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Commit 41963c10 authored by Benjamin Coddington's avatar Benjamin Coddington Committed by Trond Myklebust
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pnfs/blocklayout: update last_write_offset atomically with extents 



Block/SCSI layout write completion may add committable extents to the
extent tree before updating the layout's last-written byte under the inode
lock.  If a sync happens before this value is updated, then
prepare_layoutcommit may find and encode these extents which would produce
a LAYOUTCOMMIT request whose encoded extents are larger than the request's
loca_length.

Fix this by using a last-written byte value that is updated atomically with
the extent tree so that commitable extents always match.

Signed-off-by: default avatarBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent b88fa69e

fs/nfs/blocklayout/blocklayout.c

+1 −1
Original line number Diff line number Diff line
@@ -346,7 +346,7 @@ static void bl_write_cleanup(struct work_struct *work) 
			PAGE_SIZE - 1) & (loff_t)PAGE_MASK;



		ext_tree_mark_written(bl, start >> SECTOR_SHIFT,

					(end - start) >> SECTOR_SHIFT);

					(end - start) >> SECTOR_SHIFT, end);

	}



	pnfs_ld_write_done(hdr);

fs/nfs/blocklayout/blocklayout.h

+2 −1
Original line number Diff line number Diff line
@@ -141,6 +141,7 @@ struct pnfs_block_layout { 
	struct rb_root		bl_ext_ro;

	spinlock_t		bl_ext_lock;   /* Protects list manipulation */

	bool			bl_scsi_layout;

	u64			bl_lwb;

};



static inline struct pnfs_block_layout *
@@ -182,7 +183,7 @@ int ext_tree_insert(struct pnfs_block_layout *bl, 
int ext_tree_remove(struct pnfs_block_layout *bl, bool rw, sector_t start,

		sector_t end);

int ext_tree_mark_written(struct pnfs_block_layout *bl, sector_t start,

		sector_t len);

		sector_t len, u64 lwb);

bool ext_tree_lookup(struct pnfs_block_layout *bl, sector_t isect,

		struct pnfs_block_extent *ret, bool rw);

int ext_tree_prepare_commit(struct nfs4_layoutcommit_args *arg);

fs/nfs/blocklayout/extent_tree.c

+7 −3
Original line number Diff line number Diff line
@@ -402,7 +402,7 @@ ext_tree_split(struct rb_root *root, struct pnfs_block_extent *be, 


int

ext_tree_mark_written(struct pnfs_block_layout *bl, sector_t start,

		sector_t len)

		sector_t len, u64 lwb)

{

	struct rb_root *root = &bl->bl_ext_rw;

	sector_t end = start + len;
@@ -471,6 +471,8 @@ ext_tree_mark_written(struct pnfs_block_layout *bl, sector_t start, 
		}

	}

out:

	if (bl->bl_lwb < lwb)

		bl->bl_lwb = lwb;

	spin_unlock(&bl->bl_ext_lock);



	__ext_put_deviceids(&tmp);
@@ -518,7 +520,7 @@ static __be32 *encode_scsi_range(struct pnfs_block_extent *be, __be32 *p) 
}



static int ext_tree_encode_commit(struct pnfs_block_layout *bl, __be32 *p,

		size_t buffer_size, size_t *count)

		size_t buffer_size, size_t *count, __u64 *lastbyte)

{

	struct pnfs_block_extent *be;

	int ret = 0;
@@ -542,6 +544,8 @@ static int ext_tree_encode_commit(struct pnfs_block_layout *bl, __be32 *p, 
			p = encode_block_extent(be, p);

		be->be_tag = EXTENT_COMMITTING;

	}

	*lastbyte = bl->bl_lwb - 1;

	bl->bl_lwb = 0;

	spin_unlock(&bl->bl_ext_lock);



	return ret;
@@ -564,7 +568,7 @@ ext_tree_prepare_commit(struct nfs4_layoutcommit_args *arg) 
	arg->layoutupdate_pages = &arg->layoutupdate_page;



retry:

	ret = ext_tree_encode_commit(bl, start_p + 1, buffer_size, &count);

	ret = ext_tree_encode_commit(bl, start_p + 1, buffer_size, &count, &arg->lastbytewritten);

	if (unlikely(ret)) {

		ext_tree_free_commitdata(arg, buffer_size);