From: Chuck Lever Date: Thu, 7 May 2026 08:53:03 +0000 (-0400) Subject: nfs: Implement fileattr_get for case sensitivity X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=92d67628a1a91c0585e004ffce8975c7898f9ed1;p=thirdparty%2Fkernel%2Flinux.git nfs: Implement fileattr_get for case sensitivity An NFS server re-exporting an NFS mount point needs to report the case sensitivity behavior of the underlying filesystem to its clients. NFSD's attribute encoder obtains that information by calling vfs_fileattr_get() on the lower filesystem, so the NFS client must implement fileattr_get to surface what it learned from its own server. 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. PATHCONF is now invoked unconditionally for NFSv2 and NFSv3 mounts so the case-sensitivity capabilities are established even when the user pins server->namelen with the namlen= mount option. That option is orthogonal to case handling, and skipping PATHCONF because namelen was already known would leave the caps unset. The two capability bits carry opposite polarity because their POSIX defaults differ. Most servers are case-sensitive and case- preserving, matching "neither xflag set." NFS_CAP_CASE_INSENSITIVE is set only when the server affirms case insensitivity, so "server said no" and "server did not answer" both collapse to the case- sensitive default. NFS_CAP_CASE_NONPRESERVING follows the same pattern in the opposite direction: set only when the server affirms that it does not preserve case, so that silence or a missing attribute lands on the case-preserving default. The NFSv4 probe checks res.attr_bitmask[0] to distinguish "server said false" from "server omitted the attribute" before setting the bit. Both capability bits are cleared before each probe so a remount, an NFSv4 transparent state migration to a server with different case semantics, or a probe whose reply does not arrive does not retain stale capabilities from the prior probe. Reviewed-by: Roland Mainz Signed-off-by: Chuck Lever Link: https://patch.msgid.link/20260507-case-sensitivity-v14-10-e62cc8200435@oracle.com Signed-off-by: Christian Brauner --- diff --git a/fs/nfs/client.c b/fs/nfs/client.c index be02bb227741d..3db2f18315b87 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -914,6 +914,7 @@ static void nfs_server_set_fsinfo(struct nfs_server *server, */ static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, struct nfs_fattr *fattr) { + struct nfs_pathconf pathinfo = { }; struct nfs_fsinfo fsinfo; struct nfs_client *clp = server->nfs_client; int error; @@ -933,15 +934,23 @@ static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, str nfs_server_set_fsinfo(server, &fsinfo); - /* Get some general file system info */ - if (server->namelen == 0) { - struct nfs_pathconf pathinfo; + pathinfo.fattr = fattr; + nfs_fattr_init(fattr); - pathinfo.fattr = fattr; - nfs_fattr_init(fattr); + /* Clear before probing so a failed RPC does not retain stale bits. */ + if (clp->rpc_ops->version < 4) + server->caps &= ~(NFS_CAP_CASE_INSENSITIVE | + NFS_CAP_CASE_NONPRESERVING); - if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0) + if (clp->rpc_ops->pathconf(server, mntfh, &pathinfo) >= 0) { + if (server->namelen == 0) server->namelen = pathinfo.max_namelen; + if (clp->rpc_ops->version < 4) { + if (pathinfo.case_insensitive) + server->caps |= NFS_CAP_CASE_INSENSITIVE; + if (!pathinfo.case_preserving) + server->caps |= NFS_CAP_CASE_NONPRESERVING; + } } if (clp->rpc_ops->discover_trunking != NULL && diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index e26030e736966..170d32c217ae4 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -41,6 +41,7 @@ #include #include #include +#include #include "nfs4_fs.h" #include "callback.h" @@ -1095,6 +1096,20 @@ out: } EXPORT_SYMBOL_GPL(nfs_getattr); +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; + fa->flags |= FS_CASEFOLD_FL; + } + if (nfs_server_capable(inode, NFS_CAP_CASE_NONPRESERVING)) + 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 18d46b0e71ddc..ec2b3d9843989 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -451,6 +451,9 @@ 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/namespace.c b/fs/nfs/namespace.c index af9be0c5f5163..6d0073c24771b 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -246,11 +246,13 @@ nfs_namespace_setattr(struct mnt_idmap *idmap, struct dentry *dentry, const struct inode_operations nfs_mountpoint_inode_operations = { .getattr = nfs_getattr, .setattr = nfs_setattr, + .fileattr_get = nfs_fileattr_get, }; const struct inode_operations nfs_referral_inode_operations = { .getattr = nfs_namespace_getattr, .setattr = nfs_namespace_setattr, + .fileattr_get = nfs_fileattr_get, }; static void nfs_expire_automounts(struct work_struct *work) diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c index 95d7cd564b746..b80d0c5efc279 100644 --- a/fs/nfs/nfs3proc.c +++ b/fs/nfs/nfs3proc.c @@ -1053,6 +1053,7 @@ 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, @@ -1064,6 +1065,7 @@ 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 e17d729084125..e745e78faab0a 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 a9b8d482d2894..0715a6745d1fa 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3933,7 +3933,8 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f server->caps &= ~(NFS_CAP_ACLS | NFS_CAP_HARDLINKS | NFS_CAP_SYMLINKS | NFS_CAP_SECURITY_LABEL | NFS_CAP_FS_LOCATIONS | - NFS_CAP_OPEN_XOR | NFS_CAP_DELEGTIME); + NFS_CAP_OPEN_XOR | NFS_CAP_DELEGTIME | + NFS_CAP_CASE_INSENSITIVE | NFS_CAP_CASE_NONPRESERVING); server->fattr_valid = NFS_ATTR_FATTR_V4; if (res.attr_bitmask[0] & FATTR4_WORD0_ACL && res.acl_bitmask & ACL4_SUPPORT_ALLOW_ACL) @@ -3944,8 +3945,9 @@ static int _nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *f server->caps |= NFS_CAP_SYMLINKS; if (res.case_insensitive) server->caps |= NFS_CAP_CASE_INSENSITIVE; - if (res.case_preserving) - server->caps |= NFS_CAP_CASE_PRESERVING; + if ((res.attr_bitmask[0] & FATTR4_WORD0_CASE_PRESERVING) && + !res.case_preserving) + server->caps |= NFS_CAP_CASE_NONPRESERVING; #ifdef CONFIG_NFS_V4_SECURITY_LABEL if (res.attr_bitmask[2] & FATTR4_WORD2_SECURITY_LABEL) server->caps |= NFS_CAP_SECURITY_LABEL; @@ -10617,6 +10619,7 @@ 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 = { @@ -10624,6 +10627,7 @@ 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 70795684b8e84..03c2c1f31be9a 100644 --- a/fs/nfs/proc.c +++ b/fs/nfs/proc.c @@ -598,6 +598,7 @@ 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; } @@ -718,12 +719,14 @@ 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 58146e9354020..74a072896f8d9 100644 --- a/fs/nfs/symlink.c +++ b/fs/nfs/symlink.c @@ -22,6 +22,8 @@ #include #include +#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_fs_sb.h b/include/linux/nfs_fs_sb.h index 4daee27fa5eb4..34d294774f8ce 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -306,7 +306,7 @@ struct nfs_server { #define NFS_CAP_ATOMIC_OPEN (1U << 4) #define NFS_CAP_LGOPEN (1U << 5) #define NFS_CAP_CASE_INSENSITIVE (1U << 6) -#define NFS_CAP_CASE_PRESERVING (1U << 7) +#define NFS_CAP_CASE_NONPRESERVING (1U << 7) #define NFS_CAP_REBOOT_LAYOUTRETURN (1U << 8) #define NFS_CAP_OFFLOAD_STATUS (1U << 9) #define NFS_CAP_ZERO_RANGE (1U << 10) diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h index fcbd21b5685f4..83ee991cde2be 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 {