[PATCH 45/62] xfs: Convert pag_ici_root to XArray

Matthew Wilcox
2017-11-22T21:12:52Z

Rename pag_ici_root to pag_ici_xa and use XArray APIs instead of radix
tree APIs. Shorter code, typechecking on tag numbers, better error
checking in xfs_reclaim_inode(), and eliminates a call to
radix_tree_preload().

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
---
fs/xfs/libxfs/xfs_sb.c | 2 +-
fs/xfs/libxfs/xfs_sb.h | 2 +-
fs/xfs/xfs_icache.c | 107 ++++++++++++++++++++-----------------------------
fs/xfs/xfs_icache.h | 4 +-
fs/xfs/xfs_inode.c | 24 ++++-------
fs/xfs/xfs_mount.c | 3 +-
fs/xfs/xfs_mount.h | 3 +-
7 files changed, 57 insertions(+), 88 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 811fa57007c9..9345fad57db8 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -76,7 +76,7 @@ struct xfs_perag *
xfs_perag_get_tag(
struct xfs_mount *mp,
xfs_agnumber_t first,
- int tag)
+ xa_tag_t tag)
{
XA_STATE(xas, first);
struct xfs_perag *pag;
diff --git a/fs/xfs/libxfs/xfs_sb.h b/fs/xfs/libxfs/xfs_sb.h
index 961e6475a309..d2de90b8f39c 100644
--- a/fs/xfs/libxfs/xfs_sb.h
+++ b/fs/xfs/libxfs/xfs_sb.h
@@ -23,7 +23,7 @@
*/
extern struct xfs_perag *xfs_perag_get(struct xfs_mount *, xfs_agnumber_t);
extern struct xfs_perag *xfs_perag_get_tag(struct xfs_mount *, xfs_agnumber_t,
- int tag);
+ xa_tag_t tag);
extern void xfs_perag_put(struct xfs_perag *pag);
extern int xfs_initialize_perag_data(struct xfs_mount *, xfs_agnumber_t);

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index f56e500d89e2..26f261ef708a 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -186,7 +186,7 @@ xfs_perag_set_reclaim_tag(
{
struct xfs_mount *mp = pag->pag_mount;

- lockdep_assert_held(&pag->pag_ici_lock);
+ lockdep_assert_held(&pag->pag_ici_xa.xa_lock);
if (pag->pag_ici_reclaimable++)
return;

@@ -205,7 +205,7 @@ xfs_perag_clear_reclaim_tag(
{
struct xfs_mount *mp = pag->pag_mount;

- lockdep_assert_held(&pag->pag_ici_lock);
+ lockdep_assert_held(&pag->pag_ici_xa.xa_lock);
if (--pag->pag_ici_reclaimable)
return;

@@ -228,16 +228,16 @@ xfs_inode_set_reclaim_tag(
struct xfs_perag *pag;

pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
- spin_lock(&pag->pag_ici_lock);
+ xa_lock(&pag->pag_ici_xa);
spin_lock(&ip->i_flags_lock);

- radix_tree_tag_set(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino),
+ __xa_set_tag(&pag->pag_ici_xa, 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);
+ xa_unlock(&pag->pag_ici_xa);
xfs_perag_put(pag);
}

@@ -246,7 +246,7 @@ xfs_inode_clear_reclaim_tag(
struct xfs_perag *pag,
xfs_ino_t ino)
{
- radix_tree_tag_clear(&pag->pag_ici_root,
+ __xa_clear_tag(&pag->pag_ici_xa,
XFS_INO_TO_AGINO(pag->pag_mount, ino),
XFS_ICI_RECLAIM_TAG);
xfs_perag_clear_reclaim_tag(pag);
@@ -367,8 +367,8 @@ xfs_iget_cache_hit(
/*
* 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.
+ * clear the xarray reclaimable tag yet as it requires
+ * pag_ici_xa.xa_lock to be held exclusive.
*/
ip->i_flags |= XFS_IRECLAIM;

@@ -393,7 +393,7 @@ xfs_iget_cache_hit(
goto out_error;
}

- spin_lock(&pag->pag_ici_lock);
+ xa_lock(&pag->pag_ici_xa);
spin_lock(&ip->i_flags_lock);

/*
@@ -410,7 +410,7 @@ xfs_iget_cache_hit(
init_rwsem(&inode->i_rwsem);

spin_unlock(&ip->i_flags_lock);
- spin_unlock(&pag->pag_ici_lock);
+ xa_unlock(&pag->pag_ici_xa);
} else {
/* If the VFS inode is being torn down, pause and try again. */
if (!igrab(inode)) {
@@ -451,7 +451,7 @@ xfs_iget_cache_miss(
int flags,
int lock_flags)
{
- struct xfs_inode *ip;
+ struct xfs_inode *ip, *curr;
int error;
xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino);
int iflags;
@@ -471,17 +471,6 @@ xfs_iget_cache_miss(
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.
@@ -509,23 +498,18 @@ xfs_iget_cache_miss(
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);
+ curr = xa_cmpxchg(&pag->pag_ici_xa, agino, NULL, ip, GFP_NOFS);
+ if (unlikely(curr)) {
+ WARN_ON(IS_ERR(curr));
XFS_STATS_INC(mp, xs_ig_dup);
error = -EAGAIN;
- goto out_preload_end;
+ goto out_unlock;
}
- 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();
+out_unlock:
if (lock_flags)
xfs_iunlock(ip, lock_flags);
out_destroy:
@@ -592,7 +576,7 @@ xfs_iget(
again:
error = 0;
rcu_read_lock();
- ip = radix_tree_lookup(&pag->pag_ici_root, agino);
+ ip = xa_load(&pag->pag_ici_xa, agino);

if (ip) {
error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags);
@@ -731,7 +715,7 @@ xfs_inode_ag_walk(
void *args),
int flags,
void *args,
- int tag,
+ xa_tag_t tag,
int iter_flags)
{
uint32_t first_index;
@@ -752,14 +736,13 @@ xfs_inode_ag_walk(

rcu_read_lock();

- if (tag == -1)
- nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
- (void **)batch, first_index,
+ if (tag == XFS_ICI_NO_TAG)
+ nr_found = xa_get_entries(&pag->pag_ici_xa,
+ (void **)batch, first_index, ULONG_MAX,
XFS_LOOKUP_BATCH);
else
- nr_found = radix_tree_gang_lookup_tag(
- &pag->pag_ici_root,
- (void **) batch, first_index,
+ nr_found = xa_get_tagged(&pag->pag_ici_xa,
+ (void **)batch, first_index, ULONG_MAX,
XFS_LOOKUP_BATCH, tag);

if (!nr_found) {
@@ -896,8 +879,8 @@ xfs_inode_ag_iterator_flags(
ag = 0;
while ((pag = xfs_perag_get(mp, ag))) {
ag = pag->pag_agno + 1;
- error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1,
- iter_flags);
+ error = xfs_inode_ag_walk(mp, pag, execute, flags, args,
+ XFS_ICI_NO_TAG, iter_flags);
xfs_perag_put(pag);
if (error) {
last_error = error;
@@ -926,7 +909,7 @@ xfs_inode_ag_iterator_tag(
void *args),
int flags,
void *args,
- int tag)
+ xa_tag_t tag)
{
struct xfs_perag *pag;
int error = 0;
@@ -1040,8 +1023,9 @@ xfs_reclaim_inode(
int sync_mode)
{
struct xfs_buf *bp = NULL;
- xfs_ino_t ino = ip->i_ino; /* for radix_tree_delete */
+ xfs_ino_t ino = ip->i_ino;
int error;
+ XA_STATE(xas, XFS_INO_TO_AGINO(ip->i_mount, ino));

restart:
error = 0;
@@ -1128,16 +1112,14 @@ xfs_reclaim_inode(
/*
* 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.
+ * Check that it was 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)))
+ xa_lock(&pag->pag_ici_xa);
+ if (xas_store(&pag->pag_ici_xa, &xas, NULL) != ip)
ASSERT(0);
xfs_perag_clear_reclaim_tag(pag);
- spin_unlock(&pag->pag_ici_lock);
+ xa_unlock(&pag->pag_ici_xa);

/*
* Here we do an (almost) spurious inode lock in order to coordinate
@@ -1213,9 +1195,8 @@ xfs_reclaim_inodes_ag(
int i;

rcu_read_lock();
- nr_found = radix_tree_gang_lookup_tag(
- &pag->pag_ici_root,
- (void **)batch, first_index,
+ nr_found = xa_get_tagged(&pag->pag_ici_xa,
+ (void **)batch, first_index, ULONG_MAX,
XFS_LOOKUP_BATCH,
XFS_ICI_RECLAIM_TAG);
if (!nr_found) {
@@ -1450,7 +1431,7 @@ __xfs_icache_free_eofblocks(
struct xfs_eofblocks *eofb,
int (*execute)(struct xfs_inode *ip, int flags,
void *args),
- int tag)
+ xa_tag_t tag)
{
int flags = SYNC_TRYLOCK;

@@ -1546,10 +1527,10 @@ __xfs_inode_set_eofblocks_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);
+ xa_lock(&pag->pag_ici_xa);

- tagged = radix_tree_tagged(&pag->pag_ici_root, tag);
- radix_tree_tag_set(&pag->pag_ici_root,
+ tagged = xa_tagged(&pag->pag_ici_xa, tag);
+ __xa_set_tag(&pag->pag_ici_xa,
XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag);
if (!tagged) {
/* propagate the eofblocks tag up into the perag radix tree */
@@ -1563,7 +1544,7 @@ __xfs_inode_set_eofblocks_tag(
set_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_);
}

- spin_unlock(&pag->pag_ici_lock);
+ xa_unlock(&pag->pag_ici_xa);
xfs_perag_put(pag);
}

@@ -1592,11 +1573,11 @@ __xfs_inode_clear_eofblocks_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);
+ xa_lock(&pag->pag_ici_xa);

- radix_tree_tag_clear(&pag->pag_ici_root,
+ __xa_clear_tag(&pag->pag_ici_xa,
XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino), tag);
- if (!radix_tree_tagged(&pag->pag_ici_root, tag)) {
+ if (!xa_tagged(&pag->pag_ici_xa, tag)) {
/* clear the eofblocks tag from the perag radix tree */
xa_clear_tag(&ip->i_mount->m_perag_xa,
XFS_INO_TO_AGNO(ip->i_mount, ip->i_ino),
@@ -1604,7 +1585,7 @@ __xfs_inode_clear_eofblocks_tag(
clear_tp(ip->i_mount, pag->pag_agno, -1, _RET_IP_);
}

- spin_unlock(&pag->pag_ici_lock);
+ xa_unlock(&pag->pag_ici_xa);
xfs_perag_put(pag);
}

diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
index bd04d5adadfe..436e7f0b1ecc 100644
--- a/fs/xfs/xfs_icache.h
+++ b/fs/xfs/xfs_icache.h
@@ -35,7 +35,7 @@ struct xfs_eofblocks {
/*
* tags for inode radix tree
*/
-#define XFS_ICI_NO_TAG (-1) /* special flag for an untagged lookup
+#define XFS_ICI_NO_TAG XA_NO_TAG /* special flag for an untagged lookup
in xfs_inode_ag_iterator */
#define XFS_ICI_RECLAIM_TAG XA_TAG_0 /* inode is to be reclaimed */
#define XFS_ICI_EOFBLOCKS_TAG XA_TAG_1 /* inode has blocks beyond EOF */
@@ -90,7 +90,7 @@ int xfs_inode_ag_iterator_flags(struct xfs_mount *mp,
int flags, void *args, int iter_flags);
int xfs_inode_ag_iterator_tag(struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, int flags, void *args),
- int flags, void *args, int tag);
+ int flags, void *args, xa_tag_t tag);

static inline int
xfs_fs_eofblocks_from_user(
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 61d1cb7dc10d..661f0ac655fa 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2309,7 +2309,7 @@ xfs_ifree_cluster(
for (i = 0; i < inodes_per_cluster; i++) {
retry:
rcu_read_lock();
- ip = radix_tree_lookup(&pag->pag_ici_root,
+ ip = xa_load(&pag->pag_ici_xa,
XFS_INO_TO_AGINO(mp, (inum + i)));

/* Inode not in memory, nothing to do */
@@ -3186,7 +3186,7 @@ xfs_iflush_cluster(
{
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
- unsigned long first_index, mask;
+ unsigned long first_index, last_index, mask;
unsigned long inodes_per_cluster;
int cilist_size;
struct xfs_inode **cilist;
@@ -3204,12 +3204,12 @@ xfs_iflush_cluster(
if (!cilist)
goto out_put;

- mask = ~(((mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog)) - 1);
- first_index = XFS_INO_TO_AGINO(mp, ip->i_ino) & mask;
+ mask = (((mp->m_inode_cluster_size >> mp->m_sb.sb_inodelog)) - 1);
+ first_index = XFS_INO_TO_AGINO(mp, ip->i_ino) & ~mask;
+ last_index = first_index | mask;
rcu_read_lock();
- /* really need a gang lookup range call here */
- nr_found = radix_tree_gang_lookup(&pag->pag_ici_root, (void**)cilist,
- first_index, inodes_per_cluster);
+ nr_found = xa_get_entries(&pag->pag_ici_xa, (void**)cilist, first_index,
+ last_index, inodes_per_cluster);
if (nr_found == 0)
goto out_free;

@@ -3230,16 +3230,6 @@ xfs_iflush_cluster(
spin_unlock(&cip->i_flags_lock);
continue;
}
-
- /*
- * Once we fall off the end of the cluster, no point checking
- * any more inodes in the list because they will also all be
- * outside the cluster.
- */
- if ((XFS_INO_TO_AGINO(mp, cip->i_ino) & mask) != first_index) {
- spin_unlock(&cip->i_flags_lock);
- break;
- }
spin_unlock(&cip->i_flags_lock);

/*
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index ae90f6f8fa5c..d5185657f030 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -210,9 +210,8 @@ xfs_initialize_perag(
goto out_unwind_new_pags;
pag->pag_agno = index;
pag->pag_mount = mp;
- spin_lock_init(&pag->pag_ici_lock);
mutex_init(&pag->pag_ici_reclaim_lock);
- INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
+ xa_init(&pag->pag_ici_xa);
if (xfs_buf_hash_init(pag))
goto out_free_pag;
init_waitqueue_head(&pag->pagb_wait);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 6e5ad7b26f46..ab0f706d2fd7 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -374,8 +374,7 @@ typedef struct xfs_perag {

atomic_t pagf_fstrms; /* # of filestreams active in this AG */

- spinlock_t pag_ici_lock; /* incore inode cache lock */
- struct radix_tree_root pag_ici_root; /* incore inode cache root */
+ struct xarray pag_ici_xa; /* incore inode cache */
int pag_ici_reclaimable; /* reclaimable inodes */
struct mutex pag_ici_reclaim_lock; /* serialisation point */
unsigned long pag_ici_reclaim_cursor; /* reclaim restart point */
--
2.15.0