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afs: Skip truncation on the server of data we haven't written yet 

Don't send a truncation RPC to the server if we're only shortening data
that's in the pagecache and is beyond the server's EOF.

Also don't automatically force writeback on setattr, but do wait to store
RPCs that are in the region to be removed on a shortening truncation.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing@auristor.com
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/163819663275.215744.4781075713714590913.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906972600.143852.14237659724463048094.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967177522.1823006.15336589054269480601.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021571880.640689.1837025861707111004.stgit@warthog.procyon.org.uk/ # v4
This commit is contained in:
David Howells 2020-07-22 10:44:34 +01:00
parent c7f75ef33b
commit 0770bd4187
1 changed files with 35 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
fs/afs/inode.c
View File

@ -848,42 +848,67 @@ static const struct afs_operation_ops afs_setattr_operation = {
int afs_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
struct iattr *attr)
{
const unsigned int supported =
ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET | ATTR_TOUCH;
struct afs_operation *op;
struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
struct inode *inode = &vnode->vfs_inode;
loff_t i_size;
int ret;
_enter("{%llx:%llu},{n=%pd},%x",
vnode->fid.vid, vnode->fid.vnode, dentry,
attr->ia_valid);
if (!(attr->ia_valid & (ATTR_SIZE | ATTR_MODE | ATTR_UID | ATTR_GID |
ATTR_MTIME | ATTR_MTIME_SET | ATTR_TIMES_SET |
ATTR_TOUCH))) {
if (!(attr->ia_valid & supported)) {
_leave(" = 0 [unsupported]");
return 0;
}
i_size = i_size_read(inode);
if (attr->ia_valid & ATTR_SIZE) {
if (!S_ISREG(vnode->vfs_inode.i_mode))
if (!S_ISREG(inode->i_mode))
return -EISDIR;
ret = inode_newsize_ok(&vnode->vfs_inode, attr->ia_size);
ret = inode_newsize_ok(inode, attr->ia_size);
if (ret)
return ret;
if (attr->ia_size == i_size_read(&vnode->vfs_inode))
if (attr->ia_size == i_size)
attr->ia_valid &= ~ATTR_SIZE;
}
fscache_use_cookie(afs_vnode_cache(vnode), true);
/* flush any dirty data outstanding on a regular file */
if (S_ISREG(vnode->vfs_inode.i_mode))
filemap_write_and_wait(vnode->vfs_inode.i_mapping);
/* Prevent any new writebacks from starting whilst we do this. */
down_write(&vnode->validate_lock);
if ((attr->ia_valid & ATTR_SIZE) && S_ISREG(inode->i_mode)) {
loff_t size = attr->ia_size;
/* Wait for any outstanding writes to the server to complete */
loff_t from = min(size, i_size);
loff_t to = max(size, i_size);
ret = filemap_fdatawait_range(inode->i_mapping, from, to);
if (ret < 0)
goto out_unlock;
/* Don't talk to the server if we're just shortening in-memory
* writes that haven't gone to the server yet.
*/
if (!(attr->ia_valid & (supported & ~ATTR_SIZE & ~ATTR_MTIME)) &&
attr->ia_size < i_size &&
attr->ia_size > vnode->status.size) {
truncate_pagecache(inode, attr->ia_size);
fscache_resize_cookie(afs_vnode_cache(vnode),
attr->ia_size);
i_size_write(inode, attr->ia_size);
ret = 0;
goto out_unlock;
}
}
op = afs_alloc_operation(((attr->ia_valid & ATTR_FILE) ?
afs_file_key(attr->ia_file) : NULL),
vnode->volume);