From: Amir Goldstein <amir73il@xxxxxxxxxxxx>
Cleanup snapshots list and reclaim unused blocks of deleted snapshots.
Oldest snapshot can be removed from list and its blocks can be freed.
Non-oldest snapshots have to be shrunk and merged before they can be
removed from the list. All snapshot blocks must be excluded in order
to properly shrink/merge deleted old snapshots.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxxxxx>
Signed-off-by: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
---
fs/ext4/ext4.h | 16 ++++++++++++++++
fs/ext4/inode.c | 19 +++++++++++--------
2 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 37c608b..7650515 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1748,6 +1748,12 @@ struct ext4_features {
struct completion f_kobj_unregister;
};
+typedef struct {
+ __le32 *p;
+ __le32 key;
+ struct buffer_head *bh;
+} Indirect;
+
/*
* Function prototypes
*/
@@ -1889,6 +1895,16 @@ extern void ext4_da_update_reserve_space(struct inode *inode,
/* snapshot_inode.c */
extern int ext4_snapshot_readpage(struct file *file, struct page *page);
+extern int ext4_block_to_path(struct inode *inode,
+ ext4_lblk_t i_block,
+ ext4_lblk_t offsets[4], int *boundary);
+extern Indirect *ext4_get_branch(struct inode *inode, int depth,
+ ext4_lblk_t *offsets,
+ Indirect chain[4], int *err);
+extern void ext4_free_branches(handle_t *handle, struct inode *inode,
+ struct buffer_head *parent_bh,
+ __le32 *first, __le32 *last,
+ int depth);
/* ioctl.c */
extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
extern long ext4_compat_ioctl(struct file *, unsigned int, unsigned long);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 794b29f..d46da6a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -176,6 +176,14 @@ int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
*/
BUG_ON(EXT4_JOURNAL(inode) == NULL);
jbd_debug(2, "restarting handle %p\n", handle);
+ /*
+ * Snapshot shrink/merge/clean do not take i_data_sem, so we cannot
+ * release it here. Luckily, snapshot files are not writable,
+ * so deadlock with ext4_map_blocks on writepage is impossible.
+ * Snapshot files also don't have preallocations.
+ */
+ if (ext4_snapshot_file(inode))
+ return ext4_journal_restart(handle, nblocks);
up_write(&EXT4_I(inode)->i_data_sem);
ret = ext4_journal_restart(handle, nblocks);
down_write(&EXT4_I(inode)->i_data_sem);
@@ -281,11 +289,6 @@ no_delete:
ext4_clear_inode(inode); /* We must guarantee clearing of inode... */
}
-typedef struct {
- __le32 *p;
- __le32 key;
- struct buffer_head *bh;
-} Indirect;
static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
{
@@ -324,7 +327,7 @@ static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
* get there at all.
*/
-static int ext4_block_to_path(struct inode *inode,
+int ext4_block_to_path(struct inode *inode,
ext4_lblk_t i_block,
ext4_lblk_t offsets[4], int *boundary)
{
@@ -440,7 +443,7 @@ static int __ext4_check_blockref(const char *function, unsigned int line,
* Need to be called with
* down_read(&EXT4_I(inode)->i_data_sem)
*/
-static Indirect *ext4_get_branch(struct inode *inode, int depth,
+Indirect *ext4_get_branch(struct inode *inode, int depth,
ext4_lblk_t *offsets,
Indirect chain[4], int *err)
{
@@ -4702,7 +4705,7 @@ static void ext4_free_data(handle_t *handle, struct inode *inode,
* stored as little-endian 32-bit) and updating @inode->i_blocks
* appropriately.
*/
-static void ext4_free_branches(handle_t *handle, struct inode *inode,
+void ext4_free_branches(handle_t *handle, struct inode *inode,
struct buffer_head *parent_bh,
__le32 *first, __le32 *last, int depth)
{
--
1.7.0.4
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