Hey Linus,
/* Summary */
This cycle saw a lot of work for tmpfs that required changes to the vfs
layer. Andrew, Hugh, and I decided to take tmpfs through vfs this cycle.
Things will go back to mm next cycle.
Features
========
* By far the biggest work is the quota support for tmpfs. New tmpfs
quota infrastructure is added to support it and a new QFMT_SHMEM uapi
option is exposed.
This offers user and group quotas to tmpfs (project quotas will be
added later). Similar to other filesystems tmpfs quota are not
supported within user namespaces yet.
* Add support for user xattrs. While tmpfs already supports security
xattrs (security.*) and POSIX ACLs for a long time it lacked support
for user xattrs (user.*). With this pull request tmpfs will be able to
support a limited number of user xattrs. This is accompanied by a fix
(see below) to limit persistent simple xattr allocations.
* Add support for stable directory offsets. Currently tmpfs relies on
the libfs provided cursor-based mechanism for readdir. This causes
issues when a tmpfs filesystem is exported via NFS.
NFS clients do not open directories. Instead, each server-side readdir
operation opens the directory, reads it, and then closes it. Since the
cursor state for that directory is associated with the opened file it
is discarded after each readdir operation. Such directory offsets are
not just cached by NFS clients but also various userspace libraries
based on these clients.
As it stands there is no way to invalidate the caches when directory
offsets have changed and the whole application depends on unchanging
directory offsets.
At LSFMM we discussed how to solve this problem and decided to support
stable directory offsets. libfs now allows filesystems like tmpfs to
use an xarrary to map a directory offset to a dentry. This mechanism
is currently only used by tmpfs but can be supported by others as well.
Fixes
=====
* Change persistent simple xattrs allocations in libfs from GFP_KERNEL
to GPF_KERNEL_ACCOUNT so they're subject to memory cgroup limits.
Since this is a change to libfs it affects both tmpfs and kernfs.
* Correctly verify {g,u}id mount options.
A new filesystem context is created via fsopen() which records the
namespace that becomes the owning namespace of the superblock when
fsconfig(FSCONFIG_CMD_CREATE) is called for filesystems that are
mountable in namespaces. However, fsconfig() calls can occur in a
namespace different from the namespace where fsopen() has been called.
Currently, when fsconfig() is called to set {g,u}id mount options the
requested {g,u}id is mapped into a k{g,u}id according to the namespace
where fsconfig() was called from. The resulting k{g,u}id is not
guaranteed to be resolvable in the namespace of the filesystem (the
one that fsopen() was called in).
This means it's possible for an unprivileged user to create files
owned by any group in a tmpfs mount since it's possible to set the
setid bits on the tmpfs directory.
The contract for {g,u}id mount options and {g,u}id values in general
set from userspace has always been that they are translated according
to the caller's idmapping. In so far, tmpfs has been doing the correct
thing. But since tmpfs is mountable in unprivileged contexts it is
also necessary to verify that the resulting {k,g}uid is representable
in the namespace of the superblock to avoid such bugs.
The new mount api's cross-namespace delegation abilities are already
widely used. Having talked to a bunch of userspace this is the most
faithful solution with minimal regression risks.
/* Testing */
clang: Ubuntu clang version 15.0.7
gcc: (Ubuntu 12.2.0-3ubuntu1) 12.2.0
All patches are based on v6.5-rc4 and have been sitting in linux-next.
No build failures or warnings were observed. All old and new tests in
selftests, and LTP pass without regressions.
/* Conflicts */
This will cause a merge conflict with the v6.6-vfs.ctime pull request.
The pull request should have been sent and hopefully merged first. In
this case I'd suggest the following conflict resolution should you
decide to pull this branch:
diff --cc mm/shmem.c
index 98cc4be7a8a8,11298c797cdc..a7b15ed56eff
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@@ -2363,67 -2437,75 +2437,74 @@@ static struct inode *__shmem_get_inode(
struct shmem_inode_info *info;
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
ino_t ino;
+ int err;
+
+ err = shmem_reserve_inode(sb, &ino);
+ if (err)
+ return ERR_PTR(err);
- if (shmem_reserve_inode(sb, &ino))
- return NULL;
inode = new_inode(sb);
- if (inode) {
- inode->i_ino = ino;
- inode_init_owner(idmap, inode, dir, mode);
- inode->i_blocks = 0;
- inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
- inode->i_generation = get_random_u32();
- info = SHMEM_I(inode);
- memset(info, 0, (char *)inode - (char *)info);
- spin_lock_init(&info->lock);
- atomic_set(&info->stop_eviction, 0);
- info->seals = F_SEAL_SEAL;
- info->flags = flags & VM_NORESERVE;
- info->i_crtime = inode->i_mtime;
- info->fsflags = (dir == NULL) ? 0 :
- SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
- if (info->fsflags)
- shmem_set_inode_flags(inode, info->fsflags);
- INIT_LIST_HEAD(&info->shrinklist);
- INIT_LIST_HEAD(&info->swaplist);
- if (sbinfo->noswap)
- mapping_set_unevictable(inode->i_mapping);
- simple_xattrs_init(&info->xattrs);
- cache_no_acl(inode);
- mapping_set_large_folios(inode->i_mapping);
--
- switch (mode & S_IFMT) {
- default:
- inode->i_op = &shmem_special_inode_operations;
- init_special_inode(inode, mode, dev);
- break;
- case S_IFREG:
- inode->i_mapping->a_ops = &shmem_aops;
- inode->i_op = &shmem_inode_operations;
- inode->i_fop = &shmem_file_operations;
- mpol_shared_policy_init(&info->policy,
- shmem_get_sbmpol(sbinfo));
- break;
- case S_IFDIR:
- inc_nlink(inode);
- /* Some things misbehave if size == 0 on a directory */
- inode->i_size = 2 * BOGO_DIRENT_SIZE;
- inode->i_op = &shmem_dir_inode_operations;
- inode->i_fop = &simple_dir_operations;
- break;
- case S_IFLNK:
- /*
- * Must not load anything in the rbtree,
- * mpol_free_shared_policy will not be called.
- */
- mpol_shared_policy_init(&info->policy, NULL);
- break;
- }
+ if (!inode) {
+ shmem_free_inode(sb, 0);
+ return ERR_PTR(-ENOSPC);
+ }
- lockdep_annotate_inode_mutex_key(inode);
- } else
- shmem_free_inode(sb);
+ inode->i_ino = ino;
+ inode_init_owner(idmap, inode, dir, mode);
+ inode->i_blocks = 0;
- inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
++ inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
+ inode->i_generation = get_random_u32();
+ info = SHMEM_I(inode);
+ memset(info, 0, (char *)inode - (char *)info);
+ spin_lock_init(&info->lock);
+ atomic_set(&info->stop_eviction, 0);
+ info->seals = F_SEAL_SEAL;
+ info->flags = flags & VM_NORESERVE;
+ info->i_crtime = inode->i_mtime;
+ info->fsflags = (dir == NULL) ? 0 :
+ SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
+ if (info->fsflags)
+ shmem_set_inode_flags(inode, info->fsflags);
+ INIT_LIST_HEAD(&info->shrinklist);
+ INIT_LIST_HEAD(&info->swaplist);
+ INIT_LIST_HEAD(&info->swaplist);
+ if (sbinfo->noswap)
+ mapping_set_unevictable(inode->i_mapping);
+ simple_xattrs_init(&info->xattrs);
+ cache_no_acl(inode);
+ mapping_set_large_folios(inode->i_mapping);
+
+ switch (mode & S_IFMT) {
+ default:
+ inode->i_op = &shmem_special_inode_operations;
+ init_special_inode(inode, mode, dev);
+ break;
+ case S_IFREG:
+ inode->i_mapping->a_ops = &shmem_aops;
+ inode->i_op = &shmem_inode_operations;
+ inode->i_fop = &shmem_file_operations;
+ mpol_shared_policy_init(&info->policy,
+ shmem_get_sbmpol(sbinfo));
+ break;
+ case S_IFDIR:
+ inc_nlink(inode);
+ /* Some things misbehave if size == 0 on a directory */
+ inode->i_size = 2 * BOGO_DIRENT_SIZE;
+ inode->i_op = &shmem_dir_inode_operations;
+ inode->i_fop = &simple_offset_dir_operations;
+ simple_offset_init(shmem_get_offset_ctx(inode));
+ break;
+ case S_IFLNK:
+ /*
+ * Must not load anything in the rbtree,
+ * mpol_free_shared_policy will not be called.
+ */
+ mpol_shared_policy_init(&info->policy, NULL);
+ break;
+ }
+
+ lockdep_annotate_inode_mutex_key(inode);
return inode;
}
@@@ -3069,27 -3208,33 +3207,32 @@@ shmem_mknod(struct mnt_idmap *idmap, st
struct dentry *dentry, umode_t mode, dev_t dev)
{
struct inode *inode;
- int error = -ENOSPC;
+ int error;
inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, dev, VM_NORESERVE);
- if (inode) {
- error = simple_acl_create(dir, inode);
- if (error)
- goto out_iput;
- error = security_inode_init_security(inode, dir,
- &dentry->d_name,
- shmem_initxattrs, NULL);
- if (error && error != -EOPNOTSUPP)
- goto out_iput;
-
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
- error = 0;
- dir->i_size += BOGO_DIRENT_SIZE;
- dir->i_mtime = inode_set_ctime_current(dir);
- inode_inc_iversion(dir);
- d_instantiate(dentry, inode);
- dget(dentry); /* Extra count - pin the dentry in core */
- }
+ error = simple_acl_create(dir, inode);
+ if (error)
+ goto out_iput;
+ error = security_inode_init_security(inode, dir,
+ &dentry->d_name,
+ shmem_initxattrs, NULL);
+ if (error && error != -EOPNOTSUPP)
+ goto out_iput;
+
+ error = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
+ if (error)
+ goto out_iput;
+
+ dir->i_size += BOGO_DIRENT_SIZE;
- dir->i_ctime = dir->i_mtime = current_time(dir);
++ dir->i_mtime = inode_set_ctime_current(dir);
+ inode_inc_iversion(dir);
+ d_instantiate(dentry, inode);
+ dget(dentry); /* Extra count - pin the dentry in core */
return error;
+
out_iput:
iput(inode);
return error;
@@@ -3159,9 -3310,15 +3308,16 @@@ static int shmem_link(struct dentry *ol
goto out;
}
+ ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry);
+ if (ret) {
+ if (inode->i_nlink)
+ shmem_free_inode(inode->i_sb, 0);
+ goto out;
+ }
+
dir->i_size += BOGO_DIRENT_SIZE;
- inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
+ dir->i_mtime = inode_set_ctime_to_ts(dir,
+ inode_set_ctime_current(inode));
inode_inc_iversion(dir);
inc_nlink(inode);
ihold(inode); /* New dentry reference */
@@@ -3176,11 -3333,12 +3332,13 @@@ static int shmem_unlink(struct inode *d
struct inode *inode = d_inode(dentry);
if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
- shmem_free_inode(inode->i_sb);
+ shmem_free_inode(inode->i_sb, 0);
+
+ simple_offset_remove(shmem_get_offset_ctx(dir), dentry);
dir->i_size -= BOGO_DIRENT_SIZE;
- inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
+ dir->i_mtime = inode_set_ctime_to_ts(dir,
+ inode_set_ctime_current(inode));
inode_inc_iversion(dir);
drop_nlink(inode);
dput(dentry); /* Undo the count from "create" - this does all the work */
@@@ -3459,15 -3660,40 +3658,40 @@@ static int shmem_xattr_handler_set(cons
size_t size, int flags)
{
struct shmem_inode_info *info = SHMEM_I(inode);
- int err;
+ struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
+ struct simple_xattr *old_xattr;
+ size_t ispace = 0;
name = xattr_full_name(handler, name);
- err = simple_xattr_set(&info->xattrs, name, value, size, flags, NULL);
- if (!err) {
+ if (value && sbinfo->max_inodes) {
+ ispace = simple_xattr_space(name, size);
+ raw_spin_lock(&sbinfo->stat_lock);
+ if (sbinfo->free_ispace < ispace)
+ ispace = 0;
+ else
+ sbinfo->free_ispace -= ispace;
+ raw_spin_unlock(&sbinfo->stat_lock);
+ if (!ispace)
+ return -ENOSPC;
+ }
+
+ old_xattr = simple_xattr_set(&info->xattrs, name, value, size, flags);
+ if (!IS_ERR(old_xattr)) {
+ ispace = 0;
+ if (old_xattr && sbinfo->max_inodes)
+ ispace = simple_xattr_space(old_xattr->name,
+ old_xattr->size);
+ simple_xattr_free(old_xattr);
+ old_xattr = NULL;
- inode->i_ctime = current_time(inode);
+ inode_set_ctime_current(inode);
inode_inc_iversion(inode);
}
- return err;
+ if (ispace) {
+ raw_spin_lock(&sbinfo->stat_lock);
+ sbinfo->free_ispace += ispace;
+ raw_spin_unlock(&sbinfo->stat_lock);
+ }
+ return PTR_ERR(old_xattr);
}
static const struct xattr_handler shmem_security_xattr_handler = {
The following changes since commit 5d0c230f1de8c7515b6567d9afba1f196fb4e2f4:
Linux 6.5-rc4 (2023-07-30 13:23:47 -0700)
are available in the Git repository at:
git@xxxxxxxxxxxxxxxxxxx:pub/scm/linux/kernel/git/vfs/vfs tags/v6.6-vfs.tmpfs
for you to fetch changes up to 572a3d1e5d3a3e335b92e2c28a63c0b27944480c:
tmpfs,xattr: GFP_KERNEL_ACCOUNT for simple xattrs (2023-08-22 10:57:46 +0200)
Please consider pulling these changes from the signed v6.6-vfs.tmpfs tag.
Thanks!
Christian
----------------------------------------------------------------
v6.6-vfs.tmpfs
----------------------------------------------------------------
Carlos Maiolino (3):
shmem: make shmem_get_inode() return ERR_PTR instead of NULL
shmem: prepare shmem quota infrastructure
shmem: quota support
Christian Brauner (1):
tmpfs: verify {g,u}id mount options correctly
Chuck Lever (5):
libfs: Add directory operations for stable offsets
shmem: Refactor shmem_symlink()
shmem: stable directory offsets
libfs: Add a lock class for the offset map's xa_lock
libfs: Remove parent dentry locking in offset_iterate_dir()
Hugh Dickins (8):
shmem: fix quota lock nesting in huge hole handling
shmem: move spinlock into shmem_recalc_inode() to fix quota support
xattr: simple_xattr_set() return old_xattr to be freed
tmpfs: track free_ispace instead of free_inodes
tmpfs,xattr: enable limited user extended attributes
tmpfs: trivial support for direct IO
mm: invalidation check mapping before folio_contains
tmpfs,xattr: GFP_KERNEL_ACCOUNT for simple xattrs
Jan Kara (1):
quota: Check presence of quota operation structures instead of ->quota_read and ->quota_write callbacks
Lukas Czerner (2):
shmem: make shmem_inode_acct_block() return error
shmem: Add default quota limit mount options
Documentation/filesystems/locking.rst | 8 +-
Documentation/filesystems/tmpfs.rst | 38 +-
Documentation/filesystems/vfs.rst | 6 +-
fs/Kconfig | 16 +-
fs/kernfs/dir.c | 2 +-
fs/kernfs/inode.c | 46 +-
fs/libfs.c | 248 ++++++++++
fs/quota/dquot.c | 2 +-
fs/xattr.c | 83 ++--
include/linux/fs.h | 18 +
include/linux/shmem_fs.h | 31 +-
include/linux/xattr.h | 10 +-
include/uapi/linux/quota.h | 1 +
mm/Makefile | 2 +-
mm/huge_memory.c | 6 +-
mm/khugepaged.c | 13 +-
mm/shmem.c | 827 +++++++++++++++++++++++++---------
mm/shmem_quota.c | 350 ++++++++++++++
mm/truncate.c | 4 +-
19 files changed, 1414 insertions(+), 297 deletions(-)
create mode 100644 mm/shmem_quota.c
