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-rw-r--r--fs/file.c2
-rw-r--r--fs/open.c6
-rw-r--r--include/linux/fs.h2
3 files changed, 8 insertions, 2 deletions
diff --git a/fs/file.c b/fs/file.c
index b241ea7f1aa4..3da91a112bab 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -795,7 +795,7 @@ unsigned long __fdget_pos(unsigned int fd)
unsigned long v = __fdget(fd);
struct file *file = (struct file *)(v & ~3);
- if (file && !(file->f_mode & FMODE_STREAM)) {
+ if (file && (file->f_mode & FMODE_ATOMIC_POS)) {
if (file_count(file) > 1) {
v |= FDPUT_POS_UNLOCK;
mutex_lock(&file->f_pos_lock);
diff --git a/fs/open.c b/fs/open.c
index 5c68282ea79e..b62f5c0923a8 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -771,6 +771,10 @@ static int do_dentry_open(struct file *f,
f->f_mode |= FMODE_WRITER;
}
+ /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
+ if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
+ f->f_mode |= FMODE_ATOMIC_POS;
+
f->f_op = fops_get(inode->i_fop);
if (WARN_ON(!f->f_op)) {
error = -ENODEV;
@@ -1252,7 +1256,7 @@ EXPORT_SYMBOL(nonseekable_open);
*/
int stream_open(struct inode *inode, struct file *filp)
{
- filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
+ filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
filp->f_mode |= FMODE_STREAM;
return 0;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index dde6dc4492a0..ae6c5c37f3ae 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -148,6 +148,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
/* File is opened with O_PATH; almost nothing can be done with it */
#define FMODE_PATH ((__force fmode_t)0x4000)
+/* File needs atomic accesses to f_pos */
+#define FMODE_ATOMIC_POS ((__force fmode_t)0x8000)
/* Write access to underlying fs */
#define FMODE_WRITER ((__force fmode_t)0x10000)
/* Has read method(s) */