android_kernel_xiaomi_sm8350/fs/xfs/xfs_iget.c
David Chinner 4c60658e0f [XFS] Prevent a deadlock when xfslogd unpins inodes.
The previous fixes for the use after free in xfs_iunpin left a nasty log
deadlock when xfslogd unpinned the inode and dropped the last reference to
the inode. the ->clear_inode() method can issue transactions, and if the
log was full, the transaction could push on the log and get stuck trying
to push the inode it was currently unpinning.

To fix this, we provide xfs_iunpin a guarantee that it will always have a
valid xfs_inode <-> linux inode link or a particular flag will be set on
the inode. We then use log forces during lookup to ensure transactions are
completed before we recycle the inode. This ensures that xfs_iunpin will
never use the linux inode after it is being freed, and any lookup on an
inode on the reclaim list will wait until it is safe to attach a new linux
inode to the xfs inode.

SGI-PV: 956832
SGI-Modid: xfs-linux-melb:xfs-kern:27359a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Shailendra Tripathi <stripathi@agami.com>
Signed-off-by: Takenori Nagano <t-nagano@ah.jp.nec.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
2006-11-11 18:05:00 +11:00

1062 lines
27 KiB
C

/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_quota.h"
#include "xfs_utils.h"
/*
* Initialize the inode hash table for the newly mounted file system.
* Choose an initial table size based on user specified value, else
* use a simple algorithm using the maximum number of inodes as an
* indicator for table size, and clamp it between one and some large
* number of pages.
*/
void
xfs_ihash_init(xfs_mount_t *mp)
{
__uint64_t icount;
uint i;
if (!mp->m_ihsize) {
icount = mp->m_maxicount ? mp->m_maxicount :
(mp->m_sb.sb_dblocks << mp->m_sb.sb_inopblog);
mp->m_ihsize = 1 << max_t(uint, 8,
(xfs_highbit64(icount) + 1) / 2);
mp->m_ihsize = min_t(uint, mp->m_ihsize,
(64 * NBPP) / sizeof(xfs_ihash_t));
}
mp->m_ihash = kmem_zalloc_greedy(&mp->m_ihsize,
NBPC * sizeof(xfs_ihash_t),
mp->m_ihsize * sizeof(xfs_ihash_t),
KM_SLEEP | KM_MAYFAIL | KM_LARGE);
mp->m_ihsize /= sizeof(xfs_ihash_t);
for (i = 0; i < mp->m_ihsize; i++)
rwlock_init(&(mp->m_ihash[i].ih_lock));
}
/*
* Free up structures allocated by xfs_ihash_init, at unmount time.
*/
void
xfs_ihash_free(xfs_mount_t *mp)
{
kmem_free(mp->m_ihash, mp->m_ihsize * sizeof(xfs_ihash_t));
mp->m_ihash = NULL;
}
/*
* Initialize the inode cluster hash table for the newly mounted file system.
* Its size is derived from the ihash table size.
*/
void
xfs_chash_init(xfs_mount_t *mp)
{
uint i;
mp->m_chsize = max_t(uint, 1, mp->m_ihsize /
(XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog));
mp->m_chsize = min_t(uint, mp->m_chsize, mp->m_ihsize);
mp->m_chash = (xfs_chash_t *)kmem_zalloc(mp->m_chsize
* sizeof(xfs_chash_t),
KM_SLEEP | KM_LARGE);
for (i = 0; i < mp->m_chsize; i++) {
spinlock_init(&mp->m_chash[i].ch_lock,"xfshash");
}
}
/*
* Free up structures allocated by xfs_chash_init, at unmount time.
*/
void
xfs_chash_free(xfs_mount_t *mp)
{
int i;
for (i = 0; i < mp->m_chsize; i++) {
spinlock_destroy(&mp->m_chash[i].ch_lock);
}
kmem_free(mp->m_chash, mp->m_chsize*sizeof(xfs_chash_t));
mp->m_chash = NULL;
}
/*
* Try to move an inode to the front of its hash list if possible
* (and if its not there already). Called right after obtaining
* the list version number and then dropping the read_lock on the
* hash list in question (which is done right after looking up the
* inode in question...).
*/
STATIC void
xfs_ihash_promote(
xfs_ihash_t *ih,
xfs_inode_t *ip,
ulong version)
{
xfs_inode_t *iq;
if ((ip->i_prevp != &ih->ih_next) && write_trylock(&ih->ih_lock)) {
if (likely(version == ih->ih_version)) {
/* remove from list */
if ((iq = ip->i_next)) {
iq->i_prevp = ip->i_prevp;
}
*ip->i_prevp = iq;
/* insert at list head */
iq = ih->ih_next;
iq->i_prevp = &ip->i_next;
ip->i_next = iq;
ip->i_prevp = &ih->ih_next;
ih->ih_next = ip;
}
write_unlock(&ih->ih_lock);
}
}
/*
* Look up an inode by number in the given file system.
* The inode is looked up in the hash table for the file system
* represented by the mount point parameter mp. Each bucket of
* the hash table is guarded by an individual semaphore.
*
* If the inode is found in the hash table, its corresponding vnode
* is obtained with a call to vn_get(). This call takes care of
* coordination with the reclamation of the inode and vnode. Note
* that the vmap structure is filled in while holding the hash lock.
* This gives us the state of the inode/vnode when we found it and
* is used for coordination in vn_get().
*
* If it is not in core, read it in from the file system's device and
* add the inode into the hash table.
*
* The inode is locked according to the value of the lock_flags parameter.
* This flag parameter indicates how and if the inode's IO lock and inode lock
* should be taken.
*
* mp -- the mount point structure for the current file system. It points
* to the inode hash table.
* tp -- a pointer to the current transaction if there is one. This is
* simply passed through to the xfs_iread() call.
* ino -- the number of the inode desired. This is the unique identifier
* within the file system for the inode being requested.
* lock_flags -- flags indicating how to lock the inode. See the comment
* for xfs_ilock() for a list of valid values.
* bno -- the block number starting the buffer containing the inode,
* if known (as by bulkstat), else 0.
*/
STATIC int
xfs_iget_core(
bhv_vnode_t *vp,
xfs_mount_t *mp,
xfs_trans_t *tp,
xfs_ino_t ino,
uint flags,
uint lock_flags,
xfs_inode_t **ipp,
xfs_daddr_t bno)
{
xfs_ihash_t *ih;
xfs_inode_t *ip;
xfs_inode_t *iq;
bhv_vnode_t *inode_vp;
ulong version;
int error;
/* REFERENCED */
xfs_chash_t *ch;
xfs_chashlist_t *chl, *chlnew;
SPLDECL(s);
ih = XFS_IHASH(mp, ino);
again:
read_lock(&ih->ih_lock);
for (ip = ih->ih_next; ip != NULL; ip = ip->i_next) {
if (ip->i_ino == ino) {
/*
* If INEW is set this inode is being set up
* we need to pause and try again.
*/
if (xfs_iflags_test(ip, XFS_INEW)) {
read_unlock(&ih->ih_lock);
delay(1);
XFS_STATS_INC(xs_ig_frecycle);
goto again;
}
inode_vp = XFS_ITOV_NULL(ip);
if (inode_vp == NULL) {
/*
* If IRECLAIM is set this inode is
* on its way out of the system,
* we need to pause and try again.
*/
if (xfs_iflags_test(ip, XFS_IRECLAIM)) {
read_unlock(&ih->ih_lock);
delay(1);
XFS_STATS_INC(xs_ig_frecycle);
goto again;
}
ASSERT(xfs_iflags_test(ip, XFS_IRECLAIMABLE));
/*
* If lookup is racing with unlink, then we
* should return an error immediately so we
* don't remove it from the reclaim list and
* potentially leak the inode.
*/
if ((ip->i_d.di_mode == 0) &&
!(flags & XFS_IGET_CREATE)) {
read_unlock(&ih->ih_lock);
return ENOENT;
}
/*
* There may be transactions sitting in the
* incore log buffers or being flushed to disk
* at this time. We can't clear the
* XFS_IRECLAIMABLE flag until these
* transactions have hit the disk, otherwise we
* will void the guarantee the flag provides
* xfs_iunpin()
*/
if (xfs_ipincount(ip)) {
read_unlock(&ih->ih_lock);
xfs_log_force(mp, 0,
XFS_LOG_FORCE|XFS_LOG_SYNC);
XFS_STATS_INC(xs_ig_frecycle);
goto again;
}
vn_trace_exit(vp, "xfs_iget.alloc",
(inst_t *)__return_address);
XFS_STATS_INC(xs_ig_found);
xfs_iflags_clear(ip, XFS_IRECLAIMABLE);
version = ih->ih_version;
read_unlock(&ih->ih_lock);
xfs_ihash_promote(ih, ip, version);
XFS_MOUNT_ILOCK(mp);
list_del_init(&ip->i_reclaim);
XFS_MOUNT_IUNLOCK(mp);
goto finish_inode;
} else if (vp != inode_vp) {
struct inode *inode = vn_to_inode(inode_vp);
/* The inode is being torn down, pause and
* try again.
*/
if (inode->i_state & (I_FREEING | I_CLEAR)) {
read_unlock(&ih->ih_lock);
delay(1);
XFS_STATS_INC(xs_ig_frecycle);
goto again;
}
/* Chances are the other vnode (the one in the inode) is being torn
* down right now, and we landed on top of it. Question is, what do
* we do? Unhook the old inode and hook up the new one?
*/
cmn_err(CE_PANIC,
"xfs_iget_core: ambiguous vns: vp/0x%p, invp/0x%p",
inode_vp, vp);
}
/*
* Inode cache hit: if ip is not at the front of
* its hash chain, move it there now.
* Do this with the lock held for update, but
* do statistics after releasing the lock.
*/
version = ih->ih_version;
read_unlock(&ih->ih_lock);
xfs_ihash_promote(ih, ip, version);
XFS_STATS_INC(xs_ig_found);
finish_inode:
if (ip->i_d.di_mode == 0) {
if (!(flags & XFS_IGET_CREATE))
return ENOENT;
xfs_iocore_inode_reinit(ip);
}
if (lock_flags != 0)
xfs_ilock(ip, lock_flags);
xfs_iflags_clear(ip, XFS_ISTALE);
vn_trace_exit(vp, "xfs_iget.found",
(inst_t *)__return_address);
goto return_ip;
}
}
/*
* Inode cache miss: save the hash chain version stamp and unlock
* the chain, so we don't deadlock in vn_alloc.
*/
XFS_STATS_INC(xs_ig_missed);
version = ih->ih_version;
read_unlock(&ih->ih_lock);
/*
* Read the disk inode attributes into a new inode structure and get
* a new vnode for it. This should also initialize i_ino and i_mount.
*/
error = xfs_iread(mp, tp, ino, &ip, bno,
(flags & XFS_IGET_BULKSTAT) ? XFS_IMAP_BULKSTAT : 0);
if (error)
return error;
vn_trace_exit(vp, "xfs_iget.alloc", (inst_t *)__return_address);
xfs_inode_lock_init(ip, vp);
xfs_iocore_inode_init(ip);
if (lock_flags)
xfs_ilock(ip, lock_flags);
if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
xfs_idestroy(ip);
return ENOENT;
}
/*
* Put ip on its hash chain, unless someone else hashed a duplicate
* after we released the hash lock.
*/
write_lock(&ih->ih_lock);
if (ih->ih_version != version) {
for (iq = ih->ih_next; iq != NULL; iq = iq->i_next) {
if (iq->i_ino == ino) {
write_unlock(&ih->ih_lock);
xfs_idestroy(ip);
XFS_STATS_INC(xs_ig_dup);
goto again;
}
}
}
/*
* These values _must_ be set before releasing ihlock!
*/
ip->i_hash = ih;
if ((iq = ih->ih_next)) {
iq->i_prevp = &ip->i_next;
}
ip->i_next = iq;
ip->i_prevp = &ih->ih_next;
ih->ih_next = ip;
ip->i_udquot = ip->i_gdquot = NULL;
ih->ih_version++;
xfs_iflags_set(ip, XFS_INEW);
write_unlock(&ih->ih_lock);
/*
* put ip on its cluster's hash chain
*/
ASSERT(ip->i_chash == NULL && ip->i_cprev == NULL &&
ip->i_cnext == NULL);
chlnew = NULL;
ch = XFS_CHASH(mp, ip->i_blkno);
chlredo:
s = mutex_spinlock(&ch->ch_lock);
for (chl = ch->ch_list; chl != NULL; chl = chl->chl_next) {
if (chl->chl_blkno == ip->i_blkno) {
/* insert this inode into the doubly-linked list
* where chl points */
if ((iq = chl->chl_ip)) {
ip->i_cprev = iq->i_cprev;
iq->i_cprev->i_cnext = ip;
iq->i_cprev = ip;
ip->i_cnext = iq;
} else {
ip->i_cnext = ip;
ip->i_cprev = ip;
}
chl->chl_ip = ip;
ip->i_chash = chl;
break;
}
}
/* no hash list found for this block; add a new hash list */
if (chl == NULL) {
if (chlnew == NULL) {
mutex_spinunlock(&ch->ch_lock, s);
ASSERT(xfs_chashlist_zone != NULL);
chlnew = (xfs_chashlist_t *)
kmem_zone_alloc(xfs_chashlist_zone,
KM_SLEEP);
ASSERT(chlnew != NULL);
goto chlredo;
} else {
ip->i_cnext = ip;
ip->i_cprev = ip;
ip->i_chash = chlnew;
chlnew->chl_ip = ip;
chlnew->chl_blkno = ip->i_blkno;
if (ch->ch_list)
ch->ch_list->chl_prev = chlnew;
chlnew->chl_next = ch->ch_list;
chlnew->chl_prev = NULL;
ch->ch_list = chlnew;
chlnew = NULL;
}
} else {
if (chlnew != NULL) {
kmem_zone_free(xfs_chashlist_zone, chlnew);
}
}
mutex_spinunlock(&ch->ch_lock, s);
/*
* Link ip to its mount and thread it on the mount's inode list.
*/
XFS_MOUNT_ILOCK(mp);
if ((iq = mp->m_inodes)) {
ASSERT(iq->i_mprev->i_mnext == iq);
ip->i_mprev = iq->i_mprev;
iq->i_mprev->i_mnext = ip;
iq->i_mprev = ip;
ip->i_mnext = iq;
} else {
ip->i_mnext = ip;
ip->i_mprev = ip;
}
mp->m_inodes = ip;
XFS_MOUNT_IUNLOCK(mp);
return_ip:
ASSERT(ip->i_df.if_ext_max ==
XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t));
ASSERT(((ip->i_d.di_flags & XFS_DIFLAG_REALTIME) != 0) ==
((ip->i_iocore.io_flags & XFS_IOCORE_RT) != 0));
*ipp = ip;
/*
* If we have a real type for an on-disk inode, we can set ops(&unlock)
* now. If it's a new inode being created, xfs_ialloc will handle it.
*/
bhv_vfs_init_vnode(XFS_MTOVFS(mp), vp, XFS_ITOBHV(ip), 1);
return 0;
}
/*
* The 'normal' internal xfs_iget, if needed it will
* 'allocate', or 'get', the vnode.
*/
int
xfs_iget(
xfs_mount_t *mp,
xfs_trans_t *tp,
xfs_ino_t ino,
uint flags,
uint lock_flags,
xfs_inode_t **ipp,
xfs_daddr_t bno)
{
struct inode *inode;
bhv_vnode_t *vp = NULL;
int error;
XFS_STATS_INC(xs_ig_attempts);
retry:
if ((inode = iget_locked(XFS_MTOVFS(mp)->vfs_super, ino))) {
xfs_inode_t *ip;
vp = vn_from_inode(inode);
if (inode->i_state & I_NEW) {
vn_initialize(inode);
error = xfs_iget_core(vp, mp, tp, ino, flags,
lock_flags, ipp, bno);
if (error) {
vn_mark_bad(vp);
if (inode->i_state & I_NEW)
unlock_new_inode(inode);
iput(inode);
}
} else {
/*
* If the inode is not fully constructed due to
* filehandle mismatches wait for the inode to go
* away and try again.
*
* iget_locked will call __wait_on_freeing_inode
* to wait for the inode to go away.
*/
if (is_bad_inode(inode) ||
((ip = xfs_vtoi(vp)) == NULL)) {
iput(inode);
delay(1);
goto retry;
}
if (lock_flags != 0)
xfs_ilock(ip, lock_flags);
XFS_STATS_INC(xs_ig_found);
*ipp = ip;
error = 0;
}
} else
error = ENOMEM; /* If we got no inode we are out of memory */
return error;
}
/*
* Do the setup for the various locks within the incore inode.
*/
void
xfs_inode_lock_init(
xfs_inode_t *ip,
bhv_vnode_t *vp)
{
mrlock_init(&ip->i_lock, MRLOCK_ALLOW_EQUAL_PRI|MRLOCK_BARRIER,
"xfsino", (long)vp->v_number);
mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", vp->v_number);
init_waitqueue_head(&ip->i_ipin_wait);
atomic_set(&ip->i_pincount, 0);
initnsema(&ip->i_flock, 1, "xfsfino");
}
/*
* Look for the inode corresponding to the given ino in the hash table.
* If it is there and its i_transp pointer matches tp, return it.
* Otherwise, return NULL.
*/
xfs_inode_t *
xfs_inode_incore(xfs_mount_t *mp,
xfs_ino_t ino,
xfs_trans_t *tp)
{
xfs_ihash_t *ih;
xfs_inode_t *ip;
ulong version;
ih = XFS_IHASH(mp, ino);
read_lock(&ih->ih_lock);
for (ip = ih->ih_next; ip != NULL; ip = ip->i_next) {
if (ip->i_ino == ino) {
/*
* If we find it and tp matches, return it.
* Also move it to the front of the hash list
* if we find it and it is not already there.
* Otherwise break from the loop and return
* NULL.
*/
if (ip->i_transp == tp) {
version = ih->ih_version;
read_unlock(&ih->ih_lock);
xfs_ihash_promote(ih, ip, version);
return (ip);
}
break;
}
}
read_unlock(&ih->ih_lock);
return (NULL);
}
/*
* Decrement reference count of an inode structure and unlock it.
*
* ip -- the inode being released
* lock_flags -- this parameter indicates the inode's locks to be
* to be released. See the comment on xfs_iunlock() for a list
* of valid values.
*/
void
xfs_iput(xfs_inode_t *ip,
uint lock_flags)
{
bhv_vnode_t *vp = XFS_ITOV(ip);
vn_trace_entry(vp, "xfs_iput", (inst_t *)__return_address);
xfs_iunlock(ip, lock_flags);
VN_RELE(vp);
}
/*
* Special iput for brand-new inodes that are still locked
*/
void
xfs_iput_new(xfs_inode_t *ip,
uint lock_flags)
{
bhv_vnode_t *vp = XFS_ITOV(ip);
struct inode *inode = vn_to_inode(vp);
vn_trace_entry(vp, "xfs_iput_new", (inst_t *)__return_address);
if ((ip->i_d.di_mode == 0)) {
ASSERT(!xfs_iflags_test(ip, XFS_IRECLAIMABLE));
vn_mark_bad(vp);
}
if (inode->i_state & I_NEW)
unlock_new_inode(inode);
if (lock_flags)
xfs_iunlock(ip, lock_flags);
VN_RELE(vp);
}
/*
* This routine embodies the part of the reclaim code that pulls
* the inode from the inode hash table and the mount structure's
* inode list.
* This should only be called from xfs_reclaim().
*/
void
xfs_ireclaim(xfs_inode_t *ip)
{
bhv_vnode_t *vp;
/*
* Remove from old hash list and mount list.
*/
XFS_STATS_INC(xs_ig_reclaims);
xfs_iextract(ip);
/*
* Here we do a spurious inode lock in order to coordinate with
* xfs_sync(). This is because xfs_sync() references the inodes
* in the mount list without taking references on the corresponding
* vnodes. We make that OK here by ensuring that we wait until
* the inode is unlocked in xfs_sync() before we go ahead and
* free it. We get both the regular lock and the io lock because
* the xfs_sync() code may need to drop the regular one but will
* still hold the io lock.
*/
xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
/*
* Release dquots (and their references) if any. An inode may escape
* xfs_inactive and get here via vn_alloc->vn_reclaim path.
*/
XFS_QM_DQDETACH(ip->i_mount, ip);
/*
* Pull our behavior descriptor from the vnode chain.
*/
vp = XFS_ITOV_NULL(ip);
if (vp) {
vn_bhv_remove(VN_BHV_HEAD(vp), XFS_ITOBHV(ip));
}
/*
* Free all memory associated with the inode.
*/
xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
xfs_idestroy(ip);
}
/*
* This routine removes an about-to-be-destroyed inode from
* all of the lists in which it is located with the exception
* of the behavior chain.
*/
void
xfs_iextract(
xfs_inode_t *ip)
{
xfs_ihash_t *ih;
xfs_inode_t *iq;
xfs_mount_t *mp;
xfs_chash_t *ch;
xfs_chashlist_t *chl, *chm;
SPLDECL(s);
ih = ip->i_hash;
write_lock(&ih->ih_lock);
if ((iq = ip->i_next)) {
iq->i_prevp = ip->i_prevp;
}
*ip->i_prevp = iq;
ih->ih_version++;
write_unlock(&ih->ih_lock);
/*
* Remove from cluster hash list
* 1) delete the chashlist if this is the last inode on the chashlist
* 2) unchain from list of inodes
* 3) point chashlist->chl_ip to 'chl_next' if to this inode.
*/
mp = ip->i_mount;
ch = XFS_CHASH(mp, ip->i_blkno);
s = mutex_spinlock(&ch->ch_lock);
if (ip->i_cnext == ip) {
/* Last inode on chashlist */
ASSERT(ip->i_cnext == ip && ip->i_cprev == ip);
ASSERT(ip->i_chash != NULL);
chm=NULL;
chl = ip->i_chash;
if (chl->chl_prev)
chl->chl_prev->chl_next = chl->chl_next;
else
ch->ch_list = chl->chl_next;
if (chl->chl_next)
chl->chl_next->chl_prev = chl->chl_prev;
kmem_zone_free(xfs_chashlist_zone, chl);
} else {
/* delete one inode from a non-empty list */
iq = ip->i_cnext;
iq->i_cprev = ip->i_cprev;
ip->i_cprev->i_cnext = iq;
if (ip->i_chash->chl_ip == ip) {
ip->i_chash->chl_ip = iq;
}
ip->i_chash = __return_address;
ip->i_cprev = __return_address;
ip->i_cnext = __return_address;
}
mutex_spinunlock(&ch->ch_lock, s);
/*
* Remove from mount's inode list.
*/
XFS_MOUNT_ILOCK(mp);
ASSERT((ip->i_mnext != NULL) && (ip->i_mprev != NULL));
iq = ip->i_mnext;
iq->i_mprev = ip->i_mprev;
ip->i_mprev->i_mnext = iq;
/*
* Fix up the head pointer if it points to the inode being deleted.
*/
if (mp->m_inodes == ip) {
if (ip == iq) {
mp->m_inodes = NULL;
} else {
mp->m_inodes = iq;
}
}
/* Deal with the deleted inodes list */
list_del_init(&ip->i_reclaim);
mp->m_ireclaims++;
XFS_MOUNT_IUNLOCK(mp);
}
/*
* This is a wrapper routine around the xfs_ilock() routine
* used to centralize some grungy code. It is used in places
* that wish to lock the inode solely for reading the extents.
* The reason these places can't just call xfs_ilock(SHARED)
* is that the inode lock also guards to bringing in of the
* extents from disk for a file in b-tree format. If the inode
* is in b-tree format, then we need to lock the inode exclusively
* until the extents are read in. Locking it exclusively all
* the time would limit our parallelism unnecessarily, though.
* What we do instead is check to see if the extents have been
* read in yet, and only lock the inode exclusively if they
* have not.
*
* The function returns a value which should be given to the
* corresponding xfs_iunlock_map_shared(). This value is
* the mode in which the lock was actually taken.
*/
uint
xfs_ilock_map_shared(
xfs_inode_t *ip)
{
uint lock_mode;
if ((ip->i_d.di_format == XFS_DINODE_FMT_BTREE) &&
((ip->i_df.if_flags & XFS_IFEXTENTS) == 0)) {
lock_mode = XFS_ILOCK_EXCL;
} else {
lock_mode = XFS_ILOCK_SHARED;
}
xfs_ilock(ip, lock_mode);
return lock_mode;
}
/*
* This is simply the unlock routine to go with xfs_ilock_map_shared().
* All it does is call xfs_iunlock() with the given lock_mode.
*/
void
xfs_iunlock_map_shared(
xfs_inode_t *ip,
unsigned int lock_mode)
{
xfs_iunlock(ip, lock_mode);
}
/*
* The xfs inode contains 2 locks: a multi-reader lock called the
* i_iolock and a multi-reader lock called the i_lock. This routine
* allows either or both of the locks to be obtained.
*
* The 2 locks should always be ordered so that the IO lock is
* obtained first in order to prevent deadlock.
*
* ip -- the inode being locked
* lock_flags -- this parameter indicates the inode's locks
* to be locked. It can be:
* XFS_IOLOCK_SHARED,
* XFS_IOLOCK_EXCL,
* XFS_ILOCK_SHARED,
* XFS_ILOCK_EXCL,
* XFS_IOLOCK_SHARED | XFS_ILOCK_SHARED,
* XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL,
* XFS_IOLOCK_EXCL | XFS_ILOCK_SHARED,
* XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL
*/
void
xfs_ilock(xfs_inode_t *ip,
uint lock_flags)
{
/*
* You can't set both SHARED and EXCL for the same lock,
* and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
* and XFS_ILOCK_EXCL are valid values to set in lock_flags.
*/
ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
(XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
ASSERT((lock_flags & ~XFS_LOCK_MASK) == 0);
if (lock_flags & XFS_IOLOCK_EXCL) {
mrupdate(&ip->i_iolock);
} else if (lock_flags & XFS_IOLOCK_SHARED) {
mraccess(&ip->i_iolock);
}
if (lock_flags & XFS_ILOCK_EXCL) {
mrupdate(&ip->i_lock);
} else if (lock_flags & XFS_ILOCK_SHARED) {
mraccess(&ip->i_lock);
}
xfs_ilock_trace(ip, 1, lock_flags, (inst_t *)__return_address);
}
/*
* This is just like xfs_ilock(), except that the caller
* is guaranteed not to sleep. It returns 1 if it gets
* the requested locks and 0 otherwise. If the IO lock is
* obtained but the inode lock cannot be, then the IO lock
* is dropped before returning.
*
* ip -- the inode being locked
* lock_flags -- this parameter indicates the inode's locks to be
* to be locked. See the comment for xfs_ilock() for a list
* of valid values.
*
*/
int
xfs_ilock_nowait(xfs_inode_t *ip,
uint lock_flags)
{
int iolocked;
int ilocked;
/*
* You can't set both SHARED and EXCL for the same lock,
* and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
* and XFS_ILOCK_EXCL are valid values to set in lock_flags.
*/
ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
(XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
ASSERT((lock_flags & ~XFS_LOCK_MASK) == 0);
iolocked = 0;
if (lock_flags & XFS_IOLOCK_EXCL) {
iolocked = mrtryupdate(&ip->i_iolock);
if (!iolocked) {
return 0;
}
} else if (lock_flags & XFS_IOLOCK_SHARED) {
iolocked = mrtryaccess(&ip->i_iolock);
if (!iolocked) {
return 0;
}
}
if (lock_flags & XFS_ILOCK_EXCL) {
ilocked = mrtryupdate(&ip->i_lock);
if (!ilocked) {
if (iolocked) {
mrunlock(&ip->i_iolock);
}
return 0;
}
} else if (lock_flags & XFS_ILOCK_SHARED) {
ilocked = mrtryaccess(&ip->i_lock);
if (!ilocked) {
if (iolocked) {
mrunlock(&ip->i_iolock);
}
return 0;
}
}
xfs_ilock_trace(ip, 2, lock_flags, (inst_t *)__return_address);
return 1;
}
/*
* xfs_iunlock() is used to drop the inode locks acquired with
* xfs_ilock() and xfs_ilock_nowait(). The caller must pass
* in the flags given to xfs_ilock() or xfs_ilock_nowait() so
* that we know which locks to drop.
*
* ip -- the inode being unlocked
* lock_flags -- this parameter indicates the inode's locks to be
* to be unlocked. See the comment for xfs_ilock() for a list
* of valid values for this parameter.
*
*/
void
xfs_iunlock(xfs_inode_t *ip,
uint lock_flags)
{
/*
* You can't set both SHARED and EXCL for the same lock,
* and only XFS_IOLOCK_SHARED, XFS_IOLOCK_EXCL, XFS_ILOCK_SHARED,
* and XFS_ILOCK_EXCL are valid values to set in lock_flags.
*/
ASSERT((lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) !=
(XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL));
ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_IUNLOCK_NONOTIFY)) == 0);
ASSERT(lock_flags != 0);
if (lock_flags & (XFS_IOLOCK_SHARED | XFS_IOLOCK_EXCL)) {
ASSERT(!(lock_flags & XFS_IOLOCK_SHARED) ||
(ismrlocked(&ip->i_iolock, MR_ACCESS)));
ASSERT(!(lock_flags & XFS_IOLOCK_EXCL) ||
(ismrlocked(&ip->i_iolock, MR_UPDATE)));
mrunlock(&ip->i_iolock);
}
if (lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) {
ASSERT(!(lock_flags & XFS_ILOCK_SHARED) ||
(ismrlocked(&ip->i_lock, MR_ACCESS)));
ASSERT(!(lock_flags & XFS_ILOCK_EXCL) ||
(ismrlocked(&ip->i_lock, MR_UPDATE)));
mrunlock(&ip->i_lock);
/*
* Let the AIL know that this item has been unlocked in case
* it is in the AIL and anyone is waiting on it. Don't do
* this if the caller has asked us not to.
*/
if (!(lock_flags & XFS_IUNLOCK_NONOTIFY) &&
ip->i_itemp != NULL) {
xfs_trans_unlocked_item(ip->i_mount,
(xfs_log_item_t*)(ip->i_itemp));
}
}
xfs_ilock_trace(ip, 3, lock_flags, (inst_t *)__return_address);
}
/*
* give up write locks. the i/o lock cannot be held nested
* if it is being demoted.
*/
void
xfs_ilock_demote(xfs_inode_t *ip,
uint lock_flags)
{
ASSERT(lock_flags & (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL));
ASSERT((lock_flags & ~(XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)) == 0);
if (lock_flags & XFS_ILOCK_EXCL) {
ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE));
mrdemote(&ip->i_lock);
}
if (lock_flags & XFS_IOLOCK_EXCL) {
ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE));
mrdemote(&ip->i_iolock);
}
}
/*
* The following three routines simply manage the i_flock
* semaphore embedded in the inode. This semaphore synchronizes
* processes attempting to flush the in-core inode back to disk.
*/
void
xfs_iflock(xfs_inode_t *ip)
{
psema(&(ip->i_flock), PINOD|PLTWAIT);
}
int
xfs_iflock_nowait(xfs_inode_t *ip)
{
return (cpsema(&(ip->i_flock)));
}
void
xfs_ifunlock(xfs_inode_t *ip)
{
ASSERT(issemalocked(&(ip->i_flock)));
vsema(&(ip->i_flock));
}