From b5bcdda32736b94a7d178d156d80a69f536ad468 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 20 Jul 2012 23:28:46 +0400 Subject: take grabbing f->f_path to do_dentry_open() Signed-off-by: Al Viro --- fs/open.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'fs/open.c') diff --git a/fs/open.c b/fs/open.c index 1e914b3..8d2c897 100644 --- a/fs/open.c +++ b/fs/open.c @@ -654,6 +654,7 @@ static int do_dentry_open(struct file *f, if (unlikely(f->f_flags & O_PATH)) f->f_mode = FMODE_PATH; + path_get(&f->f_path); inode = f->f_path.dentry->d_inode; if (f->f_mode & FMODE_WRITE) { error = __get_file_write_access(inode, f->f_path.mnt); @@ -739,9 +740,7 @@ int finish_open(struct file *file, struct dentry *dentry, int error; BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */ - mntget(file->f_path.mnt); - file->f_path.dentry = dget(dentry); - + file->f_path.dentry = dentry; error = do_dentry_open(file, open, current_cred()); if (!error) *opened |= FILE_OPENED; @@ -784,7 +783,6 @@ struct file *dentry_open(const struct path *path, int flags, f->f_flags = flags; f->f_path = *path; - path_get(&f->f_path); error = do_dentry_open(f, NULL, cred); if (!error) { error = open_check_o_direct(f); -- cgit v1.1 From eb04c28288bb0098d0e75d81ba2a575239de71d8 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 12 Jun 2012 16:20:35 +0200 Subject: fs: Add freezing handling to mnt_want_write() / mnt_drop_write() Most of places where we want freeze protection coincides with the places where we also have remount-ro protection. So make mnt_want_write() and mnt_drop_write() (and their _file alternative) prevent freezing as well. For the few cases that are really interested only in remount-ro protection provide new function variants. BugLink: https://bugs.launchpad.net/bugs/897421 Tested-by: Kamal Mostafa Tested-by: Peter M. Petrakis Tested-by: Dann Frazier Tested-by: Massimo Morana Signed-off-by: Jan Kara Signed-off-by: Al Viro --- fs/open.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/open.c') diff --git a/fs/open.c b/fs/open.c index 8d2c897..9ddc185 100644 --- a/fs/open.c +++ b/fs/open.c @@ -620,7 +620,7 @@ static inline int __get_file_write_access(struct inode *inode, /* * Balanced in __fput() */ - error = mnt_want_write(mnt); + error = __mnt_want_write(mnt); if (error) put_write_access(inode); } -- cgit v1.1 From 14da9200140f8d722ad1767dfabadebd8b34f2ad Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Tue, 12 Jun 2012 16:20:37 +0200 Subject: fs: Protect write paths by sb_start_write - sb_end_write There are several entry points which dirty pages in a filesystem. mmap (handled by block_page_mkwrite()), buffered write (handled by __generic_file_aio_write()), splice write (generic_file_splice_write), truncate, and fallocate (these can dirty last partial page - handled inside each filesystem separately). Protect these places with sb_start_write() and sb_end_write(). ->page_mkwrite() calls are particularly complex since they are called with mmap_sem held and thus we cannot use standard sb_start_write() due to lock ordering constraints. We solve the problem by using a special freeze protection sb_start_pagefault() which ranks below mmap_sem. BugLink: https://bugs.launchpad.net/bugs/897421 Tested-by: Kamal Mostafa Tested-by: Peter M. Petrakis Tested-by: Dann Frazier Tested-by: Massimo Morana Signed-off-by: Jan Kara Signed-off-by: Al Viro --- fs/open.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'fs/open.c') diff --git a/fs/open.c b/fs/open.c index 9ddc185..f3d96e7 100644 --- a/fs/open.c +++ b/fs/open.c @@ -164,11 +164,13 @@ static long do_sys_ftruncate(unsigned int fd, loff_t length, int small) if (IS_APPEND(inode)) goto out_putf; + sb_start_write(inode->i_sb); error = locks_verify_truncate(inode, file, length); if (!error) error = security_path_truncate(&file->f_path); if (!error) error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, file); + sb_end_write(inode->i_sb); out_putf: fput(file); out: @@ -266,7 +268,10 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (!file->f_op->fallocate) return -EOPNOTSUPP; - return file->f_op->fallocate(file, mode, offset, len); + sb_start_write(inode->i_sb); + ret = file->f_op->fallocate(file, mode, offset, len); + sb_end_write(inode->i_sb); + return ret; } SYSCALL_DEFINE(fallocate)(int fd, int mode, loff_t offset, loff_t len) -- cgit v1.1