This is a combined posting of two previously posted patches. The first
unconditionally adds the type attribute to the list of requested attributes
for v4 READDIR. The second patch enables a per-mount modification via sysfs
of any of the attributes the client will currently decode for v4 READDIR.
The first patch solves a real problem but may cause a performance regression
for some servers that require extra processing to return inode information
along with the namespace. We performed an informal survey of most of the
major NFSv4 server vendors and although we did not learn of any that may be
impacted, the potential remains.
The second patch gives us a way to disable this new READDIR behavior should
we find a serious impact in an existing setup. I would appreciate serious
consideration of this patch in light of the number of claimed performance
regressions that have been reported almost every time we touch this
sensitive operation on the client.
For example:
echo 0x800 0x800000 0x0 > /sys/fs/nfs/0\:57/v4_readdir_attrs
.. will revert the behavior change from patch 1.
Benjamin Coddington (2):
NFSv4: Always ask for type with READDIR
NFSv4: Allow per-mount tuning of READDIR attrs
fs/nfs/client.c | 2 +
fs/nfs/nfs4client.c | 4 ++
fs/nfs/nfs4proc.c | 1 +
fs/nfs/nfs4xdr.c | 9 ++---
fs/nfs/sysfs.c | 81 +++++++++++++++++++++++++++++++++++++++
include/linux/nfs_fs_sb.h | 1 +
include/linux/nfs_xdr.h | 1 +
7 files changed, 94 insertions(+), 5 deletions(-)
--
2.41.0
Again we have claimed regressions for walking a directory tree, this time
with the "find" utility which always tries to optimize away asking for any
attributes until it has a complete list of entries. This behavior makes
the readdir plus heuristic do the wrong thing, which causes a storm of
GETATTRs to determine each entry's type in order to continue the walk.
For v4 add the type attribute to each READDIR request to include it no
matter the heuristic. This allows a simple `find` command to proceed
quickly through a directory tree.
Suggested-by: Jeff Layton <[email protected]>
Signed-off-by: Benjamin Coddington <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
---
fs/nfs/nfs4xdr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index deec76cf5afe..7200d6f7cd7b 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1602,7 +1602,7 @@ static void encode_read(struct xdr_stream *xdr, const struct nfs_pgio_args *args
static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg *readdir, struct rpc_rqst *req, struct compound_hdr *hdr)
{
uint32_t attrs[3] = {
- FATTR4_WORD0_RDATTR_ERROR,
+ FATTR4_WORD0_TYPE|FATTR4_WORD0_RDATTR_ERROR,
FATTR4_WORD1_MOUNTED_ON_FILEID,
};
uint32_t dircount = readdir->count;
@@ -1612,7 +1612,7 @@ static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
unsigned int i;
if (readdir->plus) {
- attrs[0] |= FATTR4_WORD0_TYPE|FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE|
+ attrs[0] |= FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE|
FATTR4_WORD0_FSID|FATTR4_WORD0_FILEHANDLE|FATTR4_WORD0_FILEID;
attrs[1] |= FATTR4_WORD1_MODE|FATTR4_WORD1_NUMLINKS|FATTR4_WORD1_OWNER|
FATTR4_WORD1_OWNER_GROUP|FATTR4_WORD1_RAWDEV|
--
2.41.0