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authorDavid Sterba <dsterba@suse.com>2020-06-09 19:21:48 +0200
committerDavid Sterba <dsterba@suse.com>2020-06-09 19:21:48 +0200
commit8e0fa5d7b3df6e7e23e13a7250b00afe32d4e618 (patch)
tree517ea3796f05783f5c034231ec9d9e01b173d6ab
parentf4c48b44080e18d86d7983c1a60ee5a7f9d07e3e (diff)
downloadlinux-8e0fa5d7b3df6e7e23e13a7250b00afe32d4e618.tar.gz
Revert "btrfs: remove BTRFS_INODE_READDIO_NEED_LOCK"
This reverts commit 5f008163a559d566a0ee1190a0a24f3eec6f1ea7. The patch is a simplification after direct IO port to iomap infrastructure, which gets reverted. Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/btrfs_inode.h18
-rw-r--r--fs/btrfs/inode.c3
2 files changed, 21 insertions, 0 deletions
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index aeff56a..e7d7095 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -28,6 +28,7 @@ enum {
BTRFS_INODE_NEEDS_FULL_SYNC,
BTRFS_INODE_COPY_EVERYTHING,
BTRFS_INODE_IN_DELALLOC_LIST,
+ BTRFS_INODE_READDIO_NEED_LOCK,
BTRFS_INODE_HAS_PROPS,
BTRFS_INODE_SNAPSHOT_FLUSH,
};
@@ -312,6 +313,23 @@ struct btrfs_dio_private {
u8 csums[];
};
+/*
+ * Disable DIO read nolock optimization, so new dio readers will be forced
+ * to grab i_mutex. It is used to avoid the endless truncate due to
+ * nonlocked dio read.
+ */
+static inline void btrfs_inode_block_unlocked_dio(struct btrfs_inode *inode)
+{
+ set_bit(BTRFS_INODE_READDIO_NEED_LOCK, &inode->runtime_flags);
+ smp_mb();
+}
+
+static inline void btrfs_inode_resume_unlocked_dio(struct btrfs_inode *inode)
+{
+ smp_mb__before_atomic();
+ clear_bit(BTRFS_INODE_READDIO_NEED_LOCK, &inode->runtime_flags);
+}
+
/* Array of bytes with variable length, hexadecimal format 0x1234 */
#define CSUM_FMT "0x%*phN"
#define CSUM_FMT_VALUE(size, bytes) size, bytes
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 44d948f..2b40fcf 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4811,7 +4811,10 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr)
truncate_setsize(inode, newsize);
+ /* Disable nonlocked read DIO to avoid the endless truncate */
+ btrfs_inode_block_unlocked_dio(BTRFS_I(inode));
inode_dio_wait(inode);
+ btrfs_inode_resume_unlocked_dio(BTRFS_I(inode));
ret = btrfs_truncate(inode, newsize == oldsize);
if (ret && inode->i_nlink) {