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Message-Id: <20190811195108.24308-1-tytso@mit.edu>
Date: Sun, 11 Aug 2019 15:51:06 -0400
From: "Theodore Ts'o" <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: "Theodore Ts'o" <tytso@....edu>
Subject: [PATCH v2 1/3] ext4: add a new ioctl EXT4_IOC_CLEAR_ES_CACHE
The new ioctl EXT4_IOC_CLEAR_ES_CACHE will force an inode's extent
status cache to be cleared out. This is intended for use for
debugging.
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
fs/ext4/ext4.h | 2 ++
fs/ext4/extents_status.c | 28 ++++++++++++++++++++++++++++
fs/ext4/extents_status.h | 1 +
fs/ext4/ioctl.c | 9 +++++++++
4 files changed, 40 insertions(+)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index bf660aa7a9e0..b22f24f1d365 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -649,6 +649,8 @@ enum {
#define EXT4_IOC_SET_ENCRYPTION_POLICY FS_IOC_SET_ENCRYPTION_POLICY
#define EXT4_IOC_GET_ENCRYPTION_PWSALT FS_IOC_GET_ENCRYPTION_PWSALT
#define EXT4_IOC_GET_ENCRYPTION_POLICY FS_IOC_GET_ENCRYPTION_POLICY
+/* ioctl codes 19--39 are reserved for fscrypt */
+#define EXT4_IOC_CLEAR_ES_CACHE _IO('f', 40)
#define EXT4_IOC_FSGETXATTR FS_IOC_FSGETXATTR
#define EXT4_IOC_FSSETXATTR FS_IOC_FSSETXATTR
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 7521de2dcf3a..02cc8eb3eb0e 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -1374,6 +1374,34 @@ static int es_reclaim_extents(struct ext4_inode_info *ei, int *nr_to_scan)
return nr_shrunk;
}
+/*
+ * Called to support EXT4_IOC_CLEAR_ES_CACHE. We can only remove
+ * discretionary entries from the extent status cache. (Some entries
+ * must be present for proper operations.)
+ */
+void ext4_clear_inode_es(struct inode *inode)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct extent_status *es;
+ struct ext4_es_tree *tree;
+ struct rb_node *node;
+
+ write_lock(&ei->i_es_lock);
+ tree = &EXT4_I(inode)->i_es_tree;
+ tree->cache_es = NULL;
+ node = rb_first(&tree->root);
+ while (node) {
+ es = rb_entry(node, struct extent_status, rb_node);
+ node = rb_next(node);
+ if (!ext4_es_is_delayed(es)) {
+ rb_erase(&es->rb_node, &tree->root);
+ ext4_es_free_extent(inode, es);
+ }
+ }
+ ext4_clear_inode_state(inode, EXT4_STATE_EXT_PRECACHED);
+ write_unlock(&ei->i_es_lock);
+}
+
#ifdef ES_DEBUG__
static void ext4_print_pending_tree(struct inode *inode)
{
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index 131a8b7df265..e16785f431e7 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -248,5 +248,6 @@ extern unsigned int ext4_es_delayed_clu(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len);
extern void ext4_es_remove_blks(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t len);
+extern void ext4_clear_inode_es(struct inode *inode);
#endif /* _EXT4_EXTENTS_STATUS_H */
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 442f7ef873fc..15b1047878ab 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -1115,6 +1115,14 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
case EXT4_IOC_GET_ENCRYPTION_POLICY:
return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
+ case EXT4_IOC_CLEAR_ES_CACHE:
+ {
+ if (!inode_owner_or_capable(inode))
+ return -EACCES;
+ ext4_clear_inode_es(inode);
+ return 0;
+ }
+
case EXT4_IOC_FSGETXATTR:
{
struct fsxattr fa;
@@ -1233,6 +1241,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case EXT4_IOC_GET_ENCRYPTION_POLICY:
case EXT4_IOC_SHUTDOWN:
case FS_IOC_GETFSMAP:
+ case EXT4_IOC_CLEAR_ES_CACHE:
break;
default:
return -ENOIOCTLCMD;
--
2.22.0
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