| Message ID | 20240429132620.659012-1-mszeredi@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ovl: implement tmpfile | expand |
On Mon, Apr 29, 2024 at 4:26 PM Miklos Szeredi <mszeredi@redhat.com> wrote: > > Combine inode creation with opening a file. > > There are six separate objects that are being set up: the backing inode, > dentry and file, and the overlay inode, dentry and file. Cleanup in case > of an error is a bit of a challenge and is difficult to test, so careful > review is needed. > > All tmpfile testcases except generic/509 now run/pass, and no regressions > are observed with full xfstests. > > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> I have nothing queued in the overlayfs tree for 6.10 and no plans of driving any ovl work for 6.10, so feel free to use the overlayfs-next branch to queue this patch. Thanks, Amir. > --- > v2: > - don't pass real_idmap to backing_tmpfile_open() > - move ovl_dir_modified() from ovl_instantiate() to callers > - use ovl_instantiate() for tmpfile > - call d_mark_tmpfile() before d_instantiate() in ovl_instantiate(); > no longer need to mess with nlink > - extract helper ovl_setup_cred_for_create() from ovl_create_or_link() > - don't apply umask to mode, VFS will do that when creating the tmpfile > - add comment above file->private_data cleanup > > --- > fs/backing-file.c | 23 ++++++ > fs/internal.h | 3 + > fs/namei.c | 6 +- > fs/overlayfs/dir.c | 145 ++++++++++++++++++++++++++++++----- > fs/overlayfs/file.c | 3 - > fs/overlayfs/overlayfs.h | 3 + > include/linux/backing-file.h | 3 + > 7 files changed, 161 insertions(+), 25 deletions(-) > > diff --git a/fs/backing-file.c b/fs/backing-file.c > index 740185198db3..afb557446c27 100644 > --- a/fs/backing-file.c > +++ b/fs/backing-file.c > @@ -52,6 +52,29 @@ struct file *backing_file_open(const struct path *user_path, int flags, > } > EXPORT_SYMBOL_GPL(backing_file_open); > > +struct file *backing_tmpfile_open(const struct path *user_path, int flags, > + const struct path *real_parentpath, > + umode_t mode, const struct cred *cred) > +{ > + struct mnt_idmap *real_idmap = mnt_idmap(real_parentpath->mnt); > + struct file *f; > + int error; > + > + f = alloc_empty_backing_file(flags, cred); > + if (IS_ERR(f)) > + return f; > + > + path_get(user_path); > + *backing_file_user_path(f) = *user_path; > + error = vfs_tmpfile(real_idmap, real_parentpath, f, mode); > + if (error) { > + fput(f); > + f = ERR_PTR(error); > + } > + return f; > +} > +EXPORT_SYMBOL(backing_tmpfile_open); > + > struct backing_aio { > struct kiocb iocb; > refcount_t ref; > diff --git a/fs/internal.h b/fs/internal.h > index 7ca738904e34..ab2225136f60 100644 > --- a/fs/internal.h > +++ b/fs/internal.h > @@ -62,6 +62,9 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode); > int do_symlinkat(struct filename *from, int newdfd, struct filename *to); > int do_linkat(int olddfd, struct filename *old, int newdfd, > struct filename *new, int flags); > +int vfs_tmpfile(struct mnt_idmap *idmap, > + const struct path *parentpath, > + struct file *file, umode_t mode); > > /* > * namespace.c > diff --git a/fs/namei.c b/fs/namei.c > index c5b2a25be7d0..13e50b0a49d2 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -3668,9 +3668,9 @@ static int do_open(struct nameidata *nd, > * On non-idmapped mounts or if permission checking is to be performed on the > * raw inode simply pass @nop_mnt_idmap. > */ > -static int vfs_tmpfile(struct mnt_idmap *idmap, > - const struct path *parentpath, > - struct file *file, umode_t mode) > +int vfs_tmpfile(struct mnt_idmap *idmap, > + const struct path *parentpath, > + struct file *file, umode_t mode) > { > struct dentry *child; > struct inode *dir = d_inode(parentpath->dentry); > diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c > index 0f8b4a719237..cac21ef546fe 100644 > --- a/fs/overlayfs/dir.c > +++ b/fs/overlayfs/dir.c > @@ -14,6 +14,7 @@ > #include <linux/posix_acl_xattr.h> > #include <linux/atomic.h> > #include <linux/ratelimit.h> > +#include <linux/backing-file.h> > #include "overlayfs.h" > > static unsigned short ovl_redirect_max = 256; > @@ -260,14 +261,13 @@ static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry) > * may not use to instantiate the new dentry. > */ > static int ovl_instantiate(struct dentry *dentry, struct inode *inode, > - struct dentry *newdentry, bool hardlink) > + struct dentry *newdentry, bool hardlink, struct file *tmpfile) > { > struct ovl_inode_params oip = { > .upperdentry = newdentry, > .newinode = inode, > }; > > - ovl_dir_modified(dentry->d_parent, false); > ovl_dentry_set_upper_alias(dentry); > ovl_dentry_init_reval(dentry, newdentry, NULL); > > @@ -295,6 +295,9 @@ static int ovl_instantiate(struct dentry *dentry, struct inode *inode, > inc_nlink(inode); > } > > + if (tmpfile) > + d_mark_tmpfile(tmpfile, inode); > + > d_instantiate(dentry, inode); > if (inode != oip.newinode) { > pr_warn_ratelimited("newly created inode found in cache (%pd2)\n", > @@ -345,7 +348,8 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode, > ovl_set_opaque(dentry, newdentry); > } > > - err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink); > + ovl_dir_modified(dentry->d_parent, false); > + err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink, NULL); > if (err) > goto out_cleanup; > out_unlock: > @@ -529,7 +533,8 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, > if (err) > goto out_cleanup; > } > - err = ovl_instantiate(dentry, inode, newdentry, hardlink); > + ovl_dir_modified(dentry->d_parent, false); > + err = ovl_instantiate(dentry, inode, newdentry, hardlink, NULL); > if (err) { > ovl_cleanup(ofs, udir, newdentry); > dput(newdentry); > @@ -551,12 +556,35 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, > goto out_dput; > } > > +static int ovl_setup_cred_for_create(struct dentry *dentry, struct inode *inode, > + umode_t mode, const struct cred *old_cred) > +{ > + int err; > + struct cred *override_cred; > + > + override_cred = prepare_creds(); > + if (!override_cred) > + return -ENOMEM; > + > + override_cred->fsuid = inode->i_uid; > + override_cred->fsgid = inode->i_gid; > + err = security_dentry_create_files_as(dentry, mode, &dentry->d_name, > + old_cred, override_cred); > + if (err) { > + put_cred(override_cred); > + return err; > + } > + put_cred(override_creds(override_cred)); > + put_cred(override_cred); > + > + return 0; > +} > + > static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, > struct ovl_cattr *attr, bool origin) > { > int err; > const struct cred *old_cred; > - struct cred *override_cred; > struct dentry *parent = dentry->d_parent; > > old_cred = ovl_override_creds(dentry->d_sb); > @@ -572,10 +600,6 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, > } > > if (!attr->hardlink) { > - err = -ENOMEM; > - override_cred = prepare_creds(); > - if (!override_cred) > - goto out_revert_creds; > /* > * In the creation cases(create, mkdir, mknod, symlink), > * ovl should transfer current's fs{u,g}id to underlying > @@ -589,17 +613,9 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, > * create a new inode, so just use the ovl mounter's > * fs{u,g}id. > */ > - override_cred->fsuid = inode->i_uid; > - override_cred->fsgid = inode->i_gid; > - err = security_dentry_create_files_as(dentry, > - attr->mode, &dentry->d_name, old_cred, > - override_cred); > - if (err) { > - put_cred(override_cred); > + err = ovl_setup_cred_for_create(dentry, inode, attr->mode, old_cred); > + if (err) > goto out_revert_creds; > - } > - put_cred(override_creds(override_cred)); > - put_cred(override_cred); > } > > if (!ovl_dentry_is_whiteout(dentry)) > @@ -1290,6 +1306,96 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, > return err; > } > > +static int ovl_create_tmpfile(struct file *file, struct dentry *dentry, > + struct inode *inode, umode_t mode) > +{ > + const struct cred *old_cred; > + struct path realparentpath; > + struct file *realfile; > + struct dentry *newdentry; > + /* It's okay to set O_NOATIME, since the owner will be current fsuid */ > + int flags = file->f_flags | OVL_OPEN_FLAGS; > + int err; > + > + err = ovl_copy_up(dentry->d_parent); > + if (err) > + return err; > + > + old_cred = ovl_override_creds(dentry->d_sb); > + err = ovl_setup_cred_for_create(dentry, inode, mode, old_cred); > + if (err) > + goto out_revert_creds; > + > + ovl_path_upper(dentry->d_parent, &realparentpath); > + realfile = backing_tmpfile_open(&file->f_path, flags, &realparentpath, > + mode, current_cred()); > + err = PTR_ERR(realfile); > + if (IS_ERR(realfile)) > + goto out_revert_creds; > + > + /* ovl_instantiate() consumes the newdentry reference on success */ > + newdentry = dget(realfile->f_path.dentry); > + err = ovl_instantiate(dentry, inode, newdentry, false, file); > + if (!err) { > + file->private_data = realfile; > + } else { > + dput(newdentry); > + fput(realfile); > + } > +out_revert_creds: > + revert_creds(old_cred); > + return err; > +} > + > +static int ovl_dummy_open(struct inode *inode, struct file *file) > +{ > + return 0; > +} > + > +static int ovl_tmpfile(struct mnt_idmap *idmap, struct inode *dir, > + struct file *file, umode_t mode) > +{ > + int err; > + struct dentry *dentry = file->f_path.dentry; > + struct inode *inode; > + > + err = ovl_want_write(dentry); > + if (err) > + return err; > + > + err = -ENOMEM; > + inode = ovl_new_inode(dentry->d_sb, mode, 0); > + if (!inode) > + goto drop_write; > + > + inode_init_owner(&nop_mnt_idmap, inode, dir, mode); > + err = ovl_create_tmpfile(file, dentry, inode, inode->i_mode); > + if (err) > + goto put_inode; > + > + /* > + * Check if the preallocated inode was actually used. Having something > + * else assigned to the dentry shouldn't happen as that would indicate > + * that the backing tmpfile "leaked" out of overlayfs. > + */ > + err = -EIO; > + if (WARN_ON(inode != d_inode(dentry))) > + goto put_realfile; > + > + /* inode reference was transferred to dentry */ > + inode = NULL; > + err = finish_open(file, dentry, ovl_dummy_open); > +put_realfile: > + /* Without FMODE_OPENED ->release() won't be called on @file */ > + if (!(file->f_mode & FMODE_OPENED)) > + fput(file->private_data); > +put_inode: > + iput(inode); > +drop_write: > + ovl_drop_write(dentry); > + return err; > +} > + > const struct inode_operations ovl_dir_inode_operations = { > .lookup = ovl_lookup, > .mkdir = ovl_mkdir, > @@ -1310,4 +1416,5 @@ const struct inode_operations ovl_dir_inode_operations = { > .update_time = ovl_update_time, > .fileattr_get = ovl_fileattr_get, > .fileattr_set = ovl_fileattr_set, > + .tmpfile = ovl_tmpfile, > }; > diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c > index 05536964d37f..1a411cae57ed 100644 > --- a/fs/overlayfs/file.c > +++ b/fs/overlayfs/file.c > @@ -24,9 +24,6 @@ static char ovl_whatisit(struct inode *inode, struct inode *realinode) > return 'm'; > } > > -/* No atime modification on underlying */ > -#define OVL_OPEN_FLAGS (O_NOATIME) > - > static struct file *ovl_open_realfile(const struct file *file, > const struct path *realpath) > { > diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h > index ee949f3e7c77..0bfe35da4b7b 100644 > --- a/fs/overlayfs/overlayfs.h > +++ b/fs/overlayfs/overlayfs.h > @@ -175,6 +175,9 @@ static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy) > return (int)metacopy->len - OVL_METACOPY_MIN_SIZE; > } > > +/* No atime modification on underlying */ > +#define OVL_OPEN_FLAGS (O_NOATIME) > + > extern const char *const ovl_xattr_table[][2]; > static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) > { > diff --git a/include/linux/backing-file.h b/include/linux/backing-file.h > index 3f1fe1774f1b..4b61b0e57720 100644 > --- a/include/linux/backing-file.h > +++ b/include/linux/backing-file.h > @@ -22,6 +22,9 @@ struct backing_file_ctx { > struct file *backing_file_open(const struct path *user_path, int flags, > const struct path *real_path, > const struct cred *cred); > +struct file *backing_tmpfile_open(const struct path *user_path, int flags, > + const struct path *real_parentpath, > + umode_t mode, const struct cred *cred); > ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter, > struct kiocb *iocb, int flags, > struct backing_file_ctx *ctx); > -- > 2.44.0 >
diff --git a/fs/backing-file.c b/fs/backing-file.c index 740185198db3..afb557446c27 100644 --- a/fs/backing-file.c +++ b/fs/backing-file.c @@ -52,6 +52,29 @@ struct file *backing_file_open(const struct path *user_path, int flags, } EXPORT_SYMBOL_GPL(backing_file_open); +struct file *backing_tmpfile_open(const struct path *user_path, int flags, + const struct path *real_parentpath, + umode_t mode, const struct cred *cred) +{ + struct mnt_idmap *real_idmap = mnt_idmap(real_parentpath->mnt); + struct file *f; + int error; + + f = alloc_empty_backing_file(flags, cred); + if (IS_ERR(f)) + return f; + + path_get(user_path); + *backing_file_user_path(f) = *user_path; + error = vfs_tmpfile(real_idmap, real_parentpath, f, mode); + if (error) { + fput(f); + f = ERR_PTR(error); + } + return f; +} +EXPORT_SYMBOL(backing_tmpfile_open); + struct backing_aio { struct kiocb iocb; refcount_t ref; diff --git a/fs/internal.h b/fs/internal.h index 7ca738904e34..ab2225136f60 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -62,6 +62,9 @@ int do_mkdirat(int dfd, struct filename *name, umode_t mode); int do_symlinkat(struct filename *from, int newdfd, struct filename *to); int do_linkat(int olddfd, struct filename *old, int newdfd, struct filename *new, int flags); +int vfs_tmpfile(struct mnt_idmap *idmap, + const struct path *parentpath, + struct file *file, umode_t mode); /* * namespace.c diff --git a/fs/namei.c b/fs/namei.c index c5b2a25be7d0..13e50b0a49d2 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3668,9 +3668,9 @@ static int do_open(struct nameidata *nd, * On non-idmapped mounts or if permission checking is to be performed on the * raw inode simply pass @nop_mnt_idmap. */ -static int vfs_tmpfile(struct mnt_idmap *idmap, - const struct path *parentpath, - struct file *file, umode_t mode) +int vfs_tmpfile(struct mnt_idmap *idmap, + const struct path *parentpath, + struct file *file, umode_t mode) { struct dentry *child; struct inode *dir = d_inode(parentpath->dentry); diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 0f8b4a719237..cac21ef546fe 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -14,6 +14,7 @@ #include <linux/posix_acl_xattr.h> #include <linux/atomic.h> #include <linux/ratelimit.h> +#include <linux/backing-file.h> #include "overlayfs.h" static unsigned short ovl_redirect_max = 256; @@ -260,14 +261,13 @@ static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry) * may not use to instantiate the new dentry. */ static int ovl_instantiate(struct dentry *dentry, struct inode *inode, - struct dentry *newdentry, bool hardlink) + struct dentry *newdentry, bool hardlink, struct file *tmpfile) { struct ovl_inode_params oip = { .upperdentry = newdentry, .newinode = inode, }; - ovl_dir_modified(dentry->d_parent, false); ovl_dentry_set_upper_alias(dentry); ovl_dentry_init_reval(dentry, newdentry, NULL); @@ -295,6 +295,9 @@ static int ovl_instantiate(struct dentry *dentry, struct inode *inode, inc_nlink(inode); } + if (tmpfile) + d_mark_tmpfile(tmpfile, inode); + d_instantiate(dentry, inode); if (inode != oip.newinode) { pr_warn_ratelimited("newly created inode found in cache (%pd2)\n", @@ -345,7 +348,8 @@ static int ovl_create_upper(struct dentry *dentry, struct inode *inode, ovl_set_opaque(dentry, newdentry); } - err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink); + ovl_dir_modified(dentry->d_parent, false); + err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink, NULL); if (err) goto out_cleanup; out_unlock: @@ -529,7 +533,8 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, if (err) goto out_cleanup; } - err = ovl_instantiate(dentry, inode, newdentry, hardlink); + ovl_dir_modified(dentry->d_parent, false); + err = ovl_instantiate(dentry, inode, newdentry, hardlink, NULL); if (err) { ovl_cleanup(ofs, udir, newdentry); dput(newdentry); @@ -551,12 +556,35 @@ static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, goto out_dput; } +static int ovl_setup_cred_for_create(struct dentry *dentry, struct inode *inode, + umode_t mode, const struct cred *old_cred) +{ + int err; + struct cred *override_cred; + + override_cred = prepare_creds(); + if (!override_cred) + return -ENOMEM; + + override_cred->fsuid = inode->i_uid; + override_cred->fsgid = inode->i_gid; + err = security_dentry_create_files_as(dentry, mode, &dentry->d_name, + old_cred, override_cred); + if (err) { + put_cred(override_cred); + return err; + } + put_cred(override_creds(override_cred)); + put_cred(override_cred); + + return 0; +} + static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, struct ovl_cattr *attr, bool origin) { int err; const struct cred *old_cred; - struct cred *override_cred; struct dentry *parent = dentry->d_parent; old_cred = ovl_override_creds(dentry->d_sb); @@ -572,10 +600,6 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, } if (!attr->hardlink) { - err = -ENOMEM; - override_cred = prepare_creds(); - if (!override_cred) - goto out_revert_creds; /* * In the creation cases(create, mkdir, mknod, symlink), * ovl should transfer current's fs{u,g}id to underlying @@ -589,17 +613,9 @@ static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, * create a new inode, so just use the ovl mounter's * fs{u,g}id. */ - override_cred->fsuid = inode->i_uid; - override_cred->fsgid = inode->i_gid; - err = security_dentry_create_files_as(dentry, - attr->mode, &dentry->d_name, old_cred, - override_cred); - if (err) { - put_cred(override_cred); + err = ovl_setup_cred_for_create(dentry, inode, attr->mode, old_cred); + if (err) goto out_revert_creds; - } - put_cred(override_creds(override_cred)); - put_cred(override_cred); } if (!ovl_dentry_is_whiteout(dentry)) @@ -1290,6 +1306,96 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, return err; } +static int ovl_create_tmpfile(struct file *file, struct dentry *dentry, + struct inode *inode, umode_t mode) +{ + const struct cred *old_cred; + struct path realparentpath; + struct file *realfile; + struct dentry *newdentry; + /* It's okay to set O_NOATIME, since the owner will be current fsuid */ + int flags = file->f_flags | OVL_OPEN_FLAGS; + int err; + + err = ovl_copy_up(dentry->d_parent); + if (err) + return err; + + old_cred = ovl_override_creds(dentry->d_sb); + err = ovl_setup_cred_for_create(dentry, inode, mode, old_cred); + if (err) + goto out_revert_creds; + + ovl_path_upper(dentry->d_parent, &realparentpath); + realfile = backing_tmpfile_open(&file->f_path, flags, &realparentpath, + mode, current_cred()); + err = PTR_ERR(realfile); + if (IS_ERR(realfile)) + goto out_revert_creds; + + /* ovl_instantiate() consumes the newdentry reference on success */ + newdentry = dget(realfile->f_path.dentry); + err = ovl_instantiate(dentry, inode, newdentry, false, file); + if (!err) { + file->private_data = realfile; + } else { + dput(newdentry); + fput(realfile); + } +out_revert_creds: + revert_creds(old_cred); + return err; +} + +static int ovl_dummy_open(struct inode *inode, struct file *file) +{ + return 0; +} + +static int ovl_tmpfile(struct mnt_idmap *idmap, struct inode *dir, + struct file *file, umode_t mode) +{ + int err; + struct dentry *dentry = file->f_path.dentry; + struct inode *inode; + + err = ovl_want_write(dentry); + if (err) + return err; + + err = -ENOMEM; + inode = ovl_new_inode(dentry->d_sb, mode, 0); + if (!inode) + goto drop_write; + + inode_init_owner(&nop_mnt_idmap, inode, dir, mode); + err = ovl_create_tmpfile(file, dentry, inode, inode->i_mode); + if (err) + goto put_inode; + + /* + * Check if the preallocated inode was actually used. Having something + * else assigned to the dentry shouldn't happen as that would indicate + * that the backing tmpfile "leaked" out of overlayfs. + */ + err = -EIO; + if (WARN_ON(inode != d_inode(dentry))) + goto put_realfile; + + /* inode reference was transferred to dentry */ + inode = NULL; + err = finish_open(file, dentry, ovl_dummy_open); +put_realfile: + /* Without FMODE_OPENED ->release() won't be called on @file */ + if (!(file->f_mode & FMODE_OPENED)) + fput(file->private_data); +put_inode: + iput(inode); +drop_write: + ovl_drop_write(dentry); + return err; +} + const struct inode_operations ovl_dir_inode_operations = { .lookup = ovl_lookup, .mkdir = ovl_mkdir, @@ -1310,4 +1416,5 @@ const struct inode_operations ovl_dir_inode_operations = { .update_time = ovl_update_time, .fileattr_get = ovl_fileattr_get, .fileattr_set = ovl_fileattr_set, + .tmpfile = ovl_tmpfile, }; diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 05536964d37f..1a411cae57ed 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -24,9 +24,6 @@ static char ovl_whatisit(struct inode *inode, struct inode *realinode) return 'm'; } -/* No atime modification on underlying */ -#define OVL_OPEN_FLAGS (O_NOATIME) - static struct file *ovl_open_realfile(const struct file *file, const struct path *realpath) { diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index ee949f3e7c77..0bfe35da4b7b 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -175,6 +175,9 @@ static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy) return (int)metacopy->len - OVL_METACOPY_MIN_SIZE; } +/* No atime modification on underlying */ +#define OVL_OPEN_FLAGS (O_NOATIME) + extern const char *const ovl_xattr_table[][2]; static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) { diff --git a/include/linux/backing-file.h b/include/linux/backing-file.h index 3f1fe1774f1b..4b61b0e57720 100644 --- a/include/linux/backing-file.h +++ b/include/linux/backing-file.h @@ -22,6 +22,9 @@ struct backing_file_ctx { struct file *backing_file_open(const struct path *user_path, int flags, const struct path *real_path, const struct cred *cred); +struct file *backing_tmpfile_open(const struct path *user_path, int flags, + const struct path *real_parentpath, + umode_t mode, const struct cred *cred); ssize_t backing_file_read_iter(struct file *file, struct iov_iter *iter, struct kiocb *iocb, int flags, struct backing_file_ctx *ctx);
Combine inode creation with opening a file. There are six separate objects that are being set up: the backing inode, dentry and file, and the overlay inode, dentry and file. Cleanup in case of an error is a bit of a challenge and is difficult to test, so careful review is needed. All tmpfile testcases except generic/509 now run/pass, and no regressions are observed with full xfstests. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> --- v2: - don't pass real_idmap to backing_tmpfile_open() - move ovl_dir_modified() from ovl_instantiate() to callers - use ovl_instantiate() for tmpfile - call d_mark_tmpfile() before d_instantiate() in ovl_instantiate(); no longer need to mess with nlink - extract helper ovl_setup_cred_for_create() from ovl_create_or_link() - don't apply umask to mode, VFS will do that when creating the tmpfile - add comment above file->private_data cleanup --- fs/backing-file.c | 23 ++++++ fs/internal.h | 3 + fs/namei.c | 6 +- fs/overlayfs/dir.c | 145 ++++++++++++++++++++++++++++++----- fs/overlayfs/file.c | 3 - fs/overlayfs/overlayfs.h | 3 + include/linux/backing-file.h | 3 + 7 files changed, 161 insertions(+), 25 deletions(-)