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f2fs: avoid deadlock on init_inode_metadata
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Previously, init_inode_metadata does not hold any parent directory's inode
page. So, f2fs_init_acl can grab its parent inode page without any problem.
But, when we use inline_dentry, that page is grabbed during f2fs_add_link,
so that we can fall into deadlock condition like below.

INFO: task mknod:11006 blocked for more than 120 seconds.
      Tainted: G           OE  3.17.0-rc1+ #13
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mknod           D ffff88003fc94580     0 11006  11004 0x00000000
 ffff880007717b10 0000000000000002 ffff88003c323220 ffff880007717fd8
 0000000000014580 0000000000014580 ffff88003daecb30 ffff88003c323220
 ffff88003fc94e80 ffff88003ffbb4e8 ffff880007717ba0 0000000000000002
Call Trace:
 [<ffffffff8173dc40>] ? bit_wait+0x50/0x50
 [<ffffffff8173d4cd>] io_schedule+0x9d/0x130
 [<ffffffff8173dc6c>] bit_wait_io+0x2c/0x50
 [<ffffffff8173da3b>] __wait_on_bit_lock+0x4b/0xb0
 [<ffffffff811640a7>] __lock_page+0x67/0x70
 [<ffffffff810acf50>] ? autoremove_wake_function+0x40/0x40
 [<ffffffff811652cc>] pagecache_get_page+0x14c/0x1e0
 [<ffffffffa029afa9>] get_node_page+0x59/0x130 [f2fs]
 [<ffffffffa02a63ad>] read_all_xattrs+0x24d/0x430 [f2fs]
 [<ffffffffa02a6ca2>] f2fs_getxattr+0x52/0xe0 [f2fs]
 [<ffffffffa02a7481>] f2fs_get_acl+0x41/0x2d0 [f2fs]
 [<ffffffff8122d847>] get_acl+0x47/0x70
 [<ffffffff8122db5a>] posix_acl_create+0x5a/0x150
 [<ffffffffa02a7759>] f2fs_init_acl+0x29/0xcb [f2fs]
 [<ffffffffa0286a8d>] init_inode_metadata+0x5d/0x340 [f2fs]
 [<ffffffffa029253a>] f2fs_add_inline_entry+0x12a/0x2e0 [f2fs]
 [<ffffffffa0286ea5>] __f2fs_add_link+0x45/0x4a0 [f2fs]
 [<ffffffffa028b5b6>] ? f2fs_new_inode+0x146/0x220 [f2fs]
 [<ffffffffa028b816>] f2fs_mknod+0x86/0xf0 [f2fs]
 [<ffffffff811e3ec1>] vfs_mknod+0xe1/0x160
 [<ffffffff811e4b26>] SyS_mknod+0x1f6/0x200
 [<ffffffff81741d7f>] tracesys+0xe1/0xe6

Signed-off-by: Jaegeuk Kim <[email protected]>
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Jaegeuk Kim committed Nov 4, 2014
1 parent 59a0615 commit bce8d11
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Showing 7 changed files with 157 additions and 22 deletions.
144 changes: 138 additions & 6 deletions fs/f2fs/acl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -162,7 +162,8 @@ static void *f2fs_acl_to_disk(const struct posix_acl *acl, size_t *size)
return ERR_PTR(-EINVAL);
}

struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
struct page *dpage)
{
int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
void *value = NULL;
Expand All @@ -172,12 +173,13 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
if (type == ACL_TYPE_ACCESS)
name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;

retval = f2fs_getxattr(inode, name_index, "", NULL, 0);
retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
if (retval > 0) {
value = kmalloc(retval, GFP_F2FS_ZERO);
if (!value)
return ERR_PTR(-ENOMEM);
retval = f2fs_getxattr(inode, name_index, "", value, retval);
retval = f2fs_getxattr(inode, name_index, "", value,
retval, dpage);
}

if (retval > 0)
Expand All @@ -194,6 +196,11 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
return acl;
}

struct posix_acl *f2fs_get_acl(struct inode *inode, int type)
{
return __f2fs_get_acl(inode, type, NULL);
}

static int __f2fs_set_acl(struct inode *inode, int type,
struct posix_acl *acl, struct page *ipage)
{
Expand Down Expand Up @@ -249,12 +256,137 @@ int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
return __f2fs_set_acl(inode, type, acl, NULL);
}

int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage)
/*
* Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
* are copied from posix_acl.c
*/
static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
gfp_t flags)
{
struct posix_acl *clone = NULL;

if (acl) {
int size = sizeof(struct posix_acl) + acl->a_count *
sizeof(struct posix_acl_entry);
clone = kmemdup(acl, size, flags);
if (clone)
atomic_set(&clone->a_refcount, 1);
}
return clone;
}

static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
{
struct posix_acl_entry *pa, *pe;
struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
umode_t mode = *mode_p;
int not_equiv = 0;

/* assert(atomic_read(acl->a_refcount) == 1); */

FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
case ACL_USER_OBJ:
pa->e_perm &= (mode >> 6) | ~S_IRWXO;
mode &= (pa->e_perm << 6) | ~S_IRWXU;
break;

case ACL_USER:
case ACL_GROUP:
not_equiv = 1;
break;

case ACL_GROUP_OBJ:
group_obj = pa;
break;

case ACL_OTHER:
pa->e_perm &= mode | ~S_IRWXO;
mode &= pa->e_perm | ~S_IRWXO;
break;

case ACL_MASK:
mask_obj = pa;
not_equiv = 1;
break;

default:
return -EIO;
}
}

if (mask_obj) {
mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
} else {
if (!group_obj)
return -EIO;
group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
}

*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
return not_equiv;
}

static int f2fs_acl_create(struct inode *dir, umode_t *mode,
struct posix_acl **default_acl, struct posix_acl **acl,
struct page *dpage)
{
struct posix_acl *p;
int ret;

if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
goto no_acl;

p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
if (IS_ERR(p)) {
if (p == ERR_PTR(-EOPNOTSUPP))
goto apply_umask;
return PTR_ERR(p);
}

if (!p)
goto apply_umask;

*acl = f2fs_acl_clone(p, GFP_NOFS);
if (!*acl)
return -ENOMEM;

ret = f2fs_acl_create_masq(*acl, mode);
if (ret < 0) {
posix_acl_release(*acl);
return -ENOMEM;
}

if (ret == 0) {
posix_acl_release(*acl);
*acl = NULL;
}

if (!S_ISDIR(*mode)) {
posix_acl_release(p);
*default_acl = NULL;
} else {
*default_acl = p;
}
return 0;

apply_umask:
*mode &= ~current_umask();
no_acl:
*default_acl = NULL;
*acl = NULL;
return 0;
}

int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
struct page *dpage)
{
struct posix_acl *default_acl, *acl;
struct posix_acl *default_acl = NULL, *acl = NULL;
int error = 0;

error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
if (error)
return error;

Expand Down
5 changes: 3 additions & 2 deletions fs/f2fs/acl.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,14 +38,15 @@ struct f2fs_acl_header {

extern struct posix_acl *f2fs_get_acl(struct inode *, int);
extern int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
extern int f2fs_init_acl(struct inode *, struct inode *, struct page *);
extern int f2fs_init_acl(struct inode *, struct inode *, struct page *,
struct page *);
#else
#define f2fs_check_acl NULL
#define f2fs_get_acl NULL
#define f2fs_set_acl NULL

static inline int f2fs_init_acl(struct inode *inode, struct inode *dir,
struct page *page)
struct page *ipage, struct page *dpage)
{
return 0;
}
Expand Down
10 changes: 5 additions & 5 deletions fs/f2fs/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -363,8 +363,8 @@ static int make_empty_dir(struct inode *inode,
return 0;
}

struct page *init_inode_metadata(struct inode *inode,
struct inode *dir, const struct qstr *name)
struct page *init_inode_metadata(struct inode *inode, struct inode *dir,
const struct qstr *name, struct page *dpage)
{
struct page *page;
int err;
Expand All @@ -380,7 +380,7 @@ struct page *init_inode_metadata(struct inode *inode,
goto error;
}

err = f2fs_init_acl(inode, dir, page);
err = f2fs_init_acl(inode, dir, page, dpage);
if (err)
goto put_error;

Expand Down Expand Up @@ -541,7 +541,7 @@ int __f2fs_add_link(struct inode *dir, const struct qstr *name,
f2fs_wait_on_page_writeback(dentry_page, DATA);

down_write(&F2FS_I(inode)->i_sem);
page = init_inode_metadata(inode, dir, name);
page = init_inode_metadata(inode, dir, name, NULL);
if (IS_ERR(page)) {
err = PTR_ERR(page);
goto fail;
Expand Down Expand Up @@ -580,7 +580,7 @@ int f2fs_do_tmpfile(struct inode *inode, struct inode *dir)
int err = 0;

down_write(&F2FS_I(inode)->i_sem);
page = init_inode_metadata(inode, dir, NULL);
page = init_inode_metadata(inode, dir, NULL, NULL);
if (IS_ERR(page)) {
err = PTR_ERR(page);
goto fail;
Expand Down
2 changes: 1 addition & 1 deletion fs/f2fs/f2fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1247,7 +1247,7 @@ void set_de_type(struct f2fs_dir_entry *, struct inode *);
struct f2fs_dir_entry *find_target_dentry(struct qstr *, int *, const void *,
struct f2fs_dir_entry *, __u8 (*)[F2FS_SLOT_LEN]);
struct page *init_inode_metadata(struct inode *, struct inode *,
const struct qstr *);
const struct qstr *, struct page *);
void update_parent_metadata(struct inode *, struct inode *, unsigned int);
int room_for_filename(const void *, int, int);
void f2fs_drop_nlink(struct inode *, struct inode *, struct page *);
Expand Down
6 changes: 3 additions & 3 deletions fs/f2fs/inline.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -427,14 +427,14 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name,
goto out;
}

f2fs_wait_on_page_writeback(ipage, NODE);

down_write(&F2FS_I(inode)->i_sem);
page = init_inode_metadata(inode, dir, name);
page = init_inode_metadata(inode, dir, name, ipage);
if (IS_ERR(page)) {
err = PTR_ERR(page);
goto fail;
}

f2fs_wait_on_page_writeback(ipage, NODE);
de = &dentry_blk->dentry[bit_pos];
de->hash_code = name_hash;
de->name_len = cpu_to_le16(namelen);
Expand Down
6 changes: 3 additions & 3 deletions fs/f2fs/xattr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -83,7 +83,7 @@ static int f2fs_xattr_generic_get(struct dentry *dentry, const char *name,
}
if (strcmp(name, "") == 0)
return -EINVAL;
return f2fs_getxattr(dentry->d_inode, type, name, buffer, size);
return f2fs_getxattr(dentry->d_inode, type, name, buffer, size, NULL);
}

static int f2fs_xattr_generic_set(struct dentry *dentry, const char *name,
Expand Down Expand Up @@ -398,7 +398,7 @@ static inline int write_all_xattrs(struct inode *inode, __u32 hsize,
}

int f2fs_getxattr(struct inode *inode, int index, const char *name,
void *buffer, size_t buffer_size)
void *buffer, size_t buffer_size, struct page *ipage)
{
struct f2fs_xattr_entry *entry;
void *base_addr;
Expand All @@ -412,7 +412,7 @@ int f2fs_getxattr(struct inode *inode, int index, const char *name,
if (len > F2FS_NAME_LEN)
return -ERANGE;

base_addr = read_all_xattrs(inode, NULL);
base_addr = read_all_xattrs(inode, ipage);
if (!base_addr)
return -ENOMEM;

Expand Down
6 changes: 4 additions & 2 deletions fs/f2fs/xattr.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -115,7 +115,8 @@ extern const struct xattr_handler *f2fs_xattr_handlers[];

extern int f2fs_setxattr(struct inode *, int, const char *,
const void *, size_t, struct page *, int);
extern int f2fs_getxattr(struct inode *, int, const char *, void *, size_t);
extern int f2fs_getxattr(struct inode *, int, const char *, void *,
size_t, struct page *);
extern ssize_t f2fs_listxattr(struct dentry *, char *, size_t);
#else

Expand All @@ -126,7 +127,8 @@ static inline int f2fs_setxattr(struct inode *inode, int index,
return -EOPNOTSUPP;
}
static inline int f2fs_getxattr(struct inode *inode, int index,
const char *name, void *buffer, size_t buffer_size)
const char *name, void *buffer,
size_t buffer_size, struct page *dpage)
{
return -EOPNOTSUPP;
}
Expand Down

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