From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Drop using inode->i_mutex from read, since that can result in deadlock with mmap. Ideally we can extend the patch to make sure we don't increase i_size in mmap. But that will break userspace, because application will have to now use truncate(2) to increase i_size in hugetlbfs. AFAIU i_mutex was added in hugetlbfs_read as per http://lkml.indiana.edu/hypermail/linux/kernel/0707.2/3066.html Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> --- fs/hugetlbfs/inode.c | 13 +++++++++---- include/linux/hugetlb.h | 1 + 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 1e85a7a..3d541dd 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -237,8 +237,9 @@ static ssize_t hugetlbfs_read(struct file *filp, char __user *buf, unsigned long end_index; loff_t isize; ssize_t retval = 0; + struct hugetlbfs_inode_info *hinfo = HUGETLBFS_I(inode); - mutex_lock(&inode->i_mutex); + down_read(&hinfo->truncate_sem); /* validate length */ if (len == 0) @@ -308,7 +309,7 @@ static ssize_t hugetlbfs_read(struct file *filp, char __user *buf, } out: *ppos = ((loff_t)index << huge_page_shift(h)) + offset; - mutex_unlock(&inode->i_mutex); + up_read(&hinfo->truncate_sem); return retval; } @@ -407,16 +408,19 @@ static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) pgoff_t pgoff; struct address_space *mapping = inode->i_mapping; struct hstate *h = hstate_inode(inode); + struct hugetlbfs_inode_info *hinfo = HUGETLBFS_I(inode); BUG_ON(offset & ~huge_page_mask(h)); pgoff = offset >> PAGE_SHIFT; + down_write(&hinfo->truncate_sem); i_size_write(inode, offset); mutex_lock(&mapping->i_mmap_mutex); if (!prio_tree_empty(&mapping->i_mmap)) hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); mutex_unlock(&mapping->i_mmap_mutex); truncate_hugepages(inode, offset); + up_write(&hinfo->truncate_sem); return 0; } @@ -694,9 +698,10 @@ static const struct address_space_operations hugetlbfs_aops = { static void init_once(void *foo) { - struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; + struct hugetlbfs_inode_info *hinfo = (struct hugetlbfs_inode_info *)foo; - inode_init_once(&ei->vfs_inode); + init_rwsem(&hinfo->truncate_sem); + inode_init_once(&hinfo->vfs_inode); } const struct file_operations hugetlbfs_file_operations = { diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 8aef867..6d8469a 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -150,6 +150,7 @@ struct hugetlbfs_sb_info { struct hugetlbfs_inode_info { struct shared_policy policy; + struct rw_semaphore truncate_sem; struct inode vfs_inode; }; -- 1.7.9 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>