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- Keep a valid f_path for page cache sharing to fix a recent mincore()
    NULL pointer dereference
 
  - Limit LZMA stream pool size when too many processors are available
 
  - Sync up with Hongbo Li's latest email address
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Merge tag 'erofs-for-7.2-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:
 "Fix a regression in page cache sharing which can cause a NULL pointer
  dereference, and limit LZMA stream memory usage on systems with many
  CPUs.

   - Keep a valid f_path for page cache sharing to fix a recent
     mincore() NULL pointer dereference

   - Limit LZMA stream pool size when too many processors are available

   - Sync up with Hongbo Li's latest email address"

* tag 'erofs-for-7.2-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: cap LZMA stream pool size
  erofs: ensure valid f_path for page cache sharing
  MAINTAINERS: update Hongbo Li's email address
This commit is contained in:
Linus Torvalds 2026-07-27 09:31:44 -07:00
commit e895a6fc20
5 changed files with 47 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
MAINTAINERS
View File

@ -9617,7 +9617,7 @@ M: Chao Yu <chao@kernel.org>
R: Yue Hu <zbestahu@gmail.com>
R: Jeffle Xu <jefflexu@linux.alibaba.com>
R: Sandeep Dhavale <dhavale@google.com>
R: Hongbo Li <lihongbo22@huawei.com>
R: Hongbo Li <hongbohbli@tencent.com>
R: Chunhai Guo <guochunhai@vivo.com>
L: linux-erofs@lists.ozlabs.org
S: Maintained

15
fs/erofs/Kconfig
View File

@ -131,6 +131,20 @@ config EROFS_FS_ZIP_LZMA
Say N if you want to disable LZMA compression support.
config EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS
int "EROFS LZMA default maximum decompression streams"
depends on EROFS_FS_ZIP_LZMA
range 1 NR_CPUS
default 16
help
By default EROFS allocates one LZMA decompression stream per CPU.
Each stream can hold a dictionary of up to 8 MiB taken from the
mounted image, so on systems with many CPUs this can reserve a lot
of memory. This caps the default; the lzma_streams module parameter
still overrides it.
If unsure, keep the default of 16.
config EROFS_FS_ZIP_DEFLATE
bool "EROFS DEFLATE compressed data support"
depends on EROFS_FS_ZIP
@ -189,6 +203,7 @@ config EROFS_FS_PCPU_KTHREAD_HIPRI
config EROFS_FS_PAGE_CACHE_SHARE
bool "EROFS page cache share support (experimental)"
depends on EROFS_FS && EROFS_FS_XATTR
select FS_STACK
help
This enables page cache sharing among inodes with identical
content fingerprints on the same machine.

3
fs/erofs/decompressor_lzma.c
View File

@ -51,7 +51,8 @@ static int __init z_erofs_lzma_init(void)
/* by default, use # of possible CPUs instead */
if (!z_erofs_lzma_nstrms)
z_erofs_lzma_nstrms = num_possible_cpus();
z_erofs_lzma_nstrms = min_t(unsigned int, num_possible_cpus(),
CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS);
for (i = 0; i < z_erofs_lzma_nstrms; ++i) {
struct z_erofs_lzma *strm = kzalloc_obj(*strm);

4
fs/erofs/internal.h
View File

@ -288,8 +288,8 @@ struct erofs_inode {
struct erofs_inode_fingerprint fingerprint;
spinlock_t ishare_lock;
};
/* for each real inode */
struct inode *sharedinode;
/* for each real filesystem inode */
struct dentry *sharedentry;
};
#endif
/* the corresponding vfs inode */

56
fs/erofs/ishare.c
View File

@ -2,14 +2,13 @@
/*
* Copyright (C) 2024, Alibaba Cloud
*/
#include <linux/backing-file.h>
#include <linux/xxhash.h>
#include <linux/mount.h>
#include <linux/security.h>
#include "internal.h"
#include "xattr.h"
#include "../internal.h"
static struct vfsmount *erofs_ishare_mnt;
static int erofs_ishare_iget5_eq(struct inode *inode, void *data)
@ -33,10 +32,12 @@ static int erofs_ishare_iget5_set(struct inode *inode, void *data)
bool erofs_ishare_fill_inode(struct inode *inode)
{
static const struct file_operations empty_fops = {};
struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
const struct address_space_operations *aops;
struct erofs_inode *vi = EROFS_I(inode);
struct erofs_inode_fingerprint fp;
struct dentry *sd;
struct inode *si;
aops = erofs_get_aops(inode);
@ -49,7 +50,9 @@ bool erofs_ishare_fill_inode(struct inode *inode)
xxh32(fp.opaque, fp.size, 0),
erofs_ishare_iget5_eq, erofs_ishare_iget5_set, &fp);
if (si && (inode_state_read_once(si) & I_NEW)) {
si->i_fop = &empty_fops;
si->i_mapping->a_ops = aops;
si->i_mode = 0444 | S_IFREG;
si->i_size = inode->i_size;
unlock_new_inode(si);
} else {
@ -65,7 +68,10 @@ bool erofs_ishare_fill_inode(struct inode *inode)
return false;
}
}
vi->sharedinode = si;
sd = d_obtain_alias(si); /* disconnected denties for sharedinodes */
if (IS_ERR(sd))
return false;
vi->sharedentry = sd;
INIT_LIST_HEAD(&vi->ishare_list);
spin_lock(&EROFS_I(si)->ishare_lock);
list_add(&vi->ishare_list, &EROFS_I(si)->ishare_list);
@ -75,48 +81,40 @@ bool erofs_ishare_fill_inode(struct inode *inode)
void erofs_ishare_free_inode(struct inode *inode)
{
struct erofs_inode *vi = EROFS_I(inode);
struct inode *sharedinode = vi->sharedinode;
struct erofs_inode *vi = EROFS_I(inode), *svi;
if (!sharedinode)
if (!vi->sharedentry)
return;
spin_lock(&EROFS_I(sharedinode)->ishare_lock);
svi = EROFS_I(d_inode(vi->sharedentry));
spin_lock(&svi->ishare_lock);
list_del(&vi->ishare_list);
spin_unlock(&EROFS_I(sharedinode)->ishare_lock);
iput(sharedinode);
vi->sharedinode = NULL;
spin_unlock(&svi->ishare_lock);
dput(vi->sharedentry);
vi->sharedentry = NULL;
}
static int erofs_ishare_file_open(struct inode *inode, struct file *file)
{
struct inode *sharedinode = EROFS_I(inode)->sharedinode;
struct file *realfile;
struct path sharedpath = {
.mnt = erofs_ishare_mnt,
.dentry = EROFS_I(inode)->sharedentry,
};
struct file *rf;
if (file->f_flags & O_DIRECT)
return -EINVAL;
realfile = alloc_empty_backing_file(O_RDONLY|O_NOATIME, current_cred(),
file);
if (IS_ERR(realfile))
return PTR_ERR(realfile);
ihold(sharedinode);
realfile->f_op = &erofs_file_fops;
realfile->f_inode = sharedinode;
realfile->f_mapping = sharedinode->i_mapping;
path_get(&file->f_path);
backing_file_set_user_path(realfile, &file->f_path);
file_ra_state_init(&realfile->f_ra, file->f_mapping);
realfile->private_data = EROFS_I(inode);
file->private_data = realfile;
rf = backing_file_open(file, file->f_flags | O_NOATIME,
&sharedpath, current_cred());
if (IS_ERR(rf))
return PTR_ERR(rf);
file->private_data = rf;
return 0;
}
static int erofs_ishare_file_release(struct inode *inode, struct file *file)
{
struct file *realfile = file->private_data;
iput(realfile->f_inode);
fput(realfile);
fput(file->private_data);
file->private_data = NULL;
return 0;
}