* [PATCH v3 1/4] 9p: Cache negative dentries for lookup performance
2026-02-27 7:56 [PATCH v3 0/4] 9p: Performance improvements for build workloads Remi Pommarel
@ 2026-02-27 7:56 ` Remi Pommarel
2026-03-04 12:50 ` Christian Schoenebeck
2026-02-27 7:56 ` [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention Remi Pommarel
` (2 subsequent siblings)
3 siblings, 1 reply; 14+ messages in thread
From: Remi Pommarel @ 2026-02-27 7:56 UTC (permalink / raw)
To: v9fs
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Christian Schoenebeck,
Remi Pommarel
Not caching negative dentries can result in poor performance for
workloads that repeatedly look up non-existent paths. Each such
lookup triggers a full 9P transaction with the server, adding
unnecessary overhead.
A typical example is source compilation, where multiple cc1 processes
are spawned and repeatedly search for the same missing header files
over and over again.
This change enables caching of negative dentries, so that lookups for
known non-existent paths do not require a full 9P transaction. The
cached negative dentries are retained for a configurable duration
(expressed in milliseconds), as specified by the ndentry_timeout
field in struct v9fs_session_info. If set to -1, negative dentries
are cached indefinitely.
This optimization reduces lookup overhead and improves performance for
workloads involving frequent access to non-existent paths.
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
---
fs/9p/fid.c | 11 +++--
fs/9p/v9fs.c | 1 +
fs/9p/v9fs.h | 5 ++
fs/9p/v9fs_vfs.h | 15 ++++++
fs/9p/vfs_dentry.c | 105 ++++++++++++++++++++++++++++++++++------
fs/9p/vfs_inode.c | 12 +++--
fs/9p/vfs_super.c | 1 +
include/net/9p/client.h | 2 +
8 files changed, 128 insertions(+), 24 deletions(-)
diff --git a/fs/9p/fid.c b/fs/9p/fid.c
index f84412290a30..76242d450aa7 100644
--- a/fs/9p/fid.c
+++ b/fs/9p/fid.c
@@ -20,7 +20,9 @@
static inline void __add_fid(struct dentry *dentry, struct p9_fid *fid)
{
- hlist_add_head(&fid->dlist, (struct hlist_head *)&dentry->d_fsdata);
+ struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
+
+ hlist_add_head(&fid->dlist, &v9fs_dentry->head);
}
@@ -112,6 +114,7 @@ void v9fs_open_fid_add(struct inode *inode, struct p9_fid **pfid)
static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
{
+ struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
struct p9_fid *fid, *ret;
p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p) uid %d any %d\n",
@@ -119,11 +122,9 @@ static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
any);
ret = NULL;
/* we'll recheck under lock if there's anything to look in */
- if (dentry->d_fsdata) {
- struct hlist_head *h = (struct hlist_head *)&dentry->d_fsdata;
-
+ if (!hlist_empty(&v9fs_dentry->head)) {
spin_lock(&dentry->d_lock);
- hlist_for_each_entry(fid, h, dlist) {
+ hlist_for_each_entry(fid, &v9fs_dentry->head, dlist) {
if (any || uid_eq(fid->uid, uid)) {
ret = fid;
p9_fid_get(ret);
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 057487efaaeb..c5dca81a553e 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -422,6 +422,7 @@ static void v9fs_apply_options(struct v9fs_session_info *v9ses,
v9ses->cache = ctx->session_opts.cache;
v9ses->uid = ctx->session_opts.uid;
v9ses->session_lock_timeout = ctx->session_opts.session_lock_timeout;
+ v9ses->ndentry_timeout_ms = ctx->session_opts.ndentry_timeout_ms;
}
/**
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 6a12445d3858..8410f7883109 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -91,6 +91,7 @@ enum p9_cache_bits {
* @debug: debug level
* @afid: authentication handle
* @cache: cache mode of type &p9_cache_bits
+ * @ndentry_timeout: Negative dentry lookup cache retention time in ms
* @cachetag: the tag of the cache associated with this session
* @fscache: session cookie associated with FS-Cache
* @uname: string user name to mount hierarchy as
@@ -101,6 +102,7 @@ enum p9_cache_bits {
* @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
* @clnt: reference to 9P network client instantiated for this session
* @slist: reference to list of registered 9p sessions
+ * @ndentry_timeout_ms: Negative dentry caching retention time
*
* This structure holds state for each session instance established during
* a sys_mount() .
@@ -116,6 +118,7 @@ struct v9fs_session_info {
unsigned short debug;
unsigned int afid;
unsigned int cache;
+ unsigned int ndentry_timeout_ms;
#ifdef CONFIG_9P_FSCACHE
char *cachetag;
struct fscache_volume *fscache;
@@ -133,6 +136,8 @@ struct v9fs_session_info {
long session_lock_timeout; /* retry interval for blocking locks */
};
+#define NDENTRY_TMOUT_NEVER (-1U)
+
/* cache_validity flags */
#define V9FS_INO_INVALID_ATTR 0x01
diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
index d3aefbec4de6..83c2335f438d 100644
--- a/fs/9p/v9fs_vfs.h
+++ b/fs/9p/v9fs_vfs.h
@@ -28,6 +28,19 @@
/* flags for v9fs_stat2inode() & v9fs_stat2inode_dotl() */
#define V9FS_STAT2INODE_KEEP_ISIZE 1
+/**
+ * struct v9fs_dentry - v9fs specific dentry data
+ * @head: List of fid associated with this dentry
+ * @expire_time: Lookup cache expiration time for negative dentries
+ * @rcu: used by kfree_rcu to schedule clean up job
+ */
+struct v9fs_dentry {
+ struct hlist_head head;
+ u64 expire_time;
+ struct rcu_head rcu;
+};
+#define to_v9fs_dentry(d) ((struct v9fs_dentry *)((d)->d_fsdata))
+
extern struct file_system_type v9fs_fs_type;
extern const struct address_space_operations v9fs_addr_operations;
extern const struct file_operations v9fs_file_operations;
@@ -35,6 +48,8 @@ extern const struct file_operations v9fs_file_operations_dotl;
extern const struct file_operations v9fs_dir_operations;
extern const struct file_operations v9fs_dir_operations_dotl;
extern const struct dentry_operations v9fs_dentry_operations;
+extern void v9fs_ndentry_refresh_timeout(struct dentry *dentry);
+extern void v9fs_dentry_fid_remove(struct dentry *dentry);
extern const struct dentry_operations v9fs_cached_dentry_operations;
extern struct kmem_cache *v9fs_inode_cache;
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index c5bf74d547e8..5a900d3cef89 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -23,6 +23,46 @@
#include "v9fs_vfs.h"
#include "fid.h"
+/**
+ * v9fs_ndentry_is_expired - Check if negative dentry lookup has expired
+ *
+ * This should be called to know if a negative dentry should be removed from
+ * cache.
+ *
+ * @dentry: dentry in question
+ *
+ */
+static bool v9fs_ndentry_is_expired(struct dentry const *dentry)
+{
+ struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
+ struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
+
+ if (v9ses->ndentry_timeout_ms == NDENTRY_TMOUT_NEVER)
+ return false;
+
+ return time_before_eq64(v9fs_dentry->expire_time, get_jiffies_64());
+}
+
+/**
+ * v9fs_ndentry_refresh_timeout - Refresh negative dentry lookup cache timeout
+ *
+ * This should be called when a look up yields a negative entry.
+ *
+ * @dentry: dentry in question
+ *
+ */
+void v9fs_ndentry_refresh_timeout(struct dentry *dentry)
+{
+ struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
+ struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
+
+ if (v9ses->ndentry_timeout_ms == NDENTRY_TMOUT_NEVER)
+ return;
+
+ v9fs_dentry->expire_time = get_jiffies_64() +
+ msecs_to_jiffies(v9ses->ndentry_timeout_ms);
+}
+
/**
* v9fs_cached_dentry_delete - called when dentry refcount equals 0
* @dentry: dentry in question
@@ -33,20 +73,15 @@ static int v9fs_cached_dentry_delete(const struct dentry *dentry)
p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
dentry, dentry);
- /* Don't cache negative dentries */
- if (d_really_is_negative(dentry))
- return 1;
- return 0;
-}
+ if (!d_really_is_negative(dentry))
+ return 0;
-/**
- * v9fs_dentry_release - called when dentry is going to be freed
- * @dentry: dentry that is being release
- *
- */
+ return v9fs_ndentry_is_expired(dentry);
+}
-static void v9fs_dentry_release(struct dentry *dentry)
+static void __v9fs_dentry_fid_remove(struct dentry *dentry)
{
+ struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
struct hlist_node *p, *n;
struct hlist_head head;
@@ -54,13 +89,54 @@ static void v9fs_dentry_release(struct dentry *dentry)
dentry, dentry);
spin_lock(&dentry->d_lock);
- hlist_move_list((struct hlist_head *)&dentry->d_fsdata, &head);
+ hlist_move_list(&v9fs_dentry->head, &head);
spin_unlock(&dentry->d_lock);
hlist_for_each_safe(p, n, &head)
p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
}
+/**
+ * v9fs_dentry_fid_remove - Release all dentry's fids
+ * @dentry: dentry in question
+ *
+ */
+void v9fs_dentry_fid_remove(struct dentry *dentry)
+{
+ __v9fs_dentry_fid_remove(dentry);
+}
+
+/**
+ * v9fs_dentry_init - Initialize v9fs dentry data
+ * @dentry: dentry in question
+ *
+ */
+static int v9fs_dentry_init(struct dentry *dentry)
+{
+ struct v9fs_dentry *v9fs_dentry = kzalloc(sizeof(*v9fs_dentry),
+ GFP_KERNEL);
+
+ if (!v9fs_dentry)
+ return -ENOMEM;
+
+ INIT_HLIST_HEAD(&v9fs_dentry->head);
+ dentry->d_fsdata = (void *)v9fs_dentry;
+ return 0;
+}
+
+/**
+ * v9fs_dentry_release - called when dentry is going to be freed
+ * @dentry: dentry that is being released
+ *
+ */
+static void v9fs_dentry_release(struct dentry *dentry)
+{
+ struct v9fs_dentry *v9fs_dentry = to_v9fs_dentry(dentry);
+
+ __v9fs_dentry_fid_remove(dentry);
+ kfree_rcu(v9fs_dentry, rcu);
+}
+
static int __v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
{
struct p9_fid *fid;
@@ -72,7 +148,7 @@ static int __v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
inode = d_inode(dentry);
if (!inode)
- goto out_valid;
+ return !v9fs_ndentry_is_expired(dentry);
v9inode = V9FS_I(inode);
if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
@@ -112,7 +188,6 @@ static int __v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
return retval;
}
}
-out_valid:
p9_debug(P9_DEBUG_VFS, "dentry: %pd (%p) is valid\n", dentry, dentry);
return 1;
}
@@ -139,12 +214,14 @@ const struct dentry_operations v9fs_cached_dentry_operations = {
.d_revalidate = v9fs_lookup_revalidate,
.d_weak_revalidate = __v9fs_lookup_revalidate,
.d_delete = v9fs_cached_dentry_delete,
+ .d_init = v9fs_dentry_init,
.d_release = v9fs_dentry_release,
.d_unalias_trylock = v9fs_dentry_unalias_trylock,
.d_unalias_unlock = v9fs_dentry_unalias_unlock,
};
const struct dentry_operations v9fs_dentry_operations = {
+ .d_init = v9fs_dentry_init,
.d_release = v9fs_dentry_release,
.d_unalias_trylock = v9fs_dentry_unalias_trylock,
.d_unalias_unlock = v9fs_dentry_unalias_unlock,
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 97abe65bf7c1..c82db6fe0c39 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -549,7 +549,7 @@ static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
/* invalidate all fids associated with dentry */
/* NOTE: This will not include open fids */
- dentry->d_op->d_release(dentry);
+ v9fs_dentry_fid_remove(dentry);
}
return retval;
}
@@ -732,14 +732,16 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
name = dentry->d_name.name;
fid = p9_client_walk(dfid, 1, &name, 1);
p9_fid_put(dfid);
- if (fid == ERR_PTR(-ENOENT))
+ if (fid == ERR_PTR(-ENOENT)) {
inode = NULL;
- else if (IS_ERR(fid))
+ v9fs_ndentry_refresh_timeout(dentry);
+ } else if (IS_ERR(fid)) {
inode = ERR_CAST(fid);
- else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
+ } else if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
- else
+ } else {
inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+ }
/*
* If we had a rename on the server and a parallel lookup
* for the new name, then make sure we instantiate with
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index 0a1c4f7cb001..3b2a906528cd 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -327,6 +327,7 @@ static int v9fs_init_fs_context(struct fs_context *fc)
ctx->session_opts.uid = INVALID_UID;
ctx->session_opts.dfltuid = V9FS_DEFUID;
ctx->session_opts.dfltgid = V9FS_DEFGID;
+ ctx->session_opts.ndentry_timeout_ms = 0;
/* initialize client options */
ctx->client_opts.proto_version = p9_proto_2000L;
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index 838a94218b59..55c6cb54bd25 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -192,6 +192,7 @@ struct p9_rdma_opts {
* @dfltgid: default numeric groupid to mount hierarchy as
* @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
* @session_lock_timeout: retry interval for blocking locks
+ * @ndentry_timeout_ms: Negative dentry lookup cache retention time in ms
*
* This strucure holds options which are parsed and will be transferred
* to the v9fs_session_info structure when mounted, and therefore largely
@@ -203,6 +204,7 @@ struct p9_session_opts {
unsigned short debug;
unsigned int afid;
unsigned int cache;
+ unsigned int ndentry_timeout_ms;
#ifdef CONFIG_9P_FSCACHE
char *cachetag;
#endif
--
2.52.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [PATCH v3 1/4] 9p: Cache negative dentries for lookup performance
2026-02-27 7:56 ` [PATCH v3 1/4] 9p: Cache negative dentries for lookup performance Remi Pommarel
@ 2026-03-04 12:50 ` Christian Schoenebeck
0 siblings, 0 replies; 14+ messages in thread
From: Christian Schoenebeck @ 2026-03-04 12:50 UTC (permalink / raw)
To: v9fs, Remi Pommarel
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Remi Pommarel
On Friday, 27 February 2026 08:56:52 CET Remi Pommarel wrote:
> Not caching negative dentries can result in poor performance for
> workloads that repeatedly look up non-existent paths. Each such
> lookup triggers a full 9P transaction with the server, adding
> unnecessary overhead.
>
> A typical example is source compilation, where multiple cc1 processes
> are spawned and repeatedly search for the same missing header files
> over and over again.
>
> This change enables caching of negative dentries, so that lookups for
> known non-existent paths do not require a full 9P transaction. The
> cached negative dentries are retained for a configurable duration
> (expressed in milliseconds), as specified by the ndentry_timeout
> field in struct v9fs_session_info. If set to -1, negative dentries
> are cached indefinitely.
>
> This optimization reduces lookup overhead and improves performance for
> workloads involving frequent access to non-existent paths.
>
> Signed-off-by: Remi Pommarel <repk@triplefau.lt>
> ---
> fs/9p/fid.c | 11 +++--
> fs/9p/v9fs.c | 1 +
> fs/9p/v9fs.h | 5 ++
> fs/9p/v9fs_vfs.h | 15 ++++++
> fs/9p/vfs_dentry.c | 105 ++++++++++++++++++++++++++++++++++------
> fs/9p/vfs_inode.c | 12 +++--
> fs/9p/vfs_super.c | 1 +
> include/net/9p/client.h | 2 +
> 8 files changed, 128 insertions(+), 24 deletions(-)
[...]
> diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
> index 6a12445d3858..8410f7883109 100644
> --- a/fs/9p/v9fs.h
> +++ b/fs/9p/v9fs.h
> @@ -91,6 +91,7 @@ enum p9_cache_bits {
> * @debug: debug level
> * @afid: authentication handle
> * @cache: cache mode of type &p9_cache_bits
> + * @ndentry_timeout: Negative dentry lookup cache retention time in ms
> * @cachetag: the tag of the cache associated with this session
> * @fscache: session cookie associated with FS-Cache
> * @uname: string user name to mount hierarchy as
> @@ -101,6 +102,7 @@ enum p9_cache_bits {
> * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the
> hierarchy * @clnt: reference to 9P network client instantiated for this
> session * @slist: reference to list of registered 9p sessions
> + * @ndentry_timeout_ms: Negative dentry caching retention time
> *
> * This structure holds state for each session instance established during
> * a sys_mount() .
> @@ -116,6 +118,7 @@ struct v9fs_session_info {
> unsigned short debug;
> unsigned int afid;
> unsigned int cache;
> + unsigned int ndentry_timeout_ms;
> #ifdef CONFIG_9P_FSCACHE
> char *cachetag;
> struct fscache_volume *fscache;
> @@ -133,6 +136,8 @@ struct v9fs_session_info {
> long session_lock_timeout; /* retry interval for blocking locks */
> };
[...]
> diff --git a/include/net/9p/client.h b/include/net/9p/client.h
> index 838a94218b59..55c6cb54bd25 100644
> --- a/include/net/9p/client.h
> +++ b/include/net/9p/client.h
> @@ -192,6 +192,7 @@ struct p9_rdma_opts {
> * @dfltgid: default numeric groupid to mount hierarchy as
> * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the
> hierarchy * @session_lock_timeout: retry interval for blocking locks
> + * @ndentry_timeout_ms: Negative dentry lookup cache retention time in ms
> *
> * This strucure holds options which are parsed and will be transferred
> * to the v9fs_session_info structure when mounted, and therefore largely
> @@ -203,6 +204,7 @@ struct p9_session_opts {
> unsigned short debug;
> unsigned int afid;
> unsigned int cache;
> + unsigned int ndentry_timeout_ms;
> #ifdef CONFIG_9P_FSCACHE
> char *cachetag;
> #endif
Depending on what turns out to be chosen for the mount option eventually,
these types could be increased in size. But in general, LGTM:
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention
2026-02-27 7:56 [PATCH v3 0/4] 9p: Performance improvements for build workloads Remi Pommarel
2026-02-27 7:56 ` [PATCH v3 1/4] 9p: Cache negative dentries for lookup performance Remi Pommarel
@ 2026-02-27 7:56 ` Remi Pommarel
2026-03-03 14:53 ` Christian Schoenebeck
2026-03-04 12:45 ` Christian Schoenebeck
2026-02-27 7:56 ` [PATCH v3 3/4] 9p: Set default negative dentry retention time for cache=loose Remi Pommarel
2026-02-27 7:56 ` [PATCH v3 4/4] 9p: Enable symlink caching in page cache Remi Pommarel
3 siblings, 2 replies; 14+ messages in thread
From: Remi Pommarel @ 2026-02-27 7:56 UTC (permalink / raw)
To: v9fs
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Christian Schoenebeck,
Remi Pommarel
Introduce a new mount option, ndentrycache, for v9fs that allows users
to specify how long negative dentries are retained in the cache. The
retention time can be set in milliseconds (e.g. ndentrycache=10000 for
a 10secs retention time), or negative entries can be kept until the
buffer cache management removes them by using the option without a
value (i.e. ndentrycache).
For consistency reasons, this option should only be used in exclusive
or read-only mount scenarios, aligning with the cache=loose usage.
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
---
fs/9p/v9fs.c | 73 ++++++++++++++++++++++++++++++++--------------------
fs/9p/v9fs.h | 23 ++++++++++-------
2 files changed, 58 insertions(+), 38 deletions(-)
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index c5dca81a553e..a26bd9070786 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -39,11 +39,12 @@ enum {
* source if we rejected it as EINVAL */
Opt_source,
/* Options that take integer arguments */
- Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
+ Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid, Opt_ndentrycachetmo,
/* String options */
Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
/* Options that take no arguments */
Opt_nodevmap, Opt_noxattr, Opt_directio, Opt_ignoreqv,
+ Opt_ndentrycache,
/* Access options */
Opt_access, Opt_posixacl,
/* Lock timeout option */
@@ -77,41 +78,43 @@ static const struct constant_table p9_versions[] = {
* the client, and all the transports.
*/
const struct fs_parameter_spec v9fs_param_spec[] = {
- fsparam_string ("source", Opt_source),
- fsparam_u32hex ("debug", Opt_debug),
- fsparam_uid ("dfltuid", Opt_dfltuid),
- fsparam_gid ("dfltgid", Opt_dfltgid),
- fsparam_u32 ("afid", Opt_afid),
- fsparam_string ("uname", Opt_uname),
- fsparam_string ("aname", Opt_remotename),
- fsparam_flag ("nodevmap", Opt_nodevmap),
- fsparam_flag ("noxattr", Opt_noxattr),
- fsparam_flag ("directio", Opt_directio),
- fsparam_flag ("ignoreqv", Opt_ignoreqv),
- fsparam_string ("cache", Opt_cache),
- fsparam_string ("cachetag", Opt_cachetag),
- fsparam_string ("access", Opt_access),
- fsparam_flag ("posixacl", Opt_posixacl),
- fsparam_u32 ("locktimeout", Opt_locktimeout),
+ fsparam_string ("source", Opt_source),
+ fsparam_u32hex ("debug", Opt_debug),
+ fsparam_uid ("dfltuid", Opt_dfltuid),
+ fsparam_gid ("dfltgid", Opt_dfltgid),
+ fsparam_u32 ("afid", Opt_afid),
+ fsparam_string ("uname", Opt_uname),
+ fsparam_string ("aname", Opt_remotename),
+ fsparam_flag ("nodevmap", Opt_nodevmap),
+ fsparam_flag ("noxattr", Opt_noxattr),
+ fsparam_flag ("directio", Opt_directio),
+ fsparam_flag ("ignoreqv", Opt_ignoreqv),
+ fsparam_string ("cache", Opt_cache),
+ fsparam_string ("cachetag", Opt_cachetag),
+ fsparam_string ("access", Opt_access),
+ fsparam_flag ("posixacl", Opt_posixacl),
+ fsparam_u32 ("locktimeout", Opt_locktimeout),
+ fsparam_flag ("ndentrycache", Opt_ndentrycache),
+ fsparam_u32 ("ndentrycache", Opt_ndentrycachetmo),
/* client options */
- fsparam_u32 ("msize", Opt_msize),
- fsparam_flag ("noextend", Opt_legacy),
- fsparam_string ("trans", Opt_trans),
- fsparam_enum ("version", Opt_version, p9_versions),
+ fsparam_u32 ("msize", Opt_msize),
+ fsparam_flag ("noextend", Opt_legacy),
+ fsparam_string ("trans", Opt_trans),
+ fsparam_enum ("version", Opt_version, p9_versions),
/* fd transport options */
- fsparam_u32 ("rfdno", Opt_rfdno),
- fsparam_u32 ("wfdno", Opt_wfdno),
+ fsparam_u32 ("rfdno", Opt_rfdno),
+ fsparam_u32 ("wfdno", Opt_wfdno),
/* rdma transport options */
- fsparam_u32 ("sq", Opt_sq_depth),
- fsparam_u32 ("rq", Opt_rq_depth),
- fsparam_u32 ("timeout", Opt_timeout),
+ fsparam_u32 ("sq", Opt_sq_depth),
+ fsparam_u32 ("rq", Opt_rq_depth),
+ fsparam_u32 ("timeout", Opt_timeout),
/* fd and rdma transprt options */
- fsparam_u32 ("port", Opt_port),
- fsparam_flag ("privport", Opt_privport),
+ fsparam_u32 ("port", Opt_port),
+ fsparam_flag ("privport", Opt_privport),
{}
};
@@ -159,6 +162,10 @@ int v9fs_show_options(struct seq_file *m, struct dentry *root)
from_kgid_munged(&init_user_ns, v9ses->dfltgid));
if (v9ses->afid != ~0)
seq_printf(m, ",afid=%u", v9ses->afid);
+ if (v9ses->ndentry_timeout_ms == NDENTRY_TMOUT_NEVER)
+ seq_printf(m, ",ndentrycache");
+ else if (v9ses->flags & V9FS_NDENTRY_TMOUT_SET)
+ seq_printf(m, ",ndentrycache=%u", v9ses->ndentry_timeout_ms);
if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
seq_printf(m, ",uname=%s", v9ses->uname);
if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
@@ -337,6 +344,16 @@ int v9fs_parse_param(struct fs_context *fc, struct fs_parameter *param)
session_opts->session_lock_timeout = (long)result.uint_32 * HZ;
break;
+ case Opt_ndentrycache:
+ session_opts->flags |= V9FS_NDENTRY_TMOUT_SET;
+ session_opts->ndentry_timeout_ms = NDENTRY_TMOUT_NEVER;
+ break;
+
+ case Opt_ndentrycachetmo:
+ session_opts->flags |= V9FS_NDENTRY_TMOUT_SET;
+ session_opts->ndentry_timeout_ms = result.uint_64;
+ break;
+
/* Options for client */
case Opt_msize:
if (result.uint_32 < 4096) {
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 8410f7883109..2e42729c6c20 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -24,6 +24,8 @@
* @V9FS_ACCESS_ANY: use a single attach for all users
* @V9FS_ACCESS_MASK: bit mask of different ACCESS options
* @V9FS_POSIX_ACL: POSIX ACLs are enforced
+ * @V9FS_NDENTRY_TMOUT_SET: Has negative dentry timeout retention time been
+ * overriden by ndentrycache mount option
*
* Session flags reflect options selected by users at mount time
*/
@@ -34,16 +36,17 @@
#define V9FS_ACL_MASK V9FS_POSIX_ACL
enum p9_session_flags {
- V9FS_PROTO_2000U = 0x01,
- V9FS_PROTO_2000L = 0x02,
- V9FS_ACCESS_SINGLE = 0x04,
- V9FS_ACCESS_USER = 0x08,
- V9FS_ACCESS_CLIENT = 0x10,
- V9FS_POSIX_ACL = 0x20,
- V9FS_NO_XATTR = 0x40,
- V9FS_IGNORE_QV = 0x80, /* ignore qid.version for cache hints */
- V9FS_DIRECT_IO = 0x100,
- V9FS_SYNC = 0x200
+ V9FS_PROTO_2000U = 0x01,
+ V9FS_PROTO_2000L = 0x02,
+ V9FS_ACCESS_SINGLE = 0x04,
+ V9FS_ACCESS_USER = 0x08,
+ V9FS_ACCESS_CLIENT = 0x10,
+ V9FS_POSIX_ACL = 0x20,
+ V9FS_NO_XATTR = 0x40,
+ V9FS_IGNORE_QV = 0x80, /* ignore qid.version for cache hints */
+ V9FS_DIRECT_IO = 0x100,
+ V9FS_SYNC = 0x200,
+ V9FS_NDENTRY_TMOUT_SET = 0x400,
};
/**
--
2.52.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention
2026-02-27 7:56 ` [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention Remi Pommarel
@ 2026-03-03 14:53 ` Christian Schoenebeck
2026-03-03 21:45 ` Dominique Martinet
2026-03-04 12:45 ` Christian Schoenebeck
1 sibling, 1 reply; 14+ messages in thread
From: Christian Schoenebeck @ 2026-03-03 14:53 UTC (permalink / raw)
To: v9fs, Remi Pommarel, Dominique Martinet
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Remi Pommarel
On Friday, 27 February 2026 08:56:53 CET Remi Pommarel wrote:
> Introduce a new mount option, ndentrycache, for v9fs that allows users
> to specify how long negative dentries are retained in the cache. The
> retention time can be set in milliseconds (e.g. ndentrycache=10000 for
> a 10secs retention time), or negative entries can be kept until the
> buffer cache management removes them by using the option without a
> value (i.e. ndentrycache).
>
> For consistency reasons, this option should only be used in exclusive
> or read-only mount scenarios, aligning with the cache=loose usage.
>
> Signed-off-by: Remi Pommarel <repk@triplefau.lt>
> ---
> fs/9p/v9fs.c | 73 ++++++++++++++++++++++++++++++++--------------------
> fs/9p/v9fs.h | 23 ++++++++++-------
> 2 files changed, 58 insertions(+), 38 deletions(-)
>
> diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
> index c5dca81a553e..a26bd9070786 100644
> --- a/fs/9p/v9fs.c
> +++ b/fs/9p/v9fs.c
> @@ -39,11 +39,12 @@ enum {
> * source if we rejected it as EINVAL */
> Opt_source,
> /* Options that take integer arguments */
> - Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
> + Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid, Opt_ndentrycachetmo,
> /* String options */
> Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
> /* Options that take no arguments */
> Opt_nodevmap, Opt_noxattr, Opt_directio, Opt_ignoreqv,
> + Opt_ndentrycache,
> /* Access options */
> Opt_access, Opt_posixacl,
> /* Lock timeout option */
> @@ -77,41 +78,43 @@ static const struct constant_table p9_versions[] = {
> * the client, and all the transports.
> */
> const struct fs_parameter_spec v9fs_param_spec[] = {
> - fsparam_string ("source", Opt_source),
> - fsparam_u32hex ("debug", Opt_debug),
> - fsparam_uid ("dfltuid", Opt_dfltuid),
> - fsparam_gid ("dfltgid", Opt_dfltgid),
> - fsparam_u32 ("afid", Opt_afid),
> - fsparam_string ("uname", Opt_uname),
> - fsparam_string ("aname", Opt_remotename),
> - fsparam_flag ("nodevmap", Opt_nodevmap),
> - fsparam_flag ("noxattr", Opt_noxattr),
> - fsparam_flag ("directio", Opt_directio),
> - fsparam_flag ("ignoreqv", Opt_ignoreqv),
> - fsparam_string ("cache", Opt_cache),
> - fsparam_string ("cachetag", Opt_cachetag),
> - fsparam_string ("access", Opt_access),
> - fsparam_flag ("posixacl", Opt_posixacl),
> - fsparam_u32 ("locktimeout", Opt_locktimeout),
> + fsparam_string ("source", Opt_source),
> + fsparam_u32hex ("debug", Opt_debug),
> + fsparam_uid ("dfltuid", Opt_dfltuid),
> + fsparam_gid ("dfltgid", Opt_dfltgid),
> + fsparam_u32 ("afid", Opt_afid),
> + fsparam_string ("uname", Opt_uname),
> + fsparam_string ("aname", Opt_remotename),
> + fsparam_flag ("nodevmap", Opt_nodevmap),
> + fsparam_flag ("noxattr", Opt_noxattr),
> + fsparam_flag ("directio", Opt_directio),
> + fsparam_flag ("ignoreqv", Opt_ignoreqv),
> + fsparam_string ("cache", Opt_cache),
> + fsparam_string ("cachetag", Opt_cachetag),
> + fsparam_string ("access", Opt_access),
> + fsparam_flag ("posixacl", Opt_posixacl),
> + fsparam_u32 ("locktimeout", Opt_locktimeout),
> + fsparam_flag ("ndentrycache", Opt_ndentrycache),
> + fsparam_u32 ("ndentrycache", Opt_ndentrycachetmo),
That double entry is surprising. So this mount option is supposed to be used
like ndentrycache=n for a specific timeout value (in ms) and just ndentrycache
(without any assignment) for infinite timeout. That's a bit weird.
Documentation/filesystems/9p.rst should be updated as well BTW.
Nevertheless, like mentioned before, I really think the string "timeout"
should be used, at least in a user visible mount option. Keep in mind that
timeouts are a common issue to look at, so it is common to just grep for
"timeout" in a code base or documentation. An abbrevation like "tmo" or
leaving it out entirely is for me therefore IMHO inappropriate.
You found "ndentrycachetimeout" too horribly long, or was that again just
motivated by the code indention below? I personally find those indention
alignments completely irrelevant, not sure how Dominique sees that.
Personally I avoid them, as they cost unnecessary time on git blame.
/Christian
> /* client options */
> - fsparam_u32 ("msize", Opt_msize),
> - fsparam_flag ("noextend", Opt_legacy),
> - fsparam_string ("trans", Opt_trans),
> - fsparam_enum ("version", Opt_version, p9_versions),
> + fsparam_u32 ("msize", Opt_msize),
> + fsparam_flag ("noextend", Opt_legacy),
> + fsparam_string ("trans", Opt_trans),
> + fsparam_enum ("version", Opt_version, p9_versions),
>
> /* fd transport options */
> - fsparam_u32 ("rfdno", Opt_rfdno),
> - fsparam_u32 ("wfdno", Opt_wfdno),
> + fsparam_u32 ("rfdno", Opt_rfdno),
> + fsparam_u32 ("wfdno", Opt_wfdno),
>
> /* rdma transport options */
> - fsparam_u32 ("sq", Opt_sq_depth),
> - fsparam_u32 ("rq", Opt_rq_depth),
> - fsparam_u32 ("timeout", Opt_timeout),
> + fsparam_u32 ("sq", Opt_sq_depth),
> + fsparam_u32 ("rq", Opt_rq_depth),
> + fsparam_u32 ("timeout", Opt_timeout),
>
> /* fd and rdma transprt options */
> - fsparam_u32 ("port", Opt_port),
> - fsparam_flag ("privport", Opt_privport),
> + fsparam_u32 ("port", Opt_port),
> + fsparam_flag ("privport", Opt_privport),
> {}
> };
>
> @@ -159,6 +162,10 @@ int v9fs_show_options(struct seq_file *m, struct dentry
> *root) from_kgid_munged(&init_user_ns, v9ses->dfltgid));
> if (v9ses->afid != ~0)
> seq_printf(m, ",afid=%u", v9ses->afid);
> + if (v9ses->ndentry_timeout_ms == NDENTRY_TMOUT_NEVER)
> + seq_printf(m, ",ndentrycache");
> + else if (v9ses->flags & V9FS_NDENTRY_TMOUT_SET)
> + seq_printf(m, ",ndentrycache=%u", v9ses->ndentry_timeout_ms);
> if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
> seq_printf(m, ",uname=%s", v9ses->uname);
> if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
> @@ -337,6 +344,16 @@ int v9fs_parse_param(struct fs_context *fc, struct
> fs_parameter *param) session_opts->session_lock_timeout =
> (long)result.uint_32 * HZ; break;
>
> + case Opt_ndentrycache:
> + session_opts->flags |= V9FS_NDENTRY_TMOUT_SET;
> + session_opts->ndentry_timeout_ms = NDENTRY_TMOUT_NEVER;
> + break;
> +
> + case Opt_ndentrycachetmo:
> + session_opts->flags |= V9FS_NDENTRY_TMOUT_SET;
> + session_opts->ndentry_timeout_ms = result.uint_64;
> + break;
> +
> /* Options for client */
> case Opt_msize:
> if (result.uint_32 < 4096) {
> diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
> index 8410f7883109..2e42729c6c20 100644
> --- a/fs/9p/v9fs.h
> +++ b/fs/9p/v9fs.h
> @@ -24,6 +24,8 @@
> * @V9FS_ACCESS_ANY: use a single attach for all users
> * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
> * @V9FS_POSIX_ACL: POSIX ACLs are enforced
> + * @V9FS_NDENTRY_TMOUT_SET: Has negative dentry timeout retention time been
> + * overriden by ndentrycache mount option
> *
> * Session flags reflect options selected by users at mount time
> */
> @@ -34,16 +36,17 @@
> #define V9FS_ACL_MASK V9FS_POSIX_ACL
>
> enum p9_session_flags {
> - V9FS_PROTO_2000U = 0x01,
> - V9FS_PROTO_2000L = 0x02,
> - V9FS_ACCESS_SINGLE = 0x04,
> - V9FS_ACCESS_USER = 0x08,
> - V9FS_ACCESS_CLIENT = 0x10,
> - V9FS_POSIX_ACL = 0x20,
> - V9FS_NO_XATTR = 0x40,
> - V9FS_IGNORE_QV = 0x80, /* ignore qid.version for cache hints */
> - V9FS_DIRECT_IO = 0x100,
> - V9FS_SYNC = 0x200
> + V9FS_PROTO_2000U = 0x01,
> + V9FS_PROTO_2000L = 0x02,
> + V9FS_ACCESS_SINGLE = 0x04,
> + V9FS_ACCESS_USER = 0x08,
> + V9FS_ACCESS_CLIENT = 0x10,
> + V9FS_POSIX_ACL = 0x20,
> + V9FS_NO_XATTR = 0x40,
> + V9FS_IGNORE_QV = 0x80, /* ignore qid.version for cache hints */
> + V9FS_DIRECT_IO = 0x100,
> + V9FS_SYNC = 0x200,
> + V9FS_NDENTRY_TMOUT_SET = 0x400,
> };
>
> /**
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention
2026-03-03 14:53 ` Christian Schoenebeck
@ 2026-03-03 21:45 ` Dominique Martinet
2026-03-04 8:25 ` Remi Pommarel
0 siblings, 1 reply; 14+ messages in thread
From: Dominique Martinet @ 2026-03-03 21:45 UTC (permalink / raw)
To: Christian Schoenebeck
Cc: v9fs, Remi Pommarel, linux-fsdevel, linux-kernel,
Eric Van Hensbergen, Latchesar Ionkov
Christian Schoenebeck wrote on Tue, Mar 03, 2026 at 03:53:47PM +0100:
> > + fsparam_string ("source", Opt_source),
> > + fsparam_u32hex ("debug", Opt_debug),
> > + fsparam_uid ("dfltuid", Opt_dfltuid),
> > + fsparam_gid ("dfltgid", Opt_dfltgid),
> > + fsparam_u32 ("afid", Opt_afid),
> > + fsparam_string ("uname", Opt_uname),
> > + fsparam_string ("aname", Opt_remotename),
> > + fsparam_flag ("nodevmap", Opt_nodevmap),
> > + fsparam_flag ("noxattr", Opt_noxattr),
> > + fsparam_flag ("directio", Opt_directio),
> > + fsparam_flag ("ignoreqv", Opt_ignoreqv),
> > + fsparam_string ("cache", Opt_cache),
> > + fsparam_string ("cachetag", Opt_cachetag),
> > + fsparam_string ("access", Opt_access),
> > + fsparam_flag ("posixacl", Opt_posixacl),
> > + fsparam_u32 ("locktimeout", Opt_locktimeout),
> > + fsparam_flag ("ndentrycache", Opt_ndentrycache),
> > + fsparam_u32 ("ndentrycache", Opt_ndentrycachetmo),
>
> That double entry is surprising. So this mount option is supposed to be used
> like ndentrycache=n for a specific timeout value (in ms) and just ndentrycache
> (without any assignment) for infinite timeout. That's a bit weird.
Could make it a s32 and say <0 means infinite? I think we have that
somewhere
> Documentation/filesystems/9p.rst should be updated as well BTW.
>
> Nevertheless, like mentioned before, I really think the string "timeout"
> should be used, at least in a user visible mount option. Keep in mind that
> timeouts are a common issue to look at, so it is common to just grep for
> "timeout" in a code base or documentation. An abbrevation like "tmo" or
> leaving it out entirely is for me therefore IMHO inappropriate.
>
> You found "ndentrycachetimeout" too horribly long, or was that again just
> motivated by the code indention below? I personally find those indention
> alignments completely irrelevant, not sure how Dominique sees that.
> Personally I avoid them, as they cost unnecessary time on git blame.
I rarely use blame at all and it's possible to ignore whitespaces for
blame, but I'd tend to agree here, I don't care if this stays aligned.
OTOH ndentrycachetimeout as a mount option is a mouthful,
negativetimeout or negtimeout sounds clear enough to me?
I can't think of anything else that'd be negative related
to timeouts, but perhaps it's the lack of sleep speaking
--
Dominique Martinet | Asmadeus
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention
2026-03-03 21:45 ` Dominique Martinet
@ 2026-03-04 8:25 ` Remi Pommarel
2026-03-04 9:01 ` Christian Schoenebeck
0 siblings, 1 reply; 14+ messages in thread
From: Remi Pommarel @ 2026-03-04 8:25 UTC (permalink / raw)
To: Dominique Martinet
Cc: Christian Schoenebeck, v9fs, linux-fsdevel, linux-kernel,
Eric Van Hensbergen, Latchesar Ionkov
On Wed, Mar 04, 2026 at 06:45:35AM +0900, Dominique Martinet wrote:
> Christian Schoenebeck wrote on Tue, Mar 03, 2026 at 03:53:47PM +0100:
> > > + fsparam_string ("source", Opt_source),
> > > + fsparam_u32hex ("debug", Opt_debug),
> > > + fsparam_uid ("dfltuid", Opt_dfltuid),
> > > + fsparam_gid ("dfltgid", Opt_dfltgid),
> > > + fsparam_u32 ("afid", Opt_afid),
> > > + fsparam_string ("uname", Opt_uname),
> > > + fsparam_string ("aname", Opt_remotename),
> > > + fsparam_flag ("nodevmap", Opt_nodevmap),
> > > + fsparam_flag ("noxattr", Opt_noxattr),
> > > + fsparam_flag ("directio", Opt_directio),
> > > + fsparam_flag ("ignoreqv", Opt_ignoreqv),
> > > + fsparam_string ("cache", Opt_cache),
> > > + fsparam_string ("cachetag", Opt_cachetag),
> > > + fsparam_string ("access", Opt_access),
> > > + fsparam_flag ("posixacl", Opt_posixacl),
> > > + fsparam_u32 ("locktimeout", Opt_locktimeout),
> > > + fsparam_flag ("ndentrycache", Opt_ndentrycache),
> > > + fsparam_u32 ("ndentrycache", Opt_ndentrycachetmo),
> >
> > That double entry is surprising. So this mount option is supposed to be used
> > like ndentrycache=n for a specific timeout value (in ms) and just ndentrycache
> > (without any assignment) for infinite timeout. That's a bit weird.
Yes I have seen this used in several other fs (see init_itable mount
option for ext4fs or compress one for btrfs). I do agree that is a bit
weird but this allow the whole 32bit range for timeout.
>
> Could make it a s32 and say <0 means infinite? I think we have that
> somewhere
I did that on previous version, but was afraid that ~20days timeout max
value may be too restrictive?
I do agree that this is a bit odd though and if you both think s32 is
better that is fine with me.
>
> > Documentation/filesystems/9p.rst should be updated as well BTW.
> >
> > Nevertheless, like mentioned before, I really think the string "timeout"
> > should be used, at least in a user visible mount option. Keep in mind that
> > timeouts are a common issue to look at, so it is common to just grep for
> > "timeout" in a code base or documentation. An abbrevation like "tmo" or
> > leaving it out entirely is for me therefore IMHO inappropriate.
> >
> > You found "ndentrycachetimeout" too horribly long, or was that again just
> > motivated by the code indention below? I personally find those indention
> > alignments completely irrelevant, not sure how Dominique sees that.
> > Personally I avoid them, as they cost unnecessary time on git blame.
>
> I rarely use blame at all and it's possible to ignore whitespaces for
> blame, but I'd tend to agree here, I don't care if this stays aligned.
>
> OTOH ndentrycachetimeout as a mount option is a mouthful,
> negativetimeout or negtimeout sounds clear enough to me?
> I can't think of anything else that'd be negative related
> to timeouts, but perhaps it's the lack of sleep speaking
No strong opinion on the option name though so any name that suits you
is alse fine by me.
--
Remi
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention
2026-03-04 8:25 ` Remi Pommarel
@ 2026-03-04 9:01 ` Christian Schoenebeck
2026-03-04 9:16 ` Dominique Martinet
0 siblings, 1 reply; 14+ messages in thread
From: Christian Schoenebeck @ 2026-03-04 9:01 UTC (permalink / raw)
To: Dominique Martinet, Remi Pommarel
Cc: v9fs, linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov
On Wednesday, 4 March 2026 09:25:27 CET Remi Pommarel wrote:
> On Wed, Mar 04, 2026 at 06:45:35AM +0900, Dominique Martinet wrote:
> > Christian Schoenebeck wrote on Tue, Mar 03, 2026 at 03:53:47PM +0100:
> > > > + fsparam_string ("source", Opt_source),
> > > > + fsparam_u32hex ("debug", Opt_debug),
> > > > + fsparam_uid ("dfltuid", Opt_dfltuid),
> > > > + fsparam_gid ("dfltgid", Opt_dfltgid),
> > > > + fsparam_u32 ("afid", Opt_afid),
> > > > + fsparam_string ("uname", Opt_uname),
> > > > + fsparam_string ("aname", Opt_remotename),
> > > > + fsparam_flag ("nodevmap", Opt_nodevmap),
> > > > + fsparam_flag ("noxattr", Opt_noxattr),
> > > > + fsparam_flag ("directio", Opt_directio),
> > > > + fsparam_flag ("ignoreqv", Opt_ignoreqv),
> > > > + fsparam_string ("cache", Opt_cache),
> > > > + fsparam_string ("cachetag", Opt_cachetag),
> > > > + fsparam_string ("access", Opt_access),
> > > > + fsparam_flag ("posixacl", Opt_posixacl),
> > > > + fsparam_u32 ("locktimeout", Opt_locktimeout),
> > > > + fsparam_flag ("ndentrycache", Opt_ndentrycache),
> > > > + fsparam_u32 ("ndentrycache", Opt_ndentrycachetmo),
> > >
> > > That double entry is surprising. So this mount option is supposed to be
> > > used like ndentrycache=n for a specific timeout value (in ms) and just
> > > ndentrycache (without any assignment) for infinite timeout. That's a
> > > bit weird.
> Yes I have seen this used in several other fs (see init_itable mount
> option for ext4fs or compress one for btrfs). I do agree that is a bit
> weird but this allow the whole 32bit range for timeout.
>
> > Could make it a s32 and say <0 means infinite? I think we have that
> > somewhere
>
> I did that on previous version, but was afraid that ~20days timeout max
> value may be too restrictive?
>
> I do agree that this is a bit odd though and if you both think s32 is
> better that is fine with me.
What about just making this mount option a string and doing the parsing on our
end? That would have the benefit of simply allowing arguments like "i00s",
"5d", "1y", and if you really wanted "inf".
I would find units for this much more useful in practice than allowing
infinite. Like discussed before, it is in general a bad idea to configure
negative dentries to persist for good due to the huge amount of bogus entries
that pile up.
> > > Documentation/filesystems/9p.rst should be updated as well BTW.
> > >
> > > Nevertheless, like mentioned before, I really think the string "timeout"
> > > should be used, at least in a user visible mount option. Keep in mind
> > > that
> > > timeouts are a common issue to look at, so it is common to just grep for
> > > "timeout" in a code base or documentation. An abbrevation like "tmo" or
> > > leaving it out entirely is for me therefore IMHO inappropriate.
> > >
> > > You found "ndentrycachetimeout" too horribly long, or was that again
> > > just
> > > motivated by the code indention below? I personally find those indention
> > > alignments completely irrelevant, not sure how Dominique sees that.
> > > Personally I avoid them, as they cost unnecessary time on git blame.
> >
> > I rarely use blame at all and it's possible to ignore whitespaces for
> > blame, but I'd tend to agree here, I don't care if this stays aligned.
> >
> > OTOH ndentrycachetimeout as a mount option is a mouthful,
> > negativetimeout or negtimeout sounds clear enough to me?
> > I can't think of anything else that'd be negative related
> > to timeouts, but perhaps it's the lack of sleep speaking
>
> No strong opinion on the option name though so any name that suits you
> is alse fine by me.
Another suggestion: "ndtimeout"?
/Christian
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention
2026-03-04 9:01 ` Christian Schoenebeck
@ 2026-03-04 9:16 ` Dominique Martinet
0 siblings, 0 replies; 14+ messages in thread
From: Dominique Martinet @ 2026-03-04 9:16 UTC (permalink / raw)
To: Christian Schoenebeck
Cc: Remi Pommarel, v9fs, linux-fsdevel, linux-kernel,
Eric Van Hensbergen, Latchesar Ionkov
Christian Schoenebeck wrote on Wed, Mar 04, 2026 at 10:01:42AM +0100:
> > I did that on previous version, but was afraid that ~20days timeout max
> > value may be too restrictive?
> >
> > I do agree that this is a bit odd though and if you both think s32 is
> > better that is fine with me.
>
> What about just making this mount option a string and doing the parsing on our
> end? That would have the benefit of simply allowing arguments like "i00s",
> "5d", "1y", and if you really wanted "inf".
>
> I would find units for this much more useful in practice than allowing
> infinite. Like discussed before, it is in general a bad idea to configure
> negative dentries to persist for good due to the huge amount of bogus entries
> that pile up.
I don't mind either way -- I think 20 days for such a timeout is enough,
but I agree being able to set something like '60s' or '100ms' would
certainly be convenient.
I'm actually surprised there's no such parsing helper in the kernel?!
The only related code I could find was parse_ns_duration /
parse_seconds_duration in tools/tracing/rtla/src/utils.c but that's for
tools, and there doesn't seem to be anything we could use..
Well, it's not that bad, so I'm not fussy here.
> > > OTOH ndentrycachetimeout as a mount option is a mouthful,
> > > negativetimeout or negtimeout sounds clear enough to me?
> > > I can't think of anything else that'd be negative related
> > > to timeouts, but perhaps it's the lack of sleep speaking
> >
> > No strong opinion on the option name though so any name that suits you
> > is alse fine by me.
>
> Another suggestion: "ndtimeout"?
I'd slightly favor negtimeout over ndtimeout but am fine with either
here.
('nd' sounds like something network-y to me, network discovery or ndo,
but that's not a hard no)
Thanks,
--
Dominique Martinet | Asmadeus
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention
2026-02-27 7:56 ` [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention Remi Pommarel
2026-03-03 14:53 ` Christian Schoenebeck
@ 2026-03-04 12:45 ` Christian Schoenebeck
1 sibling, 0 replies; 14+ messages in thread
From: Christian Schoenebeck @ 2026-03-04 12:45 UTC (permalink / raw)
To: v9fs, Remi Pommarel
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Remi Pommarel
On Friday, 27 February 2026 08:56:53 CET Remi Pommarel wrote:
[...]
> diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
> index 8410f7883109..2e42729c6c20 100644
> --- a/fs/9p/v9fs.h
> +++ b/fs/9p/v9fs.h
> @@ -24,6 +24,8 @@
> * @V9FS_ACCESS_ANY: use a single attach for all users
> * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
> * @V9FS_POSIX_ACL: POSIX ACLs are enforced
> + * @V9FS_NDENTRY_TMOUT_SET: Has negative dentry timeout retention time been
> + * overriden by ndentrycache mount option
Nit: misaligned indention due to tabs. :-)
/Christian
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH v3 3/4] 9p: Set default negative dentry retention time for cache=loose
2026-02-27 7:56 [PATCH v3 0/4] 9p: Performance improvements for build workloads Remi Pommarel
2026-02-27 7:56 ` [PATCH v3 1/4] 9p: Cache negative dentries for lookup performance Remi Pommarel
2026-02-27 7:56 ` [PATCH v3 2/4] 9p: Add mount option for negative dentry cache retention Remi Pommarel
@ 2026-02-27 7:56 ` Remi Pommarel
2026-03-04 12:54 ` Christian Schoenebeck
2026-02-27 7:56 ` [PATCH v3 4/4] 9p: Enable symlink caching in page cache Remi Pommarel
3 siblings, 1 reply; 14+ messages in thread
From: Remi Pommarel @ 2026-02-27 7:56 UTC (permalink / raw)
To: v9fs
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Christian Schoenebeck,
Remi Pommarel
For cache=loose mounts, set the default negative dentry cache retention
time to 24 hours.
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
---
fs/9p/v9fs.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index a26bd9070786..d14f6eda94d6 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -24,6 +24,9 @@
#include "v9fs_vfs.h"
#include "cache.h"
+/* cache=loose default negative dentry retention time is 24hours */
+#define CACHE_LOOSE_NDENTRY_TMOUT_DEFAULT (24 * 60 * 60 * 1000)
+
static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
static LIST_HEAD(v9fs_sessionlist);
struct kmem_cache *v9fs_inode_cache;
@@ -440,6 +443,13 @@ static void v9fs_apply_options(struct v9fs_session_info *v9ses,
v9ses->uid = ctx->session_opts.uid;
v9ses->session_lock_timeout = ctx->session_opts.session_lock_timeout;
v9ses->ndentry_timeout_ms = ctx->session_opts.ndentry_timeout_ms;
+
+ /* If negative dentry timeout has not been overriden set default for
+ * cache=loose
+ */
+ if (!(v9ses->flags & V9FS_NDENTRY_TMOUT_SET) &&
+ (v9ses->cache & CACHE_LOOSE))
+ v9ses->ndentry_timeout_ms = CACHE_LOOSE_NDENTRY_TMOUT_DEFAULT;
}
/**
--
2.52.0
^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH v3 3/4] 9p: Set default negative dentry retention time for cache=loose
2026-02-27 7:56 ` [PATCH v3 3/4] 9p: Set default negative dentry retention time for cache=loose Remi Pommarel
@ 2026-03-04 12:54 ` Christian Schoenebeck
0 siblings, 0 replies; 14+ messages in thread
From: Christian Schoenebeck @ 2026-03-04 12:54 UTC (permalink / raw)
To: v9fs, Remi Pommarel
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Remi Pommarel
On Friday, 27 February 2026 08:56:54 CET Remi Pommarel wrote:
> For cache=loose mounts, set the default negative dentry cache retention
> time to 24 hours.
>
> Signed-off-by: Remi Pommarel <repk@triplefau.lt>
> ---
> fs/9p/v9fs.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
> index a26bd9070786..d14f6eda94d6 100644
> --- a/fs/9p/v9fs.c
> +++ b/fs/9p/v9fs.c
> @@ -24,6 +24,9 @@
> #include "v9fs_vfs.h"
> #include "cache.h"
>
> +/* cache=loose default negative dentry retention time is 24hours */
> +#define CACHE_LOOSE_NDENTRY_TMOUT_DEFAULT (24 * 60 * 60 * 1000)
> +
Come on, really worth to save 4 characters here as well? :)
Whatever:
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
> static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
> static LIST_HEAD(v9fs_sessionlist);
> struct kmem_cache *v9fs_inode_cache;
> @@ -440,6 +443,13 @@ static void v9fs_apply_options(struct v9fs_session_info
> *v9ses, v9ses->uid = ctx->session_opts.uid;
> v9ses->session_lock_timeout = ctx->session_opts.session_lock_timeout;
> v9ses->ndentry_timeout_ms = ctx->session_opts.ndentry_timeout_ms;
> +
> + /* If negative dentry timeout has not been overriden set default for
> + * cache=loose
> + */
> + if (!(v9ses->flags & V9FS_NDENTRY_TMOUT_SET) &&
> + (v9ses->cache & CACHE_LOOSE))
> + v9ses->ndentry_timeout_ms = CACHE_LOOSE_NDENTRY_TMOUT_DEFAULT;
> }
>
> /**
^ permalink raw reply [flat|nested] 14+ messages in thread
* [PATCH v3 4/4] 9p: Enable symlink caching in page cache
2026-02-27 7:56 [PATCH v3 0/4] 9p: Performance improvements for build workloads Remi Pommarel
` (2 preceding siblings ...)
2026-02-27 7:56 ` [PATCH v3 3/4] 9p: Set default negative dentry retention time for cache=loose Remi Pommarel
@ 2026-02-27 7:56 ` Remi Pommarel
2026-03-04 13:01 ` Christian Schoenebeck
3 siblings, 1 reply; 14+ messages in thread
From: Remi Pommarel @ 2026-02-27 7:56 UTC (permalink / raw)
To: v9fs
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Christian Schoenebeck,
Remi Pommarel
Currently, when cache=loose is enabled, file reads are cached in the
page cache, but symlink reads are not. This patch allows the results
of p9_client_readlink() to be stored in the page cache, eliminating
the need for repeated 9P transactions on subsequent symlink accesses.
This change improves performance for workloads that involve frequent
symlink resolution.
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
---
fs/9p/vfs_addr.c | 29 +++++++++++++++--
fs/9p/vfs_inode.c | 6 ++--
fs/9p/vfs_inode_dotl.c | 72 +++++++++++++++++++++++++++++++++++++-----
3 files changed, 94 insertions(+), 13 deletions(-)
diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index 862164181bac..0683090a5f15 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -70,10 +70,24 @@ static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
{
struct netfs_io_request *rreq = subreq->rreq;
struct p9_fid *fid = rreq->netfs_priv;
+ char *target;
unsigned long long pos = subreq->start + subreq->transferred;
- int total, err;
-
- total = p9_client_read(fid, pos, &subreq->io_iter, &err);
+ int total, err, len, n;
+
+ if (S_ISLNK(rreq->inode->i_mode)) {
+ /* p9_client_readlink() must not be called for legacy protocols
+ * 9p2000 or 9p2000.u.
+ */
+ BUG_ON(!p9_is_proto_dotl(fid->clnt));
+ err = p9_client_readlink(fid, &target);
+ len = strnlen(target, PAGE_SIZE - 1);
+ n = copy_to_iter(target, len, &subreq->io_iter);
+ if (n != len)
+ err = -EFAULT;
+ total = i_size_read(rreq->inode);
+ } else {
+ total = p9_client_read(fid, pos, &subreq->io_iter, &err);
+ }
/* if we just extended the file size, any portion not in
* cache won't be on server and is zeroes */
@@ -99,6 +113,7 @@ static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
{
struct p9_fid *fid;
+ struct dentry *dentry;
bool writing = (rreq->origin == NETFS_READ_FOR_WRITE ||
rreq->origin == NETFS_WRITETHROUGH ||
rreq->origin == NETFS_UNBUFFERED_WRITE ||
@@ -115,6 +130,14 @@ static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
if (!fid)
goto no_fid;
p9_fid_get(fid);
+ } else if (S_ISLNK(rreq->inode->i_mode)){
+ dentry = d_find_alias(rreq->inode);
+ if (!dentry)
+ goto no_fid;
+ fid = v9fs_fid_lookup(dentry);
+ dput(dentry);
+ if (IS_ERR(fid))
+ goto no_fid;
} else {
fid = v9fs_fid_find_inode(rreq->inode, writing, INVALID_UID, true);
if (!fid)
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index c82db6fe0c39..98644f27d6f1 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -302,10 +302,12 @@ int v9fs_init_inode(struct v9fs_session_info *v9ses,
goto error;
}
- if (v9fs_proto_dotl(v9ses))
+ if (v9fs_proto_dotl(v9ses)) {
inode->i_op = &v9fs_symlink_inode_operations_dotl;
- else
+ inode_nohighmem(inode);
+ } else {
inode->i_op = &v9fs_symlink_inode_operations;
+ }
break;
case S_IFDIR:
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index 643e759eacb2..a286a078d6a6 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -686,9 +686,13 @@ v9fs_vfs_symlink_dotl(struct mnt_idmap *idmap, struct inode *dir,
int err;
kgid_t gid;
const unsigned char *name;
+ umode_t mode;
+ struct v9fs_session_info *v9ses;
struct p9_qid qid;
struct p9_fid *dfid;
struct p9_fid *fid = NULL;
+ struct inode *inode;
+ struct posix_acl *dacl = NULL, *pacl = NULL;
name = dentry->d_name.name;
p9_debug(P9_DEBUG_VFS, "%lu,%s,%s\n", dir->i_ino, name, symname);
@@ -702,6 +706,14 @@ v9fs_vfs_symlink_dotl(struct mnt_idmap *idmap, struct inode *dir,
gid = v9fs_get_fsgid_for_create(dir);
+ /* Update mode based on ACL value */
+ err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
+ if (err) {
+ p9_debug(P9_DEBUG_VFS, "Failed to get acl values in mknod %d\n",
+ err);
+ goto error;
+ }
+
/* Server doesn't alter fid on TSYMLINK. Hence no need to clone it. */
err = p9_client_symlink(dfid, name, symname, gid, &qid);
@@ -712,8 +724,30 @@ v9fs_vfs_symlink_dotl(struct mnt_idmap *idmap, struct inode *dir,
v9fs_invalidate_inode_attr(dir);
+ /* instantiate inode and assign the unopened fid to the dentry */
+ fid = p9_client_walk(dfid, 1, &name, 1);
+ if (IS_ERR(fid)) {
+ err = PTR_ERR(fid);
+ p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
+ err);
+ goto error;
+ }
+
+ v9ses = v9fs_inode2v9ses(dir);
+ inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
+ if (IS_ERR(inode)) {
+ err = PTR_ERR(inode);
+ p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
+ err);
+ goto error;
+ }
+ v9fs_set_create_acl(inode, fid, dacl, pacl);
+ v9fs_fid_add(dentry, &fid);
+ d_instantiate(dentry, inode);
+ err = 0;
error:
p9_fid_put(fid);
+ v9fs_put_acl(dacl, pacl);
p9_fid_put(dfid);
return err;
}
@@ -853,24 +887,23 @@ v9fs_vfs_mknod_dotl(struct mnt_idmap *idmap, struct inode *dir,
}
/**
- * v9fs_vfs_get_link_dotl - follow a symlink path
+ * v9fs_vfs_get_link_nocache_dotl - Resolve a symlink directly.
+ *
+ * To be used when symlink caching is not enabled.
+ *
* @dentry: dentry for symlink
* @inode: inode for symlink
* @done: destructor for return value
*/
-
static const char *
-v9fs_vfs_get_link_dotl(struct dentry *dentry,
- struct inode *inode,
- struct delayed_call *done)
+v9fs_vfs_get_link_nocache_dotl(struct dentry *dentry,
+ struct inode *inode,
+ struct delayed_call *done)
{
struct p9_fid *fid;
char *target;
int retval;
- if (!dentry)
- return ERR_PTR(-ECHILD);
-
p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
fid = v9fs_fid_lookup(dentry);
@@ -884,6 +917,29 @@ v9fs_vfs_get_link_dotl(struct dentry *dentry,
return target;
}
+/**
+ * v9fs_vfs_get_link_dotl - follow a symlink path
+ * @dentry: dentry for symlink
+ * @inode: inode for symlink
+ * @done: destructor for return value
+ */
+static const char *
+v9fs_vfs_get_link_dotl(struct dentry *dentry,
+ struct inode *inode,
+ struct delayed_call *done)
+{
+ struct v9fs_session_info *v9ses;
+
+ if (!dentry)
+ return ERR_PTR(-ECHILD);
+
+ v9ses = v9fs_inode2v9ses(inode);
+ if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
+ return page_get_link(dentry, inode, done);
+
+ return v9fs_vfs_get_link_nocache_dotl(dentry, inode, done);
+}
+
int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
{
struct p9_stat_dotl *st;
--
2.52.0
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [PATCH v3 4/4] 9p: Enable symlink caching in page cache
2026-02-27 7:56 ` [PATCH v3 4/4] 9p: Enable symlink caching in page cache Remi Pommarel
@ 2026-03-04 13:01 ` Christian Schoenebeck
0 siblings, 0 replies; 14+ messages in thread
From: Christian Schoenebeck @ 2026-03-04 13:01 UTC (permalink / raw)
To: v9fs, Remi Pommarel
Cc: linux-fsdevel, linux-kernel, Eric Van Hensbergen,
Latchesar Ionkov, Dominique Martinet, Remi Pommarel
On Friday, 27 February 2026 08:56:55 CET Remi Pommarel wrote:
> Currently, when cache=loose is enabled, file reads are cached in the
> page cache, but symlink reads are not. This patch allows the results
> of p9_client_readlink() to be stored in the page cache, eliminating
> the need for repeated 9P transactions on subsequent symlink accesses.
>
> This change improves performance for workloads that involve frequent
> symlink resolution.
>
> Signed-off-by: Remi Pommarel <repk@triplefau.lt>
> ---
> fs/9p/vfs_addr.c | 29 +++++++++++++++--
> fs/9p/vfs_inode.c | 6 ++--
> fs/9p/vfs_inode_dotl.c | 72 +++++++++++++++++++++++++++++++++++++-----
> 3 files changed, 94 insertions(+), 13 deletions(-)
>
> diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
> index 862164181bac..0683090a5f15 100644
> --- a/fs/9p/vfs_addr.c
> +++ b/fs/9p/vfs_addr.c
> @@ -70,10 +70,24 @@ static void v9fs_issue_read(struct netfs_io_subrequest
> *subreq) {
> struct netfs_io_request *rreq = subreq->rreq;
> struct p9_fid *fid = rreq->netfs_priv;
> + char *target;
> unsigned long long pos = subreq->start + subreq->transferred;
> - int total, err;
> -
> - total = p9_client_read(fid, pos, &subreq->io_iter, &err);
> + int total, err, len, n;
> +
> + if (S_ISLNK(rreq->inode->i_mode)) {
> + /* p9_client_readlink() must not be called for legacy protocols
> + * 9p2000 or 9p2000.u.
> + */
> + BUG_ON(!p9_is_proto_dotl(fid->clnt));
I would have added this to p9_client_readlink() instead, as it is in general a
bug if someone calls that function without 9p2000.L. But I take it that you
wanted to make it clear that way that this context is only executed by
9p2000.L in the first place, so OK.
> + err = p9_client_readlink(fid, &target);
> + len = strnlen(target, PAGE_SIZE - 1);
> + n = copy_to_iter(target, len, &subreq->io_iter);
> + if (n != len)
> + err = -EFAULT;
> + total = i_size_read(rreq->inode);
> + } else {
> + total = p9_client_read(fid, pos, &subreq->io_iter, &err);
> + }
>
> /* if we just extended the file size, any portion not in
> * cache won't be on server and is zeroes */
> @@ -99,6 +113,7 @@ static void v9fs_issue_read(struct netfs_io_subrequest
> *subreq) static int v9fs_init_request(struct netfs_io_request *rreq, struct
> file *file) {
> struct p9_fid *fid;
> + struct dentry *dentry;
> bool writing = (rreq->origin == NETFS_READ_FOR_WRITE ||
> rreq->origin == NETFS_WRITETHROUGH ||
> rreq->origin == NETFS_UNBUFFERED_WRITE ||
> @@ -115,6 +130,14 @@ static int v9fs_init_request(struct netfs_io_request
> *rreq, struct file *file) if (!fid)
> goto no_fid;
> p9_fid_get(fid);
> + } else if (S_ISLNK(rreq->inode->i_mode)){
Nit: missing space between ) and {
Except of that:
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
/Christian
> + dentry = d_find_alias(rreq->inode);
> + if (!dentry)
> + goto no_fid;
> + fid = v9fs_fid_lookup(dentry);
> + dput(dentry);
> + if (IS_ERR(fid))
> + goto no_fid;
> } else {
> fid = v9fs_fid_find_inode(rreq->inode, writing, INVALID_UID, true);
> if (!fid)
> diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
> index c82db6fe0c39..98644f27d6f1 100644
> --- a/fs/9p/vfs_inode.c
> +++ b/fs/9p/vfs_inode.c
> @@ -302,10 +302,12 @@ int v9fs_init_inode(struct v9fs_session_info *v9ses,
> goto error;
> }
>
> - if (v9fs_proto_dotl(v9ses))
> + if (v9fs_proto_dotl(v9ses)) {
> inode->i_op = &v9fs_symlink_inode_operations_dotl;
> - else
> + inode_nohighmem(inode);
> + } else {
> inode->i_op = &v9fs_symlink_inode_operations;
> + }
>
> break;
> case S_IFDIR:
> diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
> index 643e759eacb2..a286a078d6a6 100644
> --- a/fs/9p/vfs_inode_dotl.c
> +++ b/fs/9p/vfs_inode_dotl.c
> @@ -686,9 +686,13 @@ v9fs_vfs_symlink_dotl(struct mnt_idmap *idmap, struct
> inode *dir, int err;
> kgid_t gid;
> const unsigned char *name;
> + umode_t mode;
> + struct v9fs_session_info *v9ses;
> struct p9_qid qid;
> struct p9_fid *dfid;
> struct p9_fid *fid = NULL;
> + struct inode *inode;
> + struct posix_acl *dacl = NULL, *pacl = NULL;
>
> name = dentry->d_name.name;
> p9_debug(P9_DEBUG_VFS, "%lu,%s,%s\n", dir->i_ino, name, symname);
> @@ -702,6 +706,14 @@ v9fs_vfs_symlink_dotl(struct mnt_idmap *idmap, struct
> inode *dir,
>
> gid = v9fs_get_fsgid_for_create(dir);
>
> + /* Update mode based on ACL value */
> + err = v9fs_acl_mode(dir, &mode, &dacl, &pacl);
> + if (err) {
> + p9_debug(P9_DEBUG_VFS, "Failed to get acl values in mknod %d\n",
> + err);
> + goto error;
> + }
> +
> /* Server doesn't alter fid on TSYMLINK. Hence no need to clone it. */
> err = p9_client_symlink(dfid, name, symname, gid, &qid);
>
> @@ -712,8 +724,30 @@ v9fs_vfs_symlink_dotl(struct mnt_idmap *idmap, struct
> inode *dir,
>
> v9fs_invalidate_inode_attr(dir);
>
> + /* instantiate inode and assign the unopened fid to the dentry */
> + fid = p9_client_walk(dfid, 1, &name, 1);
> + if (IS_ERR(fid)) {
> + err = PTR_ERR(fid);
> + p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n",
> + err);
> + goto error;
> + }
> +
> + v9ses = v9fs_inode2v9ses(dir);
> + inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
> + if (IS_ERR(inode)) {
> + err = PTR_ERR(inode);
> + p9_debug(P9_DEBUG_VFS, "inode creation failed %d\n",
> + err);
> + goto error;
> + }
> + v9fs_set_create_acl(inode, fid, dacl, pacl);
> + v9fs_fid_add(dentry, &fid);
> + d_instantiate(dentry, inode);
> + err = 0;
> error:
> p9_fid_put(fid);
> + v9fs_put_acl(dacl, pacl);
> p9_fid_put(dfid);
> return err;
> }
> @@ -853,24 +887,23 @@ v9fs_vfs_mknod_dotl(struct mnt_idmap *idmap, struct
> inode *dir, }
>
> /**
> - * v9fs_vfs_get_link_dotl - follow a symlink path
> + * v9fs_vfs_get_link_nocache_dotl - Resolve a symlink directly.
> + *
> + * To be used when symlink caching is not enabled.
> + *
> * @dentry: dentry for symlink
> * @inode: inode for symlink
> * @done: destructor for return value
> */
> -
> static const char *
> -v9fs_vfs_get_link_dotl(struct dentry *dentry,
> - struct inode *inode,
> - struct delayed_call *done)
> +v9fs_vfs_get_link_nocache_dotl(struct dentry *dentry,
> + struct inode *inode,
> + struct delayed_call *done)
> {
> struct p9_fid *fid;
> char *target;
> int retval;
>
> - if (!dentry)
> - return ERR_PTR(-ECHILD);
> -
> p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
>
> fid = v9fs_fid_lookup(dentry);
> @@ -884,6 +917,29 @@ v9fs_vfs_get_link_dotl(struct dentry *dentry,
> return target;
> }
>
> +/**
> + * v9fs_vfs_get_link_dotl - follow a symlink path
> + * @dentry: dentry for symlink
> + * @inode: inode for symlink
> + * @done: destructor for return value
> + */
> +static const char *
> +v9fs_vfs_get_link_dotl(struct dentry *dentry,
> + struct inode *inode,
> + struct delayed_call *done)
> +{
> + struct v9fs_session_info *v9ses;
> +
> + if (!dentry)
> + return ERR_PTR(-ECHILD);
> +
> + v9ses = v9fs_inode2v9ses(inode);
> + if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
> + return page_get_link(dentry, inode, done);
> +
> + return v9fs_vfs_get_link_nocache_dotl(dentry, inode, done);
> +}
> +
> int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
> {
> struct p9_stat_dotl *st;
^ permalink raw reply [flat|nested] 14+ messages in thread