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nfsd: Don't garbage collect files that might contain write errors 

If a file may contain unstable writes that can error out, then we want
to avoid garbage collecting the struct nfsd_file that may be
tracking those errors.
So in the garbage collector, we try to avoid collecting files that aren't
clean. Furthermore, we avoid immediately kicking off the garbage collector
in the case where the reference drops to zero for the case where there
is a write error that is being tracked.

If the file is unhashed while an error is pending, then declare a
reboot, to ensure the client resends any unstable writes.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
alistair/sunxi64-5.4-dsi
Trond Myklebust 2019-09-02 13:02:57 -04:00 committed by J. Bruce Fields
parent 27c438f53e
commit 055b24a8f2
1 changed files with 42 additions and 1 deletions
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43
fs/nfsd/filecache.c
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@ -215,6 +215,36 @@ nfsd_file_free(struct nfsd_file *nf)
return flush;
}
static bool
nfsd_file_check_writeback(struct nfsd_file *nf)
{
struct file *file = nf->nf_file;
struct address_space *mapping;
if (!file || !(file->f_mode & FMODE_WRITE))
return false;
mapping = file->f_mapping;
return mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) ||
mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK);
}
static int
nfsd_file_check_write_error(struct nfsd_file *nf)
{
struct file *file = nf->nf_file;
if (!file || !(file->f_mode & FMODE_WRITE))
return 0;
return filemap_check_wb_err(file->f_mapping, READ_ONCE(file->f_wb_err));
}
static bool
nfsd_file_in_use(struct nfsd_file *nf)
{
return nfsd_file_check_writeback(nf) ||
nfsd_file_check_write_error(nf);
}
static void
nfsd_file_do_unhash(struct nfsd_file *nf)
{
@ -222,6 +252,8 @@ nfsd_file_do_unhash(struct nfsd_file *nf)
trace_nfsd_file_unhash(nf);
if (nfsd_file_check_write_error(nf))
nfsd_reset_boot_verifier(net_generic(nf->nf_net, nfsd_net_id));
--nfsd_file_hashtbl[nf->nf_hashval].nfb_count;
hlist_del_rcu(&nf->nf_node);
if (!list_empty(&nf->nf_lru))
@ -276,9 +308,10 @@ void
nfsd_file_put(struct nfsd_file *nf)
{
bool is_hashed = test_bit(NFSD_FILE_HASHED, &nf->nf_flags) != 0;
bool unused = !nfsd_file_in_use(nf);
set_bit(NFSD_FILE_REFERENCED, &nf->nf_flags);
if (nfsd_file_put_noref(nf) == 1 && is_hashed)
if (nfsd_file_put_noref(nf) == 1 && is_hashed && unused)
nfsd_file_schedule_laundrette(NFSD_FILE_LAUNDRETTE_MAY_FLUSH);
}
@ -344,6 +377,14 @@ nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru,
*/
if (atomic_read(&nf->nf_ref) > 1)
goto out_skip;
/*
* Don't throw out files that are still undergoing I/O or
* that have uncleared errors pending.
*/
if (nfsd_file_check_writeback(nf))
goto out_skip;
if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags))
goto out_rescan;