diff options
Diffstat (limited to 'fs/xfs/xfs_iget.c')
| -rw-r--r-- | fs/xfs/xfs_iget.c | 1022 |
1 files changed, 1022 insertions, 0 deletions
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c new file mode 100644 index 00000000000..3a0ba1dfd0e --- /dev/null +++ b/fs/xfs/xfs_iget.c @@ -0,0 +1,1022 @@ +/* + * 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 version 2 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. + * + * Further, this software is distributed without any warranty that it is + * free of the rightful claim of any third person regarding infringement + * or the like. Any license provided herein, whether implied or + * otherwise, applies only to this software file. Patent licenses, if + * any, provided herein do not apply to combinations of this program with + * other software, or any other product whatsoever. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write the Free Software Foundation, Inc., 59 + * Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, + * Mountain View, CA 94043, or: + * + * http://www.sgi.com + * + * For further information regarding this notice, see: + * + * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/ + */ + +#include "xfs.h" + +#include "xfs_macros.h" +#include "xfs_types.h" +#include "xfs_inum.h" +#include "xfs_log.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_alloc_btree.h" +#include "xfs_bmap_btree.h" +#include "xfs_ialloc_btree.h" +#include "xfs_btree.h" +#include "xfs_ialloc.h" +#include "xfs_attr_sf.h" +#include "xfs_dir_sf.h" +#include "xfs_dir2_sf.h" +#include "xfs_dinode.h" +#include "xfs_inode.h" +#include "xfs_quota.h" +#include "xfs_utils.h" +#include "xfs_bit.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; +} + +/* + * 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; + read_unlock(&ih->ih_lock); + + 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); + } + + read_unlock(&ih->ih_lock); + + 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; + +retry: + XFS_STATS_INC(xs_ig_attempts); + + if ((inode = iget_locked(XFS_MTOVFS(mp)->vfs_super, ino))) { + bhv_desc_t *bdp; + xfs_inode_t *ip; + int newnode; + + vp = LINVFS_GET_VP(inode); + if (inode->i_state & I_NEW) { +inode_allocate: + 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 { + /* These are true if the inode is in inactive or + * reclaim. The linux inode is about to go away, + * wait for that path to finish, and try again. + */ + if (vp->v_flag & (VINACT | VRECLM)) { + vn_wait(vp); + iput(inode); + goto retry; + } + + if (is_bad_inode(inode)) { + iput(inode); + return EIO; + } + + bdp = vn_bhv_lookup(VN_BHV_HEAD(vp), &xfs_vnodeops); + if (bdp == NULL) { + XFS_STATS_INC(xs_ig_dup); + goto inode_allocate; + } + ip = XFS_BHVTOI(bdp); + if (lock_flags != 0) + xfs_ilock(ip, lock_flags); + newnode = (ip->i_d.di_mode == 0); + if (newnode) + xfs_iocore_inode_reinit(ip); + 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; + + 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. + * Otherwise break from the loop and return + * NULL. + */ + if (ip->i_transp == tp) { + read_unlock(&ih->ih_lock); + 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; + 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)); +} |