[PATCH 17/18] xfs: implement pnfs export operations

Christoph Hellwig
2015-01-06T16:29:54Z

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 | 2 +
fs/xfs/xfs_pnfs.c | 270 ++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_pnfs.h | 11 +++
8 files changed, 294 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 fdc6422..2b86be8 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -601,6 +601,8 @@ 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..aba26c8 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -175,6 +175,8 @@ typedef struct xfs_mount {
struct workqueue_struct *m_reclaim_workqueue;
struct workqueue_struct *m_log_workqueue;
struct workqueue_struct *m_eofblocks_workqueue;
+
+ __uint32_t m_generation; /* incremented on each growfs */
} xfs_mount_t;

/*
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
new file mode 100644
index 0000000..d95f596
--- /dev/null
+++ b/fs/xfs/xfs_pnfs.c
@@ -0,0 +1,270 @@
+/*
+ * 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_map_iomap(
+ struct xfs_inode *ip,
+ struct iomap *iomap,
+ struct xfs_bmbt_irec *imap,
+ xfs_off_t offset)
+{
+ struct xfs_mount *mp = ip->i_mount;
+
+ iomap->blkno = -1;
+ if (imap->br_startblock == HOLESTARTBLOCK)
+ iomap->type = IOMAP_HOLE;
+ else if (imap->br_startblock == DELAYSTARTBLOCK)
+ iomap->type = IOMAP_DELALLOC;
+ else {
+ /*
+ * the block number in the iomap must match the start offset we
+ * place in the iomap.
+ */
+ iomap->blkno = xfs_fsb_to_db(ip, imap->br_startblock);
+ ASSERT(iomap->blkno || XFS_IS_REALTIME_INODE(ip));
+ 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);
+}
+
+static int
+xfs_fs_update_flags(
+ struct xfs_inode *ip)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ struct xfs_trans *tp;
+ int error;
+
+ /*
+ * Update the mode, and prealloc flag bits.
+ */
+ tp = xfs_trans_alloc(mp, XFS_TRANS_WRITEID);
+ error = xfs_trans_reserve(tp, &M_RES(mp)->tr_writeid, 0, 0);
+ if (error) {
+ xfs_trans_cancel(tp, 0);
+ return error;
+ }
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
+ ip->i_d.di_mode &= ~S_ISUID;
+ if (ip->i_d.di_mode & S_IXGRP)
+ ip->i_d.di_mode &= ~S_ISGID;
+
+ ip->i_d.di_flags |= XFS_DIFLAG_PREALLOC;
+
+ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+ return xfs_trans_commit(tp, 0);
+}
+
+/*
+ * Get a layout for the pNFS client.
+ *
+ * Note that in the allocation case we do force out the transaction here.
+ * There is no metadata update that is required to be stable for NFS
+ * semantics, and layouts are not valid over a server crash. Instead
+ * we'll have to be careful in the commit routine as it might pass us
+ * blocks for an allocation that never made it to disk in the recovery
+ * case.
+ */
+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;
+
+ xfs_ilock(ip, XFS_IOLOCK_EXCL);
+ if (!write) {
+ limit = max(round_up(i_size_read(inode),
+ inode->i_sb->s_blocksize),
+ mp->m_super->s_maxbytes);
+ } else {
+ limit = mp->m_super->s_maxbytes;
+ }
+
+ error = -EINVAL;
+ if (offset > limit)
+ goto out_unlock;
+ if (offset + length > mp->m_super->s_maxbytes)
+ length = limit - offset;
+
+ /*
+ * Flush data and truncate the pagecache. pNFS block clients just
+ * like direct I/O access the disk directly.
+ */
+ error = filemap_write_and_wait(inode->i_mapping);
+ if (error)
+ goto out_unlock;
+ invalidate_inode_pages2(inode->i_mapping);
+
+ 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) {
+ if (!nimaps || imap.br_startblock == HOLESTARTBLOCK) {
+ error = xfs_iomap_write_direct(ip, offset, length,
+ &imap, nimaps);
+ if (error)
+ goto out_unlock;
+ }
+
+ error = xfs_fs_update_flags(ip);
+ if (error)
+ goto out_unlock;
+ }
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+
+ xfs_map_iomap(ip, iomap, &imap, offset);
+ *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.
+ *
+ * In the reclaim case we might get called for blocks that were only allocated
+ * in memory and not on disk. We rely on the fact that unwritten extent
+ * conversions handle this properly.
+ */
+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;
+
+ 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;
+
+ error = xfs_iomap_write_unwritten(ip, start, length);
+ if (error)
+ goto out_drop_iolock;
+ }
+
+ /*
+ * Make sure reads through the pagecache see the new data.
+ */
+ invalidate_inode_pages2(inode->i_mapping);
+
+ 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