Make fuse think that when writeback is on the inode's i_size is alway up-to-date
and not update it with the value received from the userspace. This is done because
the page cache code may update i_size without letting the FS know.
This assumption implies fixing the previously introduced short-read helper -- when
a short read occurs the 'hole' is filled with zeroes.
Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
---
fs/fuse/dir.c | 10 ++++++----
fs/fuse/file.c | 23 +++++++++++++++++++++--
fs/fuse/inode.c | 6 ++++--
3 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 334e0b1..032fb20 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -790,7 +790,7 @@ static void fuse_fillattr(struct inode *inode, struct fuse_attr *attr,
stat->mtime.tv_nsec = attr->mtimensec;
stat->ctime.tv_sec = attr->ctime;
stat->ctime.tv_nsec = attr->ctimensec;
- stat->size = attr->size;
+ stat->size = i_size_read(inode);
stat->blocks = attr->blocks;
if (attr->blksize != 0)
@@ -1350,7 +1350,7 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
struct fuse_req *req;
struct fuse_setattr_in inarg;
struct fuse_attr_out outarg;
- bool is_truncate = false;
+ bool is_truncate = false, is_wb = fc->writeback_cache;
loff_t oldsize;
int err;
@@ -1423,7 +1423,8 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
fuse_change_attributes_common(inode, &outarg.attr,
attr_timeout(&outarg));
oldsize = inode->i_size;
- i_size_write(inode, outarg.attr.size);
+ if (!is_wb || is_truncate || !S_ISREG(inode->i_mode))
+ i_size_write(inode, outarg.attr.size);
if (is_truncate) {
/* NOTE: this may release/reacquire fc->lock */
@@ -1435,7 +1436,8 @@ static int fuse_do_setattr(struct dentry *entry, struct iattr *attr,
* Only call invalidate_inode_pages2() after removing
* FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
*/
- if (S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
+ if ((is_truncate || !is_wb) &&
+ S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
truncate_pagecache(inode, oldsize, outarg.attr.size);
invalidate_inode_pages2(inode->i_mapping);
}
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 47f0f2e..9bc1390 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -541,9 +541,28 @@ static void fuse_read_update_size(struct inode *inode, loff_t size,
static void fuse_short_read(struct fuse_req *req, struct inode *inode, u64 attr_ver)
{
size_t num_read = req->out.args[0].size;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ if (fc->writeback_cache) {
+ /*
+ * A hole in a file. Some data after the hole are in page cache.
+ */
+ int i;
+ size_t off = num_read & (PAGE_CACHE_SIZE - 1);
+
+ for (i = num_read >> PAGE_CACHE_SHIFT; i < req->num_pages; i++) {
+ struct page *page = req->pages[i];
+ void *mapaddr = kmap_atomic(page, KM_USER0);
- loff_t pos = page_offset(req->pages[0]) + num_read;
- fuse_read_update_size(inode, pos, attr_ver);
+ memset(mapaddr + off, 0, PAGE_CACHE_SIZE - off);
+
+ kunmap_atomic(mapaddr, KM_USER0);
+ off = 0;
+ }
+ } else {
+ loff_t pos = page_offset(req->pages[0]) + num_read;
+ fuse_read_update_size(inode, pos, attr_ver);
+ }
}
static int fuse_readpage(struct file *file, struct page *page)
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1cd6165..88c577f 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -196,6 +196,7 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
+ bool is_wb = fc->writeback_cache;
loff_t oldsize;
spin_lock(&fc->lock);
@@ -207,10 +208,11 @@ void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
fuse_change_attributes_common(inode, attr, attr_valid);
oldsize = inode->i_size;
- i_size_write(inode, attr->size);
+ if (!is_wb || !S_ISREG(inode->i_mode))
+ i_size_write(inode, attr->size);
spin_unlock(&fc->lock);
- if (S_ISREG(inode->i_mode) && oldsize != attr->size) {
+ if (!is_wb && S_ISREG(inode->i_mode) && oldsize != attr->size) {
truncate_pagecache(inode, oldsize, attr->size);
invalidate_inode_pages2(inode->i_mapping);
}
--
1.5.5.6
--
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