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authorDominique Martinet <asmadeus@codewreck.org>2022-01-10 12:10:31 +0100
committerDominique Martinet <asmadeus@codewreck.org>2022-01-11 07:21:53 +0100
commit19d1c32652bbbf406063025354845fdddbcecd3a (patch)
tree57f52600d66502bfc8a649a573768c0fe08d870c /fs/9p
parentnet/9p: show error message if user 'msize' cannot be satisfied (diff)
downloadlinux-19d1c32652bbbf406063025354845fdddbcecd3a.tar.xz
linux-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')
-rw-r--r--fs/9p/vfs_addr.c5
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);
}