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don't put symlink bodies in pagecache into highmem

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kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.

new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases.  page_follow_link_light()
instrumented to yell about anything missed.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2015-11-17 01:07:57 -05:00
parent aa80deab33
commit 21fc61c73c
57 changed files with 81 additions and 46 deletions
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1
fs/udf/inode.c
View File

@@ -1541,6 +1541,7 @@ reread:
case ICBTAG_FILE_TYPE_SYMLINK:
inode->i_data.a_ops = &udf_symlink_aops;
inode->i_op = &page_symlink_inode_operations;
inode_nohighmem(inode);
inode->i_mode = S_IFLNK | S_IRWXUGO;
break;
case ICBTAG_FILE_TYPE_MAIN:

1
fs/udf/namei.c
View File

@@ -922,6 +922,7 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
inode->i_data.a_ops = &udf_symlink_aops;
inode->i_op = &page_symlink_inode_operations;
inode_nohighmem(inode);
if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
struct kernel_lb_addr eloc;

4
fs/udf/symlink.c
View File

@@ -107,7 +107,7 @@ static int udf_symlink_filler(struct file *file, struct page *page)
struct buffer_head *bh = NULL;
unsigned char *symlink;
int err;
unsigned char *p = kmap(page);
unsigned char *p = page_address(page);
struct udf_inode_info *iinfo;
uint32_t pos;
@@ -141,7 +141,6 @@ static int udf_symlink_filler(struct file *file, struct page *page)
up_read(&iinfo->i_data_sem);
SetPageUptodate(page);
kunmap(page);
unlock_page(page);
return 0;
@@ -149,7 +148,6 @@ out_unlock_inode:
up_read(&iinfo->i_data_sem);
SetPageError(page);
out_unmap:
kunmap(page);
unlock_page(page);
return err;
}