Quota files are usually cached in the buffer cache of the block device.
These support functions allow a filesystem to cache quota files in their
page cache instead which is more efficient.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/quota/dquot.c | 68 ++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 2 ++
include/linux/quotaops.h | 1 +
3 files changed, 71 insertions(+)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index cdb22d6d7488..ef9aeae802c7 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -59,6 +59,7 @@
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/mm.h>
+#include <linux/pagemap.h>
#include <linux/time.h>
#include <linux/types.h>
#include <linux/string.h>
@@ -73,6 +74,7 @@
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/sched.h>
+#include <linux/sched/mm.h>
#include <linux/cred.h>
#include <linux/kmod.h>
#include <linux/namei.h>
@@ -2161,6 +2163,72 @@ const struct dquot_operations dquot_operations = {
};
EXPORT_SYMBOL(dquot_operations);
+ssize_t generic_quota_read(struct super_block *sb, int type, char *data,
+ size_t len, loff_t pos)
+{
+ struct inode *inode = sb_dqopt(sb)->files[type];
+ struct address_space *mapping = inode->i_mapping;
+ size_t toread;
+ pgoff_t index;
+ loff_t i_size = i_size_read(inode);
+
+ if (pos > i_size)
+ return 0;
+ if (pos + len > i_size)
+ len = i_size - pos;
+ toread = len;
+ index = pos / PAGE_SIZE;
+
+ while (toread > 0) {
+ struct folio *folio = read_mapping_folio(mapping, index, NULL);
+ size_t tocopy = min(toread, PAGE_SIZE - offset_in_page(pos));
+ void *src;
+
+ if (folio == ERR_PTR(-ENOMEM)) {
+ memalloc_retry_wait(GFP_NOFS);
+ continue;
+ } else if (IS_ERR(folio))
+ return PTR_ERR(folio);
+
+ src = kmap_local_folio(folio, offset_in_folio(folio, pos));
+ memcpy(data, src, tocopy);
+ kunmap_local(src);
+ folio_put(folio);
+
+ toread -= tocopy;
+ data += tocopy;
+ pos += tocopy;
+ index++;
+ }
+ return len;
+}
+EXPORT_SYMBOL(generic_quota_read);
+
+int generic_quota_sync(struct super_block *sb, int type)
+{
+ struct quota_info *dqopt = sb_dqopt(sb);
+ int i, ret;
+
+ ret = dquot_writeback_dquots(sb, type);
+ if (ret)
+ return ret;
+ if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
+ return 0;
+
+ for (i = 0; i < MAXQUOTAS; i++) {
+ if (type != -1 && type != i)
+ continue;
+ if (!sb_has_quota_active(sb, i))
+ continue;
+ ret = write_inode_now(dqopt->files[i], true);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(generic_quota_sync);
+
/*
* Generic helper for ->open on filesystems supporting disk quotas.
*/
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9ad5e3520fae..2e798fc4c118 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2449,6 +2449,8 @@ struct super_block *sget(struct file_system_type *type,
int (*test)(struct super_block *,void *),
int (*set)(struct super_block *,void *),
int flags, void *data);
+ssize_t generic_quota_read(struct super_block *sb, int type, char *data,
+ size_t len, loff_t pos);
/* Alas, no aliases. Too much hassle with bringing module.h everywhere */
#define fops_get(fops) \
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index a0f6668924d3..fe12b04948f6 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -105,6 +105,7 @@ int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
int dquot_quota_off(struct super_block *sb, int type);
int dquot_writeback_dquots(struct super_block *sb, int type);
int dquot_quota_sync(struct super_block *sb, int type);
+int generic_quota_sync(struct super_block *sb, int type);
int dquot_get_state(struct super_block *sb, struct qc_state *state);
int dquot_set_dqinfo(struct super_block *sb, int type, struct qc_info *ii);
int dquot_get_dqblk(struct super_block *sb, struct kqid id,
--
2.35.1
