From 66c62769bcf6aa142e2309278980a2e52f4b08db Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Mon, 23 Oct 2023 21:07:58 +0300 Subject: [PATCH] exportfs: add helpers to check if filesystem can encode/decode file handles The logic of whether filesystem can encode/decode file handles is open coded in many places. In preparation to changing the logic, move the open coded logic into inline helpers. Reviewed-by: Jan Kara Reviewed-by: Jeff Layton Signed-off-by: Amir Goldstein Link: https://lore.kernel.org/r/20231023180801.2953446-2-amir73il@gmail.com Signed-off-by: Christian Brauner --- fs/exportfs/expfs.c | 8 ++------ fs/fhandle.c | 6 +----- fs/nfsd/export.c | 3 +-- fs/notify/fanotify/fanotify_user.c | 4 ++-- fs/overlayfs/util.c | 2 +- include/linux/exportfs.h | 27 +++++++++++++++++++++++++++ 6 files changed, 34 insertions(+), 16 deletions(-) diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c index c20704aa21b3d..9ee205df8fa76 100644 --- a/fs/exportfs/expfs.c +++ b/fs/exportfs/expfs.c @@ -396,11 +396,7 @@ int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, { const struct export_operations *nop = inode->i_sb->s_export_op; - /* - * If a decodeable file handle was requested, we need to make sure that - * filesystem can decode file handles. - */ - if (nop && !(flags & EXPORT_FH_FID) && !nop->fh_to_dentry) + if (!exportfs_can_encode_fh(nop, flags)) return -EOPNOTSUPP; if (nop && nop->encode_fh) @@ -456,7 +452,7 @@ exportfs_decode_fh_raw(struct vfsmount *mnt, struct fid *fid, int fh_len, /* * Try to get any dentry for the given file handle from the filesystem. */ - if (!nop || !nop->fh_to_dentry) + if (!exportfs_can_decode_fh(nop)) return ERR_PTR(-ESTALE); result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type); if (IS_ERR_OR_NULL(result)) diff --git a/fs/fhandle.c b/fs/fhandle.c index 6ea8d35a9382a..18b3ba8dc8ead 100644 --- a/fs/fhandle.c +++ b/fs/fhandle.c @@ -26,12 +26,8 @@ static long do_sys_name_to_handle(const struct path *path, /* * We need to make sure whether the file system support decoding of * the file handle if decodeable file handle was requested. - * Otherwise, even empty export_operations are sufficient to opt-in - * to encoding FIDs. */ - if (!path->dentry->d_sb->s_export_op || - (!(fh_flags & EXPORT_FH_FID) && - !path->dentry->d_sb->s_export_op->fh_to_dentry)) + if (!exportfs_can_encode_fh(path->dentry->d_sb->s_export_op, fh_flags)) return -EOPNOTSUPP; if (copy_from_user(&f_handle, ufh, sizeof(struct file_handle))) diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index 11a0eaa2f9140..dc99dfc1d4115 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -421,8 +421,7 @@ static int check_export(struct path *path, int *flags, unsigned char *uuid) return -EINVAL; } - if (!inode->i_sb->s_export_op || - !inode->i_sb->s_export_op->fh_to_dentry) { + if (!exportfs_can_decode_fh(inode->i_sb->s_export_op)) { dprintk("exp_export: export of invalid fs type.\n"); return -EINVAL; } diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 62fe0b679e586..0eb9622e8a9f6 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1595,7 +1595,7 @@ static int fanotify_test_fid(struct dentry *dentry, unsigned int flags) * file handles so user can use name_to_handle_at() to compare fids * reported with events to the file handle of watched objects. */ - if (!nop) + if (!exportfs_can_encode_fid(nop)) return -EOPNOTSUPP; /* @@ -1603,7 +1603,7 @@ static int fanotify_test_fid(struct dentry *dentry, unsigned int flags) * supports decoding file handles, so user has a way to map back the * reported fids to filesystem objects. */ - if (mark_type != FAN_MARK_INODE && !nop->fh_to_dentry) + if (mark_type != FAN_MARK_INODE && !exportfs_can_decode_fh(nop)) return -EOPNOTSUPP; return 0; diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index 89e0d60d35b6c..f0a712214ec22 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -55,7 +55,7 @@ int ovl_can_decode_fh(struct super_block *sb) if (!capable(CAP_DAC_READ_SEARCH)) return 0; - if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry) + if (!exportfs_can_decode_fh(sb->s_export_op)) return 0; return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN; diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h index 11fbd0ee13708..5b3c9f30b422a 100644 --- a/include/linux/exportfs.h +++ b/include/linux/exportfs.h @@ -233,6 +233,33 @@ extern int exportfs_encode_inode_fh(struct inode *inode, struct fid *fid, extern int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len, int flags); +static inline bool exportfs_can_encode_fid(const struct export_operations *nop) +{ + return nop; +} + +static inline bool exportfs_can_decode_fh(const struct export_operations *nop) +{ + return nop && nop->fh_to_dentry; +} + +static inline bool exportfs_can_encode_fh(const struct export_operations *nop, + int fh_flags) +{ + /* + * If a non-decodeable file handle was requested, we only need to make + * sure that filesystem can encode file handles. + */ + if (fh_flags & EXPORT_FH_FID) + return exportfs_can_encode_fid(nop); + + /* + * If a decodeable file handle was requested, we need to make sure that + * filesystem can also decode file handles. + */ + return exportfs_can_decode_fh(nop); +} + static inline int exportfs_encode_fid(struct inode *inode, struct fid *fid, int *max_len) { -- 2.39.2