From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- fs/xfs/xfs_trans_ail.c | 596 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 596 insertions(+) create mode 100644 fs/xfs/xfs_trans_ail.c (limited to 'fs/xfs/xfs_trans_ail.c') diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c new file mode 100644 index 00000000000..7bc5eab4c2c --- /dev/null +++ b/fs/xfs/xfs_trans_ail.c @@ -0,0 +1,596 @@ +/* + * Copyright (c) 2000-2002 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_dir.h" +#include "xfs_dmapi.h" +#include "xfs_mount.h" +#include "xfs_trans_priv.h" +#include "xfs_error.h" + +STATIC void xfs_ail_insert(xfs_ail_entry_t *, xfs_log_item_t *); +STATIC xfs_log_item_t * xfs_ail_delete(xfs_ail_entry_t *, xfs_log_item_t *); +STATIC xfs_log_item_t * xfs_ail_min(xfs_ail_entry_t *); +STATIC xfs_log_item_t * xfs_ail_next(xfs_ail_entry_t *, xfs_log_item_t *); + +#ifdef DEBUG +STATIC void xfs_ail_check(xfs_ail_entry_t *); +#else +#define xfs_ail_check(a) +#endif /* DEBUG */ + + +/* + * This is called by the log manager code to determine the LSN + * of the tail of the log. This is exactly the LSN of the first + * item in the AIL. If the AIL is empty, then this function + * returns 0. + * + * We need the AIL lock in order to get a coherent read of the + * lsn of the last item in the AIL. + */ +xfs_lsn_t +xfs_trans_tail_ail( + xfs_mount_t *mp) +{ + xfs_lsn_t lsn; + xfs_log_item_t *lip; + SPLDECL(s); + + AIL_LOCK(mp,s); + lip = xfs_ail_min(&(mp->m_ail)); + if (lip == NULL) { + lsn = (xfs_lsn_t)0; + } else { + lsn = lip->li_lsn; + } + AIL_UNLOCK(mp, s); + + return lsn; +} + +/* + * xfs_trans_push_ail + * + * This routine is called to move the tail of the AIL + * forward. It does this by trying to flush items in the AIL + * whose lsns are below the given threshold_lsn. + * + * The routine returns the lsn of the tail of the log. + */ +xfs_lsn_t +xfs_trans_push_ail( + xfs_mount_t *mp, + xfs_lsn_t threshold_lsn) +{ + xfs_lsn_t lsn; + xfs_log_item_t *lip; + int gen; + int restarts; + int lock_result; + int flush_log; + SPLDECL(s); + +#define XFS_TRANS_PUSH_AIL_RESTARTS 10 + + AIL_LOCK(mp,s); + lip = xfs_trans_first_ail(mp, &gen); + if (lip == NULL || XFS_FORCED_SHUTDOWN(mp)) { + /* + * Just return if the AIL is empty. + */ + AIL_UNLOCK(mp, s); + return (xfs_lsn_t)0; + } + + XFS_STATS_INC(xs_push_ail); + + /* + * While the item we are looking at is below the given threshold + * try to flush it out. Make sure to limit the number of times + * we allow xfs_trans_next_ail() to restart scanning from the + * beginning of the list. We'd like not to stop until we've at least + * tried to push on everything in the AIL with an LSN less than + * the given threshold. However, we may give up before that if + * we realize that we've been holding the AIL_LOCK for 'too long', + * blocking interrupts. Currently, too long is < 500us roughly. + */ + flush_log = 0; + restarts = 0; + while (((restarts < XFS_TRANS_PUSH_AIL_RESTARTS) && + (XFS_LSN_CMP(lip->li_lsn, threshold_lsn) < 0))) { + /* + * If we can lock the item without sleeping, unlock + * the AIL lock and flush the item. Then re-grab the + * AIL lock so we can look for the next item on the + * AIL. Since we unlock the AIL while we flush the + * item, the next routine may start over again at the + * the beginning of the list if anything has changed. + * That is what the generation count is for. + * + * If we can't lock the item, either its holder will flush + * it or it is already being flushed or it is being relogged. + * In any of these case it is being taken care of and we + * can just skip to the next item in the list. + */ + lock_result = IOP_TRYLOCK(lip); + switch (lock_result) { + case XFS_ITEM_SUCCESS: + AIL_UNLOCK(mp, s); + XFS_STATS_INC(xs_push_ail_success); + IOP_PUSH(lip); + AIL_LOCK(mp,s); + break; + + case XFS_ITEM_PUSHBUF: + AIL_UNLOCK(mp, s); + XFS_STATS_INC(xs_push_ail_pushbuf); +#ifdef XFSRACEDEBUG + delay_for_intr(); + delay(300); +#endif + ASSERT(lip->li_ops->iop_pushbuf); + ASSERT(lip); + IOP_PUSHBUF(lip); + AIL_LOCK(mp,s); + break; + + case XFS_ITEM_PINNED: + XFS_STATS_INC(xs_push_ail_pinned); + flush_log = 1; + break; + + case XFS_ITEM_LOCKED: + XFS_STATS_INC(xs_push_ail_locked); + break; + + case XFS_ITEM_FLUSHING: + XFS_STATS_INC(xs_push_ail_flushing); + break; + + default: + ASSERT(0); + break; + } + + lip = xfs_trans_next_ail(mp, lip, &gen, &restarts); + if (lip == NULL) { + break; + } + if (XFS_FORCED_SHUTDOWN(mp)) { + /* + * Just return if we shut down during the last try. + */ + AIL_UNLOCK(mp, s); + return (xfs_lsn_t)0; + } + + } + + if (flush_log) { + /* + * If something we need to push out was pinned, then + * push out the log so it will become unpinned and + * move forward in the AIL. + */ + AIL_UNLOCK(mp, s); + XFS_STATS_INC(xs_push_ail_flush); + xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE); + AIL_LOCK(mp, s); + } + + lip = xfs_ail_min(&(mp->m_ail)); + if (lip == NULL) { + lsn = (xfs_lsn_t)0; + } else { + lsn = lip->li_lsn; + } + + AIL_UNLOCK(mp, s); + return lsn; +} /* xfs_trans_push_ail */ + + +/* + * This is to be called when an item is unlocked that may have + * been in the AIL. It will wake up the first member of the AIL + * wait list if this item's unlocking might allow it to progress. + * If the item is in the AIL, then we need to get the AIL lock + * while doing our checking so we don't race with someone going + * to sleep waiting for this event in xfs_trans_push_ail(). + */ +void +xfs_trans_unlocked_item( + xfs_mount_t *mp, + xfs_log_item_t *lip) +{ + xfs_log_item_t *min_lip; + + /* + * If we're forcibly shutting down, we may have + * unlocked log items arbitrarily. The last thing + * we want to do is to move the tail of the log + * over some potentially valid data. + */ + if (!(lip->li_flags & XFS_LI_IN_AIL) || + XFS_FORCED_SHUTDOWN(mp)) { + return; + } + + /* + * This is the one case where we can call into xfs_ail_min() + * without holding the AIL lock because we only care about the + * case where we are at the tail of the AIL. If the object isn't + * at the tail, it doesn't matter what result we get back. This + * is slightly racy because since we were just unlocked, we could + * go to sleep between the call to xfs_ail_min and the call to + * xfs_log_move_tail, have someone else lock us, commit to us disk, + * move us out of the tail of the AIL, and then we wake up. However, + * the call to xfs_log_move_tail() doesn't do anything if there's + * not enough free space to wake people up so we're safe calling it. + */ + min_lip = xfs_ail_min(&mp->m_ail); + + if (min_lip == lip) + xfs_log_move_tail(mp, 1); +} /* xfs_trans_unlocked_item */ + + +/* + * Update the position of the item in the AIL with the new + * lsn. If it is not yet in the AIL, add it. Otherwise, move + * it to its new position by removing it and re-adding it. + * + * Wakeup anyone with an lsn less than the item's lsn. If the item + * we move in the AIL is the minimum one, update the tail lsn in the + * log manager. + * + * Increment the AIL's generation count to indicate that the tree + * has changed. + * + * This function must be called with the AIL lock held. The lock + * is dropped before returning, so the caller must pass in the + * cookie returned by AIL_LOCK. + */ +void +xfs_trans_update_ail( + xfs_mount_t *mp, + xfs_log_item_t *lip, + xfs_lsn_t lsn, + unsigned long s) +{ + xfs_ail_entry_t *ailp; + xfs_log_item_t *dlip=NULL; + xfs_log_item_t *mlip; /* ptr to minimum lip */ + + ailp = &(mp->m_ail); + mlip = xfs_ail_min(ailp); + + if (lip->li_flags & XFS_LI_IN_AIL) { + dlip = xfs_ail_delete(ailp, lip); + ASSERT(dlip == lip); + } else { + lip->li_flags |= XFS_LI_IN_AIL; + } + + lip->li_lsn = lsn; + + xfs_ail_insert(ailp, lip); + mp->m_ail_gen++; + + if (mlip == dlip) { + mlip = xfs_ail_min(&(mp->m_ail)); + AIL_UNLOCK(mp, s); + xfs_log_move_tail(mp, mlip->li_lsn); + } else { + AIL_UNLOCK(mp, s); + } + + +} /* xfs_trans_update_ail */ + +/* + * Delete the given item from the AIL. It must already be in + * the AIL. + * + * Wakeup anyone with an lsn less than item's lsn. If the item + * we delete in the AIL is the minimum one, update the tail lsn in the + * log manager. + * + * Clear the IN_AIL flag from the item, reset its lsn to 0, and + * bump the AIL's generation count to indicate that the tree + * has changed. + * + * This function must be called with the AIL lock held. The lock + * is dropped before returning, so the caller must pass in the + * cookie returned by AIL_LOCK. + */ +void +xfs_trans_delete_ail( + xfs_mount_t *mp, + xfs_log_item_t *lip, + unsigned long s) +{ + xfs_ail_entry_t *ailp; + xfs_log_item_t *dlip; + xfs_log_item_t *mlip; + + if (lip->li_flags & XFS_LI_IN_AIL) { + ailp = &(mp->m_ail); + mlip = xfs_ail_min(ailp); + dlip = xfs_ail_delete(ailp, lip); + ASSERT(dlip == lip); + + + lip->li_flags &= ~XFS_LI_IN_AIL; + lip->li_lsn = 0; + mp->m_ail_gen++; + + if (mlip == dlip) { + mlip = xfs_ail_min(&(mp->m_ail)); + AIL_UNLOCK(mp, s); + xfs_log_move_tail(mp, (mlip ? mlip->li_lsn : 0)); + } else { + AIL_UNLOCK(mp, s); + } + } + else { + /* + * If the file system is not being shutdown, we are in + * serious trouble if we get to this stage. + */ + if (XFS_FORCED_SHUTDOWN(mp)) + AIL_UNLOCK(mp, s); + else { + xfs_cmn_err(XFS_PTAG_AILDELETE, CE_ALERT, mp, + "xfs_trans_delete_ail: attempting to delete a log item that is not in the AIL"); + xfs_force_shutdown(mp, XFS_CORRUPT_INCORE); + AIL_UNLOCK(mp, s); + } + } +} + + + +/* + * Return the item in the AIL with the smallest lsn. + * Return the current tree generation number for use + * in calls to xfs_trans_next_ail(). + */ +xfs_log_item_t * +xfs_trans_first_ail( + xfs_mount_t *mp, + int *gen) +{ + xfs_log_item_t *lip; + + lip = xfs_ail_min(&(mp->m_ail)); + *gen = (int)mp->m_ail_gen; + + return (lip); +} + +/* + * If the generation count of the tree has not changed since the + * caller last took something from the AIL, then return the elmt + * in the tree which follows the one given. If the count has changed, + * then return the minimum elmt of the AIL and bump the restarts counter + * if one is given. + */ +xfs_log_item_t * +xfs_trans_next_ail( + xfs_mount_t *mp, + xfs_log_item_t *lip, + int *gen, + int *restarts) +{ + xfs_log_item_t *nlip; + + ASSERT(mp && lip && gen); + if (mp->m_ail_gen == *gen) { + nlip = xfs_ail_next(&(mp->m_ail), lip); + } else { + nlip = xfs_ail_min(&(mp->m_ail)); + *gen = (int)mp->m_ail_gen; + if (restarts != NULL) { + XFS_STATS_INC(xs_push_ail_restarts); + (*restarts)++; + } + } + + return (nlip); +} + + +/* + * The active item list (AIL) is a doubly linked list of log + * items sorted by ascending lsn. The base of the list is + * a forw/back pointer pair embedded in the xfs mount structure. + * The base is initialized with both pointers pointing to the + * base. This case always needs to be distinguished, because + * the base has no lsn to look at. We almost always insert + * at the end of the list, so on inserts we search from the + * end of the list to find where the new item belongs. + */ + +/* + * Initialize the doubly linked list to point only to itself. + */ +void +xfs_trans_ail_init( + xfs_mount_t *mp) +{ + mp->m_ail.ail_forw = (xfs_log_item_t*)&(mp->m_ail); + mp->m_ail.ail_back = (xfs_log_item_t*)&(mp->m_ail); +} + +/* + * Insert the given log item into the AIL. + * We almost always insert at the end of the list, so on inserts + * we search from the end of the list to find where the + * new item belongs. + */ +STATIC void +xfs_ail_insert( + xfs_ail_entry_t *base, + xfs_log_item_t *lip) +/* ARGSUSED */ +{ + xfs_log_item_t *next_lip; + + /* + * If the list is empty, just insert the item. + */ + if (base->ail_back == (xfs_log_item_t*)base) { + base->ail_forw = lip; + base->ail_back = lip; + lip->li_ail.ail_forw = (xfs_log_item_t*)base; + lip->li_ail.ail_back = (xfs_log_item_t*)base; + return; + } + + next_lip = base->ail_back; + while ((next_lip != (xfs_log_item_t*)base) && + (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) > 0)) { + next_lip = next_lip->li_ail.ail_back; + } + ASSERT((next_lip == (xfs_log_item_t*)base) || + (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) <= 0)); + lip->li_ail.ail_forw = next_lip->li_ail.ail_forw; + lip->li_ail.ail_back = next_lip; + next_lip->li_ail.ail_forw = lip; + lip->li_ail.ail_forw->li_ail.ail_back = lip; + + xfs_ail_check(base); + return; +} + +/* + * Delete the given item from the AIL. Return a pointer to the item. + */ +/*ARGSUSED*/ +STATIC xfs_log_item_t * +xfs_ail_delete( + xfs_ail_entry_t *base, + xfs_log_item_t *lip) +/* ARGSUSED */ +{ + lip->li_ail.ail_forw->li_ail.ail_back = lip->li_ail.ail_back; + lip->li_ail.ail_back->li_ail.ail_forw = lip->li_ail.ail_forw; + lip->li_ail.ail_forw = NULL; + lip->li_ail.ail_back = NULL; + + xfs_ail_check(base); + return lip; +} + +/* + * Return a pointer to the first item in the AIL. + * If the AIL is empty, then return NULL. + */ +STATIC xfs_log_item_t * +xfs_ail_min( + xfs_ail_entry_t *base) +/* ARGSUSED */ +{ + register xfs_log_item_t *forw = base->ail_forw; + if (forw == (xfs_log_item_t*)base) { + return NULL; + } + return forw; +} + +/* + * Return a pointer to the item which follows + * the given item in the AIL. If the given item + * is the last item in the list, then return NULL. + */ +STATIC xfs_log_item_t * +xfs_ail_next( + xfs_ail_entry_t *base, + xfs_log_item_t *lip) +/* ARGSUSED */ +{ + if (lip->li_ail.ail_forw == (xfs_log_item_t*)base) { + return NULL; + } + return lip->li_ail.ail_forw; + +} + +#ifdef DEBUG +/* + * Check that the list is sorted as it should be. + */ +STATIC void +xfs_ail_check( + xfs_ail_entry_t *base) +{ + xfs_log_item_t *lip; + xfs_log_item_t *prev_lip; + + lip = base->ail_forw; + if (lip == (xfs_log_item_t*)base) { + /* + * Make sure the pointers are correct when the list + * is empty. + */ + ASSERT(base->ail_back == (xfs_log_item_t*)base); + return; + } + + /* + * Walk the list checking forward and backward pointers, + * lsn ordering, and that every entry has the XFS_LI_IN_AIL + * flag set. + */ + prev_lip = (xfs_log_item_t*)base; + while (lip != (xfs_log_item_t*)base) { + if (prev_lip != (xfs_log_item_t*)base) { + ASSERT(prev_lip->li_ail.ail_forw == lip); + ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0); + } + ASSERT(lip->li_ail.ail_back == prev_lip); + ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0); + prev_lip = lip; + lip = lip->li_ail.ail_forw; + } + ASSERT(lip == (xfs_log_item_t*)base); + ASSERT(base->ail_back == prev_lip); +} +#endif /* DEBUG */ -- cgit v1.2.3-70-g09d2