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OpenCloudOS-Kernel/fs/xfs/xfs_iget.c

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/*
* 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_dir.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_dir_sf.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, flags = KM_SLEEP | KM_MAYFAIL;
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));
}
while (!(mp->m_ihash = (xfs_ihash_t *)kmem_zalloc(mp->m_ihsize *
sizeof(xfs_ihash_t), flags))) {
if ((mp->m_ihsize >>= 1) <= NBPP)
flags = KM_SLEEP;
}
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);
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(
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;
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 (ip->i_flags & 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 (ip->i_flags & XFS_IRECLAIM) {
read_unlock(&ih->ih_lock);
delay(1);
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);
ip->i_flags &= ~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 = LINVFS_GET_IP(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 & IGET_CREATE))
return ENOENT;
xfs_iocore_inode_reinit(ip);
}
if (lock_flags != 0)
xfs_ilock(ip, lock_flags);
ip->i_flags &= ~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);
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 != 0) {
xfs_ilock(ip, lock_flags);
}
if ((ip->i_d.di_mode == 0) && !(flags & 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++;
ip->i_flags |= 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;
chlnew->chl_next = ch->ch_list;
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.
*/
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;
vnode_t *vp = NULL;
int error;
XFS_STATS_INC(xs_ig_attempts);
retry:
if ((inode = iget_locked(XFS_MTOVFS(mp)->vfs_super, ino))) {
bhv_desc_t *bdp;
xfs_inode_t *ip;
vp = LINVFS_GET_VP(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 mistmatches 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) ||
((bdp = vn_bhv_lookup(VN_BHV_HEAD(vp),
&xfs_vnodeops)) == NULL)) {
iput(inode);
delay(1);
goto retry;
}
ip = XFS_BHVTOI(bdp);
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,
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);
init_sema(&ip->i_flock, 1, "xfsfino", vp->v_number);
}
/*
* 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)
{
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)
{
vnode_t *vp = XFS_ITOV(ip);
struct inode *inode = LINVFS_GET_IP(vp);
vn_trace_entry(vp, "xfs_iput_new", (inst_t *)__return_address);
if ((ip->i_d.di_mode == 0)) {
ASSERT(!(ip->i_flags & 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)
{
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_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;
for (chl = ch->ch_list; chl != NULL; chl = chl->chl_next) {
if (chl->chl_blkno == ip->i_blkno) {
if (chm == NULL) {
/* first item on the list */
ch->ch_list = chl->chl_next;
} else {
chm->chl_next = chl->chl_next;
}
kmem_zone_free(xfs_chashlist_zone, chl);
break;
} else {
ASSERT(chl->chl_ip != ip);
chm = chl;
}
}
ASSERT_ALWAYS(chl != NULL);
} 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(valusema(&(ip->i_flock)) <= 0);
vsema(&(ip->i_flock));
}
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