[PATCH 19/20] xfs: implement pNFS export operations

Christoph Hellwig
2015-01-22T11:11:31Z

Add operations to export pNFS block layouts from an XFS filesystem. See
the previous commit adding the operations for an explanation of them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/Makefile | 1 +
fs/xfs/xfs_export.c | 6 ++
fs/xfs/xfs_fsops.c | 2 +
fs/xfs/xfs_iops.c | 2 +-
fs/xfs/xfs_iops.h | 1 +
fs/xfs/xfs_mount.h | 11 +++
fs/xfs/xfs_pnfs.c | 243 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_pnfs.h | 11 +++
8 files changed, 276 insertions(+), 1 deletion(-)
create mode 100644 fs/xfs/xfs_pnfs.c
create mode 100644 fs/xfs/xfs_pnfs.h

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index d617999..df68285 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -121,3 +121,4 @@ xfs-$(CONFIG_XFS_POSIX_ACL) += xfs_acl.o
xfs-$(CONFIG_PROC_FS) += xfs_stats.o
xfs-$(CONFIG_SYSCTL) += xfs_sysctl.o
xfs-$(CONFIG_COMPAT) += xfs_ioctl32.o
+xfs-$(CONFIG_NFSD_PNFS) += xfs_pnfs.o
diff --git a/fs/xfs/xfs_export.c b/fs/xfs/xfs_export.c
index 5eb4a14..b97359b 100644
--- a/fs/xfs/xfs_export.c
+++ b/fs/xfs/xfs_export.c
@@ -30,6 +30,7 @@
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_log.h"
+#include "xfs_pnfs.h"

/*
* Note that we only accept fileids which are long enough rather than allow
@@ -245,4 +246,9 @@ const struct export_operations xfs_export_operations = {
.fh_to_parent = xfs_fs_fh_to_parent,
.get_parent = xfs_fs_get_parent,
.commit_metadata = xfs_fs_nfs_commit_metadata,
+#ifdef CONFIG_NFSD_PNFS
+ .get_uuid = xfs_fs_get_uuid,
+ .map_blocks = xfs_fs_map_blocks,
+ .commit_blocks = xfs_fs_commit_blocks,
+#endif
};
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 74c6211..99465ba 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -602,6 +602,8 @@ xfs_growfs_data(
if (!mutex_trylock(&mp->m_growlock))
return -EWOULDBLOCK;
error = xfs_growfs_data_private(mp, in);
+ if (!error)
+ mp->m_generation++;
mutex_unlock(&mp->m_growlock);
return error;
}
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index c50311c..6ff84e8 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -496,7 +496,7 @@ xfs_setattr_mode(
inode->i_mode |= mode & ~S_IFMT;
}

-static void
+void
xfs_setattr_time(
struct xfs_inode *ip,
struct iattr *iattr)
diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
index 1c34e43..ea7a98e 100644
--- a/fs/xfs/xfs_iops.h
+++ b/fs/xfs/xfs_iops.h
@@ -32,6 +32,7 @@ extern void xfs_setup_inode(struct xfs_inode *);
*/
#define XFS_ATTR_NOACL 0x01 /* Don't call posix_acl_chmod */

+extern void xfs_setattr_time(struct xfs_inode *ip, struct iattr *iattr);
extern int xfs_setattr_nonsize(struct xfs_inode *ip, struct iattr *vap,
int flags);
extern int xfs_setattr_size(struct xfs_inode *ip, struct iattr *vap);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 22ccf69..12925d5 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -175,6 +175,17 @@ typedef struct xfs_mount {
struct workqueue_struct *m_reclaim_workqueue;
struct workqueue_struct *m_log_workqueue;
struct workqueue_struct *m_eofblocks_workqueue;
+
+ /*
+ * Generation of the filesysyem layout. This is incremented by each
+ * growfs, and used by the pNFS server to ensure the client updates
+ * its view of the block device once it gets a layout that might
+ * reference the newly added blocks. Does not need to be persistent
+ * as long as we only allow file system size increments, but if we
+ * ever support shrinks it would have to be persisted in addition
+ * to various other kinds of pain inflicted on the pNFS server.
+ */
+ __uint32_t m_generation;
} xfs_mount_t;

/*
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
new file mode 100644
index 0000000..5d25f5d
--- /dev/null
+++ b/fs/xfs/xfs_pnfs.c
@@ -0,0 +1,243 @@
+/*
+ * Copyright (c) 2014 Christoph Hellwig.
+ */
+#include "xfs.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_log.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_util.h"
+#include "xfs_error.h"
+#include "xfs_iomap.h"
+#include "xfs_shared.h"
+#include "xfs_pnfs.h"
+
+int
+xfs_fs_get_uuid(
+ struct super_block *sb,
+ u8 *buf,
+ u32 *len,
+ u64 *offset)
+{
+ struct xfs_mount *mp = XFS_M(sb);
+
+ if (*len < sizeof(uuid_t))
+ return -EINVAL;
+
+ memcpy(buf, &mp->m_sb.sb_uuid, sizeof(uuid_t));
+ *len = sizeof(uuid_t);
+ *offset = offsetof(struct xfs_dsb, sb_uuid);
+ return 0;
+}
+
+static void
+xfs_bmbt_to_iomap(
+ struct xfs_inode *ip,
+ struct iomap *iomap,
+ struct xfs_bmbt_irec *imap)
+{
+ struct xfs_mount *mp = ip->i_mount;
+
+ if (imap->br_startblock == HOLESTARTBLOCK) {
+ iomap->blkno = -1;
+ iomap->type = IOMAP_HOLE;
+ } else if (imap->br_startblock == DELAYSTARTBLOCK) {
+ iomap->blkno = -1;
+ iomap->type = IOMAP_DELALLOC;
+ } else {
+ iomap->blkno = xfs_fsb_to_db(ip, imap->br_startblock);
+ if (imap->br_state == XFS_EXT_UNWRITTEN)
+ iomap->type = IOMAP_UNWRITTEN;
+ else
+ iomap->type = IOMAP_MAPPED;
+ }
+ iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
+ iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
+}
+
+/*
+ * Get a layout for the pNFS client.
+ */
+int
+xfs_fs_map_blocks(
+ struct inode *inode,
+ loff_t offset,
+ u64 length,
+ struct iomap *iomap,
+ bool write,
+ u32 *device_generation)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_bmbt_irec imap;
+ xfs_fileoff_t offset_fsb, end_fsb;
+ loff_t limit;
+ int bmapi_flags = XFS_BMAPI_ENTIRE;
+ int nimaps = 1;
+ uint lock_flags;
+ int error = 0;
+
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return -EIO;
+ if (XFS_IS_REALTIME_INODE(ip))
+ return -ENXIO;
+
+ /*
+ * Lock out any other I/O before we flush and invalidate the pagecache,
+ * and then hand out a layout to the remote system. This is very
+ * similar to direct I/O, except that the synchronization is much more
+ * complicated. See the comment near xfs_break_layouts for a detailed
+ * explanation.
+ */
+ xfs_ilock(ip, XFS_IOLOCK_EXCL);
+
+ error = -EINVAL;
+ limit = mp->m_super->s_maxbytes;
+ if (!write)
+ limit = max(limit, round_up(i_size_read(inode),
+ inode->i_sb->s_blocksize));
+ if (offset > limit)
+ goto out_unlock;
+ if (offset > limit - length)
+ length = limit - offset;
+
+ error = filemap_write_and_wait(inode->i_mapping);
+ if (error)
+ goto out_unlock;
+ error = invalidate_inode_pages2(inode->i_mapping);
+ if (WARN_ON_ONCE(error))
+ return error;
+
+ end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + length);
+ offset_fsb = XFS_B_TO_FSBT(mp, offset);
+
+ lock_flags = xfs_ilock_data_map_shared(ip);
+ error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
+ &imap, &nimaps, bmapi_flags);
+ xfs_iunlock(ip, lock_flags);
+
+ if (error)
+ goto out_unlock;
+
+ if (write) {
+ enum xfs_prealloc_flags flags = 0;
+
+ ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
+
+ if (!nimaps || imap.br_startblock == HOLESTARTBLOCK) {
+ error = xfs_iomap_write_direct(ip, offset, length,
+ &imap, nimaps);
+ if (error)
+ goto out_unlock;
+
+ /*
+ * Ensure the next transaction is committed
+ * synchronously so that the blocks allocated and
+ * handed out to the client are guaranteed to be
+ * present even after a server crash.
+ */
+ flags |= XFS_PREALLOC_SET | XFS_PREALLOC_SYNC;
+ }
+
+ error = xfs_update_prealloc_flags(ip, flags);
+ if (error)
+ goto out_unlock;
+ }
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+
+ xfs_bmbt_to_iomap(ip, iomap, &imap);
+ *device_generation = mp->m_generation;
+ return error;
+out_unlock:
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+ return error;
+}
+
+/*
+ * Make sure the blocks described by maps are stable on disk. This includes
+ * converting any unwritten extents, flushing the disk cache and updating the
+ * time stamps.
+ *
+ * Note that we rely on the caller to always send us a timestamp update so that
+ * we always commit a transaction here. If that stops being true we will have
+ * to manually flush the cache here similar to what the fsync code path does
+ * for datasyncs on files that have no dirty metadata.
+ */
+int
+xfs_fs_commit_blocks(
+ struct inode *inode,
+ struct iomap *maps,
+ int nr_maps,
+ struct iattr *iattr)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ int error, i;
+ loff_t size;
+
+ ASSERT(iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME));
+
+ xfs_ilock(ip, XFS_IOLOCK_EXCL);
+
+ size = i_size_read(inode);
+ if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size)
+ size = iattr->ia_size;
+
+ for (i = 0; i < nr_maps; i++) {
+ u64 start, length, end;
+
+ start = maps[i].offset;
+ if (start > size)
+ continue;
+
+ end = start + maps[i].length;
+ if (end > size)
+ end = size;
+
+ length = end - start;
+ if (!length)
+ continue;
+
+ /*
+ * Make sure reads through the pagecache see the new data.
+ */
+ error = invalidate_inode_pages2_range(inode->i_mapping,
+ start >> PAGE_CACHE_SHIFT,
+ (end - 1) >> PAGE_CACHE_SHIFT);
+ WARN_ON_ONCE(error);
+
+ error = xfs_iomap_write_unwritten(ip, start, length);
+ if (error)
+ goto out_drop_iolock;
+ }
+
+ tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
+ error = xfs_trans_reserve(tp, &M_RES(mp)->tr_ichange, 0, 0);
+ if (error)
+ goto out_drop_iolock;
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+
+ xfs_setattr_time(ip, iattr);
+ if (iattr->ia_valid & ATTR_SIZE) {
+ if (iattr->ia_size > i_size_read(inode)) {
+ i_size_write(inode, iattr->ia_size);
+ ip->i_d.di_size = iattr->ia_size;
+ }
+ }
+
+ xfs_trans_set_sync(tp);
+ error = xfs_trans_commit(tp, 0);
+
+out_drop_iolock:
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+ return error;
+}
diff --git a/fs/xfs/xfs_pnfs.h b/fs/xfs/xfs_pnfs.h
new file mode 100644
index 0000000..0d91255
--- /dev/null
+++ b/fs/xfs/xfs_pnfs.h
@@ -0,0 +1,11 @@
+#ifndef _XFS_PNFS_H
+#define _XFS_PNFS_H 1
+
+#ifdef CONFIG_NFSD_PNFS
+int xfs_fs_get_uuid(struct super_block *sb, u8 *buf, u32 *len, u64 *offset);
+int xfs_fs_map_blocks(struct inode *inode, loff_t offset, u64 length,
+ struct iomap *iomap, bool write, u32 *device_generation);
+int xfs_fs_commit_blocks(struct inode *inode, struct iomap *maps, int nr_maps,
+ struct iattr *iattr);
+#endif /* CONFIG_NFSD_PNFS */
+#endif /* _XFS_PNFS_H */
--
1.9.1