[PATCHv2 1/1] ext4: don't put symlink in pagecache into highmem
flat view
From: Jin Qian <hidden>
Date: 2018-02-06 19:09:37
Also in:
linux-fsdevel, lkml, stable
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
From: Jin Qian <redacted>
partial backport from 21fc61c73c3903c4c312d0802da01ec2b323d174 upstream
to v4.4 to prevent virt_to_page on highmem.
ext4_encrypted_follow_link uses kmap() for cpage
caddr = kmap(cpage);
_ext4_fname_disk_to_usr calls virt_to_page on the kmapped address.
_ext4_fname_disk_to_usr()
ext4_fname_decrypt()
sg_init_one()
sg_init_one(&src_sg, iname->name, iname->len);
sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jin Qian <redacted>
Signed-off-by: Jin Qian <redacted>
---
fs/ext4/inode.c | 1 +
fs/ext4/namei.c | 1 +
fs/ext4/symlink.c | 10 +++-------
fs/inode.c | 6 ++++++
include/linux/fs.h | 1 +
5 files changed, 12 insertions(+), 7 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/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 */
--
2.16.0.rc1.238.g530d649a79-goog