| /* |
| * 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_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_inode.h" |
| #include "xfs_dinode.h" |
| #include "xfs_error.h" |
| #include "xfs_filestream.h" |
| #include "xfs_vnodeops.h" |
| #include "xfs_inode_item.h" |
| #include "xfs_quota.h" |
| #include "xfs_trace.h" |
| #include "xfs_fsops.h" |
| |
| #include <linux/kthread.h> |
| #include <linux/freezer.h> |
| |
| |
| STATIC xfs_inode_t * |
| xfs_inode_ag_lookup( |
| struct xfs_mount *mp, |
| struct xfs_perag *pag, |
| uint32_t *first_index, |
| int tag) |
| { |
| int nr_found; |
| struct xfs_inode *ip; |
| |
| /* |
| * use a gang lookup to find the next inode in the tree |
| * as the tree is sparse and a gang lookup walks to find |
| * the number of objects requested. |
| */ |
| if (tag == XFS_ICI_NO_TAG) { |
| nr_found = radix_tree_gang_lookup(&pag->pag_ici_root, |
| (void **)&ip, *first_index, 1); |
| } else { |
| nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root, |
| (void **)&ip, *first_index, 1, tag); |
| } |
| if (!nr_found) |
| return NULL; |
| |
| /* |
| * Update the index for the next lookup. Catch overflows |
| * into the next AG range which can occur if we have inodes |
| * in the last block of the AG and we are currently |
| * pointing to the last inode. |
| */ |
| *first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1); |
| if (*first_index < XFS_INO_TO_AGINO(mp, ip->i_ino)) |
| return NULL; |
| return ip; |
| } |
| |
| STATIC int |
| xfs_inode_ag_walk( |
| struct xfs_mount *mp, |
| struct xfs_perag *pag, |
| int (*execute)(struct xfs_inode *ip, |
| struct xfs_perag *pag, int flags), |
| int flags, |
| int tag, |
| int exclusive, |
| int *nr_to_scan) |
| { |
| uint32_t first_index; |
| int last_error = 0; |
| int skipped; |
| |
| restart: |
| skipped = 0; |
| first_index = 0; |
| do { |
| int error = 0; |
| xfs_inode_t *ip; |
| |
| if (exclusive) |
| write_lock(&pag->pag_ici_lock); |
| else |
| read_lock(&pag->pag_ici_lock); |
| ip = xfs_inode_ag_lookup(mp, pag, &first_index, tag); |
| if (!ip) { |
| if (exclusive) |
| write_unlock(&pag->pag_ici_lock); |
| else |
| read_unlock(&pag->pag_ici_lock); |
| break; |
| } |
| |
| /* execute releases pag->pag_ici_lock */ |
| error = execute(ip, pag, flags); |
| if (error == EAGAIN) { |
| skipped++; |
| continue; |
| } |
| if (error) |
| last_error = error; |
| |
| /* bail out if the filesystem is corrupted. */ |
| if (error == EFSCORRUPTED) |
| break; |
| |
| } while ((*nr_to_scan)--); |
| |
| if (skipped) { |
| delay(1); |
| goto restart; |
| } |
| return last_error; |
| } |
| |
| /* |
| * Select the next per-ag structure to iterate during the walk. The reclaim |
| * walk is optimised only to walk AGs with reclaimable inodes in them. |
| */ |
| static struct xfs_perag * |
| xfs_inode_ag_iter_next_pag( |
| struct xfs_mount *mp, |
| xfs_agnumber_t *first, |
| int tag) |
| { |
| struct xfs_perag *pag = NULL; |
| |
| if (tag == XFS_ICI_RECLAIM_TAG) { |
| int found; |
| int ref; |
| |
| spin_lock(&mp->m_perag_lock); |
| found = radix_tree_gang_lookup_tag(&mp->m_perag_tree, |
| (void **)&pag, *first, 1, tag); |
| if (found <= 0) { |
| spin_unlock(&mp->m_perag_lock); |
| return NULL; |
| } |
| *first = pag->pag_agno + 1; |
| /* open coded pag reference increment */ |
| ref = atomic_inc_return(&pag->pag_ref); |
| spin_unlock(&mp->m_perag_lock); |
| trace_xfs_perag_get_reclaim(mp, pag->pag_agno, ref, _RET_IP_); |
| } else { |
| pag = xfs_perag_get(mp, *first); |
| (*first)++; |
| } |
| return pag; |
| } |
| |
| int |
| xfs_inode_ag_iterator( |
| struct xfs_mount *mp, |
| int (*execute)(struct xfs_inode *ip, |
| struct xfs_perag *pag, int flags), |
| int flags, |
| int tag, |
| int exclusive, |
| int *nr_to_scan) |
| { |
| struct xfs_perag *pag; |
| int error = 0; |
| int last_error = 0; |
| xfs_agnumber_t ag; |
| int nr; |
| |
| nr = nr_to_scan ? *nr_to_scan : INT_MAX; |
| ag = 0; |
| while ((pag = xfs_inode_ag_iter_next_pag(mp, &ag, tag))) { |
| error = xfs_inode_ag_walk(mp, pag, execute, flags, tag, |
| exclusive, &nr); |
| xfs_perag_put(pag); |
| if (error) { |
| last_error = error; |
| if (error == EFSCORRUPTED) |
| break; |
| } |
| if (nr <= 0) |
| break; |
| } |
| if (nr_to_scan) |
| *nr_to_scan = nr; |
| return XFS_ERROR(last_error); |
| } |
| |
| /* must be called with pag_ici_lock held and releases it */ |
| int |
| xfs_sync_inode_valid( |
| struct xfs_inode *ip, |
| struct xfs_perag *pag) |
| { |
| struct inode *inode = VFS_I(ip); |
| int error = EFSCORRUPTED; |
| |
| /* nothing to sync during shutdown */ |
| if (XFS_FORCED_SHUTDOWN(ip->i_mount)) |
| goto out_unlock; |
| |
| /* avoid new or reclaimable inodes. Leave for reclaim code to flush */ |
| error = ENOENT; |
| if (xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM)) |
| goto out_unlock; |
| |
| /* If we can't grab the inode, it must on it's way to reclaim. */ |
| if (!igrab(inode)) |
| goto out_unlock; |
| |
| if (is_bad_inode(inode)) { |
| IRELE(ip); |
| goto out_unlock; |
| } |
| |
| /* inode is valid */ |
| error = 0; |
| out_unlock: |
| read_unlock(&pag->pag_ici_lock); |
| return error; |
| } |
| |
| STATIC int |
| xfs_sync_inode_data( |
| struct xfs_inode *ip, |
| struct xfs_perag *pag, |
| int flags) |
| { |
| struct inode *inode = VFS_I(ip); |
| struct address_space *mapping = inode->i_mapping; |
| int error = 0; |
| |
| error = xfs_sync_inode_valid(ip, pag); |
| if (error) |
| return error; |
| |
| if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) |
| goto out_wait; |
| |
| if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) { |
| if (flags & SYNC_TRYLOCK) |
| goto out_wait; |
| xfs_ilock(ip, XFS_IOLOCK_SHARED); |
| } |
| |
| error = xfs_flush_pages(ip, 0, -1, (flags & SYNC_WAIT) ? |
| 0 : XBF_ASYNC, FI_NONE); |
| xfs_iunlock(ip, XFS_IOLOCK_SHARED); |
| |
| out_wait: |
| if (flags & SYNC_WAIT) |
| xfs_ioend_wait(ip); |
| IRELE(ip); |
| return error; |
| } |
| |
| STATIC int |
| xfs_sync_inode_attr( |
| struct xfs_inode *ip, |
| struct xfs_perag *pag, |
| int flags) |
| { |
| int error = 0; |
| |
| error = xfs_sync_inode_valid(ip, pag); |
| if (error) |
| return error; |
| |
| xfs_ilock(ip, XFS_ILOCK_SHARED); |
| if (xfs_inode_clean(ip)) |
| goto out_unlock; |
| if (!xfs_iflock_nowait(ip)) { |
| if (!(flags & SYNC_WAIT)) |
| goto out_unlock; |
| xfs_iflock(ip); |
| } |
| |
| if (xfs_inode_clean(ip)) { |
| xfs_ifunlock(ip); |
| goto out_unlock; |
| } |
| |
| error = xfs_iflush(ip, flags); |
| |
| out_unlock: |
| xfs_iunlock(ip, XFS_ILOCK_SHARED); |
| IRELE(ip); |
| return error; |
| } |
| |
| /* |
| * Write out pagecache data for the whole filesystem. |
| */ |
| STATIC int |
| xfs_sync_data( |
| struct xfs_mount *mp, |
| int flags) |
| { |
| int error; |
| |
| ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0); |
| |
| error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags, |
| XFS_ICI_NO_TAG, 0, NULL); |
| if (error) |
| return XFS_ERROR(error); |
| |
| xfs_log_force(mp, (flags & SYNC_WAIT) ? XFS_LOG_SYNC : 0); |
| return 0; |
| } |
| |
| /* |
| * Write out inode metadata (attributes) for the whole filesystem. |
| */ |
| STATIC int |
| xfs_sync_attr( |
| struct xfs_mount *mp, |
| int flags) |
| { |
| ASSERT((flags & ~SYNC_WAIT) == 0); |
| |
| return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags, |
| XFS_ICI_NO_TAG, 0, NULL); |
| } |
| |
| STATIC int |
| xfs_sync_fsdata( |
| struct xfs_mount *mp) |
| { |
| struct xfs_buf *bp; |
| |
| /* |
| * If the buffer is pinned then push on the log so we won't get stuck |
| * waiting in the write for someone, maybe ourselves, to flush the log. |
| * |
| * Even though we just pushed the log above, we did not have the |
| * superblock buffer locked at that point so it can become pinned in |
| * between there and here. |
| */ |
| bp = xfs_getsb(mp, 0); |
| if (XFS_BUF_ISPINNED(bp)) |
| xfs_log_force(mp, 0); |
| |
| return xfs_bwrite(mp, bp); |
| } |
| |
| /* |
| * When remounting a filesystem read-only or freezing the filesystem, we have |
| * two phases to execute. This first phase is syncing the data before we |
| * quiesce the filesystem, and the second is flushing all the inodes out after |
| * we've waited for all the transactions created by the first phase to |
| * complete. The second phase ensures that the inodes are written to their |
| * location on disk rather than just existing in transactions in the log. This |
| * means after a quiesce there is no log replay required to write the inodes to |
| * disk (this is the main difference between a sync and a quiesce). |
| */ |
| /* |
| * First stage of freeze - no writers will make progress now we are here, |
| * so we flush delwri and delalloc buffers here, then wait for all I/O to |
| * complete. Data is frozen at that point. Metadata is not frozen, |
| * transactions can still occur here so don't bother flushing the buftarg |
| * because it'll just get dirty again. |
| */ |
| int |
| xfs_quiesce_data( |
| struct xfs_mount *mp) |
| { |
| int error, error2 = 0; |
| |
| /* push non-blocking */ |
| xfs_sync_data(mp, 0); |
| xfs_qm_sync(mp, SYNC_TRYLOCK); |
| |
| /* push and block till complete */ |
| xfs_sync_data(mp, SYNC_WAIT); |
| xfs_qm_sync(mp, SYNC_WAIT); |
| |
| /* write superblock and hoover up shutdown errors */ |
| error = xfs_sync_fsdata(mp); |
| |
| /* make sure all delwri buffers are written out */ |
| xfs_flush_buftarg(mp->m_ddev_targp, 1); |
| |
| /* mark the log as covered if needed */ |
| if (xfs_log_need_covered(mp)) |
| error2 = xfs_fs_log_dummy(mp, SYNC_WAIT); |
| |
| /* flush data-only devices */ |
| if (mp->m_rtdev_targp) |
| XFS_bflush(mp->m_rtdev_targp); |
| |
| return error ? error : error2; |
| } |
| |
| STATIC void |
| xfs_quiesce_fs( |
| struct xfs_mount *mp) |
| { |
| int count = 0, pincount; |
| |
| xfs_reclaim_inodes(mp, 0); |
| xfs_flush_buftarg(mp->m_ddev_targp, 0); |
| |
| /* |
| * This loop must run at least twice. The first instance of the loop |
| * will flush most meta data but that will generate more meta data |
| * (typically directory updates). Which then must be flushed and |
| * logged before we can write the unmount record. We also so sync |
| * reclaim of inodes to catch any that the above delwri flush skipped. |
| */ |
| do { |
| xfs_reclaim_inodes(mp, SYNC_WAIT); |
| xfs_sync_attr(mp, SYNC_WAIT); |
| pincount = xfs_flush_buftarg(mp->m_ddev_targp, 1); |
| if (!pincount) { |
| delay(50); |
| count++; |
| } |
| } while (count < 2); |
| } |
| |
| /* |
| * Second stage of a quiesce. The data is already synced, now we have to take |
| * care of the metadata. New transactions are already blocked, so we need to |
| * wait for any remaining transactions to drain out before proceding. |
| */ |
| void |
| xfs_quiesce_attr( |
| struct xfs_mount *mp) |
| { |
| int error = 0; |
| |
| /* wait for all modifications to complete */ |
| while (atomic_read(&mp->m_active_trans) > 0) |
| delay(100); |
| |
| /* flush inodes and push all remaining buffers out to disk */ |
| xfs_quiesce_fs(mp); |
| |
| /* |
| * Just warn here till VFS can correctly support |
| * read-only remount without racing. |
| */ |
| WARN_ON(atomic_read(&mp->m_active_trans) != 0); |
| |
| /* Push the superblock and write an unmount record */ |
| error = xfs_log_sbcount(mp, 1); |
| if (error) |
| xfs_fs_cmn_err(CE_WARN, mp, |
| "xfs_attr_quiesce: failed to log sb changes. " |
| "Frozen image may not be consistent."); |
| xfs_log_unmount_write(mp); |
| xfs_unmountfs_writesb(mp); |
| } |
| |
| /* |
| * Enqueue a work item to be picked up by the vfs xfssyncd thread. |
| * Doing this has two advantages: |
| * - It saves on stack space, which is tight in certain situations |
| * - It can be used (with care) as a mechanism to avoid deadlocks. |
| * Flushing while allocating in a full filesystem requires both. |
| */ |
| STATIC void |
| xfs_syncd_queue_work( |
| struct xfs_mount *mp, |
| void *data, |
| void (*syncer)(struct xfs_mount *, void *), |
| struct completion *completion) |
| { |
| struct xfs_sync_work *work; |
| |
| work = kmem_alloc(sizeof(struct xfs_sync_work), KM_SLEEP); |
| INIT_LIST_HEAD(&work->w_list); |
| work->w_syncer = syncer; |
| work->w_data = data; |
| work->w_mount = mp; |
| work->w_completion = completion; |
| spin_lock(&mp->m_sync_lock); |
| list_add_tail(&work->w_list, &mp->m_sync_list); |
| spin_unlock(&mp->m_sync_lock); |
| wake_up_process(mp->m_sync_task); |
| } |
| |
| /* |
| * Flush delayed allocate data, attempting to free up reserved space |
| * from existing allocations. At this point a new allocation attempt |
| * has failed with ENOSPC and we are in the process of scratching our |
| * heads, looking about for more room... |
| */ |
| STATIC void |
| xfs_flush_inodes_work( |
| struct xfs_mount *mp, |
| void *arg) |
| { |
| struct inode *inode = arg; |
| xfs_sync_data(mp, SYNC_TRYLOCK); |
| xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT); |
| iput(inode); |
| } |
| |
| void |
| xfs_flush_inodes( |
| xfs_inode_t *ip) |
| { |
| struct inode *inode = VFS_I(ip); |
| DECLARE_COMPLETION_ONSTACK(completion); |
| |
| igrab(inode); |
| xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inodes_work, &completion); |
| wait_for_completion(&completion); |
| xfs_log_force(ip->i_mount, XFS_LOG_SYNC); |
| } |
| |
| /* |
| * Every sync period we need to unpin all items, reclaim inodes and sync |
| * disk quotas. We might need to cover the log to indicate that the |
| * filesystem is idle and not frozen. |
| */ |
| STATIC void |
| xfs_sync_worker( |
| struct xfs_mount *mp, |
| void *unused) |
| { |
| int error; |
| |
| if (!(mp->m_flags & XFS_MOUNT_RDONLY)) { |
| xfs_log_force(mp, 0); |
| xfs_reclaim_inodes(mp, 0); |
| /* dgc: errors ignored here */ |
| error = xfs_qm_sync(mp, SYNC_TRYLOCK); |
| if (mp->m_super->s_frozen == SB_UNFROZEN && |
| xfs_log_need_covered(mp)) |
| error = xfs_fs_log_dummy(mp, 0); |
| } |
| mp->m_sync_seq++; |
| wake_up(&mp->m_wait_single_sync_task); |
| } |
| |
| STATIC int |
| xfssyncd( |
| void *arg) |
| { |
| struct xfs_mount *mp = arg; |
| long timeleft; |
| xfs_sync_work_t *work, *n; |
| LIST_HEAD (tmp); |
| |
| set_freezable(); |
| timeleft = xfs_syncd_centisecs * msecs_to_jiffies(10); |
| for (;;) { |
| if (list_empty(&mp->m_sync_list)) |
| timeleft = schedule_timeout_interruptible(timeleft); |
| /* swsusp */ |
| try_to_freeze(); |
| if (kthread_should_stop() && list_empty(&mp->m_sync_list)) |
| break; |
| |
| spin_lock(&mp->m_sync_lock); |
| /* |
| * We can get woken by laptop mode, to do a sync - |
| * that's the (only!) case where the list would be |
| * empty with time remaining. |
| */ |
| if (!timeleft || list_empty(&mp->m_sync_list)) { |
| if (!timeleft) |
| timeleft = xfs_syncd_centisecs * |
| msecs_to_jiffies(10); |
| INIT_LIST_HEAD(&mp->m_sync_work.w_list); |
| list_add_tail(&mp->m_sync_work.w_list, |
| &mp->m_sync_list); |
| } |
| list_splice_init(&mp->m_sync_list, &tmp); |
| spin_unlock(&mp->m_sync_lock); |
| |
| list_for_each_entry_safe(work, n, &tmp, w_list) { |
| (*work->w_syncer)(mp, work->w_data); |
| list_del(&work->w_list); |
| if (work == &mp->m_sync_work) |
| continue; |
| if (work->w_completion) |
| complete(work->w_completion); |
| kmem_free(work); |
| } |
| } |
| |
| return 0; |
| } |
| |
| int |
| xfs_syncd_init( |
| struct xfs_mount *mp) |
| { |
| mp->m_sync_work.w_syncer = xfs_sync_worker; |
| mp->m_sync_work.w_mount = mp; |
| mp->m_sync_work.w_completion = NULL; |
| mp->m_sync_task = kthread_run(xfssyncd, mp, "xfssyncd/%s", mp->m_fsname); |
| if (IS_ERR(mp->m_sync_task)) |
| return -PTR_ERR(mp->m_sync_task); |
| return 0; |
| } |
| |
| void |
| xfs_syncd_stop( |
| struct xfs_mount *mp) |
| { |
| kthread_stop(mp->m_sync_task); |
| } |
| |
| void |
| __xfs_inode_set_reclaim_tag( |
| struct xfs_perag *pag, |
| struct xfs_inode *ip) |
| { |
| radix_tree_tag_set(&pag->pag_ici_root, |
| XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), |
| XFS_ICI_RECLAIM_TAG); |
| |
| if (!pag->pag_ici_reclaimable) { |
| /* propagate the reclaim tag up into the perag radix tree */ |
| spin_lock(&ip->i_mount->m_perag_lock); |
| radix_tree_tag_set(&ip->i_mount->m_perag_tree, |
| XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino), |
| XFS_ICI_RECLAIM_TAG); |
| spin_unlock(&ip->i_mount->m_perag_lock); |
| trace_xfs_perag_set_reclaim(ip->i_mount, pag->pag_agno, |
| -1, _RET_IP_); |
| } |
| pag->pag_ici_reclaimable++; |
| } |
| |
| /* |
| * We set the inode flag atomically with the radix tree tag. |
| * Once we get tag lookups on the radix tree, this inode flag |
| * can go away. |
| */ |
| void |
| xfs_inode_set_reclaim_tag( |
| xfs_inode_t *ip) |
| { |
| struct xfs_mount *mp = ip->i_mount; |
| struct xfs_perag *pag; |
| |
| pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino)); |
| write_lock(&pag->pag_ici_lock); |
| spin_lock(&ip->i_flags_lock); |
| __xfs_inode_set_reclaim_tag(pag, ip); |
| __xfs_iflags_set(ip, XFS_IRECLAIMABLE); |
| spin_unlock(&ip->i_flags_lock); |
| write_unlock(&pag->pag_ici_lock); |
| xfs_perag_put(pag); |
| } |
| |
| STATIC void |
| __xfs_inode_clear_reclaim( |
| xfs_perag_t *pag, |
| xfs_inode_t *ip) |
| { |
| pag->pag_ici_reclaimable--; |
| if (!pag->pag_ici_reclaimable) { |
| /* clear the reclaim tag from the perag radix tree */ |
| spin_lock(&ip->i_mount->m_perag_lock); |
| radix_tree_tag_clear(&ip->i_mount->m_perag_tree, |
| XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino), |
| XFS_ICI_RECLAIM_TAG); |
| spin_unlock(&ip->i_mount->m_perag_lock); |
| trace_xfs_perag_clear_reclaim(ip->i_mount, pag->pag_agno, |
| -1, _RET_IP_); |
| } |
| } |
| |
| void |
| __xfs_inode_clear_reclaim_tag( |
| xfs_mount_t *mp, |
| xfs_perag_t *pag, |
| xfs_inode_t *ip) |
| { |
| radix_tree_tag_clear(&pag->pag_ici_root, |
| XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG); |
| __xfs_inode_clear_reclaim(pag, ip); |
| } |
| |
| /* |
| * Inodes in different states need to be treated differently, and the return |
| * value of xfs_iflush is not sufficient to get this right. The following table |
| * lists the inode states and the reclaim actions necessary for non-blocking |
| * reclaim: |
| * |
| * |
| * inode state iflush ret required action |
| * --------------- ---------- --------------- |
| * bad - reclaim |
| * shutdown EIO unpin and reclaim |
| * clean, unpinned 0 reclaim |
| * stale, unpinned 0 reclaim |
| * clean, pinned(*) 0 requeue |
| * stale, pinned EAGAIN requeue |
| * dirty, delwri ok 0 requeue |
| * dirty, delwri blocked EAGAIN requeue |
| * dirty, sync flush 0 reclaim |
| * |
| * (*) dgc: I don't think the clean, pinned state is possible but it gets |
| * handled anyway given the order of checks implemented. |
| * |
| * As can be seen from the table, the return value of xfs_iflush() is not |
| * sufficient to correctly decide the reclaim action here. The checks in |
| * xfs_iflush() might look like duplicates, but they are not. |
| * |
| * Also, because we get the flush lock first, we know that any inode that has |
| * been flushed delwri has had the flush completed by the time we check that |
| * the inode is clean. The clean inode check needs to be done before flushing |
| * the inode delwri otherwise we would loop forever requeuing clean inodes as |
| * we cannot tell apart a successful delwri flush and a clean inode from the |
| * return value of xfs_iflush(). |
| * |
| * Note that because the inode is flushed delayed write by background |
| * writeback, the flush lock may already be held here and waiting on it can |
| * result in very long latencies. Hence for sync reclaims, where we wait on the |
| * flush lock, the caller should push out delayed write inodes first before |
| * trying to reclaim them to minimise the amount of time spent waiting. For |
| * background relaim, we just requeue the inode for the next pass. |
| * |
| * Hence the order of actions after gaining the locks should be: |
| * bad => reclaim |
| * shutdown => unpin and reclaim |
| * pinned, delwri => requeue |
| * pinned, sync => unpin |
| * stale => reclaim |
| * clean => reclaim |
| * dirty, delwri => flush and requeue |
| * dirty, sync => flush, wait and reclaim |
| */ |
| STATIC int |
| xfs_reclaim_inode( |
| struct xfs_inode *ip, |
| struct xfs_perag *pag, |
| int sync_mode) |
| { |
| int error = 0; |
| |
| /* |
| * The radix tree lock here protects a thread in xfs_iget from racing |
| * with us starting reclaim on the inode. Once we have the |
| * XFS_IRECLAIM flag set it will not touch us. |
| */ |
| spin_lock(&ip->i_flags_lock); |
| ASSERT_ALWAYS(__xfs_iflags_test(ip, XFS_IRECLAIMABLE)); |
| if (__xfs_iflags_test(ip, XFS_IRECLAIM)) { |
| /* ignore as it is already under reclaim */ |
| spin_unlock(&ip->i_flags_lock); |
| write_unlock(&pag->pag_ici_lock); |
| return 0; |
| } |
| __xfs_iflags_set(ip, XFS_IRECLAIM); |
| spin_unlock(&ip->i_flags_lock); |
| write_unlock(&pag->pag_ici_lock); |
| |
| xfs_ilock(ip, XFS_ILOCK_EXCL); |
| if (!xfs_iflock_nowait(ip)) { |
| if (!(sync_mode & SYNC_WAIT)) |
| goto out; |
| xfs_iflock(ip); |
| } |
| |
| if (is_bad_inode(VFS_I(ip))) |
| goto reclaim; |
| if (XFS_FORCED_SHUTDOWN(ip->i_mount)) { |
| xfs_iunpin_wait(ip); |
| goto reclaim; |
| } |
| if (xfs_ipincount(ip)) { |
| if (!(sync_mode & SYNC_WAIT)) { |
| xfs_ifunlock(ip); |
| goto out; |
| } |
| xfs_iunpin_wait(ip); |
| } |
| if (xfs_iflags_test(ip, XFS_ISTALE)) |
| goto reclaim; |
| if (xfs_inode_clean(ip)) |
| goto reclaim; |
| |
| /* Now we have an inode that needs flushing */ |
| error = xfs_iflush(ip, sync_mode); |
| if (sync_mode & SYNC_WAIT) { |
| xfs_iflock(ip); |
| goto reclaim; |
| } |
| |
| /* |
| * When we have to flush an inode but don't have SYNC_WAIT set, we |
| * flush the inode out using a delwri buffer and wait for the next |
| * call into reclaim to find it in a clean state instead of waiting for |
| * it now. We also don't return errors here - if the error is transient |
| * then the next reclaim pass will flush the inode, and if the error |
| * is permanent then the next sync reclaim will reclaim the inode and |
| * pass on the error. |
| */ |
| if (error && error != EAGAIN && !XFS_FORCED_SHUTDOWN(ip->i_mount)) { |
| xfs_fs_cmn_err(CE_WARN, ip->i_mount, |
| "inode 0x%llx background reclaim flush failed with %d", |
| (long long)ip->i_ino, error); |
| } |
| out: |
| xfs_iflags_clear(ip, XFS_IRECLAIM); |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| /* |
| * We could return EAGAIN here to make reclaim rescan the inode tree in |
| * a short while. However, this just burns CPU time scanning the tree |
| * waiting for IO to complete and xfssyncd never goes back to the idle |
| * state. Instead, return 0 to let the next scheduled background reclaim |
| * attempt to reclaim the inode again. |
| */ |
| return 0; |
| |
| reclaim: |
| xfs_ifunlock(ip); |
| xfs_iunlock(ip, XFS_ILOCK_EXCL); |
| |
| XFS_STATS_INC(xs_ig_reclaims); |
| /* |
| * Remove the inode from the per-AG radix tree. |
| * |
| * Because radix_tree_delete won't complain even if the item was never |
| * added to the tree assert that it's been there before to catch |
| * problems with the inode life time early on. |
| */ |
| write_lock(&pag->pag_ici_lock); |
| if (!radix_tree_delete(&pag->pag_ici_root, |
| XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino))) |
| ASSERT(0); |
| __xfs_inode_clear_reclaim(pag, ip); |
| write_unlock(&pag->pag_ici_lock); |
| |
| /* |
| * Here we do an (almost) spurious inode lock in order to coordinate |
| * with inode cache radix tree lookups. This is because the lookup |
| * can reference the inodes in the cache without taking references. |
| * |
| * We make that OK here by ensuring that we wait until the inode is |
| * unlocked after the lookup before we go ahead and free it. We get |
| * both the ilock and the iolock because the code may need to drop the |
| * ilock one but will still hold the iolock. |
| */ |
| xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL); |
| xfs_qm_dqdetach(ip); |
| xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL); |
| |
| xfs_inode_free(ip); |
| return error; |
| |
| } |
| |
| int |
| xfs_reclaim_inodes( |
| xfs_mount_t *mp, |
| int mode) |
| { |
| return xfs_inode_ag_iterator(mp, xfs_reclaim_inode, mode, |
| XFS_ICI_RECLAIM_TAG, 1, NULL); |
| } |
| |
| /* |
| * Shrinker infrastructure. |
| */ |
| static int |
| xfs_reclaim_inode_shrink( |
| struct shrinker *shrink, |
| int nr_to_scan, |
| gfp_t gfp_mask) |
| { |
| struct xfs_mount *mp; |
| struct xfs_perag *pag; |
| xfs_agnumber_t ag; |
| int reclaimable; |
| |
| mp = container_of(shrink, struct xfs_mount, m_inode_shrink); |
| if (nr_to_scan) { |
| if (!(gfp_mask & __GFP_FS)) |
| return -1; |
| |
| xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0, |
| XFS_ICI_RECLAIM_TAG, 1, &nr_to_scan); |
| /* if we don't exhaust the scan, don't bother coming back */ |
| if (nr_to_scan > 0) |
| return -1; |
| } |
| |
| reclaimable = 0; |
| ag = 0; |
| while ((pag = xfs_inode_ag_iter_next_pag(mp, &ag, |
| XFS_ICI_RECLAIM_TAG))) { |
| reclaimable += pag->pag_ici_reclaimable; |
| xfs_perag_put(pag); |
| } |
| return reclaimable; |
| } |
| |
| void |
| xfs_inode_shrinker_register( |
| struct xfs_mount *mp) |
| { |
| mp->m_inode_shrink.shrink = xfs_reclaim_inode_shrink; |
| mp->m_inode_shrink.seeks = DEFAULT_SEEKS; |
| register_shrinker(&mp->m_inode_shrink); |
| } |
| |
| void |
| xfs_inode_shrinker_unregister( |
| struct xfs_mount *mp) |
| { |
| unregister_shrinker(&mp->m_inode_shrink); |
| } |