If the inode that's being requested to track using ext4_fc_track_inode
is being committed, then wait until the inode finishes the
commit. Also, add calls to ext4_fc_track_inode at the right places.
With this patch, now calling ext4_reserve_inode_write() results in
inode being tracked for next fast commit. This ensures that by the
time ext4_reserve_inode_write() returns, it is ready to be modified
and won't be committed until the corresponding handle is open.
A subtle lock ordering requirement with i_data_sem (which is
documented in the code) requires that ext4_fc_track_inode() be called
before grabbing i_data_sem. So, this patch also adds explicit
ext4_fc_track_inode() calls in places where i_data_sem grabbed.
Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
---
fs/ext4/fast_commit.c | 35 +++++++++++++++++++++++++++++++++++
fs/ext4/inline.c | 1 +
fs/ext4/inode.c | 5 +++++
3 files changed, 41 insertions(+)
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 63859ec6d..c4d3c71d5 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -12,6 +12,7 @@
#include "ext4_extents.h"
#include "mballoc.h"
+#include <linux/lockdep.h>
/*
* Ext4 Fast Commits
* -----------------
@@ -570,6 +571,8 @@ static int __track_inode(handle_t *handle, struct inode *inode, void *arg,
void ext4_fc_track_inode(handle_t *handle, struct inode *inode)
{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ wait_queue_head_t *wq;
int ret;
if (S_ISDIR(inode->i_mode))
@@ -587,6 +590,38 @@ void ext4_fc_track_inode(handle_t *handle, struct inode *inode)
if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_INELIGIBLE))
return;
+ if (!list_empty(&ei->i_fc_list))
+ return;
+
+ /*
+ * If we come here, we may sleep while waiting for the inode to
+ * commit. We shouldn't be holding i_data_sem when we go to sleep since
+ * the commit path needs to grab the lock while committing the inode.
+ */
+ lockdep_assert_not_held(&ei->i_data_sem);
+
+ while (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
+#if (BITS_PER_LONG < 64)
+ DEFINE_WAIT_BIT(wait, &ei->i_state_flags,
+ EXT4_STATE_FC_COMMITTING);
+ wq = bit_waitqueue(&ei->i_state_flags,
+ EXT4_STATE_FC_COMMITTING);
+#else
+ DEFINE_WAIT_BIT(wait, &ei->i_flags,
+ EXT4_STATE_FC_COMMITTING);
+ wq = bit_waitqueue(&ei->i_flags,
+ EXT4_STATE_FC_COMMITTING);
+#endif
+ prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
+ if (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING))
+ schedule();
+ finish_wait(wq, &wait.wq_entry);
+ }
+
+ /*
+ * From this point on, this inode will not be committed either
+ * by fast or full commit as long as the handle is open.
+ */
ret = ext4_fc_track_template(handle, inode, __track_inode, NULL, 1);
trace_ext4_fc_track_inode(handle, inode, ret);
}
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 2c9b76292..fbc1c84b5 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -601,6 +601,7 @@ static int ext4_convert_inline_data_to_extent(struct address_space *mapping,
goto out;
}
+ ext4_fc_track_inode(handle, inode);
ret = ext4_destroy_inline_data_nolock(handle, inode);
if (ret)
goto out;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 94c7d2d82..d58b99407 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -696,6 +696,8 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
return retval;
+
+ ext4_fc_track_inode(handle, inode);
/*
* New blocks allocate and/or writing to unwritten extent
* will possibly result in updating i_data, so we take
@@ -4072,6 +4074,7 @@ int ext4_punch_hole(struct file *file, loff_t offset, loff_t length)
if (end_lblk > start_lblk) {
ext4_lblk_t hole_len = end_lblk - start_lblk;
+ ext4_fc_track_inode(handle, inode);
down_write(&EXT4_I(inode)->i_data_sem);
ext4_discard_preallocations(inode);
@@ -4224,6 +4227,7 @@ int ext4_truncate(struct inode *inode)
if (err)
goto out_stop;
+ ext4_fc_track_inode(handle, inode);
down_write(&EXT4_I(inode)->i_data_sem);
ext4_discard_preallocations(inode);
@@ -5895,6 +5899,7 @@ ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
brelse(iloc->bh);
iloc->bh = NULL;
}
+ ext4_fc_track_inode(handle, inode);
}
ext4_std_error(inode->i_sb, err);
return err;
--
2.49.0.1045.g170613ef41-goog
