_modify(hmp, chain, 0);
--ip->ip_data.nlinks;
}
} else {
/*
* Otherwise this was not a hardlink and we can just
* remove the entry and decrement nlinks.
*/
ip = chain->u.ip;
hammer2_chain_modify(hmp, chain, 0);
--ip->ip_data.nlinks;
hammer2_chain_delete(hmp, parent, chain,
(retain_ip == ip));
}
error = 0;
done:
if (chain)
hammer2_chain_unlock(hmp, chain);
if (parent)
hammer2_chain_unlock(hmp, parent);
if (oip)
hammer2_chain_drop(oip->hmp, &oip->chain);
return error;
}
