mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-30 16:13:54 +08:00
92f1c008ae
This merge pulls the XFS master branch into the latest Linus master. This results in a merge conflict whose best fix is not obvious. I manually fixed the conflict, in "fs/xfs/xfs_iget.c". Dave Chinner had done work that resulted in RCU freeing of inodes separate from what Nick Piggin had done, and their results differed slightly in xfs_inode_free(). The fix updates Nick's call_rcu() with the use of VFS_I(), while incorporating needed updates to some XFS inode fields implemented in Dave's series. Dave's RCU callback function has also been removed. Signed-off-by: Alex Elder <aelder@sgi.com>
717 lines
19 KiB
C
717 lines
19 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_acl.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_mount.h"
|
||
#include "xfs_bmap_btree.h"
|
||
#include "xfs_alloc_btree.h"
|
||
#include "xfs_ialloc_btree.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"
|
||
#include "xfs_trans_priv.h"
|
||
#include "xfs_inode_item.h"
|
||
#include "xfs_bmap.h"
|
||
#include "xfs_btree_trace.h"
|
||
#include "xfs_trace.h"
|
||
|
||
|
||
/*
|
||
* Define xfs inode iolock lockdep classes. We need to ensure that all active
|
||
* inodes are considered the same for lockdep purposes, including inodes that
|
||
* are recycled through the XFS_IRECLAIMABLE state. This is the the only way to
|
||
* guarantee the locks are considered the same when there are multiple lock
|
||
* initialisation siteѕ. Also, define a reclaimable inode class so it is
|
||
* obvious in lockdep reports which class the report is against.
|
||
*/
|
||
static struct lock_class_key xfs_iolock_active;
|
||
struct lock_class_key xfs_iolock_reclaimable;
|
||
|
||
/*
|
||
* Allocate and initialise an xfs_inode.
|
||
*/
|
||
STATIC struct xfs_inode *
|
||
xfs_inode_alloc(
|
||
struct xfs_mount *mp,
|
||
xfs_ino_t ino)
|
||
{
|
||
struct xfs_inode *ip;
|
||
|
||
/*
|
||
* if this didn't occur in transactions, we could use
|
||
* KM_MAYFAIL and return NULL here on ENOMEM. Set the
|
||
* code up to do this anyway.
|
||
*/
|
||
ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP);
|
||
if (!ip)
|
||
return NULL;
|
||
if (inode_init_always(mp->m_super, VFS_I(ip))) {
|
||
kmem_zone_free(xfs_inode_zone, ip);
|
||
return NULL;
|
||
}
|
||
|
||
ASSERT(atomic_read(&ip->i_iocount) == 0);
|
||
ASSERT(atomic_read(&ip->i_pincount) == 0);
|
||
ASSERT(!spin_is_locked(&ip->i_flags_lock));
|
||
ASSERT(completion_done(&ip->i_flush));
|
||
ASSERT(ip->i_ino == 0);
|
||
|
||
mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
|
||
lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
|
||
&xfs_iolock_active, "xfs_iolock_active");
|
||
|
||
/* initialise the xfs inode */
|
||
ip->i_ino = ino;
|
||
ip->i_mount = mp;
|
||
memset(&ip->i_imap, 0, sizeof(struct xfs_imap));
|
||
ip->i_afp = NULL;
|
||
memset(&ip->i_df, 0, sizeof(xfs_ifork_t));
|
||
ip->i_flags = 0;
|
||
ip->i_update_core = 0;
|
||
ip->i_delayed_blks = 0;
|
||
memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));
|
||
ip->i_size = 0;
|
||
ip->i_new_size = 0;
|
||
|
||
return ip;
|
||
}
|
||
|
||
STATIC void
|
||
xfs_inode_free_callback(
|
||
struct rcu_head *head)
|
||
{
|
||
struct inode *inode = container_of(head, struct inode, i_rcu);
|
||
struct xfs_inode *ip = XFS_I(inode);
|
||
|
||
INIT_LIST_HEAD(&inode->i_dentry);
|
||
kmem_zone_free(xfs_inode_zone, ip);
|
||
}
|
||
|
||
void
|
||
xfs_inode_free(
|
||
struct xfs_inode *ip)
|
||
{
|
||
switch (ip->i_d.di_mode & S_IFMT) {
|
||
case S_IFREG:
|
||
case S_IFDIR:
|
||
case S_IFLNK:
|
||
xfs_idestroy_fork(ip, XFS_DATA_FORK);
|
||
break;
|
||
}
|
||
|
||
if (ip->i_afp)
|
||
xfs_idestroy_fork(ip, XFS_ATTR_FORK);
|
||
|
||
if (ip->i_itemp) {
|
||
/*
|
||
* Only if we are shutting down the fs will we see an
|
||
* inode still in the AIL. If it is there, we should remove
|
||
* it to prevent a use-after-free from occurring.
|
||
*/
|
||
xfs_log_item_t *lip = &ip->i_itemp->ili_item;
|
||
struct xfs_ail *ailp = lip->li_ailp;
|
||
|
||
ASSERT(((lip->li_flags & XFS_LI_IN_AIL) == 0) ||
|
||
XFS_FORCED_SHUTDOWN(ip->i_mount));
|
||
if (lip->li_flags & XFS_LI_IN_AIL) {
|
||
spin_lock(&ailp->xa_lock);
|
||
if (lip->li_flags & XFS_LI_IN_AIL)
|
||
xfs_trans_ail_delete(ailp, lip);
|
||
else
|
||
spin_unlock(&ailp->xa_lock);
|
||
}
|
||
xfs_inode_item_destroy(ip);
|
||
ip->i_itemp = NULL;
|
||
}
|
||
|
||
/* asserts to verify all state is correct here */
|
||
ASSERT(atomic_read(&ip->i_iocount) == 0);
|
||
ASSERT(atomic_read(&ip->i_pincount) == 0);
|
||
ASSERT(!spin_is_locked(&ip->i_flags_lock));
|
||
ASSERT(completion_done(&ip->i_flush));
|
||
|
||
/*
|
||
* Because we use RCU freeing we need to ensure the inode always
|
||
* appears to be reclaimed with an invalid inode number when in the
|
||
* free state. The ip->i_flags_lock provides the barrier against lookup
|
||
* races.
|
||
*/
|
||
spin_lock(&ip->i_flags_lock);
|
||
ip->i_flags = XFS_IRECLAIM;
|
||
ip->i_ino = 0;
|
||
spin_unlock(&ip->i_flags_lock);
|
||
|
||
call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback);
|
||
}
|
||
|
||
/*
|
||
* Check the validity of the inode we just found it the cache
|
||
*/
|
||
static int
|
||
xfs_iget_cache_hit(
|
||
struct xfs_perag *pag,
|
||
struct xfs_inode *ip,
|
||
xfs_ino_t ino,
|
||
int flags,
|
||
int lock_flags) __releases(RCU)
|
||
{
|
||
struct inode *inode = VFS_I(ip);
|
||
struct xfs_mount *mp = ip->i_mount;
|
||
int error;
|
||
|
||
/*
|
||
* check for re-use of an inode within an RCU grace period due to the
|
||
* radix tree nodes not being updated yet. We monitor for this by
|
||
* setting the inode number to zero before freeing the inode structure.
|
||
* If the inode has been reallocated and set up, then the inode number
|
||
* will not match, so check for that, too.
|
||
*/
|
||
spin_lock(&ip->i_flags_lock);
|
||
if (ip->i_ino != ino) {
|
||
trace_xfs_iget_skip(ip);
|
||
XFS_STATS_INC(xs_ig_frecycle);
|
||
error = EAGAIN;
|
||
goto out_error;
|
||
}
|
||
|
||
|
||
/*
|
||
* If we are racing with another cache hit that is currently
|
||
* instantiating this inode or currently recycling it out of
|
||
* reclaimabe state, wait for the initialisation to complete
|
||
* before continuing.
|
||
*
|
||
* XXX(hch): eventually we should do something equivalent to
|
||
* wait_on_inode to wait for these flags to be cleared
|
||
* instead of polling for it.
|
||
*/
|
||
if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) {
|
||
trace_xfs_iget_skip(ip);
|
||
XFS_STATS_INC(xs_ig_frecycle);
|
||
error = EAGAIN;
|
||
goto out_error;
|
||
}
|
||
|
||
/*
|
||
* If lookup is racing with unlink return an error immediately.
|
||
*/
|
||
if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) {
|
||
error = ENOENT;
|
||
goto out_error;
|
||
}
|
||
|
||
/*
|
||
* If IRECLAIMABLE is set, we've torn down the VFS inode already.
|
||
* Need to carefully get it back into useable state.
|
||
*/
|
||
if (ip->i_flags & XFS_IRECLAIMABLE) {
|
||
trace_xfs_iget_reclaim(ip);
|
||
|
||
/*
|
||
* We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
|
||
* from stomping over us while we recycle the inode. We can't
|
||
* clear the radix tree reclaimable tag yet as it requires
|
||
* pag_ici_lock to be held exclusive.
|
||
*/
|
||
ip->i_flags |= XFS_IRECLAIM;
|
||
|
||
spin_unlock(&ip->i_flags_lock);
|
||
rcu_read_unlock();
|
||
|
||
error = -inode_init_always(mp->m_super, inode);
|
||
if (error) {
|
||
/*
|
||
* Re-initializing the inode failed, and we are in deep
|
||
* trouble. Try to re-add it to the reclaim list.
|
||
*/
|
||
rcu_read_lock();
|
||
spin_lock(&ip->i_flags_lock);
|
||
|
||
ip->i_flags &= ~XFS_INEW;
|
||
ip->i_flags |= XFS_IRECLAIMABLE;
|
||
__xfs_inode_set_reclaim_tag(pag, ip);
|
||
trace_xfs_iget_reclaim_fail(ip);
|
||
goto out_error;
|
||
}
|
||
|
||
spin_lock(&pag->pag_ici_lock);
|
||
spin_lock(&ip->i_flags_lock);
|
||
ip->i_flags &= ~(XFS_IRECLAIMABLE | XFS_IRECLAIM);
|
||
ip->i_flags |= XFS_INEW;
|
||
__xfs_inode_clear_reclaim_tag(mp, pag, ip);
|
||
inode->i_state = I_NEW;
|
||
|
||
ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));
|
||
mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);
|
||
lockdep_set_class_and_name(&ip->i_iolock.mr_lock,
|
||
&xfs_iolock_active, "xfs_iolock_active");
|
||
|
||
spin_unlock(&ip->i_flags_lock);
|
||
spin_unlock(&pag->pag_ici_lock);
|
||
} else {
|
||
/* If the VFS inode is being torn down, pause and try again. */
|
||
if (!igrab(inode)) {
|
||
trace_xfs_iget_skip(ip);
|
||
error = EAGAIN;
|
||
goto out_error;
|
||
}
|
||
|
||
/* We've got a live one. */
|
||
spin_unlock(&ip->i_flags_lock);
|
||
rcu_read_unlock();
|
||
trace_xfs_iget_hit(ip);
|
||
}
|
||
|
||
if (lock_flags != 0)
|
||
xfs_ilock(ip, lock_flags);
|
||
|
||
xfs_iflags_clear(ip, XFS_ISTALE);
|
||
XFS_STATS_INC(xs_ig_found);
|
||
|
||
return 0;
|
||
|
||
out_error:
|
||
spin_unlock(&ip->i_flags_lock);
|
||
rcu_read_unlock();
|
||
return error;
|
||
}
|
||
|
||
|
||
static int
|
||
xfs_iget_cache_miss(
|
||
struct xfs_mount *mp,
|
||
struct xfs_perag *pag,
|
||
xfs_trans_t *tp,
|
||
xfs_ino_t ino,
|
||
struct xfs_inode **ipp,
|
||
int flags,
|
||
int lock_flags)
|
||
{
|
||
struct xfs_inode *ip;
|
||
int error;
|
||
xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino);
|
||
|
||
ip = xfs_inode_alloc(mp, ino);
|
||
if (!ip)
|
||
return ENOMEM;
|
||
|
||
error = xfs_iread(mp, tp, ip, flags);
|
||
if (error)
|
||
goto out_destroy;
|
||
|
||
trace_xfs_iget_miss(ip);
|
||
|
||
if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) {
|
||
error = ENOENT;
|
||
goto out_destroy;
|
||
}
|
||
|
||
/*
|
||
* Preload the radix tree so we can insert safely under the
|
||
* write spinlock. Note that we cannot sleep inside the preload
|
||
* region.
|
||
*/
|
||
if (radix_tree_preload(GFP_KERNEL)) {
|
||
error = EAGAIN;
|
||
goto out_destroy;
|
||
}
|
||
|
||
/*
|
||
* Because the inode hasn't been added to the radix-tree yet it can't
|
||
* be found by another thread, so we can do the non-sleeping lock here.
|
||
*/
|
||
if (lock_flags) {
|
||
if (!xfs_ilock_nowait(ip, lock_flags))
|
||
BUG();
|
||
}
|
||
|
||
spin_lock(&pag->pag_ici_lock);
|
||
|
||
/* insert the new inode */
|
||
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;
|
||
}
|
||
|
||
/* These values _must_ be set before releasing the radix tree lock! */
|
||
ip->i_udquot = ip->i_gdquot = NULL;
|
||
xfs_iflags_set(ip, XFS_INEW);
|
||
|
||
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;
|
||
|
||
/* 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;
|
||
|
||
ASSERT(ip->i_df.if_ext_max ==
|
||
XFS_IFORK_DSIZE(ip) / sizeof(xfs_bmbt_rec_t));
|
||
/*
|
||
* 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_IUNLOCK_NONOTIFY |
|
||
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);
|
||
|
||
if ((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) &&
|
||
!(lock_flags & XFS_IUNLOCK_NONOTIFY) && ip->i_itemp) {
|
||
/*
|
||
* 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.
|
||
*/
|
||
xfs_trans_unlocked_item(ip->i_itemp->ili_item.li_ailp,
|
||
(xfs_log_item_t*)(ip->i_itemp));
|
||
}
|
||
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
|