@@ -33,6 +33,7 @@
#include <linux/ratelimit.h>
#include <crypto/hash.h>
#include <linux/falloc.h>
+#include <linux/percpu-rwsem.h>
#ifdef __KERNEL__
#include <linux/compat.h>
#endif
@@ -1475,6 +1476,9 @@ struct ext4_sb_info {
struct ratelimit_state s_err_ratelimit_state;
struct ratelimit_state s_warning_ratelimit_state;
struct ratelimit_state s_msg_ratelimit_state;
+
+ /* Barrier between changing inodes' journal flags and writepages ops. */
+ struct percpu_rw_semaphore s_journal_flag_rwsem;
};
static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
@@ -2476,6 +2476,7 @@ static int ext4_writepages(struct address_space *mapping,
struct blk_plug plug;
bool give_up_on_write = false;
+ percpu_down_read(&sbi->s_journal_flag_rwsem);
trace_ext4_writepages(inode, wbc);
/*
@@ -2646,6 +2647,7 @@ retry:
out_writepages:
trace_ext4_writepages_result(inode, wbc, ret,
nr_to_write - wbc->nr_to_write);
+ percpu_up_read(&sbi->s_journal_flag_rwsem);
return ret;
}
@@ -5362,6 +5364,7 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
journal_t *journal;
handle_t *handle;
int err;
+ struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
/*
* We have to be very careful here: changing a data block's
@@ -5401,6 +5404,7 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
}
}
+ percpu_down_write(&sbi->s_journal_flag_rwsem);
jbd2_journal_lock_updates(journal);
/*
@@ -5417,6 +5421,7 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
err = jbd2_journal_flush(journal);
if (err < 0) {
jbd2_journal_unlock_updates(journal);
+ percpu_up_write(&sbi->s_journal_flag_rwsem);
ext4_inode_resume_unlocked_dio(inode);
return err;
}
@@ -5425,6 +5430,8 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
ext4_set_aops(inode);
jbd2_journal_unlock_updates(journal);
+ percpu_up_write(&sbi->s_journal_flag_rwsem);
+
if (val)
up_write(&EXT4_I(inode)->i_mmap_sem);
ext4_inode_resume_unlocked_dio(inode);
@@ -861,6 +861,7 @@ static void ext4_put_super(struct super_block *sb)
percpu_counter_destroy(&sbi->s_freeinodes_counter);
percpu_counter_destroy(&sbi->s_dirs_counter);
percpu_counter_destroy(&sbi->s_dirtyclusters_counter);
+ percpu_free_rwsem(&sbi->s_journal_flag_rwsem);
brelse(sbi->s_sbh);
#ifdef CONFIG_QUOTA
for (i = 0; i < EXT4_MAXQUOTAS; i++)
@@ -3926,6 +3927,9 @@ no_journal:
if (!err)
err = percpu_counter_init(&sbi->s_dirtyclusters_counter, 0,
GFP_KERNEL);
+ if (!err)
+ err = percpu_init_rwsem(&sbi->s_journal_flag_rwsem);
+
if (err) {
ext4_msg(sb, KERN_ERR, "insufficient memory");
goto failed_mount6;
@@ -37,6 +37,7 @@ void percpu_free_rwsem(struct percpu_rw_semaphore *brw)
free_percpu(brw->fast_read_ctr);
brw->fast_read_ctr = NULL; /* catch use after free bugs */
}
+EXPORT_SYMBOL_GPL(percpu_free_rwsem);
/*
* This is the fast-path for down_read/up_read. If it succeeds we rely