| /* |
| * Copyright (c) 2000-2002,2005 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_log.h" |
| #include "xfs_inum.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, |
| "%s: attempting to delete a log item that is not in the AIL", |
| __FUNCTION__); |
| AIL_UNLOCK(mp, s); |
| xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE); |
| } |
| } |
| } |
| |
| |
| |
| /* |
| * 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 */ |