Commit 68ad89c7 authored by Al Viro's avatar Al Viro Committed by Greg Kroah-Hartman

don't bother with {get,put}_write_access() on non-regular files

commit dd20908a8a06b22c171f6c3fcdbdbd65bed07505 upstream.

it's pointless and actually leads to wrong behaviour in at least one
moderately convoluted case (pipe(), close one end, try to get to
another via /proc/*/fd and run into ETXTBUSY).
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cd09dfbd
......@@ -211,10 +211,10 @@ static void drop_file_write_access(struct file *file)
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
put_write_access(inode);
if (special_file(inode->i_mode))
return;
put_write_access(inode);
if (file_check_writeable(file) != 0)
return;
__mnt_drop_write(mnt);
......
......@@ -628,23 +628,12 @@ out:
static inline int __get_file_write_access(struct inode *inode,
struct vfsmount *mnt)
{
int error;
error = get_write_access(inode);
int error = get_write_access(inode);
if (error)
return error;
/*
* Do not take mount writer counts on
* special files since no writes to
* the mount itself will occur.
*/
if (!special_file(inode->i_mode)) {
/*
* Balanced in __fput()
*/
error = __mnt_want_write(mnt);
if (error)
put_write_access(inode);
}
error = __mnt_want_write(mnt);
if (error)
put_write_access(inode);
return error;
}
......@@ -677,12 +666,11 @@ static int do_dentry_open(struct file *f,
path_get(&f->f_path);
inode = f->f_inode = f->f_path.dentry->d_inode;
if (f->f_mode & FMODE_WRITE) {
if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
error = __get_file_write_access(inode, f->f_path.mnt);
if (error)
goto cleanup_file;
if (!special_file(inode->i_mode))
file_take_write(f);
file_take_write(f);
}
f->f_mapping = inode->i_mapping;
......@@ -723,7 +711,6 @@ cleanup_all:
fops_put(f->f_op);
file_sb_list_del(f);
if (f->f_mode & FMODE_WRITE) {
put_write_access(inode);
if (!special_file(inode->i_mode)) {
/*
* We don't consider this a real
......@@ -731,6 +718,7 @@ cleanup_all:
* because it all happenend right
* here, so just reset the state.
*/
put_write_access(inode);
file_reset_write(f);
__mnt_drop_write(f->f_path.mnt);
}
......
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