From: Hugh Dickins Date: Mon, 28 Jul 2008 22:46:19 +0000 (-0700) Subject: tmpfs: fix kernel BUG in shmem_delete_inode X-Git-Tag: v2.6.27-rc1~21 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=14fcc23fdc78e9d32372553ccf21758a9bd56fa1;p=linux-2.6 tmpfs: fix kernel BUG in shmem_delete_inode SuSE's insserve initscript ordering program hits kernel BUG at mm/shmem.c:814 on 2.6.26. It's using posix_fadvise on directories, and the shmem_readpage method added in 2.6.23 is letting POSIX_FADV_WILLNEED allocate useless pages to a tmpfs directory, incrementing i_blocks count but never decrementing it. Fix this by assigning shmem_aops (pointing to readpage and writepage and set_page_dirty) only when it's needed, on a regular file or a long symlink. Many thanks to Kel for outstanding bugreport and steps to reproduce it. Reported-by: Kel Modderman Tested-by: Kel Modderman Signed-off-by: Hugh Dickins Cc: [2.6.25.x, 2.6.26.x] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/shmem.c b/mm/shmem.c index 952d361774..c1e5a3b4f7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1513,7 +1513,6 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) inode->i_uid = current->fsuid; inode->i_gid = current->fsgid; inode->i_blocks = 0; - inode->i_mapping->a_ops = &shmem_aops; inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_generation = get_seconds(); @@ -1528,6 +1527,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) init_special_inode(inode, mode, dev); break; case S_IFREG: + inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_inode_operations; inode->i_fop = &shmem_file_operations; mpol_shared_policy_init(&info->policy, @@ -1929,6 +1929,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s return error; } unlock_page(page); + inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; kaddr = kmap_atomic(page, KM_USER0); memcpy(kaddr, symname, len);