This is a note to let you know that I've just added the patch titled

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

to the 3.4-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     don-t-bother-with-get-put-_write_access-on-non-regular-files.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From dd20908a8a06b22c171f6c3fcdbdbd65bed07505 Mon Sep 17 00:00:00 2001
From: Al Viro <[email protected]>
Date: Fri, 14 Mar 2014 10:56:20 -0400
Subject: don't bother with {get,put}_write_access() on non-regular files

From: Al Viro <[email protected]>

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: Al Viro <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

diff --git a/fs/file_table.c b/fs/file_table.c
index 5b24008ea4f6..79ecae62209a 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -209,10 +209,10 @@ 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);
diff --git a/fs/open.c b/fs/open.c
index b9ed8b25c108..2ed7325f713e 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -641,23 +641,12 @@ 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;
 }
 
@@ -690,12 +679,11 @@ 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;
@@ -742,7 +730,6 @@ static int do_dentry_open(struct file *f,
 cleanup_all:
        fops_put(f->f_op);
        if (f->f_mode & FMODE_WRITE) {
-               put_write_access(inode);
                if (!special_file(inode->i_mode)) {
                        /*
                         * We don't consider this a real
@@ -750,6 +737,7 @@ 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);
                }


Patches currently in stable-queue which might be from [email protected] 
are

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