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

Christoph Hellwig
2015-02-05T13:58:04Z

I've updated the patch and pushed out a new pnfsd-for-3.20-4 branch.

The changes relative to the old one are below:

diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 99465ba..48561a0 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -602,8 +602,12 @@ xfs_growfs_data(
if (!mutex_trylock(&mp->m_growlock))
return -EWOULDBLOCK;
error = xfs_growfs_data_private(mp, in);
- if (!error)
- mp->m_generation++;
+ /*
+ * Increment the generation unconditionally, the error could be from
+ * updating the secondary superblocks, in which case the new size
+ * is live already.
+ */
+ mp->m_generation++;
mutex_unlock(&mp->m_growlock);
return error;
}
diff --git a/fs/xfs/xfs_pnfs.c b/fs/xfs/xfs_pnfs.c
index ab5ee78..7440b40 100644
--- a/fs/xfs/xfs_pnfs.c
+++ b/fs/xfs/xfs_pnfs.c
@@ -15,6 +15,7 @@
#include "xfs_error.h"
#include "xfs_iomap.h"
#include "xfs_shared.h"
+#include "xfs_bit.h"
#include "xfs_pnfs.h"

/*
@@ -48,6 +49,10 @@ xfs_break_layouts(
return error;
}

+/*
+ * Get a uniqueue ID including its location so that the client can identify
+ * the exported device.
+ */
int
xfs_fs_get_uuid(
struct super_block *sb,
@@ -57,6 +62,10 @@ xfs_fs_get_uuid(
{
struct xfs_mount *mp = XFS_M(sb);

+ printk_once(KERN_NOTICE
+"XFS (%s): using experimental pNFS feature, use at your own risk!\n",
+ mp->m_fsname);
+
if (*len < sizeof(uuid_t))
return -EINVAL;

@@ -75,13 +84,14 @@ xfs_bmbt_to_iomap(
struct xfs_mount *mp = ip->i_mount;

if (imap->br_startblock == HOLESTARTBLOCK) {
- iomap->blkno = -1;
+ iomap->blkno = IOMAP_NULL_BLOCK;
iomap->type = IOMAP_HOLE;
} else if (imap->br_startblock == DELAYSTARTBLOCK) {
- iomap->blkno = -1;
+ iomap->blkno = IOMAP_NULL_BLOCK;
iomap->type = IOMAP_DELALLOC;
} else {
- iomap->blkno = xfs_fsb_to_db(ip, imap->br_startblock);
+ iomap->blkno =
+ XFS_FSB_TO_DADDR(ip->i_mount, imap->br_startblock);
if (imap->br_state == XFS_EXT_UNWRITTEN)
iomap->type = IOMAP_UNWRITTEN;
else
@@ -115,6 +125,12 @@ xfs_fs_map_blocks(

if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
+
+ /*
+ * We can't export inodes residing on the realtime device. The realtime
+ * device doesn't have a UUID to identify it, so the client has no way
+ * to find it.
+ */
if (XFS_IS_REALTIME_INODE(ip))
return -ENXIO;

@@ -190,6 +206,32 @@ out_unlock:
}

/*
+ * Ensure the size update falls into a valid allocated block.
+ */
+static int
+xfs_pnfs_validate_isize(
+ struct xfs_inode *ip,
+ xfs_off_t isize)
+{
+ struct xfs_bmbt_irec imap;
+ int nimaps = 1;
+ int error = 0;
+
+ xfs_ilock(ip, XFS_ILOCK_SHARED);
+ error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1,
+ &imap, &nimaps, 0);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ if (error)
+ return error;
+
+ if (imap.br_startblock == HOLESTARTBLOCK ||
+ imap.br_startblock == DELAYSTARTBLOCK ||
+ imap.br_state == XFS_EXT_UNWRITTEN)
+ return -EIO;
+ return 0;
+}
+
+/*
* 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.
@@ -209,6 +251,7 @@ xfs_fs_commit_blocks(
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
+ bool update_isize = false;
int error, i;
loff_t size;

@@ -217,8 +260,10 @@ xfs_fs_commit_blocks(
xfs_ilock(ip, XFS_IOLOCK_EXCL);

size = i_size_read(inode);
- if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size)
+ if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) {
+ update_isize = true;
size = iattr->ia_size;
+ }

for (i = 0; i < nr_maps; i++) {
u64 start, length, end;
@@ -248,6 +293,12 @@ xfs_fs_commit_blocks(
goto out_drop_iolock;
}

+ if (update_isize) {
+ error = xfs_pnfs_validate_isize(ip, size);
+ 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)
@@ -258,11 +309,9 @@ xfs_fs_commit_blocks(
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;
- }
+ if (update_isize) {
+ i_size_write(inode, iattr->ia_size);
+ ip->i_d.di_size = iattr->ia_size;
}

xfs_trans_set_sync(tp);
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index ff46bf7..fa05e04 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -187,6 +187,8 @@ struct fid {
#define IOMAP_MAPPED 0x03 /* blocks allocated @blkno */
#define IOMAP_UNWRITTEN 0x04 /* blocks allocated @blkno in unwritten state */

+#define IOMAP_NULL_BLOCK -1LL /* blkno is not valid */
+
struct iomap {
sector_t blkno; /* first sector of mapping */
loff_t offset; /* file offset of mapping, bytes */