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: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Chuck Lever
2021-10-04 10:10:16 -04:00
committed by Trond Myklebust
parent 0392dd51f9
commit 110cb2d2f9
3 changed files with 54 additions and 6 deletions

View File

@@ -671,6 +671,7 @@ static int nfs_vmtruncate(struct inode * inode, loff_t offset)
if (err)
goto out;
trace_nfs_size_truncate(inode, offset);
i_size_write(inode, offset);
/* Optimisation */
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)
&& i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size)
&& !nfs_have_writebacks(inode)) {
trace_nfs_size_wcc(inode, 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
* the file grown beyond our last write? */
if (!nfs_have_writebacks(inode) || new_isize > cur_isize) {
trace_nfs_size_update(inode, new_isize);
i_size_write(inode, new_isize);
if (!have_writers)
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 &&
!(fattr->valid & (NFS_ATTR_FATTR_SPACE_USED |