[PATCH]: Fill the size of FIFOs
Instead of reporting 0 in size when stating() a pipe, we give the number of
queued bytes. This might avoid using ioctl(FIONREAD) to get this information.
References: http://lkml.org/lkml/2007/4/2/138
Cc: Eric Dumazet <[email protected]>
Signed-off-by: Jan Engelhardt <[email protected]>
---
fs/pipe.c | 20 +++-----------------
fs/stat.c | 14 ++++++++++----
include/linux/pipe_fs_i.h | 2 ++
3 files changed, 15 insertions(+), 21 deletions(-)
Index: linux-2.6.23/fs/pipe.c
===================================================================
--- linux-2.6.23.orig/fs/pipe.c
+++ linux-2.6.23/fs/pipe.c
@@ -577,14 +577,15 @@ bad_pipe_w(struct file *filp, const char
return -EBADF;
}
-static unsigned int pipe_size(struct inode *inode)
+unsigned int pipe_size(struct inode *inode)
{
struct pipe_inode_info *pipe;
unsigned int count, buf;
int nrbufs;
+ if ((pipe = inode->i_pipe) == NULL)
+ return 0;
mutex_lock(&inode->i_mutex);
- pipe = inode->i_pipe;
count = 0;
buf = pipe->curbuf;
nrbufs = pipe->nrbufs;
@@ -923,20 +924,6 @@ static struct dentry_operations pipefs_d
.d_dname = pipefs_dname,
};
-int pipe_getattr(struct vfsmount *mnt, struct dentry *dentry,
- struct kstat *stat)
-{
- struct inode *inode = dentry->d_inode;
-
- generic_fillattr(inode, stat);
- stat->size = pipe_size(inode);
- return 0;
-}
-
-const struct inode_operations pipe_inode_operations = {
- .getattr = pipe_getattr,
-};
-
static struct inode * get_pipe_inode(void)
{
struct inode *inode = new_inode(pipe_mnt->mnt_sb);
@@ -950,7 +937,6 @@ static struct inode * get_pipe_inode(voi
goto fail_iput;
inode->i_pipe = pipe;
- inode->i_op = &pipe_inode_operations;
pipe->readers = pipe->writers = 1;
inode->i_fop = &rdwr_pipe_fops;
Index: linux-2.6.23/fs/stat.c
===================================================================
--- linux-2.6.23.orig/fs/stat.c
+++ linux-2.6.23/fs/stat.c
@@ -11,6 +11,7 @@
#include <linux/highuid.h>
#include <linux/fs.h>
#include <linux/namei.h>
+#include <linux/pipe_fs_i.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
@@ -46,11 +47,16 @@ int vfs_getattr(struct vfsmount *mnt, st
if (retval)
return retval;
- if (inode->i_op->getattr)
- return inode->i_op->getattr(mnt, dentry, stat);
+ if (inode->i_op->getattr) {
+ retval = inode->i_op->getattr(mnt, dentry, stat);
+ } else {
+ generic_fillattr(inode, stat);
+ retval = 0;
+ }
- generic_fillattr(inode, stat);
- return 0;
+ if (retval == 0 && S_ISFIFO(inode->i_mode))
+ stat->size = pipe_size(inode);
+ return retval;
}
EXPORT_SYMBOL(vfs_getattr);
Index: linux-2.6.23/include/linux/pipe_fs_i.h
===================================================================
--- linux-2.6.23.orig/include/linux/pipe_fs_i.h
+++ linux-2.6.23/include/linux/pipe_fs_i.h
@@ -134,6 +134,8 @@ struct pipe_buf_operations {
memory allocation, whereas PIPE_BUF makes atomicity guarantees. */
#define PIPE_SIZE PAGE_SIZE
+extern unsigned int pipe_size(struct inode *);
+
/* Drop the inode semaphore and wait for a pipe event, atomically */
void pipe_wait(struct pipe_inode_info *pipe);
-
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