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| author | Brian Foster <bfoster@redhat.com> | 2013-05-17 09:30:32 -0400 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@suse.cz> | 2013-05-20 16:58:57 +0200 |
| commit | 3634a6327815d39dd93e5c44a602daae91c66297 (patch) | |
| tree | fa8a52812af954f8604ad105263594d9d43c9c46 /fs/fuse | |
| parent | de82b923012ff8790bcfff381eb3ca9069d00f49 (diff) | |
| download | linux-3634a6327815d39dd93e5c44a602daae91c66297.tar.gz linux-3634a6327815d39dd93e5c44a602daae91c66297.tar.bz2 linux-3634a6327815d39dd93e5c44a602daae91c66297.zip | |
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>
Diffstat (limited to 'fs/fuse')
| -rw-r--r-- | fs/fuse/file.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index fe191325fefa..a200a2d80377 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -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; } |