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authorAl Viro <viro@zeniv.linux.org.uk>2014-03-14 10:56:20 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-30 21:52:12 -0700
commit68ad89c73da6085d14e18f18ec7298821d408b2d (patch)
treec426b7c447d78b45a9d0a1f07e8be23ea3056799
parentcd09dfbdad430e807be3dee98ce03f452b7ef001 (diff)
downloadlinux-linaro-stable-68ad89c73da6085d14e18f18ec7298821d408b2d.tar.gz
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: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/file_table.c4
-rw-r--r--fs/open.c26
2 files changed, 9 insertions, 21 deletions
diff --git a/fs/file_table.c b/fs/file_table.c
index 485dc0eddd67..54a34be444f9 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -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);
diff --git a/fs/open.c b/fs/open.c
index 8c741002f947..86092bde31f4 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -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);
}