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xfs_icache.c
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xfs_icache.c
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// 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_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 "xfs_ag.h"
#include <linux/iversion.h>
/* Radix tree tags for incore inode tree. */
/* inode is to be reclaimed */
#define XFS_ICI_RECLAIM_TAG 0
/* Inode has speculative preallocations (posteof or cow) to clean. */
#define XFS_ICI_BLOCKGC_TAG 1
/*
* The goal for walking incore inodes. These can correspond with incore inode
* radix tree tags when convenient. Avoid existing XFS_IWALK namespace.
*/
enum xfs_icwalk_goal {
/* Goals directly associated with tagged inodes. */
XFS_ICWALK_BLOCKGC = XFS_ICI_BLOCKGC_TAG,
XFS_ICWALK_RECLAIM = XFS_ICI_RECLAIM_TAG,
};
static int xfs_icwalk(struct xfs_mount *mp,
enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
static int xfs_icwalk_ag(struct xfs_perag *pag,
enum xfs_icwalk_goal goal, struct xfs_icwalk *icw);
/*
* Private inode cache walk flags for struct xfs_icwalk. Must not
* coincide with XFS_ICWALK_FLAGS_VALID.
*/
/* Stop scanning after icw_scan_limit inodes. */
#define XFS_ICWALK_FLAG_SCAN_LIMIT (1U << 28)
#define XFS_ICWALK_FLAG_RECLAIM_SICK (1U << 27)
#define XFS_ICWALK_FLAG_UNION (1U << 26) /* union filter algorithm */
#define XFS_ICWALK_PRIVATE_FLAGS (XFS_ICWALK_FLAG_SCAN_LIMIT | \
XFS_ICWALK_FLAG_RECLAIM_SICK | \
XFS_ICWALK_FLAG_UNION)
/*
* 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_cache, GFP_KERNEL | __GFP_NOFAIL);
if (inode_init_always(mp->m_super, VFS_I(ip))) {
kmem_cache_free(xfs_inode_cache, ip);
return NULL;
}
/* VFS doesn't initialise i_mode or i_state! */
VFS_I(ip)->i_mode = 0;
VFS_I(ip)->i_state = 0;
mapping_set_large_folios(VFS_I(ip)->i_mapping);
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;
ip->i_diflags2 = mp->m_ino_geo.new_diflags2;
ip->i_nblocks = 0;
ip->i_forkoff = 0;
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_cache, ip->i_afp);
}
if (ip->i_cowfp) {
xfs_idestroy_fork(ip->i_cowfp);
kmem_cache_free(xfs_ifork_cache, 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_cache, 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();
}
/*
* Background scanning to trim preallocated space. This is queued based on the
* 'speculative_prealloc_lifetime' tunable (5m by default).
*/
static inline void
xfs_blockgc_queue(
struct xfs_perag *pag)
{
struct xfs_mount *mp = pag->pag_mount;
if (!xfs_is_blockgc_enabled(mp))
return;
rcu_read_lock();
if (radix_tree_tagged(&pag->pag_ici_root, XFS_ICI_BLOCKGC_TAG))
queue_delayed_work(pag->pag_mount->m_blockgc_wq,
&pag->pag_blockgc_work,
msecs_to_jiffies(xfs_blockgc_secs * 1000));
rcu_read_unlock();
}
/* Set a tag on both the AG incore inode tree and the AG radix tree. */
static void
xfs_perag_set_inode_tag(
struct xfs_perag *pag,
xfs_agino_t agino,
unsigned int tag)
{
struct xfs_mount *mp = pag->pag_mount;
bool was_tagged;
lockdep_assert_held(&pag->pag_ici_lock);
was_tagged = radix_tree_tagged(&pag->pag_ici_root, tag);
radix_tree_tag_set(&pag->pag_ici_root, agino, tag);
if (tag == XFS_ICI_RECLAIM_TAG)
pag->pag_ici_reclaimable++;
if (was_tagged)
return;
/* propagate the tag up into the perag radix tree */
spin_lock(&mp->m_perag_lock);
radix_tree_tag_set(&mp->m_perag_tree, pag->pag_agno, tag);
spin_unlock(&mp->m_perag_lock);
/* start background work */
switch (tag) {
case XFS_ICI_RECLAIM_TAG:
xfs_reclaim_work_queue(mp);
break;
case XFS_ICI_BLOCKGC_TAG:
xfs_blockgc_queue(pag);
break;
}
trace_xfs_perag_set_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);
}
/* Clear a tag on both the AG incore inode tree and the AG radix tree. */
static void
xfs_perag_clear_inode_tag(
struct xfs_perag *pag,
xfs_agino_t agino,
unsigned int tag)
{
struct xfs_mount *mp = pag->pag_mount;
lockdep_assert_held(&pag->pag_ici_lock);
/*
* Reclaim can signal (with a null agino) that it cleared its own tag
* by removing the inode from the radix tree.
*/
if (agino != NULLAGINO)
radix_tree_tag_clear(&pag->pag_ici_root, agino, tag);
else
ASSERT(tag == XFS_ICI_RECLAIM_TAG);
if (tag == XFS_ICI_RECLAIM_TAG)
pag->pag_ici_reclaimable--;
if (radix_tree_tagged(&pag->pag_ici_root, tag))
return;
/* clear the tag from the perag radix tree */
spin_lock(&mp->m_perag_lock);
radix_tree_tag_clear(&mp->m_perag_tree, pag->pag_agno, tag);
spin_unlock(&mp->m_perag_lock);
trace_xfs_perag_clear_inode_tag(mp, pag->pag_agno, tag, _RET_IP_);
}
/*
* 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;
mapping_set_large_folios(inode->i_mapping);
return error;
}
/*
* Carefully nudge an inode whose VFS state has been torn down back into a
* usable state. Drops the i_flags_lock and the rcu read lock.
*/
static int
xfs_iget_recycle(
struct xfs_perag *pag,
struct xfs_inode *ip) __releases(&ip->i_flags_lock)
{
struct xfs_mount *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);
int error;
trace_xfs_iget_recycle(ip);
/*
* We need to make it look like the inode is being reclaimed to prevent
* the actual reclaim workers from stomping over us while we recycle
* the inode. We can't clear the radix tree 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) {
/*
* Re-initializing the inode failed, and we are in deep
* trouble. Try to re-add it to the reclaim list.
*/
rcu_read_lock();
spin_lock(&ip->i_flags_lock);
ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
trace_xfs_iget_recycle_fail(ip);
return 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_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
XFS_ICI_RECLAIM_TAG);
inode->i_state = I_NEW;
spin_unlock(&ip->i_flags_lock);
spin_unlock(&pag->pag_ici_lock);
return 0;
}
/*
* 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_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;
}
/* Make all pending inactivation work start immediately. */
static void
xfs_inodegc_queue_all(
struct xfs_mount *mp)
{
struct xfs_inodegc *gc;
int cpu;
for_each_online_cpu(cpu) {
gc = per_cpu_ptr(mp->m_inodegc, cpu);
if (!llist_empty(&gc->list))
queue_work_on(cpu, mp->m_inodegc_wq, &gc->work);
}
}
/*
* 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)
goto out_skip;
/*
* If we are racing with another cache hit that is currently
* instantiating this inode or currently recycling it out of
* reclaimable state, wait for the initialisation to complete
* before continuing.
*
* If we're racing with the inactivation worker we also want to wait.
* If we're creating a new file, it's possible that the worker
* previously marked the inode as free on disk but hasn't finished
* updating the incore state yet. The AGI buffer will be dirty and
* locked to the icreate transaction, so a synchronous push of the
* inodegc workers would result in deadlock. For a regular iget, the
* worker is running already, so we might as well wait.
*
* 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 | XFS_INACTIVATING))
goto out_skip;
if (ip->i_flags & XFS_NEED_INACTIVE) {
/* Unlinked inodes cannot be re-grabbed. */
if (VFS_I(ip)->i_nlink == 0) {
error = -ENOENT;
goto out_error;
}
goto out_inodegc_flush;
}
/*
* 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;
/* Skip inodes that have no vfs state. */
if ((flags & XFS_IGET_INCORE) &&
(ip->i_flags & XFS_IRECLAIMABLE))
goto out_skip;
/* The inode fits the selection criteria; process it. */
if (ip->i_flags & XFS_IRECLAIMABLE) {
/* Drops i_flags_lock and RCU read lock. */
error = xfs_iget_recycle(pag, ip);
if (error)
return error;
} else {
/* If the VFS inode is being torn down, pause and try again. */
if (!igrab(inode))
goto out_skip;
/* 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_skip:
trace_xfs_iget_skip(ip);
XFS_STATS_INC(mp, xs_ig_frecycle);
error = -EAGAIN;
out_error:
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
return error;
out_inodegc_flush:
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
/*
* Do not wait for the workers, because the caller could hold an AGI
* buffer lock. We're just going to sleep in a loop anyway.
*/
if (xfs_is_inodegc_enabled(mp))
xfs_inodegc_queue_all(mp);
return -EAGAIN;
}
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_FEAT_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 i_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_has_v3inodes(mp) &&
(flags & XFS_IGET_CREATE) && !xfs_has_ikeep(mp)) {
VFS_I(ip)->i_generation = prandom_u32();
} else {
struct xfs_buf *bp;
error = xfs_imap_to_bp(mp, tp, &ip->i_imap, &bp);
if (error)
goto out_destroy;
error = xfs_inode_from_disk(ip,
xfs_buf_offset(bp, ip->i_imap.im_boffset));
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_init_new_inode 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;
}
/*
* 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_igrab(
struct xfs_inode *ip,
struct xfs_icwalk *icw)
{
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;
}
/* Don't reclaim a sick inode unless the caller asked for it. */
if (ip->i_sick &&
(!icw || !(icw->icw_flags & XFS_ICWALK_FLAG_RECLAIM_SICK))) {
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_is_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:
trace_xfs_inode_reclaiming(ip);
/*
* 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;
ip->i_sick = 0;
ip->i_checked = 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_inode_tag(pag, NULLAGINO, XFS_ICI_RECLAIM_TAG);
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);
ASSERT(!ip->i_udquot && !ip->i_gdquot && !ip->i_pdquot);
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);
}
/* Reclaim sick inodes if we're unmounting or the fs went down. */
static inline bool
xfs_want_reclaim_sick(
struct xfs_mount *mp)
{
return xfs_is_unmounting(mp) || xfs_has_norecovery(mp) ||
xfs_is_shutdown(mp);
}
void
xfs_reclaim_inodes(
struct xfs_mount *mp)
{
struct xfs_icwalk icw = {
.icw_flags = 0,
};
if (xfs_want_reclaim_sick(mp))
icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
while (radix_tree_tagged(&mp->m_perag_tree, XFS_ICI_RECLAIM_TAG)) {
xfs_ail_push_all_sync(mp->m_ail);
xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
}
}
/*
* 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,
unsigned long nr_to_scan)
{
struct xfs_icwalk icw = {
.icw_flags = XFS_ICWALK_FLAG_SCAN_LIMIT,
.icw_scan_limit = min_t(unsigned long, LONG_MAX, nr_to_scan),
};
if (xfs_want_reclaim_sick(mp))
icw.icw_flags |= XFS_ICWALK_FLAG_RECLAIM_SICK;
/* kick background reclaimer and push the AIL */
xfs_reclaim_work_queue(mp);
xfs_ail_push_all(mp->m_ail);
xfs_icwalk(mp, XFS_ICWALK_RECLAIM, &icw);
return 0;
}