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authorAl Viro <viro@zeniv.linux.org.uk>2015-11-17 01:07:57 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-16 20:09:38 +0100
commit076e4ab3279eb3ddb206de44d04df7aeb2428e09 (patch)
tree9c68c20e8d2241455fb03c68868c1da639a15afb
parent33813d43dd593e1c32c567c75483233212b825ae (diff)
don't put symlink bodies in pagecache into highmem
commit 21fc61c73c3903c4c312d0802da01ec2b323d174 upstream. 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> Signed-off-by: Jin Qian <jinqian@google.com> Signed-off-by: Jin Qian <jinqian@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ext4/inode.c1
-rw-r--r--fs/ext4/namei.c1
-rw-r--r--fs/ext4/symlink.c10
-rw-r--r--fs/f2fs/inode.c1
-rw-r--r--fs/f2fs/namei.c5
-rw-r--r--fs/inode.c6
-rw-r--r--include/linux/fs.h1
7 files changed, 15 insertions, 10 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4df1cb19a243..f0cabc8c96cb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4417,6 +4417,7 @@ 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
index 4c36dca486cc..32960b3ecd4f 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3151,6 +3151,7 @@ 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
index e8e7af62ac95..287c3980fa0b 100644
--- 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
index 97e20decacb4..5528801a5baf 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -202,6 +202,7 @@ make_now:
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
index 2c32110f9fc0..484df6850747 100644
--- 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/inode.c b/fs/inode.c
index b0edef500590..b95615f3fc50 100644
--- 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/include/linux/fs.h b/include/linux/fs.h
index c8decb7075d6..f746a59fcc88 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3066,5 +3066,6 @@ static inline bool dir_relax(struct inode *inode)
}
extern bool path_noexec(const struct path *path);
+extern void inode_nohighmem(struct inode *inode);
#endif /* _LINUX_FS_H */