diff options
Diffstat (limited to 'fs/open.c')
| -rw-r--r-- | fs/open.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/fs/open.c b/fs/open.c index b3c904e82e2a..94bef26ff1b6 100644 --- a/fs/open.c +++ b/fs/open.c @@ -852,8 +852,17 @@ static int do_dentry_open(struct file *f, * XXX: Huge page cache doesn't support writing yet. Drop all page * cache for this file before processing writes. */ - if ((f->f_mode & FMODE_WRITE) && filemap_nr_thps(inode->i_mapping)) - truncate_pagecache(inode, 0); + if (f->f_mode & FMODE_WRITE) { + /* + * Paired with smp_mb() in collapse_file() to ensure nr_thps + * is up to date and the update to i_writecount by + * get_write_access() is visible. Ensures subsequent insertion + * of THPs into the page cache will fail. + */ + smp_mb(); + if (filemap_nr_thps(inode->i_mapping)) + truncate_pagecache(inode, 0); + } return 0; @@ -1002,12 +1011,20 @@ inline struct open_how build_open_how(int flags, umode_t mode) inline int build_open_flags(const struct open_how *how, struct open_flags *op) { - int flags = how->flags; + u64 flags = how->flags; + u64 strip = FMODE_NONOTIFY | O_CLOEXEC; int lookup_flags = 0; int acc_mode = ACC_MODE(flags); - /* Must never be set by userspace */ - flags &= ~(FMODE_NONOTIFY | O_CLOEXEC); + BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS), + "struct open_flags doesn't yet handle flags > 32 bits"); + + /* + * Strip flags that either shouldn't be set by userspace like + * FMODE_NONOTIFY or that aren't relevant in determining struct + * open_flags like O_CLOEXEC. + */ + flags &= ~strip; /* * Older syscalls implicitly clear all of the invalid flags or argument |