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mm,fs: split dump_mapping() out from dump_page()

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dump_mapping() is a big chunk of dump_page(), and it'd be handy to be
able to call it when we don't have a struct page.  Split it out and move
it to fs/inode.c.  Take the opportunity to simplify some of the debug
messages a little.

Link: https://lkml.kernel.org/r/20211121121056.2870061-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-01-14 14:05:04 -08:00 committed by Linus Torvalds
parent 26dca996ea
commit 3e9d80a891
3 changed files with 52 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

49
fs/inode.c
View File

@ -526,6 +526,55 @@ void __remove_inode_hash(struct inode *inode)
}
EXPORT_SYMBOL(__remove_inode_hash);
void dump_mapping(const struct address_space *mapping)
{
struct inode *host;
const struct address_space_operations *a_ops;
struct hlist_node *dentry_first;
struct dentry *dentry_ptr;
struct dentry dentry;
unsigned long ino;
/*
* If mapping is an invalid pointer, we don't want to crash
* accessing it, so probe everything depending on it carefully.
*/
if (get_kernel_nofault(host, &mapping->host) ||
get_kernel_nofault(a_ops, &mapping->a_ops)) {
pr_warn("invalid mapping:%px\n", mapping);
return;
}
if (!host) {
pr_warn("aops:%ps\n", a_ops);
return;
}
if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
get_kernel_nofault(ino, &host->i_ino)) {
pr_warn("aops:%ps invalid inode:%px\n", a_ops, host);
return;
}
if (!dentry_first) {
pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
return;
}
dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
if (get_kernel_nofault(dentry, dentry_ptr)) {
pr_warn("aops:%ps ino:%lx invalid dentry:%px\n",
a_ops, ino, dentry_ptr);
return;
}
/*
* if dentry is corrupted, the %pd handler may still crash,
* but it's unlikely that we reach here with a corrupt mapping
*/
pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry);
}
void clear_inode(struct inode *inode)
{
/*

1
include/linux/fs.h
View File

@ -3152,6 +3152,7 @@ extern void unlock_new_inode(struct inode *);
extern void discard_new_inode(struct inode *);
extern unsigned int get_next_ino(void);
extern void evict_inodes(struct super_block *sb);
void dump_mapping(const struct address_space *);
/*
* Userspace may rely on the the inode number being non-zero. For example, glibc

52
mm/debug.c
View File

@ -112,56 +112,8 @@ static void __dump_page(struct page *page)
type = "ksm ";
else if (PageAnon(page))
type = "anon ";
else if (mapping) {
struct inode *host;
const struct address_space_operations *a_ops;
struct hlist_node *dentry_first;
struct dentry *dentry_ptr;
struct dentry dentry;
unsigned long ino;
/*
* mapping can be invalid pointer and we don't want to crash
* accessing it, so probe everything depending on it carefully
*/
if (get_kernel_nofault(host, &mapping->host) ||
get_kernel_nofault(a_ops, &mapping->a_ops)) {
pr_warn("failed to read mapping contents, not a valid kernel address?\n");
goto out_mapping;
}
if (!host) {
pr_warn("aops:%ps\n", a_ops);
goto out_mapping;
}
if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
get_kernel_nofault(ino, &host->i_ino)) {
pr_warn("aops:%ps with invalid host inode %px\n",
a_ops, host);
goto out_mapping;
}
if (!dentry_first) {
pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
goto out_mapping;
}
dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
if (get_kernel_nofault(dentry, dentry_ptr)) {
pr_warn("aops:%ps ino:%lx with invalid dentry %px\n",
a_ops, ino, dentry_ptr);
} else {
/*
* if dentry is corrupted, the %pd handler may still
* crash, but it's unlikely that we reach here with a
* corrupted struct page
*/
pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
a_ops, ino, &dentry);
}
}
out_mapping:
else if (mapping)
dump_mapping(mapping);
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
pr_warn("%sflags: %pGp%s\n", type, &head->flags,