[PATCH v4 1/8] xfs: add EOFBLOCKS inode tagging/untagging

Brian Foster
2012-09-27T17:42:54Z

Add the XFS_ICI_EOFBLOCKS_TAG inode tag to identify inodes with
speculatively preallocated blocks beyond EOF. An inode is tagged
when speculative preallocation occurs and untagged either via
truncate down or when post-EOF blocks are freed via release or
reclaim.

The tag management is intentionally not aggressive to prefer
simplicity over the complexity of handling all the corner cases
under which post-EOF blocks could be freed (i.e., forward
truncation, fallocate, write error conditions, etc.). This means
that a tagged inode may or may not have post-EOF blocks after a
period of time. The tag is eventually cleared when the inode is
released or reclaimed.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
fs/xfs/xfs_ag.h | 1 +
fs/xfs/xfs_iomap.c | 7 +++++
fs/xfs/xfs_iops.c | 3 ++
fs/xfs/xfs_sync.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_sync.h | 3 ++
fs/xfs/xfs_trace.h | 5 ++++
fs/xfs/xfs_vnodeops.c | 2 +
7 files changed, 83 insertions(+), 0 deletions(-)

diff --git a/fs/xfs/xfs_ag.h b/fs/xfs/xfs_ag.h
index 44d65c1..22bd4db 100644
--- a/fs/xfs/xfs_ag.h
+++ b/fs/xfs/xfs_ag.h
@@ -233,6 +233,7 @@ typedef struct xfs_perag {
#define XFS_ICI_NO_TAG (-1) /* special flag for an untagged lookup
in xfs_inode_ag_iterator */
#define XFS_ICI_RECLAIM_TAG 0 /* inode is to be reclaimed */
+#define XFS_ICI_EOFBLOCKS_TAG 1 /* inode has blocks beyond EOF */

#define XFS_AG_MAXLEVELS(mp) ((mp)->m_ag_maxlevels)
#define XFS_MIN_FREELIST_RAW(bl,cl,mp) \
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 973dff6..2968ee8 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -459,6 +459,13 @@ retry:
if (!(imap[0].br_startblock || XFS_IS_REALTIME_INODE(ip)))
return xfs_alert_fsblock_zero(ip, &imap[0]);

+ /*
+ * Tag the inode as speculatively preallocated so we can reclaim this
+ * space on demand, if necessary.
+ */
+ if (prealloc)
+ xfs_inode_set_eofblocks_tag(ip);
+
*ret_imap = imap[0];
return 0;
}
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 4e00cf0..dcd1d5f 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -854,6 +854,9 @@ xfs_setattr_size(
* and do not wait the usual (long) time for writeout.
*/
xfs_iflags_set(ip, XFS_ITRUNCATED);
+
+ /* A truncate down always removes post-EOF blocks. */
+ xfs_inode_clear_eofblocks_tag(ip);
}

if (mask & ATTR_CTIME) {
diff --git a/fs/xfs/xfs_sync.c b/fs/xfs/xfs_sync.c
index 9654817..00c6224 100644
--- a/fs/xfs/xfs_sync.c
+++ b/fs/xfs/xfs_sync.c
@@ -971,3 +971,65 @@ xfs_reclaim_inodes_count(
return reclaimable;
}

+void
+xfs_inode_set_eofblocks_tag(
+ xfs_inode_t *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_perag *pag;
+ int tagged;
+
+ pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
+ spin_lock(&pag->pag_ici_lock);
+ trace_xfs_inode_set_eofblocks_tag(ip);
+
+ tagged = radix_tree_tagged(&pag->pag_ici_root,
+ XFS_ICI_EOFBLOCKS_TAG);
+ radix_tree_tag_set(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
+ XFS_ICI_EOFBLOCKS_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),
+ XFS_ICI_EOFBLOCKS_TAG);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+
+ trace_xfs_perag_set_eofblocks(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)
+{
+ 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);
+ trace_xfs_inode_clear_eofblocks_tag(ip);
+
+ radix_tree_tag_clear(&pag->pag_ici_root,
+ XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
+ XFS_ICI_EOFBLOCKS_TAG);
+ if (!radix_tree_tagged(&pag->pag_ici_root, XFS_ICI_EOFBLOCKS_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),
+ XFS_ICI_EOFBLOCKS_TAG);
+ spin_unlock(&ip->i_mount->m_perag_lock);
+ trace_xfs_perag_clear_eofblocks(ip->i_mount, pag->pag_agno,
+ -1, _RET_IP_);
+ }
+
+ spin_unlock(&pag->pag_ici_lock);
+ xfs_perag_put(pag);
+}
+
diff --git a/fs/xfs/xfs_sync.h b/fs/xfs/xfs_sync.h
index 941202e..4486491 100644
--- a/fs/xfs/xfs_sync.h
+++ b/fs/xfs/xfs_sync.h
@@ -43,6 +43,9 @@ void __xfs_inode_set_reclaim_tag(struct xfs_perag *pag, struct xfs_inode *ip);
void __xfs_inode_clear_reclaim_tag(struct xfs_mount *mp, struct xfs_perag *pag,
struct xfs_inode *ip);

+void xfs_inode_set_eofblocks_tag(struct xfs_inode *ip);
+void xfs_inode_clear_eofblocks_tag(struct xfs_inode *ip);
+
int xfs_sync_inode_grab(struct xfs_inode *ip);
int xfs_inode_ag_iterator(struct xfs_mount *mp,
int (*execute)(struct xfs_inode *ip, struct xfs_perag *pag, int flags),
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 7d36ccf..6f46e03 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -130,6 +130,8 @@ DEFINE_PERAG_REF_EVENT(xfs_perag_get_tag);
DEFINE_PERAG_REF_EVENT(xfs_perag_put);
DEFINE_PERAG_REF_EVENT(xfs_perag_set_reclaim);
DEFINE_PERAG_REF_EVENT(xfs_perag_clear_reclaim);
+DEFINE_PERAG_REF_EVENT(xfs_perag_set_eofblocks);
+DEFINE_PERAG_REF_EVENT(xfs_perag_clear_eofblocks);

TRACE_EVENT(xfs_attr_list_node_descend,
TP_PROTO(struct xfs_attr_list_context *ctx,
@@ -585,6 +587,9 @@ DEFINE_INODE_EVENT(xfs_update_time);
DEFINE_INODE_EVENT(xfs_dquot_dqalloc);
DEFINE_INODE_EVENT(xfs_dquot_dqdetach);

+DEFINE_INODE_EVENT(xfs_inode_set_eofblocks_tag);
+DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
+
DECLARE_EVENT_CLASS(xfs_iref_class,
TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),
TP_ARGS(ip, caller_ip),
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 2a5c6373..d883881 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -237,6 +237,8 @@ xfs_free_eofblocks(
} else {
error = xfs_trans_commit(tp,
XFS_TRANS_RELEASE_LOG_RES);
+ if (!error)
+ xfs_inode_clear_eofblocks_tag(ip);
}

xfs_iunlock(ip, XFS_ILOCK_EXCL);
--
1.7.7.6