Files
linux/fs/gfs2/inode.h
Andreas Gruenbacher 2c5f4a5347 gfs2: Prevent recursive memory reclaim
Function new_inode() returns a new inode with inode->i_mapping->gfp_mask
set to GFP_HIGHUSER_MOVABLE.  This value includes the __GFP_FS flag, so
allocations in that address space can recurse into filesystem memory
reclaim.  We don't want that to happen because it can consume a
significant amount of stack memory.

Worse than that is that it can also deadlock: for example, in several
places, gfs2_unstuff_dinode() is called inside filesystem transactions.
This calls filemap_grab_folio(), which can allocate a new folio, which
can trigger memory reclaim.  If memory reclaim recurses into the
filesystem and starts another transaction, a deadlock will ensue.

To fix these kinds of problems, prevent memory reclaim from recursing
into filesystem code by making sure that the gfp_mask of inode address
spaces doesn't include __GFP_FS.

The "meta" and resource group address spaces were already using GFP_NOFS
as their gfp_mask (which doesn't include __GFP_FS).  The default value
of GFP_HIGHUSER_MOVABLE is less restrictive than GFP_NOFS, though.  To
avoid being overly limiting, use the default value and only knock off
the __GFP_FS flag.  I'm not sure if this will actually make a
difference, but it also shouldn't hurt.

This patch is loosely based on commit ad22c7a043 ("xfs: prevent stack
overflows from page cache allocation").

Fixes xfstest generic/273.

Fixes: dc0b943523 ("gfs: Don't use GFP_NOFS in gfs2_unstuff_dinode")
Reviewed-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
2025-11-26 12:57:10 +00:00

136 lines
3.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*/
#ifndef __INODE_DOT_H__
#define __INODE_DOT_H__
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/mm.h>
#include "util.h"
bool gfs2_release_folio(struct folio *folio, gfp_t gfp_mask);
ssize_t gfs2_internal_read(struct gfs2_inode *ip,
char *buf, loff_t *pos, size_t size);
void gfs2_set_aops(struct inode *inode);
static inline int gfs2_is_stuffed(const struct gfs2_inode *ip)
{
return !ip->i_height;
}
static inline int gfs2_is_jdata(const struct gfs2_inode *ip)
{
return ip->i_diskflags & GFS2_DIF_JDATA;
}
static inline bool gfs2_is_ordered(const struct gfs2_sbd *sdp)
{
return sdp->sd_args.ar_data == GFS2_DATA_ORDERED;
}
static inline bool gfs2_is_writeback(const struct gfs2_sbd *sdp)
{
return sdp->sd_args.ar_data == GFS2_DATA_WRITEBACK;
}
static inline int gfs2_is_dir(const struct gfs2_inode *ip)
{
return S_ISDIR(ip->i_inode.i_mode);
}
static inline void gfs2_set_inode_blocks(struct inode *inode, u64 blocks)
{
inode->i_blocks = blocks << (inode->i_blkbits - SECTOR_SHIFT);
}
static inline u64 gfs2_get_inode_blocks(const struct inode *inode)
{
return inode->i_blocks >> (inode->i_blkbits - SECTOR_SHIFT);
}
static inline void gfs2_add_inode_blocks(struct inode *inode, s64 change)
{
change <<= inode->i_blkbits - SECTOR_SHIFT;
gfs2_assert(GFS2_SB(inode), (change >= 0 || inode->i_blocks >= -change));
inode->i_blocks += change;
}
static inline int gfs2_check_inum(const struct gfs2_inode *ip, u64 no_addr,
u64 no_formal_ino)
{
return ip->i_no_addr == no_addr && ip->i_no_formal_ino == no_formal_ino;
}
static inline void gfs2_inum_out(const struct gfs2_inode *ip,
struct gfs2_dirent *dent)
{
dent->de_inum.no_formal_ino = cpu_to_be64(ip->i_no_formal_ino);
dent->de_inum.no_addr = cpu_to_be64(ip->i_no_addr);
}
static inline int gfs2_check_internal_file_size(struct inode *inode,
u64 minsize, u64 maxsize)
{
u64 size = i_size_read(inode);
if (size < minsize || size > maxsize)
goto err;
if (size & (BIT(inode->i_blkbits) - 1))
goto err;
return 0;
err:
gfs2_consist_inode(GFS2_I(inode));
return -EIO;
}
void gfs2_setup_inode(struct inode *inode);
struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type,
u64 no_addr, u64 no_formal_ino,
unsigned int blktype);
struct inode *gfs2_lookup_by_inum(struct gfs2_sbd *sdp, u64 no_addr,
u64 no_formal_ino,
unsigned int blktype);
int gfs2_dinode_dealloc(struct gfs2_inode *ip);
struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
int is_root);
int gfs2_permission(struct mnt_idmap *idmap,
struct inode *inode, int mask);
struct inode *gfs2_lookup_meta(struct inode *dip, const char *name);
void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf);
int gfs2_open_common(struct inode *inode, struct file *file);
loff_t gfs2_seek_data(struct file *file, loff_t offset);
loff_t gfs2_seek_hole(struct file *file, loff_t offset);
extern const struct file_operations gfs2_file_fops_nolock;
extern const struct file_operations gfs2_dir_fops_nolock;
int gfs2_fileattr_get(struct dentry *dentry, struct file_kattr *fa);
int gfs2_fileattr_set(struct mnt_idmap *idmap,
struct dentry *dentry, struct file_kattr *fa);
void gfs2_set_inode_flags(struct inode *inode);
#ifdef CONFIG_GFS2_FS_LOCKING_DLM
extern const struct file_operations gfs2_file_fops;
extern const struct file_operations gfs2_dir_fops;
static inline int gfs2_localflocks(const struct gfs2_sbd *sdp)
{
return sdp->sd_args.ar_localflocks;
}
#else /* Single node only */
#define gfs2_file_fops gfs2_file_fops_nolock
#define gfs2_dir_fops gfs2_dir_fops_nolock
static inline int gfs2_localflocks(const struct gfs2_sbd *sdp)
{
return 1;
}
#endif /* CONFIG_GFS2_FS_LOCKING_DLM */
#endif /* __INODE_DOT_H__ */