diff options
Diffstat (limited to 'fs/xfs/xfs_icache.c')
| -rw-r--r-- | fs/xfs/xfs_icache.c | 1692 |
1 files changed, 1692 insertions, 0 deletions
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c new file mode 100644 index 000000000..e69a08ed7 --- /dev/null +++ b/fs/xfs/xfs_icache.c @@ -0,0 +1,1692 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2000-2005 Silicon Graphics, Inc. + * All Rights Reserved. + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_sb.h" +#include "xfs_mount.h" +#include "xfs_inode.h" +#include "xfs_trans.h" +#include "xfs_trans_priv.h" +#include "xfs_inode_item.h" +#include "xfs_quota.h" +#include "xfs_trace.h" +#include "xfs_icache.h" +#include "xfs_bmap_util.h" +#include "xfs_dquot_item.h" +#include "xfs_dquot.h" +#include "xfs_reflink.h" +#include "xfs_ialloc.h" + +#include <linux/iversion.h> + +/* + * Allocate and initialise an xfs_inode. + */ +struct xfs_inode * +xfs_inode_alloc( + struct xfs_mount *mp, + xfs_ino_t ino) +{ + struct xfs_inode *ip; + + /* + * XXX: If this didn't occur in transactions, we could drop GFP_NOFAIL + * and return NULL here on ENOMEM. + */ + ip = kmem_cache_alloc(xfs_inode_zone, GFP_KERNEL | __GFP_NOFAIL); + + if (inode_init_always(mp->m_super, VFS_I(ip))) { + kmem_cache_free(xfs_inode_zone, ip); + return NULL; + } + + /* VFS doesn't initialise i_mode or i_state! */ + VFS_I(ip)->i_mode = 0; + VFS_I(ip)->i_state = 0; + + XFS_STATS_INC(mp, vn_active); + ASSERT(atomic_read(&ip->i_pincount) == 0); + ASSERT(ip->i_ino == 0); + + /* 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; + ip->i_cowfp = NULL; + memset(&ip->i_df, 0, sizeof(ip->i_df)); + ip->i_flags = 0; + ip->i_delayed_blks = 0; + memset(&ip->i_d, 0, sizeof(ip->i_d)); + ip->i_sick = 0; + ip->i_checked = 0; + INIT_WORK(&ip->i_ioend_work, xfs_end_io); + INIT_LIST_HEAD(&ip->i_ioend_list); + spin_lock_init(&ip->i_ioend_lock); + + 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); + + switch (VFS_I(ip)->i_mode & S_IFMT) { + case S_IFREG: + case S_IFDIR: + case S_IFLNK: + xfs_idestroy_fork(&ip->i_df); + break; + } + + if (ip->i_afp) { + xfs_idestroy_fork(ip->i_afp); + kmem_cache_free(xfs_ifork_zone, ip->i_afp); + } + if (ip->i_cowfp) { + xfs_idestroy_fork(ip->i_cowfp); + kmem_cache_free(xfs_ifork_zone, ip->i_cowfp); + } + if (ip->i_itemp) { + ASSERT(!test_bit(XFS_LI_IN_AIL, + &ip->i_itemp->ili_item.li_flags)); + xfs_inode_item_destroy(ip); + ip->i_itemp = NULL; + } + + kmem_cache_free(xfs_inode_zone, ip); +} + +static void +__xfs_inode_free( + struct xfs_inode *ip) +{ + /* asserts to verify all state is correct here */ + ASSERT(atomic_read(&ip->i_pincount) == 0); + ASSERT(!ip->i_itemp || list_empty(&ip->i_itemp->ili_item.li_bio_list)); + XFS_STATS_DEC(ip->i_mount, vn_active); + + call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback); +} + +void +xfs_inode_free( + struct xfs_inode *ip) +{ + ASSERT(!xfs_iflags_test(ip, XFS_IFLUSHING)); + + /* + * 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); + + __xfs_inode_free(ip); +} + +/* + * Queue background inode reclaim work if there are reclaimable inodes and there + * isn't reclaim work already scheduled or in progress. + */ +static void +xfs_reclaim_work_queue( + struct xfs_mount *mp) +{ + + rcu_read_lock(); + if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) { + queue_delayed_work(mp->m_reclaim_workqueue, &mp->m_reclaim_work, + msecs_to_jiffies(xfs_syncd_centisecs / 6 * 10)); + } + rcu_read_unlock(); +} + +static void +xfs_perag_set_reclaim_tag( + struct xfs_perag *pag) +{ + struct xfs_mount *mp = pag->pag_mount; + + lockdep_assert_held(&pag->pag_ici_lock); + if (pag->pag_ici_reclaimable++) + return; + + /* propagate the reclaim tag up into the perag radix tree */ + spin_lock(&mp->m_perag_lock); + radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno, + XFS_ICI_RECLAIM_TAG); + spin_unlock(&mp->m_perag_lock); + + /* schedule periodic background inode reclaim */ + xfs_reclaim_work_queue(mp); + + trace_xfs_perag_set_reclaim(mp, pag->pag_agno, -1, _RET_IP_); +} + +static void +xfs_perag_clear_reclaim_tag( + struct xfs_perag *pag) +{ + struct xfs_mount *mp = pag->pag_mount; + + lockdep_assert_held(&pag->pag_ici_lock); + if (--pag->pag_ici_reclaimable) + return; + + /* clear the reclaim tag from the perag radix tree */ + spin_lock(&mp->m_perag_lock); + radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno, + XFS_ICI_RECLAIM_TAG); + spin_unlock(&mp->m_perag_lock); + trace_xfs_perag_clear_reclaim(mp, pag->pag_agno, -1, _RET_IP_); +} + + +/* + * 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( + struct xfs_inode *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)); + spin_lock(&pag->pag_ici_lock); + spin_lock(&ip->i_flags_lock); + + radix_tree_tag_set(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino), + XFS_ICI_RECLAIM_TAG); + xfs_perag_set_reclaim_tag(pag); + __xfs_iflags_set(ip, XFS_IRECLAIMABLE); + + spin_unlock(&ip->i_flags_lock); + spin_unlock(&pag->pag_ici_lock); + xfs_perag_put(pag); +} + +STATIC void +xfs_inode_clear_reclaim_tag( + struct xfs_perag *pag, + xfs_ino_t ino) +{ + radix_tree_tag_clear(&pag->pag_ici_root, + XFS_INO_TO_AGINO(pag->pag_mount, ino), + XFS_ICI_RECLAIM_TAG); + xfs_perag_clear_reclaim_tag(pag); +} + +static void +xfs_inew_wait( + struct xfs_inode *ip) +{ + wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_INEW_BIT); + DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_INEW_BIT); + + do { + prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE); + if (!xfs_iflags_test(ip, XFS_INEW)) + break; + schedule(); + } while (true); + finish_wait(wq, &wait.wq_entry); +} + +/* + * When we recycle a reclaimable inode, we need to re-initialise the VFS inode + * part of the structure. This is made more complex by the fact we store + * information about the on-disk values in the VFS inode and so we can't just + * overwrite the values unconditionally. Hence we save the parameters we + * need to retain across reinitialisation, and rewrite them into the VFS inode + * after reinitialisation even if it fails. + */ +static int +xfs_reinit_inode( + struct xfs_mount *mp, + struct inode *inode) +{ + int error; + uint32_t nlink = inode->i_nlink; + uint32_t generation = inode->i_generation; + uint64_t version = inode_peek_iversion(inode); + umode_t mode = inode->i_mode; + dev_t dev = inode->i_rdev; + kuid_t uid = inode->i_uid; + kgid_t gid = inode->i_gid; + + error = inode_init_always(mp->m_super, inode); + + set_nlink(inode, nlink); + inode->i_generation = generation; + inode_set_iversion_queried(inode, version); + inode->i_mode = mode; + inode->i_rdev = dev; + inode->i_uid = uid; + inode->i_gid = gid; + return error; +} + +/* + * If we are allocating a new inode, then check what was returned is + * actually a free, empty inode. If we are not allocating an inode, + * then check we didn't find a free inode. + * + * Returns: + * 0 if the inode free state matches the lookup context + * -ENOENT if the inode is free and we are not allocating + * -EFSCORRUPTED if there is any state mismatch at all + */ +static int +xfs_iget_check_free_state( + struct xfs_inode *ip, + int flags) +{ + if (flags & XFS_IGET_CREATE) { + /* should be a free inode */ + if (VFS_I(ip)->i_mode != 0) { + xfs_warn(ip->i_mount, +"Corruption detected! Free inode 0x%llx not marked free! (mode 0x%x)", + ip->i_ino, VFS_I(ip)->i_mode); + return -EFSCORRUPTED; + } + + if (ip->i_d.di_nblocks != 0) { + xfs_warn(ip->i_mount, +"Corruption detected! Free inode 0x%llx has blocks allocated!", + ip->i_ino); + return -EFSCORRUPTED; + } + return 0; + } + + /* should be an allocated inode */ + if (VFS_I(ip)->i_mode == 0) + return -ENOENT; + + return 0; +} + +/* + * 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(mp, 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(mp, xs_ig_frecycle); + error = -EAGAIN; + goto out_error; + } + + /* + * Check the inode free state is valid. This also detects lookup + * racing with unlinks. + */ + error = xfs_iget_check_free_state(ip, flags); + if (error) + 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); + + if (flags & XFS_IGET_INCORE) { + error = -EAGAIN; + goto out_error; + } + + /* + * 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(); + + ASSERT(!rwsem_is_locked(&inode->i_rwsem)); + error = xfs_reinit_inode(mp, inode); + if (error) { + bool wake; + /* + * 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); + wake = !!__xfs_iflags_test(ip, XFS_INEW); + ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM); + if (wake) + wake_up_bit(&ip->i_flags, __XFS_INEW_BIT); + ASSERT(ip->i_flags & XFS_IRECLAIMABLE); + trace_xfs_iget_reclaim_fail(ip); + goto out_error; + } + + spin_lock(&pag->pag_ici_lock); + spin_lock(&ip->i_flags_lock); + + /* + * Clear the per-lifetime state in the inode as we are now + * effectively a new inode and need to return to the initial + * state before reuse occurs. + */ + ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS; + ip->i_flags |= XFS_INEW; + xfs_inode_clear_reclaim_tag(pag, ip->i_ino); + inode->i_state = I_NEW; + ip->i_sick = 0; + ip->i_checked = 0; + + 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); + + if (!(flags & XFS_IGET_INCORE)) + xfs_iflags_clear(ip, XFS_ISTALE); + XFS_STATS_INC(mp, 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); + int iflags; + + ip = xfs_inode_alloc(mp, ino); + if (!ip) + return -ENOMEM; + + error = xfs_imap(mp, tp, ip->i_ino, &ip->i_imap, flags); + if (error) + goto out_destroy; + + /* + * For version 5 superblocks, if we are initialising a new inode and we + * are not utilising the XFS_MOUNT_IKEEP inode cluster mode, we can + * simply build the new inode core with a random generation number. + * + * For version 4 (and older) superblocks, log recovery is dependent on + * the di_flushiter field being initialised from the current on-disk + * value and hence we must also read the inode off disk even when + * initializing new inodes. + */ + if (xfs_sb_version_has_v3inode(&mp->m_sb) && + (flags & XFS_IGET_CREATE) && !(mp->m_flags & XFS_MOUNT_IKEEP)) { + VFS_I(ip)->i_generation = prandom_u32(); + } else { + struct xfs_dinode *dip; + struct xfs_buf *bp; + + error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &dip, &bp, 0); + if (error) + goto out_destroy; + + error = xfs_inode_from_disk(ip, dip); + if (!error) + xfs_buf_set_ref(bp, XFS_INO_REF); + xfs_trans_brelse(tp, bp); + + if (error) + goto out_destroy; + } + + trace_xfs_iget_miss(ip); + + /* + * Check the inode free state is valid. This also detects lookup + * racing with unlinks. + */ + error = xfs_iget_check_free_state(ip, flags); + if (error) + 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. Since we can be called from transaction context, don't + * recurse into the file system. + */ + if (radix_tree_preload(GFP_NOFS)) { + 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(); + } + + /* + * These values must be set before inserting the inode into the radix + * tree as the moment it is inserted a concurrent lookup (allowed by the + * RCU locking mechanism) can find it and that lookup must see that this + * 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 + * time. + */ + iflags = XFS_INEW; + if (flags & XFS_IGET_DONTCACHE) + d_mark_dontcache(VFS_I(ip)); + ip->i_udquot = NULL; + ip->i_gdquot = NULL; + ip->i_pdquot = 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(mp, 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. + * Inode lookup is only done during metadata operations and not as part of the + * data IO path. Hence we only allow locking of the XFS_ILOCK during lookup. + */ +int +xfs_iget( + struct xfs_mount *mp, + struct xfs_trans *tp, + xfs_ino_t ino, + uint flags, + uint lock_flags, + struct xfs_inode **ipp) +{ + struct xfs_inode *ip; + struct xfs_perag *pag; + xfs_agino_t agino; + int error; + + 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; + + XFS_STATS_INC(mp, xs_ig_attempts); + + /* 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(); + if (flags & XFS_IGET_INCORE) { + error = -ENODATA; + goto out_error_or_again; + } + XFS_STATS_INC(mp, 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 setup the inode + * now. If it's a new inode being created, xfs_ialloc will handle it. + */ + if (xfs_iflags_test(ip, XFS_INEW) && VFS_I(ip)->i_mode != 0) + xfs_setup_existing_inode(ip); + return 0; + +out_error_or_again: + if (!(flags & XFS_IGET_INCORE) && error == -EAGAIN) { + delay(1); + goto again; + } + xfs_perag_put(pag); + return error; +} + +/* + * "Is this a cached inode that's also allocated?" + * + * Look up an inode by number in the given file system. If the inode is + * in cache and isn't in purgatory, return 1 if the inode is allocated + * and 0 if it is not. For all other cases (not in cache, being torn + * down, etc.), return a negative error code. + * + * The caller has to prevent inode allocation and freeing activity, + * presumably by locking the AGI buffer. This is to ensure that an + * inode cannot transition from allocated to freed until the caller is + * ready to allow that. If the inode is in an intermediate state (new, + * reclaimable, or being reclaimed), -EAGAIN will be returned; if the + * inode is not in the cache, -ENOENT will be returned. The caller must + * deal with these scenarios appropriately. + * + * This is a specialized use case for the online scrubber; if you're + * reading this, you probably want xfs_iget. + */ +int +xfs_icache_inode_is_allocated( + struct xfs_mount *mp, + struct xfs_trans *tp, + xfs_ino_t ino, + bool *inuse) +{ + struct xfs_inode *ip; + int error; + + error = xfs_iget(mp, tp, ino, XFS_IGET_INCORE, 0, &ip); + if (error) + return error; + + *inuse = !!(VFS_I(ip)->i_mode); + xfs_irele(ip); + return 0; +} + +/* + * The inode lookup is done in batches to keep the amount of lock traffic and + * radix tree lookups to a minimum. The batch size is a trade off between + * lookup reduction and stack usage. This is in the reclaim path, so we can't + * be too greedy. + */ +#define XFS_LOOKUP_BATCH 32 + +/* + * Decide if the given @ip is eligible to be a part of the inode walk, and + * grab it if so. Returns true if it's ready to go or false if we should just + * ignore it. + */ +STATIC bool +xfs_inode_walk_ag_grab( + struct xfs_inode *ip, + int flags) +{ + struct inode *inode = VFS_I(ip); + bool newinos = !!(flags & XFS_INODE_WALK_INEW_WAIT); + + ASSERT(rcu_read_lock_held()); + + /* Check for stale RCU freed inode */ + spin_lock(&ip->i_flags_lock); + if (!ip->i_ino) + goto out_unlock_noent; + + /* avoid new or reclaimable inodes. Leave for reclaim code to flush */ + if ((!newinos && __xfs_iflags_test(ip, XFS_INEW)) || + __xfs_iflags_test(ip, XFS_IRECLAIMABLE | XFS_IRECLAIM)) + goto out_unlock_noent; + spin_unlock(&ip->i_flags_lock); + + /* nothing to sync during shutdown */ + if (XFS_FORCED_SHUTDOWN(ip->i_mount)) + return false; + + /* If we can't grab the inode, it must on it's way to reclaim. */ + if (!igrab(inode)) + return false; + + /* inode is valid */ + return true; + +out_unlock_noent: + spin_unlock(&ip->i_flags_lock); + return false; +} + +/* + * For a given per-AG structure @pag, grab, @execute, and rele all incore + * inodes with the given radix tree @tag. + */ +STATIC int +xfs_inode_walk_ag( + struct xfs_perag *pag, + int iter_flags, + int (*execute)(struct xfs_inode *ip, void *args), + void *args, + int tag) +{ + struct xfs_mount *mp = pag->pag_mount; + uint32_t first_index; + int last_error = 0; + int skipped; + bool done; + int nr_found; + +restart: + done = false; + skipped = 0; + first_index = 0; + nr_found = 0; + do { + struct xfs_inode *batch[XFS_LOOKUP_BATCH]; + int error = 0; + int i; + + rcu_read_lock(); + + if (tag == XFS_ICI_NO_TAG) + nr_found = radix_tree_gang_lookup(&pag->pag_ici_root, + (void **)batch, first_index, + XFS_LOOKUP_BATCH); + else + nr_found = radix_tree_gang_lookup_tag( + &pag->pag_ici_root, + (void **) batch, first_index, + XFS_LOOKUP_BATCH, tag); + + if (!nr_found) { + rcu_read_unlock(); + break; + } + + /* + * Grab the inodes before we drop the lock. if we found + * nothing, nr == 0 and the loop will be skipped. + */ + for (i = 0; i < nr_found; i++) { + struct xfs_inode *ip = batch[i]; + + if (done || !xfs_inode_walk_ag_grab(ip, iter_flags)) + batch[i] = 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. + * + * Because we may see inodes that are from the wrong AG + * due to RCU freeing and reallocation, only update the + * index if it lies in this AG. It was a race that lead + * us to see this inode, so another lookup from the + * same index will not find it again. + */ + if (XFS_INO_TO_AGNO(mp, ip->i_ino) != pag->pag_agno) + continue; + first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1); + if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino)) + done = true; + } + + /* unlock now we've grabbed the inodes. */ + rcu_read_unlock(); + + for (i = 0; i < nr_found; i++) { + if (!batch[i]) + continue; + if ((iter_flags & XFS_INODE_WALK_INEW_WAIT) && + xfs_iflags_test(batch[i], XFS_INEW)) + xfs_inew_wait(batch[i]); + error = execute(batch[i], args); + xfs_irele(batch[i]); + if (error == -EAGAIN) { + skipped++; + continue; + } + if (error && last_error != -EFSCORRUPTED) + last_error = error; + } + + /* bail out if the filesystem is corrupted. */ + if (error == -EFSCORRUPTED) + break; + + cond_resched(); + + } while (nr_found && !done); + + if (skipped) { + delay(1); + goto restart; + } + return last_error; +} + +/* Fetch the next (possibly tagged) per-AG structure. */ +static inline struct xfs_perag * +xfs_inode_walk_get_perag( + struct xfs_mount *mp, + xfs_agnumber_t agno, + int tag) +{ + if (tag == XFS_ICI_NO_TAG) + return xfs_perag_get(mp, agno); + return xfs_perag_get_tag(mp, agno, tag); +} + +/* + * Call the @execute function on all incore inodes matching the radix tree + * @tag. + */ +int +xfs_inode_walk( + struct xfs_mount *mp, + int iter_flags, + int (*execute)(struct xfs_inode *ip, void *args), + void *args, + int tag) +{ + struct xfs_perag *pag; + int error = 0; + int last_error = 0; + xfs_agnumber_t ag; + + ag = 0; + while ((pag = xfs_inode_walk_get_perag(mp, ag, tag))) { + ag = pag->pag_agno + 1; + error = xfs_inode_walk_ag(pag, iter_flags, execute, args, tag); + xfs_perag_put(pag); + if (error) { + last_error = error; + if (error == -EFSCORRUPTED) + break; + } + } + return last_error; +} + +/* + * Background scanning to trim post-EOF preallocated space. This is queued + * based on the 'speculative_prealloc_lifetime' tunable (5m by default). + */ +void +xfs_queue_eofblocks( + struct xfs_mount *mp) +{ + rcu_read_lock(); + if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_EOFBLOCKS_TAG)) + queue_delayed_work(mp->m_eofblocks_workqueue, + &mp->m_eofblocks_work, + msecs_to_jiffies(xfs_eofb_secs * 1000)); + rcu_read_unlock(); +} + +void +xfs_eofblocks_worker( + struct work_struct *work) +{ + struct xfs_mount *mp = container_of(to_delayed_work(work), + struct xfs_mount, m_eofblocks_work); + + if (!sb_start_write_trylock(mp->m_super)) + return; + xfs_icache_free_eofblocks(mp, NULL); + sb_end_write(mp->m_super); + + xfs_queue_eofblocks(mp); +} + +/* + * Background scanning to trim preallocated CoW space. This is queued + * based on the 'speculative_cow_prealloc_lifetime' tunable (5m by default). + * (We'll just piggyback on the post-EOF prealloc space workqueue.) + */ +void +xfs_queue_cowblocks( + struct xfs_mount *mp) +{ + rcu_read_lock(); + if (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_COWBLOCKS_TAG)) + queue_delayed_work(mp->m_eofblocks_workqueue, + &mp->m_cowblocks_work, + msecs_to_jiffies(xfs_cowb_secs * 1000)); + rcu_read_unlock(); +} + +void +xfs_cowblocks_worker( + struct work_struct *work) +{ + struct xfs_mount *mp = container_of(to_delayed_work(work), + struct xfs_mount, m_cowblocks_work); + + if (!sb_start_write_trylock(mp->m_super)) + return; + xfs_icache_free_cowblocks(mp, NULL); + sb_end_write(mp->m_super); + + xfs_queue_cowblocks(mp); +} + +/* + * Grab the inode for reclaim exclusively. + * + * We have found this inode via a lookup under RCU, so the inode may have + * already been freed, or it may be in the process of being recycled by + * xfs_iget(). In both cases, the inode will have XFS_IRECLAIM set. If the inode + * has been fully recycled by the time we get the i_flags_lock, XFS_IRECLAIMABLE + * will not be set. Hence we need to check for both these flag conditions to + * avoid inodes that are no longer reclaim candidates. + * + * Note: checking for other state flags here, under the i_flags_lock or not, is + * racy and should be avoided. Those races should be resolved only after we have + * ensured that we are able to reclaim this inode and the world can see that we + * are going to reclaim it. + * + * Return true if we grabbed it, false otherwise. + */ +static bool +xfs_reclaim_inode_grab( + struct xfs_inode *ip) +{ + ASSERT(rcu_read_lock_held()); + + spin_lock(&ip->i_flags_lock); + if (!__xfs_iflags_test(ip, XFS_IRECLAIMABLE) || + __xfs_iflags_test(ip, XFS_IRECLAIM)) { + /* not a reclaim candidate. */ + spin_unlock(&ip->i_flags_lock); + return false; + } + __xfs_iflags_set(ip, XFS_IRECLAIM); + spin_unlock(&ip->i_flags_lock); + return true; +} + +/* + * Inode reclaim is non-blocking, so the default action if progress cannot be + * made is to "requeue" the inode for reclaim by unlocking it and clearing the + * XFS_IRECLAIM flag. If we are in a shutdown state, we don't care about + * blocking anymore and hence we can wait for the inode to be able to reclaim + * it. + * + * We do no IO here - if callers require inodes to be cleaned they must push the + * AIL first to trigger writeback of dirty inodes. This enables writeback to be + * done in the background in a non-blocking manner, and enables memory reclaim + * to make progress without blocking. + */ +static void +xfs_reclaim_inode( + struct xfs_inode *ip, + struct xfs_perag *pag) +{ + xfs_ino_t ino = ip->i_ino; /* for radix_tree_delete */ + + if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) + goto out; + if (xfs_iflags_test_and_set(ip, XFS_IFLUSHING)) + goto out_iunlock; + + if (XFS_FORCED_SHUTDOWN(ip->i_mount)) { + xfs_iunpin_wait(ip); + xfs_iflush_abort(ip); + goto reclaim; + } + if (xfs_ipincount(ip)) + goto out_clear_flush; + if (!xfs_inode_clean(ip)) + goto out_clear_flush; + + xfs_iflags_clear(ip, XFS_IFLUSHING); +reclaim: + + /* + * 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. + * We do this as early as possible under the ILOCK so that + * xfs_iflush_cluster() and xfs_ifree_cluster() can be guaranteed to + * detect races with us here. By doing this, we guarantee that once + * xfs_iflush_cluster() or xfs_ifree_cluster() has locked XFS_ILOCK that + * it will see either a valid inode that will serialise correctly, or it + * will see an invalid inode that it can skip. + */ + spin_lock(&ip->i_flags_lock); + ip->i_flags = XFS_IRECLAIM; + ip->i_ino = 0; + spin_unlock(&ip->i_flags_lock); + + xfs_iunlock(ip, XFS_ILOCK_EXCL); + + XFS_STATS_INC(ip->i_mount, 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. + */ + spin_lock(&pag->pag_ici_lock); + if (!radix_tree_delete(&pag->pag_ici_root, + XFS_INO_TO_AGINO(ip->i_mount, ino))) + ASSERT(0); + xfs_perag_clear_reclaim_tag(pag); + spin_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. + */ + xfs_ilock(ip, XFS_ILOCK_EXCL); + xfs_qm_dqdetach(ip); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + ASSERT(xfs_inode_clean(ip)); + + __xfs_inode_free(ip); + return; + +out_clear_flush: + xfs_iflags_clear(ip, XFS_IFLUSHING); +out_iunlock: + xfs_iunlock(ip, XFS_ILOCK_EXCL); +out: + xfs_iflags_clear(ip, XFS_IRECLAIM); +} + +/* + * Walk the AGs and reclaim the inodes in them. Even if the filesystem is + * corrupted, we still want to try to reclaim all the inodes. If we don't, + * then a shut down during filesystem unmount reclaim walk leak all the + * unreclaimed inodes. + * + * Returns non-zero if any AGs or inodes were skipped in the reclaim pass + * so that callers that want to block until all dirty inodes are written back + * and reclaimed can sanely loop. + */ +static void +xfs_reclaim_inodes_ag( + struct xfs_mount *mp, + int *nr_to_scan) +{ + struct xfs_perag *pag; + xfs_agnumber_t ag = 0; + + while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) { + unsigned long first_index = 0; + int done = 0; + int nr_found = 0; + + ag = pag->pag_agno + 1; + + first_index = READ_ONCE(pag->pag_ici_reclaim_cursor); + do { + struct xfs_inode *batch[XFS_LOOKUP_BATCH]; + int i; + + rcu_read_lock(); + nr_found = radix_tree_gang_lookup_tag( + &pag->pag_ici_root, + (void **)batch, first_index, + XFS_LOOKUP_BATCH, + XFS_ICI_RECLAIM_TAG); + if (!nr_found) { + done = 1; + rcu_read_unlock(); + break; + } + + /* + * Grab the inodes before we drop the lock. if we found + * nothing, nr == 0 and the loop will be skipped. + */ + for (i = 0; i < nr_found; i++) { + struct xfs_inode *ip = batch[i]; + + if (done || !xfs_reclaim_inode_grab(ip)) + batch[i] = 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. + * + * Because we may see inodes that are from the + * wrong AG due to RCU freeing and + * reallocation, only update the index if it + * lies in this AG. It was a race that lead us + * to see this inode, so another lookup from + * the same index will not find it again. + */ + if (XFS_INO_TO_AGNO(mp, ip->i_ino) != + pag->pag_agno) + continue; + first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1); + if (first_index < XFS_INO_TO_AGINO(mp, ip->i_ino)) + done = 1; + } + + /* unlock now we've grabbed the inodes. */ + rcu_read_unlock(); + + for (i = 0; i < nr_found; i++) { + if (batch[i]) + xfs_reclaim_inode(batch[i], pag); + } + + *nr_to_scan -= XFS_LOOKUP_BATCH; + cond_resched(); + } while (nr_found && !done && *nr_to_scan > 0); + + if (done) + first_index = 0; + WRITE_ONCE(pag->pag_ici_reclaim_cursor, first_index); + xfs_perag_put(pag); + } +} + +void +xfs_reclaim_inodes( + struct xfs_mount *mp) +{ + int nr_to_scan = INT_MAX; + + while (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) { + xfs_ail_push_all_sync(mp->m_ail); + xfs_reclaim_inodes_ag(mp, &nr_to_scan); + } +} + +/* + * The shrinker infrastructure determines how many inodes we should scan for + * reclaim. We want as many clean inodes ready to reclaim as possible, so we + * push the AIL here. We also want to proactively free up memory if we can to + * minimise the amount of work memory reclaim has to do so we kick the + * background reclaim if it isn't already scheduled. + */ +long +xfs_reclaim_inodes_nr( + struct xfs_mount *mp, + int nr_to_scan) +{ + /* kick background reclaimer and push the AIL */ + xfs_reclaim_work_queue(mp); + xfs_ail_push_all(mp->m_ail); + + xfs_reclaim_inodes_ag(mp, &nr_to_scan); + return 0; +} + +/* + * Return the number of reclaimable inodes in the filesystem for + * the shrinker to determine how much to reclaim. + */ +int +xfs_reclaim_inodes_count( + struct xfs_mount *mp) +{ + struct xfs_perag *pag; + xfs_agnumber_t ag = 0; + int reclaimable = 0; + + while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) { + ag = pag->pag_agno + 1; + reclaimable += pag->pag_ici_reclaimable; + xfs_perag_put(pag); + } + return reclaimable; +} + +STATIC bool +xfs_inode_match_id( + struct xfs_inode *ip, + struct xfs_eofblocks *eofb) +{ + if ((eofb->eof_flags & XFS_EOF_FLAGS_UID) && + !uid_eq(VFS_I(ip)->i_uid, eofb->eof_uid)) + return false; + + if ((eofb->eof_flags & XFS_EOF_FLAGS_GID) && + !gid_eq(VFS_I(ip)->i_gid, eofb->eof_gid)) + return false; + + if ((eofb->eof_flags & XFS_EOF_FLAGS_PRID) && + ip->i_d.di_projid != eofb->eof_prid) + return false; + + return true; +} + +/* + * A union-based inode filtering algorithm. Process the inode if any of the + * criteria match. This is for global/internal scans only. + */ +STATIC bool +xfs_inode_match_id_union( + struct xfs_inode *ip, + struct xfs_eofblocks *eofb) +{ + if ((eofb->eof_flags & XFS_EOF_FLAGS_UID) && + uid_eq(VFS_I(ip)->i_uid, eofb->eof_uid)) + return true; + + if ((eofb->eof_flags & XFS_EOF_FLAGS_GID) && + gid_eq(VFS_I(ip)->i_gid, eofb->eof_gid)) + return true; + + if ((eofb->eof_flags & XFS_EOF_FLAGS_PRID) && + ip->i_d.di_projid == eofb->eof_prid) + return true; + + return false; +} + +/* + * Is this inode @ip eligible for eof/cow block reclamation, given some + * filtering parameters @eofb? The inode is eligible if @eofb is null or + * if the predicate functions match. + */ +static bool +xfs_inode_matches_eofb( + struct xfs_inode *ip, + struct xfs_eofblocks *eofb) +{ + bool match; + + if (!eofb) + return true; + + if (eofb->eof_flags & XFS_EOF_FLAGS_UNION) + match = xfs_inode_match_id_union(ip, eofb); + else + match = xfs_inode_match_id(ip, eofb); + if (!match) + return false; + + /* skip the inode if the file size is too small */ + if ((eofb->eof_flags & XFS_EOF_FLAGS_MINFILESIZE) && + XFS_ISIZE(ip) < eofb->eof_min_file_size) + return false; + + return true; +} + +/* + * This is a fast pass over the inode cache to try to get reclaim moving on as + * many inodes as possible in a short period of time. It kicks itself every few + * seconds, as well as being kicked by the inode cache shrinker when memory + * goes low. + */ +void +xfs_reclaim_worker( + struct work_struct *work) +{ + struct xfs_mount *mp = container_of(to_delayed_work(work), + struct xfs_mount, m_reclaim_work); + int nr_to_scan = INT_MAX; + + xfs_reclaim_inodes_ag(mp, &nr_to_scan); + xfs_reclaim_work_queue(mp); +} + +STATIC int +xfs_inode_free_eofblocks( + struct xfs_inode *ip, + void *args) +{ + struct xfs_eofblocks *eofb = args; + bool wait; + int ret; + + wait = eofb && (eofb->eof_flags & XFS_EOF_FLAGS_SYNC); + + if (!xfs_can_free_eofblocks(ip, false)) { + /* inode could be preallocated or append-only */ + trace_xfs_inode_free_eofblocks_invalid(ip); + xfs_inode_clear_eofblocks_tag(ip); + return 0; + } + + /* + * If the mapping is dirty the operation can block and wait for some + * time. Unless we are waiting, skip it. + */ + if (!wait && mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY)) + return 0; + + if (!xfs_inode_matches_eofb(ip, eofb)) + return 0; + + /* + * If the caller is waiting, return -EAGAIN to keep the background + * scanner moving and revisit the inode in a subsequent pass. + */ + if (!xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) { + if (wait) + return -EAGAIN; + return 0; + } + + ret = xfs_free_eofblocks(ip); + xfs_iunlock(ip, XFS_IOLOCK_EXCL); + + return ret; +} + +int +xfs_icache_free_eofblocks( + struct xfs_mount *mp, + struct xfs_eofblocks *eofb) +{ + return xfs_inode_walk(mp, 0, xfs_inode_free_eofblocks, eofb, + XFS_ICI_EOFBLOCKS_TAG); +} + +/* + * Run eofblocks scans on the quotas applicable to the inode. For inodes with + * multiple quotas, we don't know exactly which quota caused an allocation + * failure. We make a best effort by including each quota under low free space + * conditions (less than 1% free space) in the scan. + */ +static int +__xfs_inode_free_quota_eofblocks( + struct xfs_inode *ip, + int (*execute)(struct xfs_mount *mp, + struct xfs_eofblocks *eofb)) +{ + int scan = 0; + struct xfs_eofblocks eofb = {0}; + struct xfs_dquot *dq; + + /* + * Run a sync scan to increase effectiveness and use the union filter to + * cover all applicable quotas in a single scan. + */ + eofb.eof_flags = XFS_EOF_FLAGS_UNION|XFS_EOF_FLAGS_SYNC; + + if (XFS_IS_UQUOTA_ENFORCED(ip->i_mount)) { + dq = xfs_inode_dquot(ip, XFS_DQTYPE_USER); + if (dq && xfs_dquot_lowsp(dq)) { + eofb.eof_uid = VFS_I(ip)->i_uid; + eofb.eof_flags |= XFS_EOF_FLAGS_UID; + scan = 1; + } + } + + if (XFS_IS_GQUOTA_ENFORCED(ip->i_mount)) { + dq = xfs_inode_dquot(ip, XFS_DQTYPE_GROUP); + if (dq && xfs_dquot_lowsp(dq)) { + eofb.eof_gid = VFS_I(ip)->i_gid; + eofb.eof_flags |= XFS_EOF_FLAGS_GID; + scan = 1; + } + } + + if (scan) + execute(ip->i_mount, &eofb); + + return scan; +} + +int +xfs_inode_free_quota_eofblocks( + struct xfs_inode *ip) +{ + return __xfs_inode_free_quota_eofblocks(ip, xfs_icache_free_eofblocks); +} + +static inline unsigned long +xfs_iflag_for_tag( + int tag) +{ + switch (tag) { + case XFS_ICI_EOFBLOCKS_TAG: + return XFS_IEOFBLOCKS; + case XFS_ICI_COWBLOCKS_TAG: + return XFS_ICOWBLOCKS; + default: + ASSERT(0); + return 0; + } +} + +static void +__xfs_inode_set_blocks_tag( + xfs_inode_t *ip, + void (*execute)(struct xfs_mount *mp), + void (*set_tp)(struct xfs_mount *mp, xfs_agnumber_t agno, + int error, unsigned long caller_ip), + int tag) +{ + struct xfs_mount *mp = ip->i_mount; + struct xfs_perag *pag; + int tagged; + + /* + * Don't bother locking the AG and looking up in the radix trees + * if we already know that we have the tag set. + */ + if (ip->i_flags & xfs_iflag_for_tag(tag)) + return; + spin_lock(&ip->i_flags_lock); + ip->i_flags |= xfs_iflag_for_tag(tag); + spin_unlock(&ip->i_flags_lock); + + pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino)); + spin_lock(&pag->pag_ici_lock); + + tagged = radix_tree_tagged(&pag->pag_ici_root, tag); + radix_tree_tag_set(&pag->pag_ici_root, + XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag); + if (!tagged) { + /* propagate the eofblocks 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), + tag); + spin_unlock(&ip->i_mount->m_perag_lock); + + /* kick off background trimming */ + execute(ip->i_mount); + + set_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_); + } + + spin_unlock(&pag->pag_ici_lock); + xfs_perag_put(pag); +} + +void +xfs_inode_set_eofblocks_tag( + xfs_inode_t *ip) +{ + trace_xfs_inode_set_eofblocks_tag(ip); + return __xfs_inode_set_blocks_tag(ip, xfs_queue_eofblocks, + trace_xfs_perag_set_eofblocks, + XFS_ICI_EOFBLOCKS_TAG); +} + +static void +__xfs_inode_clear_blocks_tag( + xfs_inode_t *ip, + void (*clear_tp)(struct xfs_mount *mp, xfs_agnumber_t agno, + int error, unsigned long caller_ip), + int tag) +{ + struct xfs_mount *mp = ip->i_mount; + struct xfs_perag *pag; + + spin_lock(&ip->i_flags_lock); + ip->i_flags &= ~xfs_iflag_for_tag(tag); + spin_unlock(&ip->i_flags_lock); + + pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino)); + spin_lock(&pag->pag_ici_lock); + + radix_tree_tag_clear(&pag->pag_ici_root, + XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag); + if (!radix_tree_tagged(&pag->pag_ici_root, tag)) { + /* clear the eofblocks 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), + tag); + spin_unlock(&ip->i_mount->m_perag_lock); + clear_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_); + } + + spin_unlock(&pag->pag_ici_lock); + xfs_perag_put(pag); +} + +void +xfs_inode_clear_eofblocks_tag( + xfs_inode_t *ip) +{ + trace_xfs_inode_clear_eofblocks_tag(ip); + return __xfs_inode_clear_blocks_tag(ip, + trace_xfs_perag_clear_eofblocks, XFS_ICI_EOFBLOCKS_TAG); +} + +/* + * Set ourselves up to free CoW blocks from this file. If it's already clean + * then we can bail out quickly, but otherwise we must back off if the file + * is undergoing some kind of write. + */ +static bool +xfs_prep_free_cowblocks( + struct xfs_inode *ip) +{ + /* + * Just clear the tag if we have an empty cow fork or none at all. It's + * possible the inode was fully unshared since it was originally tagged. + */ + if (!xfs_inode_has_cow_data(ip)) { + trace_xfs_inode_free_cowblocks_invalid(ip); + xfs_inode_clear_cowblocks_tag(ip); + return false; + } + + /* + * If the mapping is dirty or under writeback we cannot touch the + * CoW fork. Leave it alone if we're in the midst of a directio. + */ + if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) || + mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) || + mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) || + atomic_read(&VFS_I(ip)->i_dio_count)) + return false; + + return true; +} + +/* + * Automatic CoW Reservation Freeing + * + * These functions automatically garbage collect leftover CoW reservations + * that were made on behalf of a cowextsize hint when we start to run out + * of quota or when the reservations sit around for too long. If the file + * has dirty pages or is undergoing writeback, its CoW reservations will + * be retained. + * + * The actual garbage collection piggybacks off the same code that runs + * the speculative EOF preallocation garbage collector. + */ +STATIC int +xfs_inode_free_cowblocks( + struct xfs_inode *ip, + void *args) +{ + struct xfs_eofblocks *eofb = args; + int ret = 0; + + if (!xfs_prep_free_cowblocks(ip)) + return 0; + + if (!xfs_inode_matches_eofb(ip, eofb)) + return 0; + + /* Free the CoW blocks */ + xfs_ilock(ip, XFS_IOLOCK_EXCL); + xfs_ilock(ip, XFS_MMAPLOCK_EXCL); + + /* + * Check again, nobody else should be able to dirty blocks or change + * the reflink iflag now that we have the first two locks held. + */ + if (xfs_prep_free_cowblocks(ip)) + ret = xfs_reflink_cancel_cow_range(ip, 0, NULLFILEOFF, false); + + xfs_iunlock(ip, XFS_MMAPLOCK_EXCL); + xfs_iunlock(ip, XFS_IOLOCK_EXCL); + + return ret; +} + +int +xfs_icache_free_cowblocks( + struct xfs_mount *mp, + struct xfs_eofblocks *eofb) +{ + return xfs_inode_walk(mp, 0, xfs_inode_free_cowblocks, eofb, + XFS_ICI_COWBLOCKS_TAG); +} + +int +xfs_inode_free_quota_cowblocks( + struct xfs_inode *ip) +{ + return __xfs_inode_free_quota_eofblocks(ip, xfs_icache_free_cowblocks); +} + +void +xfs_inode_set_cowblocks_tag( + xfs_inode_t *ip) +{ + trace_xfs_inode_set_cowblocks_tag(ip); + return __xfs_inode_set_blocks_tag(ip, xfs_queue_cowblocks, + trace_xfs_perag_set_cowblocks, + XFS_ICI_COWBLOCKS_TAG); +} + +void +xfs_inode_clear_cowblocks_tag( + xfs_inode_t *ip) +{ + trace_xfs_inode_clear_cowblocks_tag(ip); + return __xfs_inode_clear_blocks_tag(ip, + trace_xfs_perag_clear_cowblocks, XFS_ICI_COWBLOCKS_TAG); +} + +/* Disable post-EOF and CoW block auto-reclamation. */ +void +xfs_stop_block_reaping( + struct xfs_mount *mp) +{ + cancel_delayed_work_sync(&mp->m_eofblocks_work); + cancel_delayed_work_sync(&mp->m_cowblocks_work); +} + +/* Enable post-EOF and CoW block auto-reclamation. */ +void +xfs_start_block_reaping( + struct xfs_mount *mp) +{ + xfs_queue_eofblocks(mp); + xfs_queue_cowblocks(mp); +} |