* [PATCH 1/2] change the calling conventions for vfs_parse_fs_string()
2025-08-28 0:00 [PATCHES] fs_context stuff Al Viro
@ 2025-08-28 0:00 ` Al Viro
2025-08-29 7:47 ` Christian Brauner
2025-08-28 0:01 ` [PATCH 2/2] do_nfs4_mount(): switch to vfs_parse_fs_string() Al Viro
1 sibling, 1 reply; 5+ messages in thread
From: Al Viro @ 2025-08-28 0:00 UTC (permalink / raw)
To: linux-fsdevel
Cc: Linus Torvalds, Christian Brauner, Jan Kara, David Howells,
linux-nfs
Absolute majority of callers are passing the 4th argument equal to
strlen() of the 3rd one.
Drop the v_size argument, add vfs_parse_fs_qstr() for the cases that
want independent length.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
Documentation/filesystems/mount_api.rst | 10 +++++++++-
Documentation/filesystems/porting.rst | 10 ++++++++++
drivers/gpu/drm/i915/gem/i915_gemfs.c | 9 ++-------
drivers/gpu/drm/v3d/v3d_gemfs.c | 9 ++-------
fs/afs/mntpt.c | 3 ++-
fs/fs_context.c | 17 +++++++----------
fs/namespace.c | 8 +++-----
fs/nfs/fs_context.c | 3 +--
fs/nfs/namespace.c | 3 ++-
fs/smb/client/fs_context.c | 4 +---
include/linux/fs_context.h | 9 +++++++--
kernel/trace/trace.c | 3 +--
12 files changed, 47 insertions(+), 41 deletions(-)
diff --git a/Documentation/filesystems/mount_api.rst b/Documentation/filesystems/mount_api.rst
index e149b89118c8..c99ab1f7fea4 100644
--- a/Documentation/filesystems/mount_api.rst
+++ b/Documentation/filesystems/mount_api.rst
@@ -504,10 +504,18 @@ returned.
clear the pointer, but then becomes responsible for disposing of the
object.
+ * ::
+
+ int vfs_parse_fs_qstr(struct fs_context *fc, const char *key,
+ const struct qstr *value);
+
+ A wrapper around vfs_parse_fs_param() that copies the value string it is
+ passed.
+
* ::
int vfs_parse_fs_string(struct fs_context *fc, const char *key,
- const char *value, size_t v_size);
+ const char *value);
A wrapper around vfs_parse_fs_param() that copies the value string it is
passed.
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
index 85f590254f07..a9ef6851b8c0 100644
--- a/Documentation/filesystems/porting.rst
+++ b/Documentation/filesystems/porting.rst
@@ -1285,3 +1285,13 @@ rather than a VMA, as the VMA at this stage is not yet valid.
The vm_area_desc provides the minimum required information for a filesystem
to initialise state upon memory mapping of a file-backed region, and output
parameters for the file system to set this state.
+
+---
+
+**mandatory**
+
+Calling conventions for vfs_parse_fs_string() have changed; it does *not*
+take length anymore (value ? strlen(value) : 0 is used). If you want
+a different length, use
+ vfs_parse_fs_qstr(fc, key, &QSTR_LEN(value, len))
+instead.
diff --git a/drivers/gpu/drm/i915/gem/i915_gemfs.c b/drivers/gpu/drm/i915/gem/i915_gemfs.c
index a09e2eb47175..8f13ec4ff0d0 100644
--- a/drivers/gpu/drm/i915/gem/i915_gemfs.c
+++ b/drivers/gpu/drm/i915/gem/i915_gemfs.c
@@ -11,11 +11,6 @@
#include "i915_gemfs.h"
#include "i915_utils.h"
-static int add_param(struct fs_context *fc, const char *key, const char *val)
-{
- return vfs_parse_fs_string(fc, key, val, strlen(val));
-}
-
void i915_gemfs_init(struct drm_i915_private *i915)
{
struct file_system_type *type;
@@ -48,9 +43,9 @@ void i915_gemfs_init(struct drm_i915_private *i915)
fc = fs_context_for_mount(type, SB_KERNMOUNT);
if (IS_ERR(fc))
goto err;
- ret = add_param(fc, "source", "tmpfs");
+ ret = vfs_parse_fs_string(fc, "source", "tmpfs");
if (!ret)
- ret = add_param(fc, "huge", "within_size");
+ ret = vfs_parse_fs_string(fc, "huge", "within_size");
if (!ret)
gemfs = fc_mount_longterm(fc);
put_fs_context(fc);
diff --git a/drivers/gpu/drm/v3d/v3d_gemfs.c b/drivers/gpu/drm/v3d/v3d_gemfs.c
index 8ec6ed82b3d9..c1a30166c099 100644
--- a/drivers/gpu/drm/v3d/v3d_gemfs.c
+++ b/drivers/gpu/drm/v3d/v3d_gemfs.c
@@ -7,11 +7,6 @@
#include "v3d_drv.h"
-static int add_param(struct fs_context *fc, const char *key, const char *val)
-{
- return vfs_parse_fs_string(fc, key, val, strlen(val));
-}
-
void v3d_gemfs_init(struct v3d_dev *v3d)
{
struct file_system_type *type;
@@ -38,9 +33,9 @@ void v3d_gemfs_init(struct v3d_dev *v3d)
fc = fs_context_for_mount(type, SB_KERNMOUNT);
if (IS_ERR(fc))
goto err;
- ret = add_param(fc, "source", "tmpfs");
+ ret = vfs_parse_fs_string(fc, "source", "tmpfs");
if (!ret)
- ret = add_param(fc, "huge", "within_size");
+ ret = vfs_parse_fs_string(fc, "huge", "within_size");
if (!ret)
gemfs = fc_mount_longterm(fc);
put_fs_context(fc);
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index 9434a5399f2b..1ad048e6e164 100644
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -137,7 +137,8 @@ static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
ret = -EINVAL;
if (content[size - 1] == '.')
- ret = vfs_parse_fs_string(fc, "source", content, size - 1);
+ ret = vfs_parse_fs_qstr(fc, "source",
+ &QSTR_LEN(content, size - 1));
do_delayed_call(&cleanup);
if (ret < 0)
return ret;
diff --git a/fs/fs_context.c b/fs/fs_context.c
index 666e61753aed..93b7ebf8d927 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -161,25 +161,24 @@ int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param)
EXPORT_SYMBOL(vfs_parse_fs_param);
/**
- * vfs_parse_fs_string - Convenience function to just parse a string.
+ * vfs_parse_fs_qstr - Convenience function to just parse a string.
* @fc: Filesystem context.
* @key: Parameter name.
* @value: Default value.
- * @v_size: Maximum number of bytes in the value.
*/
-int vfs_parse_fs_string(struct fs_context *fc, const char *key,
- const char *value, size_t v_size)
+int vfs_parse_fs_qstr(struct fs_context *fc, const char *key,
+ const struct qstr *value)
{
int ret;
struct fs_parameter param = {
.key = key,
.type = fs_value_is_flag,
- .size = v_size,
+ .size = value ? value->len : 0,
};
if (value) {
- param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
+ param.string = kmemdup_nul(value->name, value->len, GFP_KERNEL);
if (!param.string)
return -ENOMEM;
param.type = fs_value_is_string;
@@ -189,7 +188,7 @@ int vfs_parse_fs_string(struct fs_context *fc, const char *key,
kfree(param.string);
return ret;
}
-EXPORT_SYMBOL(vfs_parse_fs_string);
+EXPORT_SYMBOL(vfs_parse_fs_qstr);
/**
* vfs_parse_monolithic_sep - Parse key[=val][,key[=val]]* mount data
@@ -218,16 +217,14 @@ int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
while ((key = sep(&options)) != NULL) {
if (*key) {
- size_t v_len = 0;
char *value = strchr(key, '=');
if (value) {
if (unlikely(value == key))
continue;
*value++ = 0;
- v_len = strlen(value);
}
- ret = vfs_parse_fs_string(fc, key, value, v_len);
+ ret = vfs_parse_fs_string(fc, key, value);
if (ret < 0)
break;
}
diff --git a/fs/namespace.c b/fs/namespace.c
index ddfd4457d338..88636124c8fe 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1281,8 +1281,7 @@ struct vfsmount *vfs_kern_mount(struct file_system_type *type,
return ERR_CAST(fc);
if (name)
- ret = vfs_parse_fs_string(fc, "source",
- name, strlen(name));
+ ret = vfs_parse_fs_string(fc, "source", name);
if (!ret)
ret = parse_monolithic_mount_data(fc, data);
if (!ret)
@@ -3793,10 +3792,9 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
fc->oldapi = true;
if (subtype)
- err = vfs_parse_fs_string(fc, "subtype",
- subtype, strlen(subtype));
+ err = vfs_parse_fs_string(fc, "subtype", subtype);
if (!err && name)
- err = vfs_parse_fs_string(fc, "source", name, strlen(name));
+ err = vfs_parse_fs_string(fc, "source", name);
if (!err)
err = parse_monolithic_mount_data(fc, data);
if (!err && !mount_capable(fc))
diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c
index 9e94d18448ff..b4679b7161b0 100644
--- a/fs/nfs/fs_context.c
+++ b/fs/nfs/fs_context.c
@@ -1269,8 +1269,7 @@ static int nfs23_parse_monolithic(struct fs_context *fc,
int ret;
data->context[NFS_MAX_CONTEXT_LEN] = '\0';
- ret = vfs_parse_fs_string(fc, "context",
- data->context, strlen(data->context));
+ ret = vfs_parse_fs_string(fc, "context", data->context);
if (ret < 0)
return ret;
#else
diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 7f1ec9c67ff2..5735c0448b4c 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -290,7 +290,8 @@ int nfs_do_submount(struct fs_context *fc)
nfs_errorf(fc, "NFS: Couldn't determine submount pathname");
ret = PTR_ERR(p);
} else {
- ret = vfs_parse_fs_string(fc, "source", p, buffer + 4096 - p);
+ ret = vfs_parse_fs_qstr(fc, "source",
+ &QSTR_LEN(p, buffer + 4096 - p));
if (!ret)
ret = vfs_get_tree(fc);
}
diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c
index 072383899e81..306b76e97783 100644
--- a/fs/smb/client/fs_context.c
+++ b/fs/smb/client/fs_context.c
@@ -773,16 +773,14 @@ static int smb3_fs_context_parse_monolithic(struct fs_context *fc,
}
- len = 0;
value = strchr(key, '=');
if (value) {
if (value == key)
continue;
*value++ = 0;
- len = strlen(value);
}
- ret = vfs_parse_fs_string(fc, key, value, len);
+ ret = vfs_parse_fs_string(fc, key, value);
if (ret < 0)
break;
}
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 7773eb870039..97b514a79a49 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -134,8 +134,13 @@ extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_ty
extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc);
extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
-extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
- const char *value, size_t v_size);
+extern int vfs_parse_fs_qstr(struct fs_context *fc, const char *key,
+ const struct qstr *value);
+static inline int vfs_parse_fs_string(struct fs_context *fc, const char *key,
+ const char *value)
+{
+ return vfs_parse_fs_qstr(fc, key, value ? &QSTR(value) : NULL);
+}
int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
char *(*sep)(char **));
extern int generic_parse_monolithic(struct fs_context *fc, void *data);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4283ed4e8f59..15375b45fd74 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -10201,8 +10201,7 @@ static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
pr_warn("NOTICE: Automounting of tracing to debugfs is deprecated and will be removed in 2030\n");
- ret = vfs_parse_fs_string(fc, "source",
- "tracefs", strlen("tracefs"));
+ ret = vfs_parse_fs_string(fc, "source", "tracefs");
if (!ret)
mnt = fc_mount(fc);
else
--
2.47.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH 2/2] do_nfs4_mount(): switch to vfs_parse_fs_string()
2025-08-28 0:00 [PATCHES] fs_context stuff Al Viro
2025-08-28 0:00 ` [PATCH 1/2] change the calling conventions for vfs_parse_fs_string() Al Viro
@ 2025-08-28 0:01 ` Al Viro
2025-08-29 7:47 ` Christian Brauner
1 sibling, 1 reply; 5+ messages in thread
From: Al Viro @ 2025-08-28 0:01 UTC (permalink / raw)
To: linux-fsdevel
Cc: Linus Torvalds, Christian Brauner, Jan Kara, David Howells,
linux-nfs
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/nfs/nfs4super.c | 44 +++++++++++---------------------------------
1 file changed, 11 insertions(+), 33 deletions(-)
diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c
index b29a26923ce0..5ec9c83f1ef0 100644
--- a/fs/nfs/nfs4super.c
+++ b/fs/nfs/nfs4super.c
@@ -149,21 +149,9 @@ static int do_nfs4_mount(struct nfs_server *server,
struct fs_context *root_fc;
struct vfsmount *root_mnt;
struct dentry *dentry;
- size_t len;
+ char *source;
int ret;
- struct fs_parameter param = {
- .key = "source",
- .type = fs_value_is_string,
- .dirfd = -1,
- };
-
- struct fs_parameter param_fsc = {
- .key = "fsc",
- .type = fs_value_is_string,
- .dirfd = -1,
- };
-
if (IS_ERR(server))
return PTR_ERR(server);
@@ -181,15 +169,7 @@ static int do_nfs4_mount(struct nfs_server *server,
root_ctx->server = server;
if (ctx->fscache_uniq) {
- len = strlen(ctx->fscache_uniq);
- param_fsc.size = len;
- param_fsc.string = kmemdup_nul(ctx->fscache_uniq, len, GFP_KERNEL);
- if (param_fsc.string == NULL) {
- put_fs_context(root_fc);
- return -ENOMEM;
- }
- ret = vfs_parse_fs_param(root_fc, ¶m_fsc);
- kfree(param_fsc.string);
+ ret = vfs_parse_fs_string(root_fc, "fsc", ctx->fscache_uniq);
if (ret < 0) {
put_fs_context(root_fc);
return ret;
@@ -197,20 +177,18 @@ static int do_nfs4_mount(struct nfs_server *server,
}
/* We leave export_path unset as it's not used to find the root. */
- len = strlen(hostname) + 5;
- param.string = kmalloc(len, GFP_KERNEL);
- if (param.string == NULL) {
- put_fs_context(root_fc);
- return -ENOMEM;
- }
-
/* Does hostname needs to be enclosed in brackets? */
if (strchr(hostname, ':'))
- param.size = snprintf(param.string, len, "[%s]:/", hostname);
+ source = kasprintf(GFP_KERNEL, "[%s]:/", hostname);
else
- param.size = snprintf(param.string, len, "%s:/", hostname);
- ret = vfs_parse_fs_param(root_fc, ¶m);
- kfree(param.string);
+ source = kasprintf(GFP_KERNEL, "%s:/", hostname);
+
+ if (!source) {
+ put_fs_context(root_fc);
+ return -ENOMEM;
+ }
+ ret = vfs_parse_fs_string(root_fc, "source", source);
+ kfree(source);
if (ret < 0) {
put_fs_context(root_fc);
return ret;
--
2.47.2
^ permalink raw reply related [flat|nested] 5+ messages in thread