* [PATCH v8 14/17] isofs: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Upper layers such as NFSD need a way to query whether a
filesystem handles filenames in a case-sensitive manner so
they can provide correct semantics to remote clients. Without
this information, NFS exports of ISO 9660 filesystems cannot
properly advertise their filename case behavior.
Implement isofs_fileattr_get() to report ISO 9660 case handling
behavior via the FS_XFLAG_CASEFOLD flag. The 'check=r' (relaxed)
mount option enables case-insensitive lookups, and this setting
determines the value reported. By default, Joliet extensions
operate in relaxed mode while plain ISO 9660 uses strict
(case-sensitive) mode. All ISO 9660 variants are case-preserving,
meaning filenames are stored exactly as they appear on the disc.
The callback is registered only on isofs_dir_inode_operations
because isofs has no custom inode_operations for regular
files, and symlinks use the generic page_symlink_inode_operations.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/isofs/dir.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/fs/isofs/dir.c b/fs/isofs/dir.c
index 2ca16c3fe5ef..225124eefa46 100644
--- a/fs/isofs/dir.c
+++ b/fs/isofs/dir.c
@@ -14,6 +14,7 @@
#include <linux/gfp.h>
#include <linux/filelock.h>
#include "isofs.h"
+#include <linux/fileattr.h>
int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
{
@@ -267,6 +268,19 @@ static int isofs_readdir(struct file *file, struct dir_context *ctx)
return result;
}
+static int isofs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ struct isofs_sb_info *sbi = ISOFS_SB(dentry->d_sb);
+
+ /*
+ * FS_XFLAG_CASEFOLD indicates case-insensitive lookups.
+ * When check=r (relaxed) is set, lookups ignore case.
+ */
+ if (sbi->s_check == 'r')
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ return 0;
+}
+
const struct file_operations isofs_dir_operations =
{
.llseek = generic_file_llseek,
@@ -281,6 +295,7 @@ const struct file_operations isofs_dir_operations =
const struct inode_operations isofs_dir_inode_operations =
{
.lookup = isofs_lookup,
+ .fileattr_get = isofs_fileattr_get,
};
--
2.53.0
^ permalink raw reply related
* [PATCH v8 13/17] vboxsf: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Upper layers such as NFSD need a way to query whether a
filesystem handles filenames in a case-sensitive manner. Report
VirtualBox shared folder case handling behavior via the
FS_XFLAG_CASEFOLD flag.
The case sensitivity property is queried from the VirtualBox host
service at mount time and cached in struct vboxsf_sbi. The host
determines case sensitivity based on the underlying host filesystem
(for example, Windows NTFS is case-insensitive while Linux ext4 is
case-sensitive).
VirtualBox shared folders always preserve filename case exactly
as provided by the guest. The host interface does not expose a
case_preserving property, so this is hardcoded to true.
The callback is registered in all three inode_operations
structures (directory, file, and symlink) to ensure consistent
reporting across all inode types.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/vboxsf/dir.c | 1 +
fs/vboxsf/file.c | 6 ++++--
fs/vboxsf/super.c | 4 ++++
fs/vboxsf/utils.c | 31 +++++++++++++++++++++++++++++++
fs/vboxsf/vfsmod.h | 6 ++++++
5 files changed, 46 insertions(+), 2 deletions(-)
diff --git a/fs/vboxsf/dir.c b/fs/vboxsf/dir.c
index 42bedc4ec7af..c5bd3271aa96 100644
--- a/fs/vboxsf/dir.c
+++ b/fs/vboxsf/dir.c
@@ -477,4 +477,5 @@ const struct inode_operations vboxsf_dir_iops = {
.symlink = vboxsf_dir_symlink,
.getattr = vboxsf_getattr,
.setattr = vboxsf_setattr,
+ .fileattr_get = vboxsf_fileattr_get,
};
diff --git a/fs/vboxsf/file.c b/fs/vboxsf/file.c
index 111752010edb..30a4f4262928 100644
--- a/fs/vboxsf/file.c
+++ b/fs/vboxsf/file.c
@@ -222,7 +222,8 @@ const struct file_operations vboxsf_reg_fops = {
const struct inode_operations vboxsf_reg_iops = {
.getattr = vboxsf_getattr,
- .setattr = vboxsf_setattr
+ .setattr = vboxsf_setattr,
+ .fileattr_get = vboxsf_fileattr_get,
};
static int vboxsf_read_folio(struct file *file, struct folio *folio)
@@ -389,5 +390,6 @@ static const char *vboxsf_get_link(struct dentry *dentry, struct inode *inode,
}
const struct inode_operations vboxsf_lnk_iops = {
- .get_link = vboxsf_get_link
+ .get_link = vboxsf_get_link,
+ .fileattr_get = vboxsf_fileattr_get,
};
diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
index 241647b060ee..fcabeca2a339 100644
--- a/fs/vboxsf/super.c
+++ b/fs/vboxsf/super.c
@@ -185,6 +185,10 @@ static int vboxsf_fill_super(struct super_block *sb, struct fs_context *fc)
if (err)
goto fail_unmap;
+ err = vboxsf_query_case_sensitive(sbi);
+ if (err)
+ goto fail_unmap;
+
sb->s_magic = VBOXSF_SUPER_MAGIC;
sb->s_blocksize = 1024;
sb->s_maxbytes = MAX_LFS_FILESIZE;
diff --git a/fs/vboxsf/utils.c b/fs/vboxsf/utils.c
index 9515bbf0b54c..658b8b0ebbd7 100644
--- a/fs/vboxsf/utils.c
+++ b/fs/vboxsf/utils.c
@@ -11,6 +11,7 @@
#include <linux/sizes.h>
#include <linux/pagemap.h>
#include <linux/vfs.h>
+#include <linux/fileattr.h>
#include "vfsmod.h"
struct inode *vboxsf_new_inode(struct super_block *sb)
@@ -567,3 +568,33 @@ int vboxsf_dir_read_all(struct vboxsf_sbi *sbi, struct vboxsf_dir_info *sf_d,
return err;
}
+
+int vboxsf_query_case_sensitive(struct vboxsf_sbi *sbi)
+{
+ struct shfl_volinfo volinfo = {};
+ u32 buf_len;
+ int err;
+
+ buf_len = sizeof(volinfo);
+ err = vboxsf_fsinfo(sbi->root, 0, SHFL_INFO_GET | SHFL_INFO_VOLUME,
+ &buf_len, &volinfo);
+ if (err)
+ return err;
+
+ sbi->case_insensitive = !volinfo.properties.case_sensitive;
+ return 0;
+}
+
+int vboxsf_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ struct vboxsf_sbi *sbi = VBOXSF_SBI(dentry->d_sb);
+
+ /*
+ * VirtualBox shared folders preserve filename case exactly as
+ * provided by the guest (the default). The host interface does
+ * not expose a case-preservation property.
+ */
+ if (sbi->case_insensitive)
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ return 0;
+}
diff --git a/fs/vboxsf/vfsmod.h b/fs/vboxsf/vfsmod.h
index 05973eb89d52..b61afd0ce842 100644
--- a/fs/vboxsf/vfsmod.h
+++ b/fs/vboxsf/vfsmod.h
@@ -47,6 +47,7 @@ struct vboxsf_sbi {
u32 next_generation;
u32 root;
int bdi_id;
+ bool case_insensitive;
};
/* per-inode information */
@@ -111,6 +112,11 @@ void vboxsf_dir_info_free(struct vboxsf_dir_info *p);
int vboxsf_dir_read_all(struct vboxsf_sbi *sbi, struct vboxsf_dir_info *sf_d,
u64 handle);
+int vboxsf_query_case_sensitive(struct vboxsf_sbi *sbi);
+
+struct file_kattr;
+int vboxsf_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
+
/* from vboxsf_wrappers.c */
int vboxsf_connect(void);
void vboxsf_disconnect(void);
--
2.53.0
^ permalink raw reply related
* [PATCH v8 12/17] f2fs: Add case sensitivity reporting to fileattr_get
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
NFS and other remote filesystem protocols need to determine
whether a local filesystem performs case-insensitive lookups
so they can provide correct semantics to clients. Without
this information, f2fs exports cannot properly advertise
their filename case behavior.
Report f2fs case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. Like ext4, f2fs supports per-directory case folding via
the casefold flag (IS_CASEFOLDED). Files are always case-preserving.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/f2fs/file.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index c8a2f17a8f11..f7f616e041dc 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -3453,6 +3453,13 @@ int f2fs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
if (f2fs_sb_has_project_quota(F2FS_I_SB(inode)))
fa->fsx_projid = from_kprojid(&init_user_ns, fi->i_projid);
+ /*
+ * f2fs preserves case (the default). If this inode is a
+ * casefolded directory, report case-insensitive; otherwise
+ * report case-sensitive (standard POSIX behavior).
+ */
+ if (IS_CASEFOLDED(inode))
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
return 0;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v8 11/17] nfs: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
An NFS server re-exporting an NFS mount point needs to report the
case sensitivity behavior of the underlying filesystem to its
clients. Without this, re-export servers cannot accurately convey
case handling semantics, potentially causing client applications to
make incorrect assumptions about filename collisions and lookups.
The NFS client already retrieves case sensitivity information from
servers during mount via PATHCONF (NFSv3) or the
FATTR4_CASE_INSENSITIVE/FATTR4_CASE_PRESERVING attributes (NFSv4).
Expose this information through fileattr_get by reporting the
FS_XFLAG_CASEFOLD and FS_XFLAG_CASENONPRESERVING flags. NFSv2 lacks
PATHCONF support, so mounts using that protocol version default to
standard POSIX behavior: case-sensitive and case-preserving.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/nfs/client.c | 9 +++++++--
fs/nfs/inode.c | 20 ++++++++++++++++++++
fs/nfs/internal.h | 3 +++
fs/nfs/nfs3proc.c | 2 ++
fs/nfs/nfs3xdr.c | 7 +++++--
fs/nfs/nfs4proc.c | 2 ++
fs/nfs/proc.c | 3 +++
fs/nfs/symlink.c | 3 +++
include/linux/nfs_xdr.h | 2 ++
9 files changed, 47 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index fd15731cf361..0410f6053bfd 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -935,13 +935,18 @@ static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, str
/* Get some general file system info */
if (server->namelen == 0) {
- struct nfs_pathconf pathinfo;
+ struct nfs_pathconf pathinfo = { };
pathinfo.fattr = fattr;
nfs_fattr_init(fattr);
- if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0)
+ if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0) {
server->namelen = pathinfo.max_namelen;
+ if (pathinfo.case_insensitive)
+ server->caps |= NFS_CAP_CASE_INSENSITIVE;
+ if (pathinfo.case_preserving)
+ server->caps |= NFS_CAP_CASE_PRESERVING;
+ }
}
if (clp->rpc_ops->discover_trunking != NULL &&
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 331cdecdd966..8a2edce22a53 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -41,6 +41,7 @@
#include <linux/freezer.h>
#include <linux/uaccess.h>
#include <linux/iversion.h>
+#include <linux/fileattr.h>
#include "nfs4_fs.h"
#include "callback.h"
@@ -1101,6 +1102,25 @@ int nfs_getattr(struct mnt_idmap *idmap, const struct path *path,
}
EXPORT_SYMBOL_GPL(nfs_getattr);
+/**
+ * nfs_fileattr_get - Retrieve file attributes
+ * @dentry: object to query
+ * @fa: file attributes to fill in
+ *
+ * Return: 0 on success
+ */
+int nfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ struct inode *inode = d_inode(dentry);
+
+ if (nfs_server_capable(inode, NFS_CAP_CASE_INSENSITIVE))
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ if (!nfs_server_capable(inode, NFS_CAP_CASE_PRESERVING))
+ fa->fsx_xflags |= FS_XFLAG_CASENONPRESERVING;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_fileattr_get);
+
static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
{
refcount_set(&l_ctx->count, 1);
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 63e09dfc27a8..e29695d4b7ed 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -449,6 +449,9 @@ extern void nfs_set_cache_invalid(struct inode *inode, unsigned long flags);
extern bool nfs_check_cache_invalid(struct inode *, unsigned long);
extern int nfs_wait_bit_killable(struct wait_bit_key *key, int mode);
+struct file_kattr;
+int nfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
+
#if IS_ENABLED(CONFIG_NFS_LOCALIO)
/* localio.c */
struct nfs_local_dio {
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index d3d2fbeba89d..c30c8c6b1b9e 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -1047,6 +1047,7 @@ static const struct inode_operations nfs3_dir_inode_operations = {
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
+ .fileattr_get = nfs_fileattr_get,
#ifdef CONFIG_NFS_V3_ACL
.listxattr = nfs3_listxattr,
.get_inode_acl = nfs3_get_acl,
@@ -1058,6 +1059,7 @@ static const struct inode_operations nfs3_file_inode_operations = {
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
+ .fileattr_get = nfs_fileattr_get,
#ifdef CONFIG_NFS_V3_ACL
.listxattr = nfs3_listxattr,
.get_inode_acl = nfs3_get_acl,
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index e17d72908412..e745e78faab0 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -2276,8 +2276,11 @@ static int decode_pathconf3resok(struct xdr_stream *xdr,
if (unlikely(!p))
return -EIO;
result->max_link = be32_to_cpup(p++);
- result->max_namelen = be32_to_cpup(p);
- /* ignore remaining fields */
+ result->max_namelen = be32_to_cpup(p++);
+ p++; /* ignore no_trunc */
+ p++; /* ignore chown_restricted */
+ result->case_insensitive = be32_to_cpup(p++) != 0;
+ result->case_preserving = be32_to_cpup(p) != 0;
return 0;
}
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 180229320731..c9ab542bdb90 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -10598,6 +10598,7 @@ static const struct inode_operations nfs4_dir_inode_operations = {
.getattr = nfs_getattr,
.setattr = nfs_setattr,
.listxattr = nfs4_listxattr,
+ .fileattr_get = nfs_fileattr_get,
};
static const struct inode_operations nfs4_file_inode_operations = {
@@ -10605,6 +10606,7 @@ static const struct inode_operations nfs4_file_inode_operations = {
.getattr = nfs_getattr,
.setattr = nfs_setattr,
.listxattr = nfs4_listxattr,
+ .fileattr_get = nfs_fileattr_get,
};
static struct nfs_server *nfs4_clone_server(struct nfs_server *source,
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index 0e440ebf5335..a92c0ea26ea0 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -597,6 +597,7 @@ nfs_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
{
info->max_link = 0;
info->max_namelen = NFS2_MAXNAMLEN;
+ info->case_preserving = true;
return 0;
}
@@ -717,12 +718,14 @@ static const struct inode_operations nfs_dir_inode_operations = {
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
+ .fileattr_get = nfs_fileattr_get,
};
static const struct inode_operations nfs_file_inode_operations = {
.permission = nfs_permission,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
+ .fileattr_get = nfs_fileattr_get,
};
const struct nfs_rpc_ops nfs_v2_clientops = {
diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c
index 58146e935402..74a072896f8d 100644
--- a/fs/nfs/symlink.c
+++ b/fs/nfs/symlink.c
@@ -22,6 +22,8 @@
#include <linux/mm.h>
#include <linux/string.h>
+#include "internal.h"
+
/* Symlink caching in the page cache is even more simplistic
* and straight-forward than readdir caching.
*/
@@ -74,4 +76,5 @@ const struct inode_operations nfs_symlink_inode_operations = {
.get_link = nfs_get_link,
.getattr = nfs_getattr,
.setattr = nfs_setattr,
+ .fileattr_get = nfs_fileattr_get,
};
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index ff1f12aa73d2..7c2057e40f99 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -182,6 +182,8 @@ struct nfs_pathconf {
struct nfs_fattr *fattr; /* Post-op attributes */
__u32 max_link; /* max # of hard links */
__u32 max_namelen; /* max name length */
+ bool case_insensitive;
+ bool case_preserving;
};
struct nfs4_change_info {
--
2.53.0
^ permalink raw reply related
* [PATCH v8 10/17] cifs: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Upper layers such as NFSD need a way to query whether a filesystem
handles filenames in a case-sensitive manner. Report CIFS/SMB case
handling behavior via the FS_XFLAG_CASEFOLD flag.
CIFS servers (typically Windows or Samba) are usually case-insensitive
but case-preserving, meaning they ignore case during lookups but store
filenames exactly as provided.
The implementation reports case sensitivity based on the nocase mount
option, which reflects whether the client expects the server to perform
case-insensitive comparisons. When nocase is set, the mount is reported
as case-insensitive.
The callback is registered in all three inode_operations structures
(directory, file, and symlink) to ensure consistent reporting across
all inode types.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/smb/client/cifsfs.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index afda1d7c1ee1..9d85785a1c67 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -30,6 +30,7 @@
#include <linux/xattr.h>
#include <linux/mm.h>
#include <linux/key-type.h>
+#include <linux/fileattr.h>
#include <uapi/linux/magic.h>
#include <net/ipv6.h>
#include "cifsfs.h"
@@ -1189,6 +1190,22 @@ struct file_system_type smb3_fs_type = {
MODULE_ALIAS_FS("smb3");
MODULE_ALIAS("smb3");
+static int cifs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
+ struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+
+ /*
+ * Case sensitivity is reported based on the nocase mount option.
+ * CIFS servers typically perform case-insensitive lookups while
+ * preserving case in stored filenames. The nocase option indicates
+ * case-insensitive comparison is in effect for this mount.
+ */
+ if (tcon->nocase)
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ return 0;
+}
+
const struct inode_operations cifs_dir_inode_ops = {
.create = cifs_create,
.atomic_open = cifs_atomic_open,
@@ -1206,6 +1223,7 @@ const struct inode_operations cifs_dir_inode_ops = {
.listxattr = cifs_listxattr,
.get_acl = cifs_get_acl,
.set_acl = cifs_set_acl,
+ .fileattr_get = cifs_fileattr_get,
};
const struct inode_operations cifs_file_inode_ops = {
@@ -1216,6 +1234,7 @@ const struct inode_operations cifs_file_inode_ops = {
.fiemap = cifs_fiemap,
.get_acl = cifs_get_acl,
.set_acl = cifs_set_acl,
+ .fileattr_get = cifs_fileattr_get,
};
const char *cifs_get_link(struct dentry *dentry, struct inode *inode,
@@ -1250,6 +1269,7 @@ const struct inode_operations cifs_symlink_inode_ops = {
.setattr = cifs_setattr,
.permission = cifs_permission,
.listxattr = cifs_listxattr,
+ .fileattr_get = cifs_fileattr_get,
};
/*
--
2.53.0
^ permalink raw reply related
* [PATCH v8 09/17] xfs: Report case sensitivity in fileattr_get
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever,
Darrick J. Wong
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Upper layers such as NFSD need to query whether a filesystem is
case-sensitive. Report case sensitivity via the FS_XFLAG_CASEFOLD
flag in xfs_fileattr_get(). XFS always preserves case. XFS is
case-sensitive by default, but supports ASCII case-insensitive
lookups when formatted with the ASCIICI feature flag.
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/xfs/xfs_ioctl.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 369555275140..41c6b4cd8ac2 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -518,6 +518,13 @@ xfs_fileattr_get(
xfs_fill_fsxattr(ip, XFS_DATA_FORK, fa);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ /*
+ * FS_XFLAG_CASEFOLD indicates case-insensitive lookups with
+ * case preservation. This matches ASCIICI behavior: lookups
+ * fold ASCII case while filenames remain stored verbatim.
+ */
+ if (xfs_has_asciici(ip->i_mount))
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
return 0;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v8 08/17] ext4: Report case sensitivity in fileattr_get
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Report ext4's case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. ext4 always preserves case at rest.
Case sensitivity is a per-directory setting in ext4. If the queried
inode is a casefolded directory, report case-insensitive; otherwise
report case-sensitive (standard POSIX behavior).
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/ext4/ioctl.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 3ae9cb50a0c0..a93017b80aa0 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -999,6 +999,13 @@ int ext4_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
if (ext4_has_feature_project(inode->i_sb))
fa->fsx_projid = from_kprojid(&init_user_ns, ei->i_projid);
+ /*
+ * Case folding is a directory attribute in ext4. Set FS_XFLAG_CASEFOLD
+ * for directories with the casefold attribute; all other inodes use
+ * standard case-sensitive semantics.
+ */
+ if (IS_CASEFOLDED(inode))
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
return 0;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v8 07/17] hfsplus: Report case sensitivity in fileattr_get
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Add case sensitivity reporting to the existing hfsplus_fileattr_get()
function via the FS_XFLAG_CASEFOLD flag. HFS+ always preserves case
at rest.
Case sensitivity depends on how the volume was formatted: HFSX
volumes may be either case-sensitive or case-insensitive, indicated
by the HFSPLUS_SB_CASEFOLD superblock flag.
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/hfsplus/inode.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index 922ff41df042..fd50f0d52c81 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -728,6 +728,7 @@ int hfsplus_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
{
struct inode *inode = d_inode(dentry);
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+ struct hfsplus_sb_info *sbi = HFSPLUS_SB(inode->i_sb);
unsigned int flags = 0;
if (inode->i_flags & S_IMMUTABLE)
@@ -739,6 +740,13 @@ int hfsplus_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
fileattr_fill_flags(fa, flags);
+ /*
+ * HFS+ preserves case (the default). Case sensitivity depends
+ * on how the filesystem was formatted: HFSX volumes may be
+ * either case-sensitive or case-insensitive.
+ */
+ if (test_bit(HFSPLUS_SB_CASEFOLD, &sbi->flags))
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
return 0;
}
--
2.53.0
^ permalink raw reply related
* [PATCH v8 06/17] hfs: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Report HFS case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. HFS is always case-insensitive (using Mac OS Roman case
folding) and always preserves case at rest.
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/hfs/dir.c | 1 +
fs/hfs/hfs_fs.h | 2 ++
fs/hfs/inode.c | 13 +++++++++++++
3 files changed, 16 insertions(+)
diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
index 0c615c078650..f85ef69a8375 100644
--- a/fs/hfs/dir.c
+++ b/fs/hfs/dir.c
@@ -328,4 +328,5 @@ const struct inode_operations hfs_dir_inode_operations = {
.rmdir = hfs_remove,
.rename = hfs_rename,
.setattr = hfs_inode_setattr,
+ .fileattr_get = hfs_fileattr_get,
};
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index ac0e83f77a0f..1b23448c9a48 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -177,6 +177,8 @@ extern int hfs_get_block(struct inode *inode, sector_t block,
extern const struct address_space_operations hfs_aops;
extern const struct address_space_operations hfs_btree_aops;
+struct file_kattr;
+int hfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
int hfs_write_begin(const struct kiocb *iocb, struct address_space *mapping,
loff_t pos, unsigned int len, struct folio **foliop,
void **fsdata);
diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 878535db64d6..b3e6e46ddd14 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -18,6 +18,7 @@
#include <linux/uio.h>
#include <linux/xattr.h>
#include <linux/blkdev.h>
+#include <linux/fileattr.h>
#include "hfs_fs.h"
#include "btree.h"
@@ -716,6 +717,17 @@ static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
return ret;
}
+int hfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ /*
+ * Report case-insensitive behavior: all name comparisons use
+ * Mac OS Roman case folding. FS_XFLAG_CASENONPRESERVING remains
+ * unset because original case is preserved on disk.
+ */
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ return 0;
+}
+
static const struct file_operations hfs_file_operations = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
@@ -732,4 +744,5 @@ static const struct inode_operations hfs_file_inode_operations = {
.lookup = hfs_file_lookup,
.setattr = hfs_inode_setattr,
.listxattr = generic_listxattr,
+ .fileattr_get = hfs_fileattr_get,
};
--
2.53.0
^ permalink raw reply related
* [PATCH v8 05/17] ntfs3: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Report NTFS case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. NTFS always preserves case at rest.
Case sensitivity depends on mount options: with "nocase", NTFS
is case-insensitive; otherwise it is case-sensitive.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/ntfs3/file.c | 23 +++++++++++++++++++++++
fs/ntfs3/inode.c | 1 +
fs/ntfs3/namei.c | 2 ++
fs/ntfs3/ntfs_fs.h | 1 +
4 files changed, 27 insertions(+)
diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index 6cb4479072a6..bf7e950ccdb8 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -147,6 +147,28 @@ long ntfs_compat_ioctl(struct file *filp, u32 cmd, unsigned long arg)
}
#endif
+/*
+ * ntfs_fileattr_get - inode_operations::fileattr_get
+ */
+int ntfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ struct inode *inode = d_inode(dentry);
+ struct ntfs_sb_info *sbi = inode->i_sb->s_fs_info;
+
+ /* Avoid any operation if inode is bad. */
+ if (unlikely(is_bad_ni(ntfs_i(inode))))
+ return -EINVAL;
+
+ /*
+ * NTFS preserves case (the default). Case sensitivity depends on
+ * mount options: with "nocase", NTFS is case-insensitive;
+ * otherwise it is case-sensitive.
+ */
+ if (sbi->options && sbi->options->nocase)
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ return 0;
+}
+
/*
* ntfs_getattr - inode_operations::getattr
*/
@@ -1461,6 +1483,7 @@ const struct inode_operations ntfs_file_inode_operations = {
.get_acl = ntfs_get_acl,
.set_acl = ntfs_set_acl,
.fiemap = ntfs_fiemap,
+ .fileattr_get = ntfs_fileattr_get,
};
const struct file_operations ntfs_file_operations = {
diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index edfb973e4e82..a6d1489cc362 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -2088,6 +2088,7 @@ const struct inode_operations ntfs_link_inode_operations = {
.get_link = ntfs_get_link,
.setattr = ntfs_setattr,
.listxattr = ntfs_listxattr,
+ .fileattr_get = ntfs_fileattr_get,
};
const struct address_space_operations ntfs_aops = {
diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index b2af8f695e60..eb241d7796ba 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -518,6 +518,7 @@ const struct inode_operations ntfs_dir_inode_operations = {
.getattr = ntfs_getattr,
.listxattr = ntfs_listxattr,
.fiemap = ntfs_fiemap,
+ .fileattr_get = ntfs_fileattr_get,
};
const struct inode_operations ntfs_special_inode_operations = {
@@ -526,6 +527,7 @@ const struct inode_operations ntfs_special_inode_operations = {
.listxattr = ntfs_listxattr,
.get_acl = ntfs_get_acl,
.set_acl = ntfs_set_acl,
+ .fileattr_get = ntfs_fileattr_get,
};
const struct dentry_operations ntfs_dentry_ops = {
diff --git a/fs/ntfs3/ntfs_fs.h b/fs/ntfs3/ntfs_fs.h
index f18349689458..94a23464c51f 100644
--- a/fs/ntfs3/ntfs_fs.h
+++ b/fs/ntfs3/ntfs_fs.h
@@ -505,6 +505,7 @@ extern const struct file_operations ntfs_dir_operations;
extern const struct file_operations ntfs_legacy_dir_operations;
/* Globals from file.c */
+int ntfs_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
int ntfs_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, u32 request_mask, u32 flags);
int ntfs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
--
2.53.0
^ permalink raw reply related
* [PATCH v8 04/17] exfat: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Report exFAT's case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. exFAT is always case-insensitive (using an upcase table for
comparison) and always preserves case at rest.
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/exfat/exfat_fs.h | 2 ++
fs/exfat/file.c | 16 ++++++++++++++--
fs/exfat/namei.c | 1 +
3 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 2dbed5f8ec26..686d4cd49546 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -468,6 +468,8 @@ int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, unsigned int request_mask,
unsigned int query_flags);
+struct file_kattr;
+int exfat_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync);
long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 90cd540afeaa..15629b0a6f6d 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -13,6 +13,7 @@
#include <linux/msdos_fs.h>
#include <linux/writeback.h>
#include <linux/filelock.h>
+#include <linux/fileattr.h>
#include "exfat_raw.h"
#include "exfat_fs.h"
@@ -282,6 +283,16 @@ int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
return 0;
}
+int exfat_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ /*
+ * exFAT is always case-insensitive (using upcase table).
+ * Case is preserved at rest (the default).
+ */
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ return 0;
+}
+
int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr)
{
@@ -775,6 +786,7 @@ const struct file_operations exfat_file_operations = {
};
const struct inode_operations exfat_file_inode_operations = {
- .setattr = exfat_setattr,
- .getattr = exfat_getattr,
+ .setattr = exfat_setattr,
+ .getattr = exfat_getattr,
+ .fileattr_get = exfat_fileattr_get,
};
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index 670116ae9ec8..7895dda5cdb4 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -1323,4 +1323,5 @@ const struct inode_operations exfat_dir_inode_operations = {
.rename = exfat_rename,
.setattr = exfat_setattr,
.getattr = exfat_getattr,
+ .fileattr_get = exfat_fileattr_get,
};
--
2.53.0
^ permalink raw reply related
* [PATCH v8 03/17] fat: Implement fileattr_get for case sensitivity
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Report FAT's case sensitivity behavior via the FS_XFLAG_CASEFOLD
and FS_XFLAG_CASENONPRESERVING flags. FAT filesystems are
case-insensitive by default.
MSDOS supports a 'nocase' mount option that enables case-sensitive
behavior; check this option when reporting case sensitivity.
VFAT long filename entries preserve case; without VFAT, only
uppercased 8.3 short names are stored. MSDOS with 'nocase' also
preserves case since the name-formatting code skips upcasing when
'nocase' is set. Check both options when reporting case preservation.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/fat/fat.h | 3 +++
fs/fat/file.c | 22 ++++++++++++++++++++++
fs/fat/namei_msdos.c | 1 +
fs/fat/namei_vfat.c | 1 +
4 files changed, 27 insertions(+)
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 0d269dba897b..c5bcd1063f9c 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -10,6 +10,8 @@
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
+struct file_kattr;
+
/*
* vfat shortname flags
*/
@@ -407,6 +409,7 @@ extern void fat_truncate_blocks(struct inode *inode, loff_t offset);
extern int fat_getattr(struct mnt_idmap *idmap,
const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int flags);
+int fat_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
extern int fat_file_fsync(struct file *file, loff_t start, loff_t end,
int datasync);
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 124d9c5431c8..6823269a8604 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -17,6 +17,7 @@
#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/falloc.h>
+#include <linux/fileattr.h>
#include "fat.h"
static long fat_fallocate(struct file *file, int mode,
@@ -396,6 +397,26 @@ void fat_truncate_blocks(struct inode *inode, loff_t offset)
fat_flush_inodes(inode->i_sb, inode, NULL);
}
+int fat_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
+
+ /*
+ * FAT filesystems are case-insensitive by default. MSDOS
+ * supports a 'nocase' mount option for case-sensitive behavior.
+ *
+ * VFAT long filename entries preserve case. Without VFAT, only
+ * uppercased 8.3 short names are stored. MSDOS with 'nocase'
+ * also preserves case.
+ */
+ if (!sbi->options.nocase)
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
+ if (!sbi->options.isvfat && !sbi->options.nocase)
+ fa->fsx_xflags |= FS_XFLAG_CASENONPRESERVING;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(fat_fileattr_get);
+
int fat_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, u32 request_mask, unsigned int flags)
{
@@ -573,5 +594,6 @@ EXPORT_SYMBOL_GPL(fat_setattr);
const struct inode_operations fat_file_inode_operations = {
.setattr = fat_setattr,
.getattr = fat_getattr,
+ .fileattr_get = fat_fileattr_get,
.update_time = fat_update_time,
};
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index 048c103b506a..4a3db08e51c0 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -642,6 +642,7 @@ static const struct inode_operations msdos_dir_inode_operations = {
.rename = msdos_rename,
.setattr = fat_setattr,
.getattr = fat_getattr,
+ .fileattr_get = fat_fileattr_get,
.update_time = fat_update_time,
};
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 2acfe3123a72..18f4c316aa05 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -1185,6 +1185,7 @@ static const struct inode_operations vfat_dir_inode_operations = {
.rename = vfat_rename2,
.setattr = fat_setattr,
.getattr = fat_getattr,
+ .fileattr_get = fat_fileattr_get,
.update_time = fat_update_time,
};
--
2.53.0
^ permalink raw reply related
* [PATCH v8 02/17] fs: Add case sensitivity flags to file_kattr
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever,
Darrick J. Wong
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
Enable upper layers such as NFSD to retrieve case sensitivity
information from file systems by adding FS_XFLAG_CASEFOLD and
FS_XFLAG_CASENONPRESERVING flags.
Filesystems report case-insensitive or case-nonpreserving behavior
by setting these flags directly in fa->fsx_xflags. The default
(flags unset) indicates POSIX semantics: case-sensitive and
case-preserving. These flags are read-only; userspace cannot set
them via ioctl.
Case sensitivity information is exported to userspace via the
fa_xflags field in the FS_IOC_FSGETXATTR ioctl and file_getattr()
system call.
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/file_attr.c | 4 ++++
include/linux/fileattr.h | 3 ++-
include/uapi/linux/fs.h | 7 +++++++
3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/fs/file_attr.c b/fs/file_attr.c
index 42aa511111a0..5d9a7ed159fb 100644
--- a/fs/file_attr.c
+++ b/fs/file_attr.c
@@ -37,6 +37,8 @@ void fileattr_fill_xflags(struct file_kattr *fa, u32 xflags)
fa->flags |= FS_PROJINHERIT_FL;
if (fa->fsx_xflags & FS_XFLAG_VERITY)
fa->flags |= FS_VERITY_FL;
+ if (fa->fsx_xflags & FS_XFLAG_CASEFOLD)
+ fa->flags |= FS_CASEFOLD_FL;
}
EXPORT_SYMBOL(fileattr_fill_xflags);
@@ -67,6 +69,8 @@ void fileattr_fill_flags(struct file_kattr *fa, u32 flags)
fa->fsx_xflags |= FS_XFLAG_PROJINHERIT;
if (fa->flags & FS_VERITY_FL)
fa->fsx_xflags |= FS_XFLAG_VERITY;
+ if (fa->flags & FS_CASEFOLD_FL)
+ fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
}
EXPORT_SYMBOL(fileattr_fill_flags);
diff --git a/include/linux/fileattr.h b/include/linux/fileattr.h
index 3780904a63a6..58044b598016 100644
--- a/include/linux/fileattr.h
+++ b/include/linux/fileattr.h
@@ -16,7 +16,8 @@
/* Read-only inode flags */
#define FS_XFLAG_RDONLY_MASK \
- (FS_XFLAG_PREALLOC | FS_XFLAG_HASATTR | FS_XFLAG_VERITY)
+ (FS_XFLAG_PREALLOC | FS_XFLAG_HASATTR | FS_XFLAG_VERITY | \
+ FS_XFLAG_CASEFOLD | FS_XFLAG_CASENONPRESERVING)
/* Flags to indicate valid value of fsx_ fields */
#define FS_XFLAG_VALUES_MASK \
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 70b2b661f42c..2fa003575e8b 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -254,6 +254,13 @@ struct file_attr {
#define FS_XFLAG_DAX 0x00008000 /* use DAX for IO */
#define FS_XFLAG_COWEXTSIZE 0x00010000 /* CoW extent size allocator hint */
#define FS_XFLAG_VERITY 0x00020000 /* fs-verity enabled */
+/*
+ * Case handling flags (read-only, cannot be set via ioctl).
+ * Default (neither set) indicates POSIX semantics: case-sensitive
+ * lookups and case-preserving storage.
+ */
+#define FS_XFLAG_CASEFOLD 0x00040000 /* case-insensitive lookups */
+#define FS_XFLAG_CASENONPRESERVING 0x00080000 /* case not preserved */
#define FS_XFLAG_HASATTR 0x80000000 /* no DIFLAG for this */
/* the read-only stuff doesn't really belong here, but any other place is
--
2.53.0
^ permalink raw reply related
* [PATCH v8 01/17] fs: Move file_kattr initialization to callers
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever,
Darrick J. Wong
In-Reply-To: <20260217214741.1928576-1-cel@kernel.org>
From: Chuck Lever <chuck.lever@oracle.com>
fileattr_fill_xflags() and fileattr_fill_flags() zero the entire
file_kattr struct before populating select fields. This behavior
prevents callers from setting flags in fa->fsx_xflags before
calling these helpers; the zeroing clears any pre-set values.
As Darrick Wong observed, when a function named "fill_xflags"
modifies more than just xflags, filesystems must understand
implementation details beyond the function's apparent scope. When
initialization occurs at entry points, helper functions need not
duplicate that zeroing.
Move struct file_kattr zero-initialization from the fill functions
to their callers. Entry points such as ioctl_setflags(),
ioctl_fssetxattr(), and the file_getattr/file_setattr syscalls
now perform aggregate initialization directly. The fill functions
retain their field-setting logic but no longer clear the struct.
This change enables subsequent patches where filesystem
->fileattr_get() handlers can set case-sensitivity flags
(FS_XFLAG_CASEFOLD, FS_XFLAG_CASENONPRESERVING) in fa->fsx_xflags
before calling the fill functions.
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
fs/file_attr.c | 14 +++++---------
fs/xfs/xfs_ioctl.c | 2 +-
2 files changed, 6 insertions(+), 10 deletions(-)
diff --git a/fs/file_attr.c b/fs/file_attr.c
index 6d2a298a786d..42aa511111a0 100644
--- a/fs/file_attr.c
+++ b/fs/file_attr.c
@@ -15,12 +15,10 @@
* @fa: fileattr pointer
* @xflags: FS_XFLAG_* flags
*
- * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags). All
- * other fields are zeroed.
+ * Set ->fsx_xflags, ->fsx_valid and ->flags (translated xflags).
*/
void fileattr_fill_xflags(struct file_kattr *fa, u32 xflags)
{
- memset(fa, 0, sizeof(*fa));
fa->fsx_valid = true;
fa->fsx_xflags = xflags;
if (fa->fsx_xflags & FS_XFLAG_IMMUTABLE)
@@ -48,11 +46,9 @@ EXPORT_SYMBOL(fileattr_fill_xflags);
* @flags: FS_*_FL flags
*
* Set ->flags, ->flags_valid and ->fsx_xflags (translated flags).
- * All other fields are zeroed.
*/
void fileattr_fill_flags(struct file_kattr *fa, u32 flags)
{
- memset(fa, 0, sizeof(*fa));
fa->flags_valid = true;
fa->flags = flags;
if (fa->flags & FS_SYNC_FL)
@@ -325,7 +321,7 @@ int ioctl_setflags(struct file *file, unsigned int __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
- struct file_kattr fa;
+ struct file_kattr fa = {};
unsigned int flags;
int err;
@@ -357,7 +353,7 @@ int ioctl_fssetxattr(struct file *file, void __user *argp)
{
struct mnt_idmap *idmap = file_mnt_idmap(file);
struct dentry *dentry = file->f_path.dentry;
- struct file_kattr fa;
+ struct file_kattr fa = {};
int err;
err = copy_fsxattr_from_user(&fa, argp);
@@ -378,7 +374,7 @@ SYSCALL_DEFINE5(file_getattr, int, dfd, const char __user *, filename,
struct path filepath __free(path_put) = {};
unsigned int lookup_flags = 0;
struct file_attr fattr;
- struct file_kattr fa;
+ struct file_kattr fa = {};
int error;
BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0);
@@ -431,7 +427,7 @@ SYSCALL_DEFINE5(file_setattr, int, dfd, const char __user *, filename,
struct path filepath __free(path_put) = {};
unsigned int lookup_flags = 0;
struct file_attr fattr;
- struct file_kattr fa;
+ struct file_kattr fa = {};
int error;
BUILD_BUG_ON(sizeof(struct file_attr) < FILE_ATTR_SIZE_VER0);
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 4eeda4d4e3ab..369555275140 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -498,7 +498,7 @@ xfs_ioc_fsgetxattra(
xfs_inode_t *ip,
void __user *arg)
{
- struct file_kattr fa;
+ struct file_kattr fa = {};
xfs_ilock(ip, XFS_ILOCK_SHARED);
xfs_fill_fsxattr(ip, XFS_ATTR_FORK, &fa);
--
2.53.0
^ permalink raw reply related
* [PATCH v8 00/17] Subject: Exposing case folding behavior
From: Chuck Lever @ 2026-02-17 21:47 UTC (permalink / raw)
To: Al Viro, Christian Brauner, Jan Kara
Cc: linux-fsdevel, linux-ext4, linux-xfs, linux-cifs, linux-nfs,
linux-api, linux-f2fs-devel, hirofumi, linkinjeon, sj1557.seo,
yuezhang.mo, almaz.alexandrovich, slava, glaubitz, frank.li,
tytso, adilger.kernel, cem, sfrench, pc, ronniesahlberg, sprasad,
trondmy, anna, jaegeuk, chao, hansg, senozhatsky, Chuck Lever
From: Chuck Lever <chuck.lever@oracle.com>
Following on from
https://lore.kernel.org/linux-nfs/20251021-zypressen-bazillus-545a44af57fd@brauner/T/#m0ba197d75b7921d994cf284f3cef3a62abb11aaa
I'm attempting to implement enough support in the Linux VFS to
enable file services like NFSD and ksmbd (and user space
equivalents) to provide the actual status of case folding support
in local file systems. The default behavior for local file systems
not explicitly supported in this series is to reflect the usual
POSIX behaviors:
case-insensitive = false
case-nonpreserving = true
The case-insensitivity and case-nonpreserving booleans can be
consumed immediately by NFSD. These two attributes have been part of
the NFSv3 and NFSv4 protocols for decades, in order to support NFS
client implementations on non-POSIX systems.
Support for user space file servers is why this series exposes case
folding information via a user-space API. I don't know of any other
category of user-space application that requires access to case
folding info.
The Linux NFS community has a growing interest in supporting NFS
clients on Windows and MacOS platforms, where file name behavior does
not align with traditional POSIX semantics.
One example of a Windows-based NFS client is [1]. This client
implementation explicitly requires servers to report
FATTR4_WORD0_CASE_INSENSITIVE = TRUE for proper operation, a hard
requirement for Windows client interoperability because Windows
applications expect case-insensitive behavior. When an NFS client
knows the server is case-insensitive, it can avoid issuing multiple
LOOKUP/READDIR requests to search for case variants, and applications
like Win32 programs work correctly without manual workarounds or
code changes.
Even the Linux client can take advantage of this information. Trond
merged patches 4 years ago [2] that introduce support for case
insensitivity, in support of the Hammerspace NFS server. In
particular, when a client detects a case-insensitive NFS share,
negative dentry caching must be disabled (a lookup for "FILE.TXT"
failing shouldn't cache a negative entry when "file.txt" exists)
and directory change invalidation must clear all cached case-folded
file name variants.
Hammerspace servers and several other NFS server implementations
operate in multi-protocol environments, where a single file service
instance caters to both NFS and SMB clients. In those cases, things
work more smoothly for everyone when the NFS client can see and adapt
to the case folding behavior that SMB users rely on and expect. NFSD
needs to support the case-insensitivity and case-nonpreserving
booleans properly in order to participate as a first-class citizen
in such environments.
Series based on 9702969978695d9a699a1f34771580cdbb153b33
[1] https://github.com/kofemann/ms-nfs41-client
[2] https://patchwork.kernel.org/project/linux-nfs/cover/20211217203658.439352-1-trondmy@kernel.org/
---
Changes since v7:
- Split file_attr initialization changes into a separate patch
Changes since v6:
- Remove the memset from vfs_fileattr_get
Changes since v5:
- Finish the conversion to FS_XFLAGs
- NFSv4 GETATTR now clears the attr mask bit if nfsd_get_case_info()
fails
Changes since v4:
- Observe the MSDOS "nocase" mount option
- Define new FS_XFLAGs for the user API
Changes since v3:
- Change fa->case_preserving to fa_case_nonpreserving
- VFAT is case preserving
- Make new fields available to user space
Changes since v2:
- Remove unicode labels
- Replace vfs_get_case_info
- Add support for several more local file system implementations
- Add support for in-kernel SMB server
Changes since RFC:
- Use file_getattr instead of statx
- Postpone exposing Unicode version until later
- Support NTFS and ext4 in addition to FAT
- Support NFSv4 fattr4 in addition to NFSv3 PATHCONF
Chuck Lever (17):
fs: Move file_kattr initialization to callers
fs: Add case sensitivity flags to file_kattr
fat: Implement fileattr_get for case sensitivity
exfat: Implement fileattr_get for case sensitivity
ntfs3: Implement fileattr_get for case sensitivity
hfs: Implement fileattr_get for case sensitivity
hfsplus: Report case sensitivity in fileattr_get
ext4: Report case sensitivity in fileattr_get
xfs: Report case sensitivity in fileattr_get
cifs: Implement fileattr_get for case sensitivity
nfs: Implement fileattr_get for case sensitivity
f2fs: Add case sensitivity reporting to fileattr_get
vboxsf: Implement fileattr_get for case sensitivity
isofs: Implement fileattr_get for case sensitivity
nfsd: Report export case-folding via NFSv3 PATHCONF
nfsd: Implement NFSv4 FATTR4_CASE_INSENSITIVE and
FATTR4_CASE_PRESERVING
ksmbd: Report filesystem case sensitivity via FS_ATTRIBUTE_INFORMATION
fs/exfat/exfat_fs.h | 2 ++
fs/exfat/file.c | 16 ++++++++++++++--
fs/exfat/namei.c | 1 +
fs/ext4/ioctl.c | 7 +++++++
fs/f2fs/file.c | 7 +++++++
fs/fat/fat.h | 3 +++
fs/fat/file.c | 22 ++++++++++++++++++++++
fs/fat/namei_msdos.c | 1 +
fs/fat/namei_vfat.c | 1 +
fs/file_attr.c | 18 +++++++++---------
fs/hfs/dir.c | 1 +
fs/hfs/hfs_fs.h | 2 ++
fs/hfs/inode.c | 13 +++++++++++++
fs/hfsplus/inode.c | 8 ++++++++
fs/isofs/dir.c | 15 +++++++++++++++
fs/nfs/client.c | 9 +++++++--
fs/nfs/inode.c | 20 ++++++++++++++++++++
fs/nfs/internal.h | 3 +++
fs/nfs/nfs3proc.c | 2 ++
fs/nfs/nfs3xdr.c | 7 +++++--
fs/nfs/nfs4proc.c | 2 ++
fs/nfs/proc.c | 3 +++
fs/nfs/symlink.c | 3 +++
fs/nfsd/nfs3proc.c | 18 ++++++++++--------
fs/nfsd/nfs4xdr.c | 31 +++++++++++++++++++++++++++----
fs/nfsd/vfs.c | 25 +++++++++++++++++++++++++
fs/nfsd/vfs.h | 2 ++
fs/ntfs3/file.c | 23 +++++++++++++++++++++++
fs/ntfs3/inode.c | 1 +
fs/ntfs3/namei.c | 2 ++
fs/ntfs3/ntfs_fs.h | 1 +
fs/smb/client/cifsfs.c | 20 ++++++++++++++++++++
fs/smb/server/smb2pdu.c | 25 +++++++++++++++++++------
fs/vboxsf/dir.c | 1 +
fs/vboxsf/file.c | 6 ++++--
fs/vboxsf/super.c | 4 ++++
fs/vboxsf/utils.c | 31 +++++++++++++++++++++++++++++++
fs/vboxsf/vfsmod.h | 6 ++++++
fs/xfs/xfs_ioctl.c | 9 ++++++++-
include/linux/fileattr.h | 3 ++-
include/linux/nfs_xdr.h | 2 ++
include/uapi/linux/fs.h | 7 +++++++
42 files changed, 346 insertions(+), 37 deletions(-)
--
2.53.0
^ permalink raw reply
* [PATCH bpf-next v11 8/8] selftests/bpf: Add tests to verify map create failure log
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
Add tests to verify that the kernel reports the expected error messages
and correct log_true_size when map creation fails.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
.../selftests/bpf/prog_tests/map_init.c | 166 ++++++++++++++++++
1 file changed, 166 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/map_init.c b/tools/testing/selftests/bpf/prog_tests/map_init.c
index 14a31109dd0e..b8b727e24b5e 100644
--- a/tools/testing/selftests/bpf/prog_tests/map_init.c
+++ b/tools/testing/selftests/bpf/prog_tests/map_init.c
@@ -212,3 +212,169 @@ void test_map_init(void)
if (test__start_subtest("pcpu_lru_map_init"))
test_pcpu_lru_map_init();
}
+
+static void test_map_create(enum bpf_map_type map_type, const char *map_name,
+ struct bpf_map_create_opts *opts, const char *exp_msg)
+{
+ const int key_size = 4, value_size = 4, max_entries = 1;
+ char log_buf[128];
+ int fd;
+ LIBBPF_OPTS(bpf_log_opts, log_opts);
+
+ log_buf[0] = '\0';
+ log_opts.log_buf = log_buf;
+ log_opts.log_size = sizeof(log_buf);
+ log_opts.log_level = 1;
+ opts->log_opts = &log_opts;
+ fd = bpf_map_create(map_type, map_name, key_size, value_size, max_entries, opts);
+ if (!ASSERT_LT(fd, 0, "bpf_map_create")) {
+ close(fd);
+ return;
+ }
+
+ ASSERT_STREQ(log_buf, exp_msg, "log_buf");
+ ASSERT_EQ(log_opts.log_true_size, strlen(exp_msg) + 1, "log_true_size");
+}
+
+static void test_map_create_array(struct bpf_map_create_opts *opts, const char *exp_msg)
+{
+ test_map_create(BPF_MAP_TYPE_ARRAY, "test_map_create", opts, exp_msg);
+}
+
+static void test_invalid_vmlinux_value_type_id_struct_ops(void)
+{
+ const char *msg = "btf_vmlinux_value_type_id can only be used with struct_ops maps.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_vmlinux_value_type_id = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_vmlinux_value_type_id_kv_type_id(void)
+{
+ const char *msg = "btf_vmlinux_value_type_id is mutually exclusive with btf_key_type_id and btf_value_type_id.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_vmlinux_value_type_id = 1,
+ .btf_key_type_id = 1,
+ );
+
+ test_map_create(BPF_MAP_TYPE_STRUCT_OPS, "test_map_create", &opts, msg);
+}
+
+static void test_invalid_value_type_id(void)
+{
+ const char *msg = "Invalid btf_value_type_id.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_key_type_id = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_map_extra(void)
+{
+ const char *msg = "Invalid map_extra.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .map_extra = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_numa_node(void)
+{
+ const char *msg = "Invalid numa_node.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .map_flags = BPF_F_NUMA_NODE,
+ .numa_node = 0xFF,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_map_type(void)
+{
+ const char *msg = "Invalid map_type.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts);
+
+ test_map_create(__MAX_BPF_MAP_TYPE, "test_map_create", &opts, msg);
+}
+
+static void test_invalid_token_fd(void)
+{
+ const char *msg = "Invalid map_token_fd.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .map_flags = BPF_F_TOKEN_FD,
+ .token_fd = 0xFF,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_invalid_map_name(void)
+{
+ const char *msg = "Invalid map_name.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts);
+
+ test_map_create(BPF_MAP_TYPE_ARRAY, "test-!@#", &opts, msg);
+}
+
+static void test_invalid_btf_fd(void)
+{
+ const char *msg = "Invalid btf_fd.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .btf_fd = -1,
+ .btf_key_type_id = 1,
+ .btf_value_type_id = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_excl_prog_hash_size_1(void)
+{
+ const char *msg = "Invalid excl_prog_hash_size.\n";
+ const char *hash = "DEADCODE";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .excl_prog_hash = hash,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+static void test_excl_prog_hash_size_2(void)
+{
+ const char *msg = "Invalid excl_prog_hash_size.\n";
+ LIBBPF_OPTS(bpf_map_create_opts, opts,
+ .excl_prog_hash_size = 1,
+ );
+
+ test_map_create_array(&opts, msg);
+}
+
+void test_map_create_failure(void)
+{
+ if (test__start_subtest("invalid_vmlinux_value_type_id_struct_ops"))
+ test_invalid_vmlinux_value_type_id_struct_ops();
+ if (test__start_subtest("invalid_vmlinux_value_type_id_kv_type_id"))
+ test_invalid_vmlinux_value_type_id_kv_type_id();
+ if (test__start_subtest("invalid_value_type_id"))
+ test_invalid_value_type_id();
+ if (test__start_subtest("invalid_map_extra"))
+ test_invalid_map_extra();
+ if (test__start_subtest("invalid_numa_node"))
+ test_invalid_numa_node();
+ if (test__start_subtest("invalid_map_type"))
+ test_invalid_map_type();
+ if (test__start_subtest("invalid_token_fd"))
+ test_invalid_token_fd();
+ if (test__start_subtest("invalid_map_name"))
+ test_invalid_map_name();
+ if (test__start_subtest("invalid_btf_fd"))
+ test_invalid_btf_fd();
+ if (test__start_subtest("invalid_excl_prog_hash_size_1"))
+ test_excl_prog_hash_size_1();
+ if (test__start_subtest("invalid_excl_prog_hash_size_2"))
+ test_excl_prog_hash_size_2();
+}
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 7/8] libbpf: Add syscall common attributes support for map_create
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
With the previous commit adding common attribute support for
BPF_MAP_CREATE, users can now retrieve detailed error messages when map
creation fails via the log_buf field.
Introduce struct bpf_log_opts with the following fields:
log_buf, log_size, log_level, and log_true_size.
Extend bpf_map_create_opts with a new field log_opts, allowing users to
capture and inspect log messages on map creation failures.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
tools/lib/bpf/bpf.c | 16 +++++++++++++++-
tools/lib/bpf/bpf.h | 17 ++++++++++++++++-
2 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 9d8740761b7a..0c3e40844d80 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -209,6 +209,9 @@ int bpf_map_create(enum bpf_map_type map_type,
const struct bpf_map_create_opts *opts)
{
const size_t attr_sz = offsetofend(union bpf_attr, excl_prog_hash_size);
+ const size_t attr_common_sz = sizeof(struct bpf_common_attr);
+ struct bpf_common_attr attr_common;
+ struct bpf_log_opts *log_opts;
union bpf_attr attr;
int fd;
@@ -242,7 +245,18 @@ int bpf_map_create(enum bpf_map_type map_type,
attr.excl_prog_hash = ptr_to_u64(OPTS_GET(opts, excl_prog_hash, NULL));
attr.excl_prog_hash_size = OPTS_GET(opts, excl_prog_hash_size, 0);
- fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
+ log_opts = OPTS_GET(opts, log_opts, NULL);
+ if (log_opts && feat_supported(NULL, FEAT_BPF_SYSCALL_COMMON_ATTRS)) {
+ memset(&attr_common, 0, attr_common_sz);
+ attr_common.log_buf = ptr_to_u64(OPTS_GET(log_opts, log_buf, NULL));
+ attr_common.log_size = OPTS_GET(log_opts, log_size, 0);
+ attr_common.log_level = OPTS_GET(log_opts, log_level, 0);
+ fd = sys_bpf_ext_fd(BPF_MAP_CREATE, &attr, attr_sz, &attr_common, attr_common_sz);
+ OPTS_SET(log_opts, log_true_size, attr_common.log_true_size);
+ } else {
+ fd = sys_bpf_fd(BPF_MAP_CREATE, &attr, attr_sz);
+ OPTS_SET(log_opts, log_true_size, 0);
+ }
return libbpf_err_errno(fd);
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 2c8e88ddb674..db834f09799e 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -37,6 +37,18 @@ extern "C" {
LIBBPF_API int libbpf_set_memlock_rlim(size_t memlock_bytes);
+struct bpf_log_opts {
+ size_t sz; /* size of this struct for forward/backward compatibility */
+
+ char *log_buf;
+ __u32 log_size;
+ __u32 log_level;
+ __u32 log_true_size; /* out parameter set by kernel */
+
+ size_t :0;
+};
+#define bpf_log_opts__last_field log_true_size
+
struct bpf_map_create_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
@@ -57,9 +69,12 @@ struct bpf_map_create_opts {
const void *excl_prog_hash;
__u32 excl_prog_hash_size;
+
+ struct bpf_log_opts *log_opts;
+
size_t :0;
};
-#define bpf_map_create_opts__last_field excl_prog_hash_size
+#define bpf_map_create_opts__last_field log_opts
LIBBPF_API int bpf_map_create(enum bpf_map_type map_type,
const char *map_name,
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 6/8] bpf: Add syscall common attributes support for map_create
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
Many BPF_MAP_CREATE validation failures currently return -EINVAL without
any explanation to userspace.
Plumb common syscall log attributes into map_create(), create a verifier
log from bpf_common_attr::log_buf/log_size/log_level, and report
map-creation failure reasons through that buffer.
This improves debuggability by allowing userspace to inspect why map
creation failed and read back log_true_size from common attributes.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/bpf_verifier.h | 3 ++
kernel/bpf/log.c | 30 +++++++++++++++++
kernel/bpf/syscall.c | 65 ++++++++++++++++++++++++++++++------
3 files changed, 88 insertions(+), 10 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index de1d42a48af5..6e02081fa24b 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -644,6 +644,9 @@ struct bpf_log_attr {
int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
u32 __user *log_true_size, struct bpf_common_attr *common, bpfptr_t uattr,
u32 size);
+struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log,
+ struct bpf_common_attr *common, bpfptr_t uattr,
+ u32 size);
int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
#define BPF_MAX_SUBPROGS 256
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index a1c0c42b0b8c..c31d4cf17517 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c
@@ -899,6 +899,36 @@ int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 l
return 0;
}
+
+struct bpf_verifier_log *bpf_log_attr_create_vlog(struct bpf_log_attr *attr_log,
+ struct bpf_common_attr *common, bpfptr_t uattr,
+ u32 size)
+{
+ struct bpf_verifier_log *log;
+ int err;
+
+ memset(attr_log, 0, sizeof(*attr_log));
+ if (size >= offsetofend(struct bpf_common_attr, log_true_size))
+ attr_log->log_true_size = uattr.user + offsetof(struct bpf_common_attr,
+ log_true_size);
+
+ if (!common->log_buf)
+ return NULL;
+
+ log = kzalloc_obj(*log, GFP_KERNEL);
+ if (!log)
+ return ERR_PTR(-ENOMEM);
+
+ err = bpf_vlog_init(log, common->log_level, u64_to_user_ptr(common->log_buf),
+ common->log_size);
+ if (err) {
+ kfree(log);
+ return ERR_PTR(err);
+ }
+
+ return log;
+}
+
int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log)
{
u32 log_true_size;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index be66b824e4cf..6f89dbbceb64 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1366,7 +1366,7 @@ static int map_check_btf(struct bpf_map *map, struct bpf_token *token,
#define BPF_MAP_CREATE_LAST_FIELD excl_prog_hash_size
/* called via syscall */
-static int map_create(union bpf_attr *attr, bpfptr_t uattr)
+static int __map_create(union bpf_attr *attr, bpfptr_t uattr, struct bpf_verifier_log *log)
{
const struct bpf_map_ops *ops;
struct bpf_token *token = NULL;
@@ -1378,8 +1378,10 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
int err;
err = CHECK_ATTR(BPF_MAP_CREATE);
- if (err)
+ if (err) {
+ bpf_log(log, "Invalid attr.\n");
return -EINVAL;
+ }
/* check BPF_F_TOKEN_FD flag, remember if it's set, and then clear it
* to avoid per-map type checks tripping on unknown flag
@@ -1388,17 +1390,25 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
attr->map_flags &= ~BPF_F_TOKEN_FD;
if (attr->btf_vmlinux_value_type_id) {
- if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS ||
- attr->btf_key_type_id || attr->btf_value_type_id)
+ if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS) {
+ bpf_log(log, "btf_vmlinux_value_type_id can only be used with struct_ops maps.\n");
return -EINVAL;
+ }
+ if (attr->btf_key_type_id || attr->btf_value_type_id) {
+ bpf_log(log, "btf_vmlinux_value_type_id is mutually exclusive with btf_key_type_id and btf_value_type_id.\n");
+ return -EINVAL;
+ }
} else if (attr->btf_key_type_id && !attr->btf_value_type_id) {
+ bpf_log(log, "Invalid btf_value_type_id.\n");
return -EINVAL;
}
if (attr->map_type != BPF_MAP_TYPE_BLOOM_FILTER &&
attr->map_type != BPF_MAP_TYPE_ARENA &&
- attr->map_extra != 0)
+ attr->map_extra != 0) {
+ bpf_log(log, "Invalid map_extra.\n");
return -EINVAL;
+ }
f_flags = bpf_get_file_flag(attr->map_flags);
if (f_flags < 0)
@@ -1406,13 +1416,17 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
if (numa_node != NUMA_NO_NODE &&
((unsigned int)numa_node >= nr_node_ids ||
- !node_online(numa_node)))
+ !node_online(numa_node))) {
+ bpf_log(log, "Invalid numa_node.\n");
return -EINVAL;
+ }
/* find map type and init map: hashtable vs rbtree vs bloom vs ... */
map_type = attr->map_type;
- if (map_type >= ARRAY_SIZE(bpf_map_types))
+ if (map_type >= ARRAY_SIZE(bpf_map_types)) {
+ bpf_log(log, "Invalid map_type.\n");
return -EINVAL;
+ }
map_type = array_index_nospec(map_type, ARRAY_SIZE(bpf_map_types));
ops = bpf_map_types[map_type];
if (!ops)
@@ -1430,8 +1444,10 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
if (token_flag) {
token = bpf_token_get_from_fd(attr->map_token_fd);
- if (IS_ERR(token))
+ if (IS_ERR(token)) {
+ bpf_log(log, "Invalid map_token_fd.\n");
return PTR_ERR(token);
+ }
/* if current token doesn't grant map creation permissions,
* then we can't use this token, so ignore it and rely on
@@ -1514,8 +1530,10 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
err = bpf_obj_name_cpy(map->name, attr->map_name,
sizeof(attr->map_name));
- if (err < 0)
+ if (err < 0) {
+ bpf_log(log, "Invalid map_name.\n");
goto free_map;
+ }
preempt_disable();
map->cookie = gen_cookie_next(&bpf_map_cookie);
@@ -1538,6 +1556,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
btf = btf_get_by_fd(attr->btf_fd);
if (IS_ERR(btf)) {
+ bpf_log(log, "Invalid btf_fd.\n");
err = PTR_ERR(btf);
goto free_map;
}
@@ -1565,6 +1584,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
bpfptr_t uprog_hash = make_bpfptr(attr->excl_prog_hash, uattr.is_kernel);
if (attr->excl_prog_hash_size != SHA256_DIGEST_SIZE) {
+ bpf_log(log, "Invalid excl_prog_hash_size.\n");
err = -EINVAL;
goto free_map;
}
@@ -1580,6 +1600,7 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
goto free_map;
}
} else if (attr->excl_prog_hash_size) {
+ bpf_log(log, "Invalid excl_prog_hash_size.\n");
err = -EINVAL;
goto free_map;
}
@@ -1618,6 +1639,30 @@ static int map_create(union bpf_attr *attr, bpfptr_t uattr)
return err;
}
+static int map_create(union bpf_attr *attr, bpfptr_t uattr, struct bpf_common_attr *attr_common,
+ bpfptr_t uattr_common, u32 size_common)
+{
+ struct bpf_verifier_log *log;
+ struct bpf_log_attr attr_log;
+ int err, ret;
+
+ log = bpf_log_attr_create_vlog(&attr_log, attr_common, uattr_common, size_common);
+ if (IS_ERR(log))
+ return PTR_ERR(log);
+
+ err = __map_create(attr, uattr, log);
+ if (err >= 0)
+ goto free;
+
+ ret = bpf_log_attr_finalize(&attr_log, log);
+ if (ret)
+ err = ret;
+
+free:
+ kfree(log);
+ return err;
+}
+
void bpf_map_inc(struct bpf_map *map)
{
atomic64_inc(&map->refcnt);
@@ -6227,7 +6272,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
switch (cmd) {
case BPF_MAP_CREATE:
- err = map_create(&attr, uattr);
+ err = map_create(&attr, uattr, &attr_common, uattr_common, size_common);
break;
case BPF_MAP_LOOKUP_ELEM:
err = map_lookup_elem(&attr);
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 5/8] bpf: Add syscall common attributes support for btf_load
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
BPF_BTF_LOAD can now take log parameters from both union bpf_attr and
struct bpf_common_attr, with the same merge rules as BPF_PROG_LOAD:
- if both sides provide a complete log tuple (buf/size/level) and they
match, use it;
- if only one side provides log parameters, use that one;
- if both sides provide complete tuples but they differ, return -EINVAL.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/btf.h | 3 ++-
kernel/bpf/btf.c | 30 +++++++-----------------------
kernel/bpf/syscall.c | 11 ++++++++---
3 files changed, 17 insertions(+), 27 deletions(-)
diff --git a/include/linux/btf.h b/include/linux/btf.h
index 48108471c5b1..f64d87315c5f 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -145,7 +145,8 @@ const char *btf_get_name(const struct btf *btf);
void btf_get(struct btf *btf);
void btf_put(struct btf *btf);
const struct btf_header *btf_header(const struct btf *btf);
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_sz);
+struct bpf_log_attr;
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log);
struct btf *btf_get_by_fd(int fd);
int btf_get_info_by_fd(const struct btf *btf,
const union bpf_attr *attr,
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 7708958e3fb8..810007028b72 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -5857,25 +5857,10 @@ static int btf_check_type_tags(struct btf_verifier_env *env,
return 0;
}
-static int finalize_log(struct bpf_verifier_log *log, bpfptr_t uattr, u32 uattr_size)
-{
- u32 log_true_size;
- int err;
-
- err = bpf_vlog_finalize(log, &log_true_size);
-
- if (uattr_size >= offsetofend(union bpf_attr, btf_log_true_size) &&
- copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, btf_log_true_size),
- &log_true_size, sizeof(log_true_size)))
- err = -EFAULT;
-
- return err;
-}
-
-static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr,
+ struct bpf_log_attr *attr_log)
{
bpfptr_t btf_data = make_bpfptr(attr->btf, uattr.is_kernel);
- char __user *log_ubuf = u64_to_user_ptr(attr->btf_log_buf);
struct btf_struct_metas *struct_meta_tab;
struct btf_verifier_env *env = NULL;
struct btf *btf = NULL;
@@ -5892,8 +5877,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
/* user could have requested verbose verifier output
* and supplied buffer to store the verification trace
*/
- err = bpf_vlog_init(&env->log, attr->btf_log_level,
- log_ubuf, attr->btf_log_size);
+ err = bpf_vlog_init(&env->log, attr_log->log_level, attr_log->log_buf, attr_log->log_size);
if (err)
goto errout_free;
@@ -5954,7 +5938,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
}
}
- err = finalize_log(&env->log, uattr, uattr_size);
+ err = bpf_log_attr_finalize(attr_log, &env->log);
if (err)
goto errout_free;
@@ -5966,7 +5950,7 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
btf_free_struct_meta_tab(btf);
errout:
/* overwrite err with -ENOSPC or -EFAULT */
- ret = finalize_log(&env->log, uattr, uattr_size);
+ ret = bpf_log_attr_finalize(attr_log, &env->log);
if (ret)
err = ret;
errout_free:
@@ -8137,12 +8121,12 @@ static int __btf_new_fd(struct btf *btf)
return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
}
-int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
{
struct btf *btf;
int ret;
- btf = btf_parse(attr, uattr, uattr_size);
+ btf = btf_parse(attr, uattr, attr_log);
if (IS_ERR(btf))
return PTR_ERR(btf);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index f37396f71e8d..be66b824e4cf 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5449,7 +5449,7 @@ static int bpf_obj_get_info_by_fd(const union bpf_attr *attr,
#define BPF_BTF_LOAD_LAST_FIELD btf_token_fd
-static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
+static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
{
struct bpf_token *token = NULL;
@@ -5476,7 +5476,7 @@ static int bpf_btf_load(const union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_
bpf_token_put(token);
- return btf_new_fd(attr, uattr, uattr_size);
+ return btf_new_fd(attr, uattr, attr_log);
}
#define BPF_BTF_GET_FD_BY_ID_LAST_FIELD fd_by_id_token_fd
@@ -6294,7 +6294,12 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
err = bpf_raw_tracepoint_open(&attr);
break;
case BPF_BTF_LOAD:
- err = bpf_btf_load(&attr, uattr, size);
+ if (from_user && size >= offsetofend(union bpf_attr, btf_log_true_size))
+ log_true_size = uattr.user + offsetof(union bpf_attr, btf_log_true_size);
+ err = bpf_log_attr_init(&attr_log, attr.btf_log_buf, attr.btf_log_size,
+ attr.btf_log_level, log_true_size, &attr_common,
+ uattr_common, size_common);
+ err = err ?: bpf_btf_load(&attr, uattr, &attr_log);
break;
case BPF_BTF_GET_FD_BY_ID:
err = bpf_btf_get_fd_by_id(&attr);
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 4/8] bpf: Add syscall common attributes support for prog_load
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
BPF_PROG_LOAD can now take log parameters from both union bpf_attr and
struct bpf_common_attr. The merge rules are:
- if both sides provide a complete log tuple (buf/size/level) and they
match, use it;
- if only one side provides log parameters, use that one;
- if both sides provide complete tuples but they differ, return -EINVAL.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/bpf_verifier.h | 3 ++-
kernel/bpf/log.c | 38 ++++++++++++++++++++++++++++--------
kernel/bpf/syscall.c | 2 +-
3 files changed, 33 insertions(+), 10 deletions(-)
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index b21cb7066f6f..de1d42a48af5 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -642,7 +642,8 @@ struct bpf_log_attr {
};
int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
- u32 __user *log_true_size);
+ u32 __user *log_true_size, struct bpf_common_attr *common, bpfptr_t uattr,
+ u32 size);
int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
#define BPF_MAX_SUBPROGS 256
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index d4dbf2465620..a1c0c42b0b8c 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c
@@ -13,17 +13,17 @@
#define verbose(env, fmt, args...) bpf_verifier_log_write(env, fmt, ##args)
-static bool bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log)
+static bool bpf_verifier_log_attr_valid(u32 log_level, char __user *log_buf, u32 log_size)
{
/* ubuf and len_total should both be specified (or not) together */
- if (!!log->ubuf != !!log->len_total)
+ if (!!log_buf != !!log_size)
return false;
/* log buf without log_level is meaningless */
- if (log->ubuf && log->level == 0)
+ if (log_buf && log_level == 0)
return false;
- if (log->level & ~BPF_LOG_MASK)
+ if (log_level & ~BPF_LOG_MASK)
return false;
- if (log->len_total > UINT_MAX >> 2)
+ if (log_size > UINT_MAX >> 2)
return false;
return true;
}
@@ -36,7 +36,7 @@ int bpf_vlog_init(struct bpf_verifier_log *log, u32 log_level,
log->len_total = log_size;
/* log attributes have to be sane */
- if (!bpf_verifier_log_attr_valid(log))
+ if (!bpf_verifier_log_attr_valid(log_level, log_buf, log_size))
return -EINVAL;
return 0;
@@ -867,13 +867,35 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st
}
int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
- u32 __user *log_true_size)
+ u32 __user *log_true_size, struct bpf_common_attr *common, bpfptr_t uattr,
+ u32 size)
{
+ char __user *ubuf_common = u64_to_user_ptr(common->log_buf);
+ char __user *ubuf = u64_to_user_ptr(log_buf);
+
+ if (!bpf_verifier_log_attr_valid(common->log_level, ubuf_common, common->log_size) ||
+ !bpf_verifier_log_attr_valid(log_level, ubuf, log_size))
+ return -EINVAL;
+
+ if (ubuf && ubuf_common && (ubuf != ubuf_common || log_size != common->log_size ||
+ log_level != common->log_level))
+ return -EINVAL;
+
memset(log, 0, sizeof(*log));
- log->log_buf = u64_to_user_ptr(log_buf);
+ log->log_buf = ubuf;
log->log_size = log_size;
log->log_level = log_level;
log->log_true_size = log_true_size;
+
+ if (!ubuf && ubuf_common) {
+ log->log_buf = ubuf_common;
+ log->log_size = common->log_size;
+ log->log_level = common->log_level;
+ log->log_true_size = NULL;
+ if (size >= offsetofend(struct bpf_common_attr, log_true_size))
+ log->log_true_size = uattr.user +
+ offsetof(struct bpf_common_attr, log_true_size);
+ }
return 0;
}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index d6fa752401a9..f37396f71e8d 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -6248,7 +6248,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
if (from_user && size >= offsetofend(union bpf_attr, log_true_size))
log_true_size = uattr.user + offsetof(union bpf_attr, log_true_size);
err = bpf_log_attr_init(&attr_log, attr.log_buf, attr.log_size, attr.log_level,
- log_true_size);
+ log_true_size, &attr_common, uattr_common, size_common);
err = err ?: bpf_prog_load(&attr, uattr, &attr_log);
break;
case BPF_OBJ_PIN:
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 3/8] bpf: Refactor reporting log_true_size for prog_load
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
The next commit will add support for reporting logs via extended common
attributes, including 'log_true_size'.
To prepare for that, refactor the 'log_true_size' reporting logic by
introducing a new struct bpf_log_attr to encapsulate log-related behavior:
* bpf_log_attr_init(): initialize log fields, which will support
extended common attributes in the next commit.
* bpf_log_attr_finalize(): handle log finalization and write back
'log_true_size' to userspace.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/bpf.h | 4 +++-
include/linux/bpf_verifier.h | 11 +++++++++++
kernel/bpf/log.c | 25 +++++++++++++++++++++++++
kernel/bpf/syscall.c | 13 ++++++++++---
kernel/bpf/verifier.c | 17 ++++-------------
5 files changed, 53 insertions(+), 17 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index cd9b96434904..d4dbcc7ad156 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2913,7 +2913,9 @@ int bpf_check_uarg_tail_zero(bpfptr_t uaddr, size_t expected_size,
size_t actual_size);
/* verify correctness of eBPF program */
-int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size);
+struct bpf_log_attr;
+int bpf_check(struct bpf_prog **fp, union bpf_attr *attr, bpfptr_t uattr,
+ struct bpf_log_attr *attr_log);
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth);
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index c1e30096ea7b..b21cb7066f6f 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -634,6 +634,17 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
return log && log->level;
}
+struct bpf_log_attr {
+ char __user *log_buf;
+ u32 log_size;
+ u32 log_level;
+ u32 __user *log_true_size;
+};
+
+int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
+ u32 __user *log_true_size);
+int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log);
+
#define BPF_MAX_SUBPROGS 256
struct bpf_subprog_arg_info {
diff --git a/kernel/bpf/log.c b/kernel/bpf/log.c
index 37d72b052192..d4dbf2465620 100644
--- a/kernel/bpf/log.c
+++ b/kernel/bpf/log.c
@@ -865,3 +865,28 @@ void print_insn_state(struct bpf_verifier_env *env, const struct bpf_verifier_st
}
print_verifier_state(env, vstate, frameno, false);
}
+
+int bpf_log_attr_init(struct bpf_log_attr *log, u64 log_buf, u32 log_size, u32 log_level,
+ u32 __user *log_true_size)
+{
+ memset(log, 0, sizeof(*log));
+ log->log_buf = u64_to_user_ptr(log_buf);
+ log->log_size = log_size;
+ log->log_level = log_level;
+ log->log_true_size = log_true_size;
+ return 0;
+}
+
+int bpf_log_attr_finalize(struct bpf_log_attr *attr, struct bpf_verifier_log *log)
+{
+ u32 log_true_size;
+ int err;
+
+ err = bpf_vlog_finalize(log, &log_true_size);
+
+ if (attr->log_true_size && copy_to_user(attr->log_true_size, &log_true_size,
+ sizeof(log_true_size)))
+ return -EFAULT;
+
+ return err;
+}
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index e7ab87908189..d6fa752401a9 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2868,7 +2868,7 @@ static int bpf_prog_mark_insn_arrays_ready(struct bpf_prog *prog)
/* last field in 'union bpf_attr' used by this command */
#define BPF_PROG_LOAD_LAST_FIELD keyring_id
-static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
+static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, struct bpf_log_attr *attr_log)
{
enum bpf_prog_type type = attr->prog_type;
struct bpf_prog *prog, *dst_prog = NULL;
@@ -3086,7 +3086,7 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
goto free_prog_sec;
/* run eBPF verifier */
- err = bpf_check(&prog, attr, uattr, uattr_size);
+ err = bpf_check(&prog, attr, uattr, attr_log);
if (err < 0)
goto free_used_maps;
@@ -6190,7 +6190,10 @@ static int prog_assoc_struct_ops(union bpf_attr *attr)
static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
bpfptr_t uattr_common, unsigned int size_common)
{
+ bool from_user = !bpfptr_is_kernel(uattr);
struct bpf_common_attr attr_common;
+ u32 __user *log_true_size = NULL;
+ struct bpf_log_attr attr_log;
union bpf_attr attr;
int err;
@@ -6242,7 +6245,11 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
err = map_freeze(&attr);
break;
case BPF_PROG_LOAD:
- err = bpf_prog_load(&attr, uattr, size);
+ if (from_user && size >= offsetofend(union bpf_attr, log_true_size))
+ log_true_size = uattr.user + offsetof(union bpf_attr, log_true_size);
+ err = bpf_log_attr_init(&attr_log, attr.log_buf, attr.log_size, attr.log_level,
+ log_true_size);
+ err = err ?: bpf_prog_load(&attr, uattr, &attr_log);
break;
case BPF_OBJ_PIN:
err = bpf_obj_pin(&attr);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 0162f946032f..779cf863dc9a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -25790,12 +25790,12 @@ static int compute_scc(struct bpf_verifier_env *env)
return err;
}
-int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
+int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr,
+ struct bpf_log_attr *attr_log)
{
u64 start_time = ktime_get_ns();
struct bpf_verifier_env *env;
int i, len, ret = -EINVAL, err;
- u32 log_true_size;
bool is_priv;
BTF_TYPE_EMIT(enum bpf_features);
@@ -25842,9 +25842,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
/* user could have requested verbose verifier output
* and supplied buffer to store the verification trace
*/
- ret = bpf_vlog_init(&env->log, attr->log_level,
- (char __user *) (unsigned long) attr->log_buf,
- attr->log_size);
+ ret = bpf_vlog_init(&env->log, attr_log->log_level, attr_log->log_buf, attr_log->log_size);
if (ret)
goto err_unlock;
@@ -25994,17 +25992,10 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
env->prog->aux->verified_insns = env->insn_processed;
/* preserve original error even if log finalization is successful */
- err = bpf_vlog_finalize(&env->log, &log_true_size);
+ err = bpf_log_attr_finalize(attr_log, &env->log);
if (err)
ret = err;
- if (uattr_size >= offsetofend(union bpf_attr, log_true_size) &&
- copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size),
- &log_true_size, sizeof(log_true_size))) {
- ret = -EFAULT;
- goto err_release_maps;
- }
-
if (ret)
goto err_release_maps;
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 2/8] libbpf: Add support for extended BPF syscall
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
To support the extended BPF syscall introduced in the previous commit,
introduce the following internal APIs:
* 'sys_bpf_ext()'
* 'sys_bpf_ext_fd()'
They wrap the raw 'syscall()' interface to support passing extended
attributes.
* 'probe_sys_bpf_ext()'
Check whether current kernel supports the BPF syscall common attributes.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
tools/lib/bpf/bpf.c | 36 +++++++++++++++++++++++++++++++++
tools/lib/bpf/features.c | 8 ++++++++
tools/lib/bpf/libbpf_internal.h | 3 +++
3 files changed, 47 insertions(+)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 5846de364209..9d8740761b7a 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -69,6 +69,42 @@ static inline __u64 ptr_to_u64(const void *ptr)
return (__u64) (unsigned long) ptr;
}
+static inline int sys_bpf_ext(enum bpf_cmd cmd, union bpf_attr *attr,
+ unsigned int size,
+ struct bpf_common_attr *attr_common,
+ unsigned int size_common)
+{
+ cmd = attr_common ? (cmd | BPF_COMMON_ATTRS) : (cmd & ~BPF_COMMON_ATTRS);
+ return syscall(__NR_bpf, cmd, attr, size, attr_common, size_common);
+}
+
+static inline int sys_bpf_ext_fd(enum bpf_cmd cmd, union bpf_attr *attr,
+ unsigned int size,
+ struct bpf_common_attr *attr_common,
+ unsigned int size_common)
+{
+ int fd;
+
+ fd = sys_bpf_ext(cmd, attr, size, attr_common, size_common);
+ return ensure_good_fd(fd);
+}
+
+int probe_sys_bpf_ext(void)
+{
+ const size_t attr_sz = offsetofend(union bpf_attr, prog_token_fd);
+ union bpf_attr attr;
+ int fd;
+
+ memset(&attr, 0, attr_sz);
+ fd = syscall(__NR_bpf, BPF_PROG_LOAD | BPF_COMMON_ATTRS, &attr, attr_sz, NULL,
+ sizeof(struct bpf_common_attr));
+ if (fd >= 0) {
+ close(fd);
+ return -EINVAL;
+ }
+ return errno == EFAULT ? 1 : 0;
+}
+
static inline int sys_bpf(enum bpf_cmd cmd, union bpf_attr *attr,
unsigned int size)
{
diff --git a/tools/lib/bpf/features.c b/tools/lib/bpf/features.c
index b842b83e2480..e0d646a9e233 100644
--- a/tools/lib/bpf/features.c
+++ b/tools/lib/bpf/features.c
@@ -506,6 +506,11 @@ static int probe_kern_arg_ctx_tag(int token_fd)
return probe_fd(prog_fd);
}
+static int probe_bpf_syscall_common_attrs(int token_fd)
+{
+ return probe_sys_bpf_ext();
+}
+
typedef int (*feature_probe_fn)(int /* token_fd */);
static struct kern_feature_cache feature_cache;
@@ -581,6 +586,9 @@ static struct kern_feature_desc {
[FEAT_BTF_QMARK_DATASEC] = {
"BTF DATASEC names starting from '?'", probe_kern_btf_qmark_datasec,
},
+ [FEAT_BPF_SYSCALL_COMMON_ATTRS] = {
+ "BPF syscall common attributes support", probe_bpf_syscall_common_attrs,
+ },
};
bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id)
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index fc59b21b51b5..aa16be869c4f 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -392,6 +392,8 @@ enum kern_feature_id {
FEAT_ARG_CTX_TAG,
/* Kernel supports '?' at the front of datasec names */
FEAT_BTF_QMARK_DATASEC,
+ /* Kernel supports BPF syscall common attributes */
+ FEAT_BPF_SYSCALL_COMMON_ATTRS,
__FEAT_CNT,
};
@@ -757,4 +759,5 @@ int probe_fd(int fd);
#define SHA256_DWORD_SIZE SHA256_DIGEST_LENGTH / sizeof(__u64)
void libbpf_sha256(const void *data, size_t len, __u8 out[SHA256_DIGEST_LENGTH]);
+int probe_sys_bpf_ext(void);
#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 1/8] bpf: Extend BPF syscall with common attributes support
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
In-Reply-To: <20260216150445.68278-1-leon.hwang@linux.dev>
Add generic BPF syscall support for passing common attributes.
The initial set of common attributes includes:
1. 'log_buf': User-provided buffer for storing logs.
2. 'log_size': Size of the log buffer.
3. 'log_level': Log verbosity level.
4. 'log_true_size': Actual log size reported by kernel.
The common-attribute pointer and its size are passed as the 4th and 5th
syscall arguments. A new command bit, 'BPF_COMMON_ATTRS' ('1 << 16'),
indicates that common attributes are supplied.
This commit adds syscall and uapi plumbing. Command-specific handling is
added in follow-up patches.
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
---
include/linux/syscalls.h | 3 ++-
include/uapi/linux/bpf.h | 8 ++++++++
kernel/bpf/syscall.c | 25 +++++++++++++++++++++----
tools/include/uapi/linux/bpf.h | 8 ++++++++
4 files changed, 39 insertions(+), 5 deletions(-)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 02bd6ddb6278..f4848c64872f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -936,7 +936,8 @@ asmlinkage long sys_seccomp(unsigned int op, unsigned int flags,
asmlinkage long sys_getrandom(char __user *buf, size_t count,
unsigned int flags);
asmlinkage long sys_memfd_create(const char __user *uname_ptr, unsigned int flags);
-asmlinkage long sys_bpf(int cmd, union bpf_attr __user *attr, unsigned int size);
+asmlinkage long sys_bpf(int cmd, union bpf_attr __user *attr, unsigned int size,
+ struct bpf_common_attr __user *attr_common, unsigned int size_common);
asmlinkage long sys_execveat(int dfd, const char __user *filename,
const char __user *const __user *argv,
const char __user *const __user *envp, int flags);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c8d400b7680a..b2126c9641ec 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -994,6 +994,7 @@ enum bpf_cmd {
BPF_PROG_STREAM_READ_BY_FD,
BPF_PROG_ASSOC_STRUCT_OPS,
__MAX_BPF_CMD,
+ BPF_COMMON_ATTRS = 1 << 16, /* Indicate carrying syscall common attrs. */
};
enum bpf_map_type {
@@ -1500,6 +1501,13 @@ struct bpf_stack_build_id {
};
};
+struct bpf_common_attr {
+ __u64 log_buf;
+ __u32 log_size;
+ __u32 log_level;
+ __u32 log_true_size;
+};
+
#define BPF_OBJ_NAME_LEN 16U
enum {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index dd89bf809772..e7ab87908189 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -6187,8 +6187,10 @@ static int prog_assoc_struct_ops(union bpf_attr *attr)
return ret;
}
-static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size)
+static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size,
+ bpfptr_t uattr_common, unsigned int size_common)
{
+ struct bpf_common_attr attr_common;
union bpf_attr attr;
int err;
@@ -6202,6 +6204,20 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size)
if (copy_from_bpfptr(&attr, uattr, size) != 0)
return -EFAULT;
+ memset(&attr_common, 0, sizeof(attr_common));
+ if (cmd & BPF_COMMON_ATTRS) {
+ err = bpf_check_uarg_tail_zero(uattr_common, sizeof(attr_common), size_common);
+ if (err)
+ return err;
+
+ cmd &= ~BPF_COMMON_ATTRS;
+ size_common = min_t(u32, size_common, sizeof(attr_common));
+ if (copy_from_bpfptr(&attr_common, uattr_common, size_common) != 0)
+ return -EFAULT;
+ } else {
+ size_common = 0;
+ }
+
err = security_bpf(cmd, &attr, size, uattr.is_kernel);
if (err < 0)
return err;
@@ -6337,9 +6353,10 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size)
return err;
}
-SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
+SYSCALL_DEFINE5(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size,
+ struct bpf_common_attr __user *, uattr_common, unsigned int, size_common)
{
- return __sys_bpf(cmd, USER_BPFPTR(uattr), size);
+ return __sys_bpf(cmd, USER_BPFPTR(uattr), size, USER_BPFPTR(uattr_common), size_common);
}
static bool syscall_prog_is_valid_access(int off, int size,
@@ -6370,7 +6387,7 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
default:
return -EINVAL;
}
- return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size);
+ return __sys_bpf(cmd, KERNEL_BPFPTR(attr), attr_size, KERNEL_BPFPTR(NULL), 0);
}
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 5e38b4887de6..c4934c2370fd 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -994,6 +994,7 @@ enum bpf_cmd {
BPF_PROG_STREAM_READ_BY_FD,
BPF_PROG_ASSOC_STRUCT_OPS,
__MAX_BPF_CMD,
+ BPF_COMMON_ATTRS = 1 << 16, /* Indicate carrying syscall common attrs. */
};
enum bpf_map_type {
@@ -1500,6 +1501,13 @@ struct bpf_stack_build_id {
};
};
+struct bpf_common_attr {
+ __u64 log_buf;
+ __u32 log_size;
+ __u32 log_level;
+ __u32 log_true_size;
+};
+
#define BPF_OBJ_NAME_LEN 16U
enum {
--
2.52.0
^ permalink raw reply related
* [PATCH bpf-next v11 0/8] bpf: Extend BPF syscall with common attributes support
From: Leon Hwang @ 2026-02-16 15:04 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, John Fastabend,
Andrii Nakryiko, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
Shuah Khan, Christian Brauner, Seth Forshee, Yuichiro Tsuji,
Andrey Albershteyn, Leon Hwang, Willem de Bruijn, Jason Xing,
Tao Chen, Mykyta Yatsenko, Kumar Kartikeya Dwivedi,
Anton Protopopov, Amery Hung, Rong Tao, linux-kernel, linux-api,
linux-kselftest, kernel-patches-bot
This patch series builds upon the discussion in
"[PATCH bpf-next v4 0/4] bpf: Improve error reporting for freplace attachment failure" [1].
This patch series introduces support for *common attributes* in the BPF
syscall, providing a unified mechanism for passing shared metadata across
all BPF commands, initially used by BPF_PROG_LOAD, BPF_BTF_LOAD, and
BPF_MAP_CREATE.
The initial set of common attributes includes:
1. 'log_buf': User-provided buffer for storing log output.
2. 'log_size': Size of the provided log buffer.
3. 'log_level': Verbosity level for logging.
4. 'log_true_size': Actual log size reported by kernel.
With this extension, the BPF syscall will be able to return meaningful
error messages (e.g., map creation failures), improving debuggability
and user experience.
Links:
[1] https://lore.kernel.org/bpf/20250224153352.64689-1-leon.hwang@linux.dev/
Changes:
v10 -> v11:
* Collect Acked-by from Andrii, thanks.
* Validate whether log_buf, log_size, and log_level are valid by reusing
bpf_verifier_log_attr_valid() in patch #4 (per Andrii).
* v10: https://lore.kernel.org/bpf/20260211151115.78013-1-leon.hwang@linux.dev/
v9 -> v10:
* Collect Acked-by from Andrii, thanks.
* Address comments from Andrii:
* Drop log NULL check in bpf_log_attr_finalize().
* Return -EFAULT early in bpf_log_attr_finalize().
* Validate whether log_buf, log_size, and log_level are set.
* Keep log_buf, log_size, log_level, and user-pointer log_true_size in struct
bpf_log_attr.
* Make prog_load and btf_load work with the new struct bpf_log_attr.
* Add comment to log_true_size of struct bpf_log_opts in libbpf.
* Address comment from Alexei:
* Avoid using BPF_LOG_FIXED as log_level in tests.
* v9: https://lore.kernel.org/bpf/20260202144046.30651-1-leon.hwang@linux.dev/
v8 -> v9:
* Rework reporting 'log_true_size' for prog_load, btf_load, and map_create to
simplify struct bpf_log_attr (per Alexei).
* v8: https://lore.kernel.org/bpf/20260126151409.52072-1-leon.hwang@linux.dev/
v7 -> v8:
* Return 0 when fd < 0 and errno != EFAULT in probe_sys_bpf_ext(), then simplify
probe_bpf_syscall_common_attrs() (per Alexei and Andrii).
* v7: https://lore.kernel.org/bpf/20260123032445.125259-1-leon.hwang@linux.dev/
v6 -> v7:
* Return -errno when fd < 0 and errno != EFAULT in probe_sys_bpf_ext().
* Convert return value of probe_sys_bpf_ext() to bool in
probe_bpf_syscall_common_attrs().
* Address comments from Andrii:
* Drop the comment, and handle fd >= 0 case explicitly in
probe_sys_bpf_ext().
* Return an error when fd >= 0 in probe_sys_bpf_ext().
* v6: https://lore.kernel.org/bpf/20260120152424.40766-1-leon.hwang@linux.dev/
v5 -> v6:
* Address comments from Andrii:
* Update some variables' name.
* Drop unnecessary 'close(fd)' in libbpf.
* Rename FEAT_EXTENDED_SYSCALL to FEAT_BPF_SYSCALL_COMMON_ATTRS with
updated description in libbpf.
* Use EINVAL instead of EUSERS, as EUSERS is not used in bpf yet.
* Rename struct bpf_syscall_common_attr_opts to bpf_log_opts in libbpf.
* Add 'OPTS_SET(log_opts, log_true_size, 0);' in libbpf's 'bpf_map_create()'.
* v5: https://lore.kernel.org/bpf/20260112145616.44195-1-leon.hwang@linux.dev/
v4 -> v5:
* Rework reporting 'log_true_size' for prog_load, btf_load, and map_create
(per Alexei).
* v4: https://lore.kernel.org/bpf/20260106172018.57757-1-leon.hwang@linux.dev/
RFC v3 -> v4:
* Drop RFC.
* Address comments from Andrii:
* Add parentheses in 'sys_bpf_ext()'.
* Avoid creating new fd in 'probe_sys_bpf_ext()'.
* Add a new struct to wrap log fields in libbpf.
* Address comments from Alexei:
* Do not skip writing to user space when log_true_size is zero.
* Do not use 'bool' arguments.
* Drop the adding WARN_ON_ONCE()'s.
* v3: https://lore.kernel.org/bpf/20251002154841.99348-1-leon.hwang@linux.dev/
RFC v2 -> RFC v3:
* Rename probe_sys_bpf_extended to probe_sys_bpf_ext.
* Refactor reporting 'log_true_size' for prog_load.
* Refactor reporting 'btf_log_true_size' for btf_load.
* Add warnings for internal bugs in map_create.
* Check log_true_size in test cases.
* Address comment from Alexei:
* Change kvzalloc/kvfree to kzalloc/kfree.
* Address comments from Andrii:
* Move BPF_COMMON_ATTRS to 'enum bpf_cmd' alongside brief comment.
* Add bpf_check_uarg_tail_zero() for extra checks.
* Rename sys_bpf_extended to sys_bpf_ext.
* Rename sys_bpf_fd_extended to sys_bpf_ext_fd.
* Probe the new feature using NULL and -EFAULT.
* Move probe_sys_bpf_ext to libbpf_internal.h and drop LIBBPF_API.
* Return -EUSERS when log attrs are conflict between bpf_attr and
bpf_common_attr.
* Avoid touching bpf_vlog_init().
* Update the reason messages in map_create.
* Finalize the log using __cleanup().
* Report log size to users.
* Change type of log_buf from '__u64' to 'const char *' and cast type
using ptr_to_u64() in bpf_map_create().
* Do not return -EOPNOTSUPP when kernel doesn't support this feature
in bpf_map_create().
* Add log_level support for map creation for consistency.
* Address comment from Eduard:
* Use common_attrs->log_level instead of BPF_LOG_FIXED.
* v2: https://lore.kernel.org/bpf/20250911163328.93490-1-leon.hwang@linux.dev/
RFC v1 -> RFC v2:
* Fix build error reported by test bot.
* Address comments from Alexei:
* Drop new uapi for freplace.
* Add common attributes support for prog_load and btf_load.
* Add common attributes support for map_create.
* v1: https://lore.kernel.org/bpf/20250728142346.95681-1-leon.hwang@linux.dev/
Leon Hwang (8):
bpf: Extend BPF syscall with common attributes support
libbpf: Add support for extended BPF syscall
bpf: Refactor reporting log_true_size for prog_load
bpf: Add syscall common attributes support for prog_load
bpf: Add syscall common attributes support for btf_load
bpf: Add syscall common attributes support for map_create
libbpf: Add syscall common attributes support for map_create
selftests/bpf: Add tests to verify map create failure log
include/linux/bpf.h | 4 +-
include/linux/bpf_verifier.h | 15 ++
include/linux/btf.h | 3 +-
include/linux/syscalls.h | 3 +-
include/uapi/linux/bpf.h | 8 +
kernel/bpf/btf.c | 30 +---
kernel/bpf/log.c | 89 +++++++++-
kernel/bpf/syscall.c | 114 +++++++++---
kernel/bpf/verifier.c | 17 +-
tools/include/uapi/linux/bpf.h | 8 +
tools/lib/bpf/bpf.c | 52 +++++-
tools/lib/bpf/bpf.h | 17 +-
tools/lib/bpf/features.c | 8 +
tools/lib/bpf/libbpf_internal.h | 3 +
.../selftests/bpf/prog_tests/map_init.c | 166 ++++++++++++++++++
15 files changed, 470 insertions(+), 67 deletions(-)
--
2.52.0
^ permalink raw reply
* Re: [PATCH v3 3/3] selftests: pidfd: add tests for PIDFD_SELF_*
From: Peter Zijlstra @ 2026-02-13 11:02 UTC (permalink / raw)
To: John Hubbard
Cc: Lorenzo Stoakes, Shuah Khan, Christian Brauner, Shuah Khan,
Liam R . Howlett, Suren Baghdasaryan, Vlastimil Babka,
pedro.falcato, linux-kselftest, linux-mm, linux-fsdevel,
linux-api, linux-kernel, Oliver Sang, seanjc
In-Reply-To: <20250501124646.GC4356@noisy.programming.kicks-ass.net>
On Thu, May 01, 2025 at 02:46:46PM +0200, Peter Zijlstra wrote:
> On Thu, May 01, 2025 at 01:42:35PM +0200, Peter Zijlstra wrote:
> > On Wed, Oct 16, 2024 at 07:14:34PM -0700, John Hubbard wrote:
> > > On 10/16/24 3:06 PM, Lorenzo Stoakes wrote:
> > > > On Wed, Oct 16, 2024 at 02:00:27PM -0600, Shuah Khan wrote:
> > > > > On 10/16/24 04:20, Lorenzo Stoakes wrote:
> > > ...
> > > > > > diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
> > > > > > index 88d6830ee004..1640b711889b 100644
> > > > > > --- a/tools/testing/selftests/pidfd/pidfd.h
> > > > > > +++ b/tools/testing/selftests/pidfd/pidfd.h
> > > > > > @@ -50,6 +50,14 @@
> > > > > > #define PIDFD_NONBLOCK O_NONBLOCK
> > > > > > #endif
> > > > > > +/* System header file may not have this available. */
> > > > > > +#ifndef PIDFD_SELF_THREAD
> > > > > > +#define PIDFD_SELF_THREAD -100
> > > > > > +#endif
> > > > > > +#ifndef PIDFD_SELF_THREAD_GROUP
> > > > > > +#define PIDFD_SELF_THREAD_GROUP -200
> > > > > > +#endif
> > > > > > +
> > > > >
> > > > > As mentioned in my response to v1 patch:
> > > > >
> > > > > kselftest has dependency on "make headers" and tests include
> > > > > headers from linux/ directory
> > > >
> > > > Right but that assumes you install the kernel headers on the build system,
> > > > which is quite a painful thing to have to do when you are quickly iterating
> > > > on a qemu setup.
> > > >
> > > > This is a use case I use all the time so not at all theoretical.
> > > >
> > >
> > > This is turning out to be a fairly typical reaction from kernel
> > > developers, when presented with the "you must first run make headers"
> > > requirement for kselftests.
> > >
> > > Peter Zijlstra's "NAK NAK NAK" response [1] last year was the most
> > > colorful, so I'll helpfully cite it here. :)
> >
> > Let me re-try this.
> >
> > This is driving me insane. I've spend the past _TWO_ days trying to
> > build KVM selftests and I'm still failing.
> >
> > This is absolute atrocious crap and is costing me valuable time.
> >
> > Please fix this fucking selftests shit to just build. This is unusable
> > garbage.
>
> So after spending more time trying to remember how to debug Makefiles (I
> hate my life), I found that not only do I need this headers shit, the
> kvm selftests Makefile is actively broken if you use: make O=foo
>
> -INSTALL_HDR_PATH = $(top_srcdir)/usr
> +INSTALL_HDR_PATH = $(top_srcdir)/$(O)/usr
>
>
> And then finally, I can do:
>
> make O=foo headers_install
> make O=foo -C tools/testing/selftests/kvm/
>
> So yeah, thank you very much for wasting my time *AGAIN*.
And *AGAIN*.. this is still the state of things. Selftests are still
hopelessly broken and useless.
Maybe we should just delete the lot?
^ permalink raw reply
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