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3ba3160374
Note xfs_iget can be called while holding a locked agi buffer. If it goes into memory reclaim then inode teardown may try to lock the same buffer. Prevent the deadlock by calling radix_tree_preload with GFP_NOFS. Signed-off-by: Peter Watkins <treestem@gmail.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Ben Myers <bpm@sgi.com>
721 lines
19 KiB
C
721 lines
19 KiB
C
/*
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* Copyright (c) 2000-2005 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_types.h"
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#include "xfs_acl.h"
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#include "xfs_log.h"
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#include "xfs_inum.h"
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#include "xfs_trans.h"
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#include "xfs_sb.h"
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#include "xfs_ag.h"
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#include "xfs_mount.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_alloc_btree.h"
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#include "xfs_ialloc_btree.h"
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#include "xfs_dinode.h"
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#include "xfs_inode.h"
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#include "xfs_btree.h"
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#include "xfs_ialloc.h"
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#include "xfs_quota.h"
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#include "xfs_utils.h"
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#include "xfs_trans_priv.h"
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#include "xfs_inode_item.h"
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#include "xfs_bmap.h"
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#include "xfs_trace.h"
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/*
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* Define xfs inode iolock lockdep classes. We need to ensure that all active
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* inodes are considered the same for lockdep purposes, including inodes that
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* are recycled through the XFS_IRECLAIMABLE state. This is the the only way to
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* guarantee the locks are considered the same when there are multiple lock
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* initialisation siteѕ. Also, define a reclaimable inode class so it is
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* obvious in lockdep reports which class the report is against.
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*/
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static struct lock_class_key xfs_iolock_active;
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struct lock_class_key xfs_iolock_reclaimable;
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/*
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* Allocate and initialise an xfs_inode.
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*/
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STATIC struct xfs_inode *
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xfs_inode_alloc(
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struct xfs_mount *mp,
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xfs_ino_t ino)
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{
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struct xfs_inode *ip;
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/*
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* if this didn't occur in transactions, we could use
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* KM_MAYFAIL and return NULL here on ENOMEM. Set the
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* code up to do this anyway.
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*/
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ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP);
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if (!ip)
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return NULL;
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if (inode_init_always(mp->m_super, VFS_I(ip))) {
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kmem_zone_free(xfs_inode_zone, ip);
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return NULL;
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}
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ASSERT(atomic_read(&ip->i_pincount) == 0);
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ASSERT(!spin_is_locked(&ip->i_flags_lock));
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ASSERT(!xfs_isiflocked(ip));
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ASSERT(ip->i_ino == 0);
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mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
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lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
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&xfs_iolock_active, "xfs_iolock_active");
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/* initialise the xfs inode */
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ip->i_ino = ino;
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ip->i_mount = mp;
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memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
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ip->i_afp = NULL;
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memset(&ip->i_df, 0, sizeof(xfs_ifork_t));
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ip->i_flags = 0;
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ip->i_delayed_blks = 0;
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memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
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return ip;
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}
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STATIC void
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xfs_inode_free_callback(
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struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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struct xfs_inode *ip = XFS_I(inode);
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kmem_zone_free(xfs_inode_zone, ip);
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}
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void
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xfs_inode_free(
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struct xfs_inode *ip)
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{
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switch (ip->i_d.di_mode & S_IFMT) {
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case S_IFREG:
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case S_IFDIR:
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case S_IFLNK:
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xfs_idestroy_fork(ip, XFS_DATA_FORK);
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break;
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}
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if (ip->i_afp)
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xfs_idestroy_fork(ip, XFS_ATTR_FORK);
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if (ip->i_itemp) {
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ASSERT(!(ip->i_itemp->ili_item.li_flags & XFS_LI_IN_AIL));
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xfs_inode_item_destroy(ip);
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ip->i_itemp = NULL;
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}
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/* asserts to verify all state is correct here */
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ASSERT(atomic_read(&ip->i_pincount) == 0);
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ASSERT(!spin_is_locked(&ip->i_flags_lock));
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ASSERT(!xfs_isiflocked(ip));
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/*
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* Because we use RCU freeing we need to ensure the inode always
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* appears to be reclaimed with an invalid inode number when in the
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* free state. The ip->i_flags_lock provides the barrier against lookup
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* races.
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*/
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spin_lock(&ip->i_flags_lock);
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ip->i_flags = XFS_IRECLAIM;
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ip->i_ino = 0;
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spin_unlock(&ip->i_flags_lock);
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call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
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}
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/*
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* Check the validity of the inode we just found it the cache
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*/
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static int
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xfs_iget_cache_hit(
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struct xfs_perag *pag,
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struct xfs_inode *ip,
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xfs_ino_t ino,
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int flags,
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int lock_flags) __releases(RCU)
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{
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struct inode *inode = VFS_I(ip);
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struct xfs_mount *mp = ip->i_mount;
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int error;
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/*
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* check for re-use of an inode within an RCU grace period due to the
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* radix tree nodes not being updated yet. We monitor for this by
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* setting the inode number to zero before freeing the inode structure.
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* If the inode has been reallocated and set up, then the inode number
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* will not match, so check for that, too.
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*/
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spin_lock(&ip->i_flags_lock);
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if (ip->i_ino != ino) {
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trace_xfs_iget_skip(ip);
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XFS_STATS_INC(xs_ig_frecycle);
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error = EAGAIN;
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goto out_error;
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}
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/*
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* If we are racing with another cache hit that is currently
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* instantiating this inode or currently recycling it out of
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* reclaimabe state, wait for the initialisation to complete
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* before continuing.
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*
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* XXX(hch): eventually we should do something equivalent to
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* wait_on_inode to wait for these flags to be cleared
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* instead of polling for it.
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*/
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if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {
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trace_xfs_iget_skip(ip);
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XFS_STATS_INC(xs_ig_frecycle);
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error = EAGAIN;
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goto out_error;
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}
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/*
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* If lookup is racing with unlink return an error immediately.
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*/
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if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
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error = ENOENT;
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goto out_error;
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}
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/*
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* If IRECLAIMABLE is set, we've torn down the VFS inode already.
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* Need to carefully get it back into useable state.
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*/
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if (ip->i_flags & XFS_IRECLAIMABLE) {
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trace_xfs_iget_reclaim(ip);
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/*
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* We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
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* from stomping over us while we recycle the inode. We can't
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* clear the radix tree reclaimable tag yet as it requires
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* pag_ici_lock to be held exclusive.
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*/
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ip->i_flags |= XFS_IRECLAIM;
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spin_unlock(&ip->i_flags_lock);
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rcu_read_unlock();
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error = -inode_init_always(mp->m_super, inode);
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if (error) {
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/*
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* Re-initializing the inode failed, and we are in deep
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* trouble. Try to re-add it to the reclaim list.
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*/
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rcu_read_lock();
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spin_lock(&ip->i_flags_lock);
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ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
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ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
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trace_xfs_iget_reclaim_fail(ip);
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goto out_error;
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}
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spin_lock(&pag->pag_ici_lock);
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spin_lock(&ip->i_flags_lock);
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/*
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* Clear the per-lifetime state in the inode as we are now
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* effectively a new inode and need to return to the initial
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* state before reuse occurs.
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*/
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ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
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ip->i_flags |= XFS_INEW;
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__xfs_inode_clear_reclaim_tag(mp, pag, ip);
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inode->i_state = I_NEW;
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ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
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mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
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lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
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&xfs_iolock_active, "xfs_iolock_active");
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spin_unlock(&ip->i_flags_lock);
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spin_unlock(&pag->pag_ici_lock);
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} else {
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/* If the VFS inode is being torn down, pause and try again. */
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if (!igrab(inode)) {
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trace_xfs_iget_skip(ip);
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error = EAGAIN;
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goto out_error;
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}
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/* We've got a live one. */
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spin_unlock(&ip->i_flags_lock);
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rcu_read_unlock();
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trace_xfs_iget_hit(ip);
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}
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if (lock_flags != 0)
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xfs_ilock(ip, lock_flags);
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xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE);
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XFS_STATS_INC(xs_ig_found);
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return 0;
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out_error:
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spin_unlock(&ip->i_flags_lock);
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rcu_read_unlock();
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return error;
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}
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static int
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xfs_iget_cache_miss(
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struct xfs_mount *mp,
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struct xfs_perag *pag,
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xfs_trans_t *tp,
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xfs_ino_t ino,
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struct xfs_inode **ipp,
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int flags,
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int lock_flags)
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{
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struct xfs_inode *ip;
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int error;
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xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino);
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int iflags;
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ip = xfs_inode_alloc(mp, ino);
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if (!ip)
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return ENOMEM;
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error = xfs_iread(mp, tp, ip, flags);
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if (error)
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goto out_destroy;
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trace_xfs_iget_miss(ip);
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|
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if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
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error = ENOENT;
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goto out_destroy;
|
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}
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|
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/*
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* Preload the radix tree so we can insert safely under the
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* write spinlock. Note that we cannot sleep inside the preload
|
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* region. Since we can be called from transaction context, don't
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* recurse into the file system.
|
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*/
|
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if (radix_tree_preload(GFP_NOFS)) {
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error = EAGAIN;
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goto out_destroy;
|
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}
|
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|
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/*
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* Because the inode hasn't been added to the radix-tree yet it can't
|
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* be found by another thread, so we can do the non-sleeping lock here.
|
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*/
|
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if (lock_flags) {
|
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if (!xfs_ilock_nowait(ip, lock_flags))
|
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BUG();
|
||
}
|
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|
||
/*
|
||
* These values must be set before inserting the inode into the radix
|
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* tree as the moment it is inserted a concurrent lookup (allowed by the
|
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* RCU locking mechanism) can find it and that lookup must see that this
|
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* is an inode currently under construction (i.e. that XFS_INEW is set).
|
||
* The ip->i_flags_lock that protects the XFS_INEW flag forms the
|
||
* memory barrier that ensures this detection works correctly at lookup
|
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* time.
|
||
*/
|
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iflags = XFS_INEW;
|
||
if (flags & XFS_IGET_DONTCACHE)
|
||
iflags |= XFS_IDONTCACHE;
|
||
ip->i_udquot = ip->i_gdquot = NULL;
|
||
xfs_iflags_set(ip, iflags);
|
||
|
||
/* insert the new inode */
|
||
spin_lock(&pag->pag_ici_lock);
|
||
error = radix_tree_insert(&pag->pag_ici_root, agino, ip);
|
||
if (unlikely(error)) {
|
||
WARN_ON(error != -EEXIST);
|
||
XFS_STATS_INC(xs_ig_dup);
|
||
error = EAGAIN;
|
||
goto out_preload_end;
|
||
}
|
||
spin_unlock(&pag->pag_ici_lock);
|
||
radix_tree_preload_end();
|
||
|
||
*ipp = ip;
|
||
return 0;
|
||
|
||
out_preload_end:
|
||
spin_unlock(&pag->pag_ici_lock);
|
||
radix_tree_preload_end();
|
||
if (lock_flags)
|
||
xfs_iunlock(ip, lock_flags);
|
||
out_destroy:
|
||
__destroy_inode(VFS_I(ip));
|
||
xfs_inode_free(ip);
|
||
return error;
|
||
}
|
||
|
||
/*
|
||
* Look up an inode by number in the given file system.
|
||
* The inode is looked up in the cache held in each AG.
|
||
* If the inode is found in the cache, initialise the vfs inode
|
||
* if necessary.
|
||
*
|
||
* If it is not in core, read it in from the file system's device,
|
||
* add it to the cache and initialise the vfs inode.
|
||
*
|
||
* 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.
|
||
*/
|
||
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_inode_t *ip;
|
||
int error;
|
||
xfs_perag_t *pag;
|
||
xfs_agino_t agino;
|
||
|
||
/*
|
||
* xfs_reclaim_inode() uses the ILOCK to ensure an inode
|
||
* doesn't get freed while it's being referenced during a
|
||
* radix tree traversal here. It assumes this function
|
||
* aqcuires only the ILOCK (and therefore it has no need to
|
||
* involve the IOLOCK in this synchronization).
|
||
*/
|
||
ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0);
|
||
|
||
/* reject inode numbers outside existing AGs */
|
||
if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount)
|
||
return EINVAL;
|
||
|
||
/* get the perag structure and ensure that it's inode capable */
|
||
pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
|
||
agino = XFS_INO_TO_AGINO(mp, ino);
|
||
|
||
again:
|
||
error = 0;
|
||
rcu_read_lock();
|
||
ip = radix_tree_lookup(&pag->pag_ici_root, agino);
|
||
|
||
if (ip) {
|
||
error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
|
||
if (error)
|
||
goto out_error_or_again;
|
||
} else {
|
||
rcu_read_unlock();
|
||
XFS_STATS_INC(xs_ig_missed);
|
||
|
||
error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip,
|
||
flags, lock_flags);
|
||
if (error)
|
||
goto out_error_or_again;
|
||
}
|
||
xfs_perag_put(pag);
|
||
|
||
*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.
|
||
*/
|
||
if (xfs_iflags_test(ip, XFS_INEW) && ip->i_d.di_mode != 0)
|
||
xfs_setup_inode(ip);
|
||
return 0;
|
||
|
||
out_error_or_again:
|
||
if (error == EAGAIN) {
|
||
delay(1);
|
||
goto again;
|
||
}
|
||
xfs_perag_put(pag);
|
||
return error;
|
||
}
|
||
|
||
/*
|
||
* 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 | XFS_LOCK_DEP_MASK)) == 0);
|
||
|
||
if (lock_flags & XFS_IOLOCK_EXCL)
|
||
mrupdate_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
|
||
else if (lock_flags & XFS_IOLOCK_SHARED)
|
||
mraccess_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
|
||
|
||
if (lock_flags & XFS_ILOCK_EXCL)
|
||
mrupdate_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
|
||
else if (lock_flags & XFS_ILOCK_SHARED)
|
||
mraccess_nested(&ip->i_lock, XFS_ILOCK_DEP(lock_flags));
|
||
|
||
trace_xfs_ilock(ip, lock_flags, _RET_IP_);
|
||
}
|
||
|
||
/*
|
||
* 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)
|
||
{
|
||
/*
|
||
* 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_LOCK_DEP_MASK)) == 0);
|
||
|
||
if (lock_flags & XFS_IOLOCK_EXCL) {
|
||
if (!mrtryupdate(&ip->i_iolock))
|
||
goto out;
|
||
} else if (lock_flags & XFS_IOLOCK_SHARED) {
|
||
if (!mrtryaccess(&ip->i_iolock))
|
||
goto out;
|
||
}
|
||
if (lock_flags & XFS_ILOCK_EXCL) {
|
||
if (!mrtryupdate(&ip->i_lock))
|
||
goto out_undo_iolock;
|
||
} else if (lock_flags & XFS_ILOCK_SHARED) {
|
||
if (!mrtryaccess(&ip->i_lock))
|
||
goto out_undo_iolock;
|
||
}
|
||
trace_xfs_ilock_nowait(ip, lock_flags, _RET_IP_);
|
||
return 1;
|
||
|
||
out_undo_iolock:
|
||
if (lock_flags & XFS_IOLOCK_EXCL)
|
||
mrunlock_excl(&ip->i_iolock);
|
||
else if (lock_flags & XFS_IOLOCK_SHARED)
|
||
mrunlock_shared(&ip->i_iolock);
|
||
out:
|
||
return 0;
|
||
}
|
||
|
||
/*
|
||
* 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_LOCK_DEP_MASK)) == 0);
|
||
ASSERT(lock_flags != 0);
|
||
|
||
if (lock_flags & XFS_IOLOCK_EXCL)
|
||
mrunlock_excl(&ip->i_iolock);
|
||
else if (lock_flags & XFS_IOLOCK_SHARED)
|
||
mrunlock_shared(&ip->i_iolock);
|
||
|
||
if (lock_flags & XFS_ILOCK_EXCL)
|
||
mrunlock_excl(&ip->i_lock);
|
||
else if (lock_flags & XFS_ILOCK_SHARED)
|
||
mrunlock_shared(&ip->i_lock);
|
||
|
||
trace_xfs_iunlock(ip, lock_flags, _RET_IP_);
|
||
}
|
||
|
||
/*
|
||
* 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)
|
||
mrdemote(&ip->i_lock);
|
||
if (lock_flags & XFS_IOLOCK_EXCL)
|
||
mrdemote(&ip->i_iolock);
|
||
|
||
trace_xfs_ilock_demote(ip, lock_flags, _RET_IP_);
|
||
}
|
||
|
||
#ifdef DEBUG
|
||
int
|
||
xfs_isilocked(
|
||
xfs_inode_t *ip,
|
||
uint lock_flags)
|
||
{
|
||
if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
|
||
if (!(lock_flags & XFS_ILOCK_SHARED))
|
||
return !!ip->i_lock.mr_writer;
|
||
return rwsem_is_locked(&ip->i_lock.mr_lock);
|
||
}
|
||
|
||
if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
|
||
if (!(lock_flags & XFS_IOLOCK_SHARED))
|
||
return !!ip->i_iolock.mr_writer;
|
||
return rwsem_is_locked(&ip->i_iolock.mr_lock);
|
||
}
|
||
|
||
ASSERT(0);
|
||
return 0;
|
||
}
|
||
#endif
|
||
|
||
void
|
||
__xfs_iflock(
|
||
struct xfs_inode *ip)
|
||
{
|
||
wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_IFLOCK_BIT);
|
||
DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_IFLOCK_BIT);
|
||
|
||
do {
|
||
prepare_to_wait_exclusive(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
|
||
if (xfs_isiflocked(ip))
|
||
io_schedule();
|
||
} while (!xfs_iflock_nowait(ip));
|
||
|
||
finish_wait(wq, &wait.wait);
|
||
}
|