2022-02-21 22:22:15

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v6 09/13] NFS: Readdirplus can't help lookup for case insensitive filesystems

From: Trond Myklebust <[email protected]>

If the filesystem is case insensitive, then readdirplus can't help with
cache misses, since it won't return case folded variants of the filename.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/dir.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index c4d962bca9ef..b1e6c56d7e1a 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -667,6 +667,8 @@ void nfs_readdir_record_entry_cache_miss(struct inode *dir)

static void nfs_lookup_advise_force_readdirplus(struct inode *dir)
{
+ if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
+ return;
nfs_readdir_record_entry_cache_miss(dir);
}

--
2.35.1


2022-02-22 01:48:28

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v6 10/13] NFS: Don't request readdirplus when revaldation was forced

From: Trond Myklebust <[email protected]>

If the revalidation was forced, due to the presence of a LOOKUP_EXCL or
a LOOKUP_REVAL flag, then readdirplus won't help. It also can't help
when we're doing a path component lookup.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/dir.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b1e6c56d7e1a..b6e21c5e1a0f 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -665,10 +665,13 @@ void nfs_readdir_record_entry_cache_miss(struct inode *dir)
}
}

-static void nfs_lookup_advise_force_readdirplus(struct inode *dir)
+static void nfs_lookup_advise_force_readdirplus(struct inode *dir,
+ unsigned int flags)
{
if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
return;
+ if (flags & (LOOKUP_EXCL | LOOKUP_PARENT | LOOKUP_REVAL))
+ return;
nfs_readdir_record_entry_cache_miss(dir);
}

@@ -1582,15 +1585,17 @@ nfs_lookup_revalidate_delegated(struct inode *dir, struct dentry *dentry,
return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
}

-static int
-nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
- struct inode *inode)
+static int nfs_lookup_revalidate_dentry(struct inode *dir,
+ struct dentry *dentry,
+ struct inode *inode, unsigned int flags)
{
struct nfs_fh *fhandle;
struct nfs_fattr *fattr;
unsigned long dir_verifier;
int ret;

+ trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
+
ret = -ENOMEM;
fhandle = nfs_alloc_fhandle();
fattr = nfs_alloc_fattr_with_label(NFS_SERVER(inode));
@@ -1611,6 +1616,10 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
}
goto out;
}
+
+ /* Request help from readdirplus */
+ nfs_lookup_advise_force_readdirplus(dir, flags);
+
ret = 0;
if (nfs_compare_fh(NFS_FH(inode), fhandle))
goto out;
@@ -1620,8 +1629,6 @@ nfs_lookup_revalidate_dentry(struct inode *dir, struct dentry *dentry,
nfs_setsecurity(inode, fattr);
nfs_set_verifier(dentry, dir_verifier);

- /* set a readdirplus hint that we had a cache miss */
- nfs_lookup_advise_force_readdirplus(dir);
ret = 1;
out:
nfs_free_fattr(fattr);
@@ -1687,8 +1694,7 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
if (NFS_STALE(inode))
goto out_bad;

- trace_nfs_lookup_revalidate_enter(dir, dentry, flags);
- return nfs_lookup_revalidate_dentry(dir, dentry, inode);
+ return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);
out_valid:
return nfs_lookup_revalidate_done(dir, dentry, inode, 1);
out_bad:
@@ -1882,7 +1888,7 @@ struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, unsigned in
goto out;

/* Notify readdir to use READDIRPLUS */
- nfs_lookup_advise_force_readdirplus(dir);
+ nfs_lookup_advise_force_readdirplus(dir, flags);

no_entry:
res = d_splice_alias(inode, dentry);
@@ -2145,7 +2151,7 @@ nfs4_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
reval_dentry:
if (flags & LOOKUP_RCU)
return -ECHILD;
- return nfs_lookup_revalidate_dentry(dir, dentry, inode);
+ return nfs_lookup_revalidate_dentry(dir, dentry, inode, flags);

full_reval:
return nfs_do_lookup_revalidate(dir, dentry, flags);
--
2.35.1

2022-02-22 04:57:08

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v6 11/13] NFS: Add basic readdir tracing

From: Trond Myklebust <[email protected]>

Add tracing to track how often the client goes to the server for updated
readdir information.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/dir.c | 13 ++++++++-
fs/nfs/nfstrace.h | 68 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index b6e21c5e1a0f..273a35851e42 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -966,10 +966,14 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
if (!nfs_readdir_may_fill_pagecache(desc))
return -EBADCOOKIE;
desc->page_index_max = desc->page_index;
+ trace_nfs_readdir_cache_fill(desc->file, nfsi->cookieverf,
+ desc->last_cookie,
+ desc->page_index, desc->dtsize);
res = nfs_readdir_xdr_to_array(desc, nfsi->cookieverf, verf,
&desc->page, 1);
if (res < 0) {
nfs_readdir_page_unlock_and_put_cached(desc);
+ trace_nfs_readdir_cache_fill_done(inode, res);
if (res == -EBADCOOKIE || res == -ENOTSYNC) {
invalidate_inode_pages2(desc->file->f_mapping);
desc->page_index = 0;
@@ -1085,7 +1089,14 @@ static int uncached_readdir(struct nfs_readdir_descriptor *desc)
desc->duped = 0;
desc->page_index_max = 0;

+ trace_nfs_readdir_uncached(desc->file, desc->verf, desc->last_cookie,
+ -1, desc->dtsize);
+
status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz);
+ if (status < 0) {
+ trace_nfs_readdir_uncached_done(file_inode(desc->file), status);
+ goto out_free;
+ }

for (i = 0; !desc->eob && i < sz && arrays[i]; i++) {
desc->page = arrays[i];
@@ -1104,7 +1115,7 @@ static int uncached_readdir(struct nfs_readdir_descriptor *desc)
i < (desc->page_index_max >> 1))
nfs_shrink_dtsize(desc);
}
-
+out_free:
for (i = 0; i < sz && arrays[i]; i++)
nfs_readdir_page_array_free(arrays[i]);
out:
diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index 3672f6703ee7..c2d0543ecb2d 100644
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -160,6 +160,8 @@ DEFINE_NFS_INODE_EVENT(nfs_fsync_enter);
DEFINE_NFS_INODE_EVENT_DONE(nfs_fsync_exit);
DEFINE_NFS_INODE_EVENT(nfs_access_enter);
DEFINE_NFS_INODE_EVENT_DONE(nfs_set_cache_invalid);
+DEFINE_NFS_INODE_EVENT_DONE(nfs_readdir_cache_fill_done);
+DEFINE_NFS_INODE_EVENT_DONE(nfs_readdir_uncached_done);

TRACE_EVENT(nfs_access_exit,
TP_PROTO(
@@ -271,6 +273,72 @@ DEFINE_NFS_UPDATE_SIZE_EVENT(wcc);
DEFINE_NFS_UPDATE_SIZE_EVENT(update);
DEFINE_NFS_UPDATE_SIZE_EVENT(grow);

+DECLARE_EVENT_CLASS(nfs_readdir_event,
+ TP_PROTO(
+ const struct file *file,
+ const __be32 *verifier,
+ u64 cookie,
+ pgoff_t page_index,
+ unsigned int dtsize
+ ),
+
+ TP_ARGS(file, verifier, cookie, page_index, dtsize),
+
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(u32, fhandle)
+ __field(u64, fileid)
+ __field(u64, version)
+ __array(char, verifier, NFS4_VERIFIER_SIZE)
+ __field(u64, cookie)
+ __field(pgoff_t, index)
+ __field(unsigned int, dtsize)
+ ),
+
+ TP_fast_assign(
+ const struct inode *dir = file_inode(file);
+ const struct nfs_inode *nfsi = NFS_I(dir);
+
+ __entry->dev = dir->i_sb->s_dev;
+ __entry->fileid = nfsi->fileid;
+ __entry->fhandle = nfs_fhandle_hash(&nfsi->fh);
+ __entry->version = inode_peek_iversion_raw(dir);
+ if (cookie != 0)
+ memcpy(__entry->verifier, verifier,
+ NFS4_VERIFIER_SIZE);
+ else
+ memset(__entry->verifier, 0,
+ NFS4_VERIFIER_SIZE);
+ __entry->cookie = cookie;
+ __entry->index = page_index;
+ __entry->dtsize = dtsize;
+ ),
+
+ TP_printk(
+ "fileid=%02x:%02x:%llu fhandle=0x%08x version=%llu "
+ "cookie=%s:0x%llx cache_index=%lu dtsize=%u",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ (unsigned long long)__entry->fileid, __entry->fhandle,
+ __entry->version, show_nfs4_verifier(__entry->verifier),
+ (unsigned long long)__entry->cookie, __entry->index,
+ __entry->dtsize
+ )
+);
+
+#define DEFINE_NFS_READDIR_EVENT(name) \
+ DEFINE_EVENT(nfs_readdir_event, name, \
+ TP_PROTO( \
+ const struct file *file, \
+ const __be32 *verifier, \
+ u64 cookie, \
+ pgoff_t page_index, \
+ unsigned int dtsize \
+ ), \
+ TP_ARGS(file, verifier, cookie, page_index, dtsize))
+
+DEFINE_NFS_READDIR_EVENT(nfs_readdir_cache_fill);
+DEFINE_NFS_READDIR_EVENT(nfs_readdir_uncached);
+
DECLARE_EVENT_CLASS(nfs_lookup_event,
TP_PROTO(
const struct inode *dir,
--
2.35.1