mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
fuse: truncate pagecache range on hole punch
fuse supports hole punch via the fallocate() FALLOC_FL_PUNCH_HOLE interface. When a hole punch is passed through, the page cache is not cleared and thus allows reading stale data from the cache. This is easily demonstrable (using FOPEN_KEEP_CACHE) by reading a smallish random data file into cache, punching a hole and creating a copy of the file. Drop caches or remount and observe that the original file no longer matches the file copied after the hole punch. The original file contains a zeroed range and the latter file contains stale data. Protect against writepage requests in progress and punch out the associated page cache range after a successful client fs hole punch. Signed-off-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This commit is contained in:
parent
de82b92301
commit
3634a63278
1 changed files with 20 additions and 2 deletions
|
@ -16,6 +16,7 @@
|
|||
#include <linux/compat.h>
|
||||
#include <linux/swap.h>
|
||||
#include <linux/aio.h>
|
||||
#include <linux/falloc.h>
|
||||
|
||||
static const struct file_operations fuse_direct_io_file_operations;
|
||||
|
||||
|
@ -2453,6 +2454,7 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
|
|||
loff_t length)
|
||||
{
|
||||
struct fuse_file *ff = file->private_data;
|
||||
struct inode *inode = file->f_inode;
|
||||
struct fuse_conn *fc = ff->fc;
|
||||
struct fuse_req *req;
|
||||
struct fuse_fallocate_in inarg = {
|
||||
|
@ -2466,9 +2468,16 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
|
|||
if (fc->no_fallocate)
|
||||
return -EOPNOTSUPP;
|
||||
|
||||
if (mode & FALLOC_FL_PUNCH_HOLE) {
|
||||
mutex_lock(&inode->i_mutex);
|
||||
fuse_set_nowrite(inode);
|
||||
}
|
||||
|
||||
req = fuse_get_req_nopages(fc);
|
||||
if (IS_ERR(req))
|
||||
return PTR_ERR(req);
|
||||
if (IS_ERR(req)) {
|
||||
err = PTR_ERR(req);
|
||||
goto out;
|
||||
}
|
||||
|
||||
req->in.h.opcode = FUSE_FALLOCATE;
|
||||
req->in.h.nodeid = ff->nodeid;
|
||||
|
@ -2483,6 +2492,15 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
|
|||
}
|
||||
fuse_put_request(fc, req);
|
||||
|
||||
out:
|
||||
if (mode & FALLOC_FL_PUNCH_HOLE) {
|
||||
if (!err)
|
||||
truncate_pagecache_range(inode, offset,
|
||||
offset + length - 1);
|
||||
fuse_release_nowrite(inode);
|
||||
mutex_unlock(&inode->i_mutex);
|
||||
}
|
||||
|
||||
return err;
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue