tmpfs: fix kernel BUG in shmem_delete_inode (14fcc23f) · Commits · 戴 / test

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 <kel@otaku42.de> Tested-by:

Kel Modderman <kel@otaku42.de> Signed-off-by:

Hugh Dickins <hugh@veritas.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x] Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/shmem.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

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