don't put symlink bodies in pagecache into highmem

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 <[email protected]>
dzndl · Dec 9, 2015 · 21fc61c · 21fc61c
1 parent aa80dea
commit 21fc61c
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Showing 57 changed files with 81 additions and 46 deletions.
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
@@ -504,3 +504,8 @@ in your dentry operations instead.
 [mandatory]
 	__fd_install() & fd_install() can now sleep. Callers should not
 	hold a spinlock	or other resources that do not allow a schedule.
+--
+[mandatory]
+	any symlink that might use page_follow_link_light/page_put_link() must
+	have inode_nohighmem(inode) called before anything might start playing with
+	its pagecache.
diff --git a/fs/affs/inode.c b/fs/affs/inode.c
@@ -140,6 +140,7 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino)
 		break;
 	case ST_SOFTLINK:
 		inode->i_mode |= S_IFLNK;
+		inode_nohighmem(inode);
 		inode->i_op = &affs_symlink_inode_operations;
 		inode->i_data.a_ops = &affs_symlink_aops;
 		break;

diff --git a/fs/affs/namei.c b/fs/affs/namei.c
@@ -344,6 +344,7 @@ affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 		return -ENOSPC;
 
 	inode->i_op = &affs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_data.a_ops = &affs_symlink_aops;
 	inode->i_mode = S_IFLNK | 0777;
 	mode_to_prot(inode);

diff --git a/fs/affs/symlink.c b/fs/affs/symlink.c
@@ -14,7 +14,7 @@ static int affs_symlink_readpage(struct file *file, struct page *page)
 {
 	struct buffer_head *bh;
 	struct inode *inode = page->mapping->host;
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct slink_front *lf;
 	int			 i, j;
 	char			 c;
@@ -57,12 +57,10 @@ static int affs_symlink_readpage(struct file *file, struct page *page)
 	link[i] = '\0';
 	affs_brelse(bh);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
@@ -56,6 +56,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
 	case AFS_FTYPE_SYMLINK:
 		inode->i_mode	= S_IFLNK | vnode->status.mode;
 		inode->i_op	= &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		break;
 	default:
 		printk("kAFS: AFS vnode with undefined type\n");

diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
@@ -397,6 +397,7 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &befs_symlink_aops;
 		} else {
 			inode->i_link = befs_ino->i_data.symlink;
@@ -469,7 +470,7 @@ static int befs_symlink_readpage(struct file *unused, struct page *page)
 	struct befs_inode_info *befs_ino = BEFS_I(inode);
 	befs_data_stream *data = &befs_ino->i_data.ds;
 	befs_off_t len = data->size;
-	char *link = kmap(page);
+	char *link = page_address(page);
 
 	if (len == 0 || len > PAGE_SIZE) {
 		befs_error(sb, "Long symlink with illegal length");
@@ -483,12 +484,10 @@ static int befs_symlink_readpage(struct file *unused, struct page *page)
 	}
 	link[len - 1] = '\0';
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
@@ -3774,6 +3774,7 @@ static void btrfs_read_locked_inode(struct inode *inode)
 		break;
 	case S_IFLNK:
 		inode->i_op = &btrfs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &btrfs_symlink_aops;
 		break;
 	default:
@@ -9705,6 +9706,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 	btrfs_free_path(path);
 
 	inode->i_op = &btrfs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &btrfs_symlink_aops;
 	inode_set_bytes(inode, name_len);
 	btrfs_i_size_write(inode, name_len);

diff --git a/fs/coda/cnode.c b/fs/coda/cnode.c
@@ -8,6 +8,7 @@
 
 #include <linux/coda.h>
 #include <linux/coda_psdev.h>
+#include <linux/pagemap.h>
 #include "coda_linux.h"
 
 static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
@@ -35,6 +36,7 @@ static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr)
                 inode->i_fop = &coda_dir_operations;
         } else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &coda_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &coda_symlink_aops;
 		inode->i_mapping = &inode->i_data;
 	} else

diff --git a/fs/coda/symlink.c b/fs/coda/symlink.c
@@ -26,21 +26,19 @@ static int coda_symlink_filler(struct file *file, struct page *page)
 	int error;
 	struct coda_inode_info *cii;
 	unsigned int len = PAGE_SIZE;
-	char *p = kmap(page);
+	char *p = page_address(page);
 
 	cii = ITOC(inode);
 
 	error = venus_readlink(inode->i_sb, &cii->c_fid, p, &len);
 	if (error)
 		goto fail;
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return error;
 }

diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
@@ -100,6 +100,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,
 		break;
 	case S_IFLNK:
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &cramfs_aops;
 		break;
 	default:

diff --git a/fs/efs/inode.c b/fs/efs/inode.c
@@ -151,6 +151,7 @@ struct inode *efs_iget(struct super_block *super, unsigned long ino)
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_data.a_ops = &efs_symlink_aops;
 			break;
 		case S_IFCHR:

diff --git a/fs/efs/symlink.c b/fs/efs/symlink.c
@@ -13,7 +13,7 @@
 
 static int efs_symlink_readpage(struct file *file, struct page *page)
 {
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct buffer_head * bh;
 	struct inode * inode = page->mapping->host;
 	efs_block_t size = inode->i_size;
@@ -39,12 +39,10 @@ static int efs_symlink_readpage(struct file *file, struct page *page)
 	}
 	link[size] = '\0';
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
@@ -1227,6 +1227,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
 			inode->i_link = (char *)oi->i_data;
 		} else {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &exofs_aops;
 		}
 	} else {

diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
@@ -111,6 +111,7 @@ static int exofs_symlink(struct inode *dir, struct dentry *dentry,
 	if (l > sizeof(oi->i_data)) {
 		/* slow symlink */
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &exofs_aops;
 		memset(oi->i_data, 0, sizeof(oi->i_data));
 

diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
@@ -1420,6 +1420,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 				sizeof(ei->i_data) - 1);
 		} else {
 			inode->i_op = &ext2_symlink_inode_operations;
+			inode_nohighmem(inode);
 			if (test_opt(inode->i_sb, NOBH))
 				inode->i_mapping->a_ops = &ext2_nobh_aops;
 			else

diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
@@ -183,6 +183,7 @@ static int ext2_symlink (struct inode * dir, struct dentry * dentry,
 	if (l > sizeof (EXT2_I(inode)->i_data)) {
 		/* slow symlink */
 		inode->i_op = &ext2_symlink_inode_operations;
+		inode_nohighmem(inode);
 		if (test_opt(inode->i_sb, NOBH))
 			inode->i_mapping->a_ops = &ext2_nobh_aops;
 		else

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
@@ -4283,6 +4283,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 			inode->i_op = &ext4_symlink_inode_operations;
 			ext4_set_aops(inode);
 		}
+		inode_nohighmem(inode);
 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 		inode->i_op = &ext4_special_inode_operations;

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
@@ -3132,6 +3132,7 @@ static int ext4_symlink(struct inode *dir,
 	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
 		if (!encryption_required)
 			inode->i_op = &ext4_symlink_inode_operations;
+		inode_nohighmem(inode);
 		ext4_set_aops(inode);
 		/*
 		 * We cannot call page_symlink() with transaction started

diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
@@ -45,7 +45,7 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook
 		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
 		if (IS_ERR(cpage))
 			return ERR_CAST(cpage);
-		caddr = kmap(cpage);
+		caddr = page_address(cpage);
 		caddr[size] = 0;
 	}
 
@@ -75,16 +75,12 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook
 	/* Null-terminate the name */
 	if (res <= plen)
 		paddr[res] = '\0';
-	if (cpage) {
-		kunmap(cpage);
+	if (cpage)
 		page_cache_release(cpage);
-	}
 	return *cookie = paddr;
 errout:
-	if (cpage) {
-		kunmap(cpage);
+	if (cpage)
 		page_cache_release(cpage);
-	}
 	kfree(paddr);
 	return ERR_PTR(res);
 }

diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
@@ -202,6 +202,7 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
 			inode->i_op = &f2fs_encrypted_symlink_inode_operations;
 		else
 			inode->i_op = &f2fs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &f2fs_dblock_aops;
 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
@@ -351,6 +351,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 		inode->i_op = &f2fs_encrypted_symlink_inode_operations;
 	else
 		inode->i_op = &f2fs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &f2fs_dblock_aops;
 
 	f2fs_lock_op(sbi);
@@ -942,7 +943,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	cpage = read_mapping_page(inode->i_mapping, 0, NULL);
 	if (IS_ERR(cpage))
 		return ERR_CAST(cpage);
-	caddr = kmap(cpage);
+	caddr = page_address(cpage);
 	caddr[size] = 0;
 
 	/* Symlink is encrypted */
@@ -982,13 +983,11 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	/* Null-terminate the name */
 	paddr[res] = '\0';
 
-	kunmap(cpage);
 	page_cache_release(cpage);
 	return *cookie = paddr;
 errout:
 	kfree(cstr.name);
 	f2fs_fname_crypto_free_buffer(&pstr);
-	kunmap(cpage);
 	page_cache_release(cpage);
 	return ERR_PTR(res);
 }

diff --git a/fs/freevxfs/vxfs_inode.c b/fs/freevxfs/vxfs_inode.c
@@ -326,6 +326,7 @@ vxfs_iget(struct super_block *sbp, ino_t ino)
 	} else if (S_ISLNK(ip->i_mode)) {
 		if (!VXFS_ISIMMED(vip)) {
 			ip->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(ip);
 			ip->i_mapping->a_ops = &vxfs_aops;
 		} else {
 			ip->i_op = &simple_symlink_inode_operations;

diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
@@ -403,6 +403,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode)
 	} else if (S_ISLNK(inode->i_mode)) {
 		sbi->file_count++;
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &hfsplus_aops;
 		hip->clump_blocks = 1;
 	} else
@@ -526,6 +527,7 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd)
 			inode->i_mapping->a_ops = &hfsplus_aops;
 		} else if (S_ISLNK(inode->i_mode)) {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &hfsplus_aops;
 		} else {
 			init_special_inode(inode, inode->i_mode,

diff --git a/fs/hpfs/inode.c b/fs/hpfs/inode.c
@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)
 			kfree(ea);
 			i->i_mode = S_IFLNK | 0777;
 			i->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(i);
 			i->i_data.a_ops = &hpfs_symlink_aops;
 			set_nlink(i, 1);
 			i->i_size = ea_size;

diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c
@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy
 	result->i_blocks = 1;
 	set_nlink(result, 1);
 	result->i_size = strlen(symlink);
+	inode_nohighmem(result);
 	result->i_op = &page_symlink_inode_operations;
 	result->i_data.a_ops = &hpfs_symlink_aops;
 
@@ -500,7 +501,7 @@ static int hpfs_rmdir(struct inode *dir, struct dentry *dentry)
 
 static int hpfs_symlink_readpage(struct file *file, struct page *page)
 {
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct inode *i = page->mapping->host;
 	struct fnode *fnode;
 	struct buffer_head *bh;
@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page)
 		goto fail;
 	hpfs_unlock(i->i_sb);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
 fail:
 	hpfs_unlock(i->i_sb);
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
@@ -760,6 +760,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			break;
 		}
 		lockdep_annotate_inode_mutex_key(inode);

diff --git a/fs/inode.c b/fs/inode.c
@@ -2028,3 +2028,9 @@ void inode_set_flags(struct inode *inode, unsigned int flags,
 				  new_flags) != old_flags));
 }
 EXPORT_SYMBOL(inode_set_flags);
+
+void inode_nohighmem(struct inode *inode)
+{
+	mapping_set_gfp_mask(inode->i_mapping, GFP_USER);
+}
+EXPORT_SYMBOL(inode_nohighmem);
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
@@ -1417,6 +1417,7 @@ static int isofs_read_inode(struct inode *inode, int relocated)
 		inode->i_fop = &isofs_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &isofs_symlink_aops;
 	} else
 		/* XXX - parse_rock_ridge_inode() had already set i_rdev. */