Commit 110cb2d2 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NFS: Instrument i_size_write() 



Generate a trace event whenever the NFS client modifies the size of
a file. These new events aid troubleshooting workloads that trigger
races around size updates.

There are four new trace points, all named nfs_size_something so
they are easy to grep for or enable as a group with a single glob.

Size updated on the server:

  kworker/u24:10-194   [010]   369.939174: nfs_size_update:      fileid=00:28:2 fhandle=0x36fbbe51 version=1752899344277980615 cursize=250471 newsize=172083

Server-side size update reported via NFSv3 WCC attributes:

             fsx-1387  [006]   380.760686: nfs_size_wcc:         fileid=00:28:2 fhandle=0x36fbbe51 version=1752899355909932456 cursize=146792 newsize=171216

File has been truncated locally:

             fsx-1387  [007]   369.437421: nfs_size_truncate:    fileid=00:28:2 fhandle=0x36fbbe51 version=1752899231200117272 cursize=215244 newsize=0

File has been extended locally:

             fsx-1387  [007]   369.439213: nfs_size_grow:        fileid=00:28:2 fhandle=0x36fbbe51 version=1752899343704248410 cursize=258048 newsize=262144

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 0392dd51

fs/nfs/inode.c

+3 −6
Original line number Original line Diff line number Diff line
@@ -671,6 +671,7 @@ static int nfs_vmtruncate(struct inode * inode, loff_t offset) 
	if (err)

	if (err)

		goto out;

		goto out;





	trace_nfs_size_truncate(inode, offset);

	i_size_write(inode, offset);

	i_size_write(inode, offset);

	/* Optimisation */

	/* Optimisation */

	if (offset == 0)

	if (offset == 0)
@@ -1456,6 +1457,7 @@ static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
			&& (fattr->valid & NFS_ATTR_FATTR_SIZE)

			&& (fattr->valid & NFS_ATTR_FATTR_SIZE)

			&& i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size)

			&& i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size)

			&& !nfs_have_writebacks(inode)) {

			&& !nfs_have_writebacks(inode)) {

		trace_nfs_size_wcc(inode, fattr->size);

		i_size_write(inode, nfs_size_to_loff_t(fattr->size));

		i_size_write(inode, nfs_size_to_loff_t(fattr->size));

	}

	}

}

}
@@ -2100,16 +2102,11 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) 
			/* Do we perhaps have any outstanding writes, or has

			/* Do we perhaps have any outstanding writes, or has

			 * the file grown beyond our last write? */

			 * the file grown beyond our last write? */

			if (!nfs_have_writebacks(inode) || new_isize > cur_isize) {

			if (!nfs_have_writebacks(inode) || new_isize > cur_isize) {

				trace_nfs_size_update(inode, new_isize);

				i_size_write(inode, new_isize);

				i_size_write(inode, new_isize);

				if (!have_writers)

				if (!have_writers)

					invalid |= NFS_INO_INVALID_DATA;

					invalid |= NFS_INO_INVALID_DATA;

			}

			}

			dprintk("NFS: isize change on server for file %s/%ld "

					"(%Ld to %Ld)\n",

					inode->i_sb->s_id,

					inode->i_ino,

					(long long)cur_isize,

					(long long)new_isize);

		}

		}

		if (new_isize == 0 &&

		if (new_isize == 0 &&

		    !(fattr->valid & (NFS_ATTR_FATTR_SPACE_USED |

		    !(fattr->valid & (NFS_ATTR_FATTR_SPACE_USED |

fs/nfs/nfstrace.h

+50 −0
Original line number Original line Diff line number Diff line
@@ -231,6 +231,56 @@ TRACE_EVENT(nfs_access_exit, 
		)

		)

);

);





DECLARE_EVENT_CLASS(nfs_update_size_class,

		TP_PROTO(

			const struct inode *inode,

			loff_t new_size

		),



		TP_ARGS(inode, new_size),



		TP_STRUCT__entry(

			__field(dev_t, dev)

			__field(u32, fhandle)

			__field(u64, fileid)

			__field(u64, version)

			__field(loff_t, cur_size)

			__field(loff_t, new_size)

		),



		TP_fast_assign(

			const struct nfs_inode *nfsi = NFS_I(inode);



			__entry->dev = inode->i_sb->s_dev;

			__entry->fhandle = nfs_fhandle_hash(&nfsi->fh);

			__entry->fileid = nfsi->fileid;

			__entry->version = inode_peek_iversion_raw(inode);

			__entry->cur_size = i_size_read(inode);

			__entry->new_size = new_size;

		),



		TP_printk(

			"fileid=%02x:%02x:%llu fhandle=0x%08x version=%llu cursize=%lld newsize=%lld",

			MAJOR(__entry->dev), MINOR(__entry->dev),

			(unsigned long long)__entry->fileid,

			__entry->fhandle, __entry->version,

			__entry->cur_size, __entry->new_size

		)

);



#define DEFINE_NFS_UPDATE_SIZE_EVENT(name) \

	DEFINE_EVENT(nfs_update_size_class, nfs_size_##name, \

			TP_PROTO( \

				const struct inode *inode, \

				loff_t new_size \

			), \

			TP_ARGS(inode, new_size))



DEFINE_NFS_UPDATE_SIZE_EVENT(truncate);

DEFINE_NFS_UPDATE_SIZE_EVENT(wcc);

DEFINE_NFS_UPDATE_SIZE_EVENT(update);

DEFINE_NFS_UPDATE_SIZE_EVENT(grow);



#define show_lookup_flags(flags) \

#define show_lookup_flags(flags) \

	__print_flags(flags, "|", \

	__print_flags(flags, "|", \

			{ LOOKUP_FOLLOW, "FOLLOW" }, \

			{ LOOKUP_FOLLOW, "FOLLOW" }, \

fs/nfs/write.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -288,6 +288,7 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c 
	end = page_file_offset(page) + ((loff_t)offset+count);

	end = page_file_offset(page) + ((loff_t)offset+count);

	if (i_size >= end)

	if (i_size >= end)

		goto out;

		goto out;

	trace_nfs_size_grow(inode, end);

	i_size_write(inode, end);

	i_size_write(inode, end);

	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;

	NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;

	nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);

	nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);