[PATCH 4.9 84/94] xfs: update ag iterator to support wait on new inodes

Greg Kroah-Hartman
2017-06-05T16:27:54Z

From: Brian Foster <bfoster@redhat.com>

commit ae2c4ac2dd39b23a87ddb14ceddc3f2872c6aef5 upstream.

The AG inode iterator currently skips new inodes as such inodes are
inserted into the inode radix tree before they are fully
constructed. Certain contexts require the ability to wait on the
construction of new inodes, however. The fs-wide dquot release from
the quotaoff sequence is an example of this.

Update the AG inode iterator to support the ability to wait on
inodes flagged with XFS_INEW upon request. Create a new
xfs_inode_ag_iterator_flags() interface and support a set of
iteration flags to modify the iteration behavior. When the
XFS_AGITER_INEW_WAIT flag is set, include XFS_INEW flags in the
radix tree inode lookup and wait on them before the callback is
executed.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/xfs/xfs_icache.c | 53 ++++++++++++++++++++++++++++++++++++++++++++--------
fs/xfs/xfs_icache.h | 8 +++++++
2 files changed, 53 insertions(+), 8 deletions(-)

--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -264,6 +264,22 @@ xfs_inode_clear_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.wait, TASK_UNINTERRUPTIBLE);
+ if (!xfs_iflags_test(ip, XFS_INEW))
+ break;
+ schedule();
+ } while (true);
+ finish_wait(wq, &wait.wait);
+}
+
/*
* 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
@@ -628,9 +644,11 @@ out_error_or_again:

STATIC int
xfs_inode_ag_walk_grab(
- struct xfs_inode *ip)
+ struct xfs_inode *ip,
+ int flags)
{
struct inode *inode = VFS_I(ip);
+ bool newinos = !!(flags & XFS_AGITER_INEW_WAIT);

ASSERT(rcu_read_lock_held());

@@ -648,7 +666,8 @@ xfs_inode_ag_walk_grab(
goto out_unlock_noent;

/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
- if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
+ 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);

@@ -676,7 +695,8 @@ xfs_inode_ag_walk(
void *args),
int flags,
void *args,
- int tag)
+ int tag,
+ int iter_flags)
{
uint32_t first_index;
int last_error = 0;
@@ -718,7 +738,7 @@ restart:
for (i = 0; i < nr_found; i++) {
struct xfs_inode *ip = batch[i];

- if (done || xfs_inode_ag_walk_grab(ip))
+ if (done || xfs_inode_ag_walk_grab(ip, iter_flags))
batch[i] = NULL;

/*
@@ -746,6 +766,9 @@ restart:
for (i = 0; i < nr_found; i++) {
if (!batch[i])
continue;
+ if ((iter_flags & XFS_AGITER_INEW_WAIT) &&
+ xfs_iflags_test(batch[i], XFS_INEW))
+ xfs_inew_wait(batch[i]);
error = execute(batch[i], flags, args);
IRELE(batch[i]);
if (error == -EAGAIN) {
@@ -825,12 +848,13 @@ xfs_cowblocks_worker(
}

int
-xfs_inode_ag_iterator(
+xfs_inode_ag_iterator_flags(
struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, int flags,
void *args),
int flags,
- void *args)
+ void *args,
+ int iter_flags)
{
struct xfs_perag *pag;
int error = 0;
@@ -840,7 +864,8 @@ xfs_inode_ag_iterator(
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);
+ error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1,
+ iter_flags);
xfs_perag_put(pag);
if (error) {
last_error = error;
@@ -852,6 +877,17 @@ xfs_inode_ag_iterator(
}

int
+xfs_inode_ag_iterator(
+ struct xfs_mount *mp,
+ int (*execute)(struct xfs_inode *ip, int flags,
+ void *args),
+ int flags,
+ void *args)
+{
+ return xfs_inode_ag_iterator_flags(mp, execute, flags, args, 0);
+}
+
+int
xfs_inode_ag_iterator_tag(
struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, int flags,
@@ -868,7 +904,8 @@ xfs_inode_ag_iterator_tag(
ag = 0;
while ((pag = xfs_perag_get_tag(mp, ag, tag))) {
ag = pag->pag_agno + 1;
- error = xfs_inode_ag_walk(mp, pag, execute, flags, args, tag);
+ error = xfs_inode_ag_walk(mp, pag, execute, flags, args, tag,
+ 0);
xfs_perag_put(pag);
if (error) {
last_error = error;
--- a/fs/xfs/xfs_icache.h
+++ b/fs/xfs/xfs_icache.h
@@ -48,6 +48,11 @@ struct xfs_eofblocks {
#define XFS_IGET_UNTRUSTED 0x2
#define XFS_IGET_DONTCACHE 0x4

+/*
+ * flags for AG inode iterator
+ */
+#define XFS_AGITER_INEW_WAIT 0x1 /* wait on new inodes */
+
int xfs_iget(struct xfs_mount *mp, struct xfs_trans *tp, xfs_ino_t ino,
uint flags, uint lock_flags, xfs_inode_t **ipp);

@@ -79,6 +84,9 @@ void xfs_cowblocks_worker(struct work_st
int xfs_inode_ag_iterator(struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, int flags, void *args),
int flags, void *args);
+int xfs_inode_ag_iterator_flags(struct xfs_mount *mp,
+ int (*execute)(struct xfs_inode *ip, int flags, void *args),
+ 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);