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| author | Dominique Martinet <asmadeus@codewreck.org> | 2022-01-10 20:10:31 +0900 |
|---|---|---|
| committer | Dominique Martinet <asmadeus@codewreck.org> | 2022-01-11 15:21:53 +0900 |
| commit | 19d1c32652bbbf406063025354845fdddbcecd3a (patch) | |
| tree | 57f52600d66502bfc8a649a573768c0fe08d870c /fs/9p/vfs_addr.c | |
| parent | 15e2721b19acb1bfb18ac90775503b75d8aecbb2 (diff) | |
| download | lwn-19d1c32652bbbf406063025354845fdddbcecd3a.tar.gz lwn-19d1c32652bbbf406063025354845fdddbcecd3a.zip | |
9p: fix enodata when reading growing file
Reading from a file that was just extended by a write, but the write had
not yet reached the server would return ENODATA as illustrated by this
command:
$ xfs_io -c 'open -ft test' -c 'w 4096 1000' -c 'r 0 1000'
wrote 1000/1000 bytes at offset 4096
1000.000000 bytes, 1 ops; 0.0001 sec (5.610 MiB/sec and 5882.3529 ops/sec)
pread: No data available
Fix this case by having netfs assume zeroes when reads from server come
short like AFS and CEPH do
Link: https://lkml.kernel.org/r/20220110111444.926753-1-asmadeus@codewreck.org
Cc: stable@vger.kernel.org
Fixes: eb497943fa21 ("9p: Convert to using the netfs helper lib to do reads and caching")
Co-authored-by: David Howells <dhowells@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Diffstat (limited to 'fs/9p/vfs_addr.c')
| -rw-r--r-- | fs/9p/vfs_addr.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c index fac918ccb305..1d554d0b6e58 100644 --- a/fs/9p/vfs_addr.c +++ b/fs/9p/vfs_addr.c @@ -42,6 +42,11 @@ static void v9fs_req_issue_op(struct netfs_read_subrequest *subreq) iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len); total = p9_client_read(fid, pos, &to, &err); + + /* if we just extended the file size, any portion not in + * cache won't be on server and is zeroes */ + __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); + netfs_subreq_terminated(subreq, err ?: total, false); } |