From: NeilBrown start_renaming() combines name lookup and locking to prepare for rename. It is used when two names need to be looked up as in nfsd and overlayfs - cases where one or both dentries are already available will be handled separately. __start_renaming() avoids the inode_permission check and hash calculation and is suitable after filename_parentat() in do_renameat2(). It subsumes quite a bit of code from that function. start_renaming() does calculate the hash and check X permission and is suitable elsewhere: - nfsd_rename() - ovl_rename() In ovl, ovl_do_rename_rd() is factored out of ovl_do_rename(), which itself will be gone by the end of the series. Acked-by: Chuck Lever (for nfsd parts) Reviewed-by: Jeff Layton Reviewed-by: Amir Goldstein Signed-off-by: NeilBrown -- Changes since v3: - added missig dput() in ovl_rename when "whiteout" is not-NULL. Changes since v2: - in __start_renaming() some label have been renamed, and err is always set before a "goto out_foo" rather than passing the error in a dentry*. - ovl_do_rename() changed to call the new ovl_do_rename_rd() rather than keeping duplicate code - code around ovl_cleanup() call in ovl_rename() restructured. --- fs/namei.c | 197 ++++++++++++++++++++++++++++----------- fs/nfsd/vfs.c | 73 +++++---------- fs/overlayfs/dir.c | 74 +++++++-------- fs/overlayfs/overlayfs.h | 23 +++-- include/linux/namei.h | 3 + 5 files changed, 218 insertions(+), 152 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index e70d056b9543..bad6c9d540f9 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3667,6 +3667,129 @@ void unlock_rename(struct dentry *p1, struct dentry *p2) } EXPORT_SYMBOL(unlock_rename); +/** + * __start_renaming - lookup and lock names for rename + * @rd: rename data containing parent and flags, and + * for receiving found dentries + * @lookup_flags: extra flags to pass to ->lookup (e.g. LOOKUP_REVAL, + * LOOKUP_NO_SYMLINKS etc). + * @old_last: name of object in @rd.old_parent + * @new_last: name of object in @rd.new_parent + * + * Look up two names and ensure locks are in place for + * rename. + * + * On success the found dentries are stored in @rd.old_dentry, + * @rd.new_dentry. These references and the lock are dropped by + * end_renaming(). + * + * The passed in qstrs must have the hash calculated, and no permission + * checking is performed. + * + * Returns: zero or an error. + */ +static int +__start_renaming(struct renamedata *rd, int lookup_flags, + struct qstr *old_last, struct qstr *new_last) +{ + struct dentry *trap; + struct dentry *d1, *d2; + int target_flags = LOOKUP_RENAME_TARGET | LOOKUP_CREATE; + int err; + + if (rd->flags & RENAME_EXCHANGE) + target_flags = 0; + if (rd->flags & RENAME_NOREPLACE) + target_flags |= LOOKUP_EXCL; + + trap = lock_rename(rd->old_parent, rd->new_parent); + if (IS_ERR(trap)) + return PTR_ERR(trap); + + d1 = lookup_one_qstr_excl(old_last, rd->old_parent, + lookup_flags); + err = PTR_ERR(d1); + if (IS_ERR(d1)) + goto out_unlock; + + d2 = lookup_one_qstr_excl(new_last, rd->new_parent, + lookup_flags | target_flags); + err = PTR_ERR(d2); + if (IS_ERR(d2)) + goto out_dput_d1; + + if (d1 == trap) { + /* source is an ancestor of target */ + err = -EINVAL; + goto out_dput_d2; + } + + if (d2 == trap) { + /* target is an ancestor of source */ + if (rd->flags & RENAME_EXCHANGE) + err = -EINVAL; + else + err = -ENOTEMPTY; + goto out_dput_d2; + } + + rd->old_dentry = d1; + rd->new_dentry = d2; + return 0; + +out_dput_d2: + dput(d2); +out_dput_d1: + dput(d1); +out_unlock: + unlock_rename(rd->old_parent, rd->new_parent); + return err; +} + +/** + * start_renaming - lookup and lock names for rename with permission checking + * @rd: rename data containing parent and flags, and + * for receiving found dentries + * @lookup_flags: extra flags to pass to ->lookup (e.g. LOOKUP_REVAL, + * LOOKUP_NO_SYMLINKS etc). + * @old_last: name of object in @rd.old_parent + * @new_last: name of object in @rd.new_parent + * + * Look up two names and ensure locks are in place for + * rename. + * + * On success the found dentries are stored in @rd.old_dentry, + * @rd.new_dentry. These references and the lock are dropped by + * end_renaming(). + * + * The passed in qstrs need not have the hash calculated, and basic + * eXecute permission checking is performed against @rd.mnt_idmap. + * + * Returns: zero or an error. + */ +int start_renaming(struct renamedata *rd, int lookup_flags, + struct qstr *old_last, struct qstr *new_last) +{ + int err; + + err = lookup_one_common(rd->mnt_idmap, old_last, rd->old_parent); + if (err) + return err; + err = lookup_one_common(rd->mnt_idmap, new_last, rd->new_parent); + if (err) + return err; + return __start_renaming(rd, lookup_flags, old_last, new_last); +} +EXPORT_SYMBOL(start_renaming); + +void end_renaming(struct renamedata *rd) +{ + unlock_rename(rd->old_parent, rd->new_parent); + dput(rd->old_dentry); + dput(rd->new_dentry); +} +EXPORT_SYMBOL(end_renaming); + /** * vfs_prepare_mode - prepare the mode to be used for a new inode * @idmap: idmap of the mount the inode was found from @@ -5504,14 +5627,11 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd, struct filename *to, unsigned int flags) { struct renamedata rd; - struct dentry *old_dentry, *new_dentry; - struct dentry *trap; struct path old_path, new_path; struct qstr old_last, new_last; int old_type, new_type; struct inode *delegated_inode = NULL; - unsigned int lookup_flags = 0, target_flags = - LOOKUP_RENAME_TARGET | LOOKUP_CREATE; + unsigned int lookup_flags = 0; bool should_retry = false; int error = -EINVAL; @@ -5522,11 +5642,6 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd, (flags & RENAME_EXCHANGE)) goto put_names; - if (flags & RENAME_EXCHANGE) - target_flags = 0; - if (flags & RENAME_NOREPLACE) - target_flags |= LOOKUP_EXCL; - retry: error = filename_parentat(olddfd, from, lookup_flags, &old_path, &old_last, &old_type); @@ -5556,66 +5671,40 @@ int do_renameat2(int olddfd, struct filename *from, int newdfd, goto exit2; retry_deleg: - trap = lock_rename(new_path.dentry, old_path.dentry); - if (IS_ERR(trap)) { - error = PTR_ERR(trap); + rd.old_parent = old_path.dentry; + rd.mnt_idmap = mnt_idmap(old_path.mnt); + rd.new_parent = new_path.dentry; + rd.delegated_inode = &delegated_inode; + rd.flags = flags; + + error = __start_renaming(&rd, lookup_flags, &old_last, &new_last); + if (error) goto exit_lock_rename; - } - old_dentry = lookup_one_qstr_excl(&old_last, old_path.dentry, - lookup_flags); - error = PTR_ERR(old_dentry); - if (IS_ERR(old_dentry)) - goto exit3; - new_dentry = lookup_one_qstr_excl(&new_last, new_path.dentry, - lookup_flags | target_flags); - error = PTR_ERR(new_dentry); - if (IS_ERR(new_dentry)) - goto exit4; if (flags & RENAME_EXCHANGE) { - if (!d_is_dir(new_dentry)) { + if (!d_is_dir(rd.new_dentry)) { error = -ENOTDIR; if (new_last.name[new_last.len]) - goto exit5; + goto exit_unlock; } } /* unless the source is a directory trailing slashes give -ENOTDIR */ - if (!d_is_dir(old_dentry)) { + if (!d_is_dir(rd.old_dentry)) { error = -ENOTDIR; if (old_last.name[old_last.len]) - goto exit5; + goto exit_unlock; if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len]) - goto exit5; - } - /* source should not be ancestor of target */ - error = -EINVAL; - if (old_dentry == trap) - goto exit5; - /* target should not be an ancestor of source */ - if (!(flags & RENAME_EXCHANGE)) - error = -ENOTEMPTY; - if (new_dentry == trap) - goto exit5; + goto exit_unlock; + } - error = security_path_rename(&old_path, old_dentry, - &new_path, new_dentry, flags); + error = security_path_rename(&old_path, rd.old_dentry, + &new_path, rd.new_dentry, flags); if (error) - goto exit5; + goto exit_unlock; - rd.old_parent = old_path.dentry; - rd.old_dentry = old_dentry; - rd.mnt_idmap = mnt_idmap(old_path.mnt); - rd.new_parent = new_path.dentry; - rd.new_dentry = new_dentry; - rd.delegated_inode = &delegated_inode; - rd.flags = flags; error = vfs_rename(&rd); -exit5: - dput(new_dentry); -exit4: - dput(old_dentry); -exit3: - unlock_rename(new_path.dentry, old_path.dentry); +exit_unlock: + end_renaming(&rd); exit_lock_rename: if (delegated_inode) { error = break_deleg_wait(&delegated_inode); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 6291c371caa7..a993f1e54182 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1885,11 +1885,12 @@ __be32 nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, struct svc_fh *tfhp, char *tname, int tlen) { - struct dentry *fdentry, *tdentry, *odentry, *ndentry, *trap; + struct dentry *fdentry, *tdentry; int type = S_IFDIR; + struct renamedata rd = {}; __be32 err; int host_err; - bool close_cached = false; + struct dentry *close_cached; trace_nfsd_vfs_rename(rqstp, ffhp, tfhp, fname, flen, tname, tlen); @@ -1915,15 +1916,22 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, goto out; retry: + close_cached = NULL; host_err = fh_want_write(ffhp); if (host_err) { err = nfserrno(host_err); goto out; } - trap = lock_rename(tdentry, fdentry); - if (IS_ERR(trap)) { - err = nfserr_xdev; + rd.mnt_idmap = &nop_mnt_idmap; + rd.old_parent = fdentry; + rd.new_parent = tdentry; + + host_err = start_renaming(&rd, 0, &QSTR_LEN(fname, flen), + &QSTR_LEN(tname, tlen)); + + if (host_err) { + err = nfserrno(host_err); goto out_want_write; } err = fh_fill_pre_attrs(ffhp); @@ -1933,48 +1941,23 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (err != nfs_ok) goto out_unlock; - odentry = lookup_one(&nop_mnt_idmap, &QSTR_LEN(fname, flen), fdentry); - host_err = PTR_ERR(odentry); - if (IS_ERR(odentry)) - goto out_nfserr; + type = d_inode(rd.old_dentry)->i_mode & S_IFMT; + + if (d_inode(rd.new_dentry)) + type = d_inode(rd.new_dentry)->i_mode & S_IFMT; - host_err = -ENOENT; - if (d_really_is_negative(odentry)) - goto out_dput_old; - host_err = -EINVAL; - if (odentry == trap) - goto out_dput_old; - type = d_inode(odentry)->i_mode & S_IFMT; - - ndentry = lookup_one(&nop_mnt_idmap, &QSTR_LEN(tname, tlen), tdentry); - host_err = PTR_ERR(ndentry); - if (IS_ERR(ndentry)) - goto out_dput_old; - if (d_inode(ndentry)) - type = d_inode(ndentry)->i_mode & S_IFMT; - host_err = -ENOTEMPTY; - if (ndentry == trap) - goto out_dput_new; - - if ((ndentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) && - nfsd_has_cached_files(ndentry)) { - close_cached = true; - goto out_dput_old; + if ((rd.new_dentry->d_sb->s_export_op->flags & EXPORT_OP_CLOSE_BEFORE_UNLINK) && + nfsd_has_cached_files(rd.new_dentry)) { + close_cached = dget(rd.new_dentry); + goto out_unlock; } else { - struct renamedata rd = { - .mnt_idmap = &nop_mnt_idmap, - .old_parent = fdentry, - .old_dentry = odentry, - .new_parent = tdentry, - .new_dentry = ndentry, - }; int retries; for (retries = 1;;) { host_err = vfs_rename(&rd); if (host_err != -EAGAIN || !retries--) break; - if (!nfsd_wait_for_delegreturn(rqstp, d_inode(odentry))) + if (!nfsd_wait_for_delegreturn(rqstp, d_inode(rd.old_dentry))) break; } if (!host_err) { @@ -1983,11 +1966,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, host_err = commit_metadata(ffhp); } } - out_dput_new: - dput(ndentry); - out_dput_old: - dput(odentry); - out_nfserr: if (host_err == -EBUSY) { /* * See RFC 8881 Section 18.26.4 para 1-3: NFSv4 RENAME @@ -2006,7 +1984,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, fh_fill_post_attrs(tfhp); } out_unlock: - unlock_rename(tdentry, fdentry); + end_renaming(&rd); out_want_write: fh_drop_write(ffhp); @@ -2017,9 +1995,8 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, * until this point and then reattempt the whole shebang. */ if (close_cached) { - close_cached = false; - nfsd_close_cached_files(ndentry); - dput(ndentry); + nfsd_close_cached_files(close_cached); + dput(close_cached); goto retry; } out: diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 6d1d0e94e287..cf6fc48459f3 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -1124,9 +1124,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, int err; struct dentry *old_upperdir; struct dentry *new_upperdir; - struct dentry *olddentry = NULL; - struct dentry *newdentry = NULL; - struct dentry *trap, *de; + struct renamedata rd = {}; bool old_opaque; bool new_opaque; bool cleanup_whiteout = false; @@ -1136,6 +1134,7 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, bool new_is_dir = d_is_dir(new); bool samedir = olddir == newdir; struct dentry *opaquedir = NULL; + struct dentry *whiteout = NULL; const struct cred *old_cred = NULL; struct ovl_fs *ofs = OVL_FS(old->d_sb); LIST_HEAD(list); @@ -1233,29 +1232,21 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, } } - trap = lock_rename(new_upperdir, old_upperdir); - if (IS_ERR(trap)) { - err = PTR_ERR(trap); - goto out_revert_creds; - } + rd.mnt_idmap = ovl_upper_mnt_idmap(ofs); + rd.old_parent = old_upperdir; + rd.new_parent = new_upperdir; + rd.flags = flags; - de = ovl_lookup_upper(ofs, old->d_name.name, old_upperdir, - old->d_name.len); - err = PTR_ERR(de); - if (IS_ERR(de)) - goto out_unlock; - olddentry = de; + err = start_renaming(&rd, 0, + &QSTR_LEN(old->d_name.name, old->d_name.len), + &QSTR_LEN(new->d_name.name, new->d_name.len)); - err = -ESTALE; - if (!ovl_matches_upper(old, olddentry)) - goto out_unlock; + if (err) + goto out_revert_creds; - de = ovl_lookup_upper(ofs, new->d_name.name, new_upperdir, - new->d_name.len); - err = PTR_ERR(de); - if (IS_ERR(de)) + err = -ESTALE; + if (!ovl_matches_upper(old, rd.old_dentry)) goto out_unlock; - newdentry = de; old_opaque = ovl_dentry_is_opaque(old); new_opaque = ovl_dentry_is_opaque(new); @@ -1263,15 +1254,15 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, err = -ESTALE; if (d_inode(new) && ovl_dentry_upper(new)) { if (opaquedir) { - if (newdentry != opaquedir) + if (rd.new_dentry != opaquedir) goto out_unlock; } else { - if (!ovl_matches_upper(new, newdentry)) + if (!ovl_matches_upper(new, rd.new_dentry)) goto out_unlock; } } else { - if (!d_is_negative(newdentry)) { - if (!new_opaque || !ovl_upper_is_whiteout(ofs, newdentry)) + if (!d_is_negative(rd.new_dentry)) { + if (!new_opaque || !ovl_upper_is_whiteout(ofs, rd.new_dentry)) goto out_unlock; } else { if (flags & RENAME_EXCHANGE) @@ -1279,19 +1270,14 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, } } - if (olddentry == trap) - goto out_unlock; - if (newdentry == trap) - goto out_unlock; - - if (olddentry->d_inode == newdentry->d_inode) + if (rd.old_dentry->d_inode == rd.new_dentry->d_inode) goto out_unlock; err = 0; if (ovl_type_merge_or_lower(old)) err = ovl_set_redirect(old, samedir); else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent)) - err = ovl_set_opaque_xerr(old, olddentry, -EXDEV); + err = ovl_set_opaque_xerr(old, rd.old_dentry, -EXDEV); if (err) goto out_unlock; @@ -1299,18 +1285,24 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, err = ovl_set_redirect(new, samedir); else if (!overwrite && new_is_dir && !new_opaque && ovl_type_merge(old->d_parent)) - err = ovl_set_opaque_xerr(new, newdentry, -EXDEV); + err = ovl_set_opaque_xerr(new, rd.new_dentry, -EXDEV); if (err) goto out_unlock; - err = ovl_do_rename(ofs, old_upperdir, olddentry, - new_upperdir, newdentry, flags); - unlock_rename(new_upperdir, old_upperdir); + err = ovl_do_rename_rd(&rd); + + if (!err && cleanup_whiteout) + whiteout = dget(rd.new_dentry); + + end_renaming(&rd); + if (err) goto out_revert_creds; - if (cleanup_whiteout) - ovl_cleanup(ofs, old_upperdir, newdentry); + if (whiteout) { + ovl_cleanup(ofs, old_upperdir, whiteout); + dput(whiteout); + } if (overwrite && d_inode(new)) { if (new_is_dir) @@ -1336,14 +1328,12 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, else ovl_drop_write(old); out: - dput(newdentry); - dput(olddentry); dput(opaquedir); ovl_cache_free(&list); return err; out_unlock: - unlock_rename(new_upperdir, old_upperdir); + end_renaming(&rd); goto out_revert_creds; } diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 49ad65f829dc..3cc85a893b5c 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -355,11 +355,24 @@ static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry, return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name); } +static inline int ovl_do_rename_rd(struct renamedata *rd) +{ + int err; + + pr_debug("rename(%pd2, %pd2, 0x%x)\n", rd->old_dentry, rd->new_dentry, + rd->flags); + err = vfs_rename(rd); + if (err) { + pr_debug("...rename(%pd2, %pd2, ...) = %i\n", + rd->old_dentry, rd->new_dentry, err); + } + return err; +} + static inline int ovl_do_rename(struct ovl_fs *ofs, struct dentry *olddir, struct dentry *olddentry, struct dentry *newdir, struct dentry *newdentry, unsigned int flags) { - int err; struct renamedata rd = { .mnt_idmap = ovl_upper_mnt_idmap(ofs), .old_parent = olddir, @@ -369,13 +382,7 @@ static inline int ovl_do_rename(struct ovl_fs *ofs, struct dentry *olddir, .flags = flags, }; - pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); - err = vfs_rename(&rd); - if (err) { - pr_debug("...rename(%pd2, %pd2, ...) = %i\n", - olddentry, newdentry, err); - } - return err; + return ovl_do_rename_rd(&rd); } static inline int ovl_do_whiteout(struct ovl_fs *ofs, diff --git a/include/linux/namei.h b/include/linux/namei.h index 196c66156a8a..7fdd9fdcbd2b 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -157,6 +157,9 @@ extern int follow_up(struct path *); extern struct dentry *lock_rename(struct dentry *, struct dentry *); extern struct dentry *lock_rename_child(struct dentry *, struct dentry *); extern void unlock_rename(struct dentry *, struct dentry *); +int start_renaming(struct renamedata *rd, int lookup_flags, + struct qstr *old_last, struct qstr *new_last); +void end_renaming(struct renamedata *rd); /** * mode_strip_umask - handle vfs umask stripping -- 2.50.0.107.gf914562f5916.dirty