fix prune_dcache()/umount() race
... and get rid of the last __put_super_and_need_restart() caller Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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parent
df40c01a92
commit
79893c17b4
1 changed files with 6 additions and 11 deletions
17
fs/dcache.c
17
fs/dcache.c
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@ -536,7 +536,7 @@ static void __shrink_dcache_sb(struct super_block *sb, int *count, int flags)
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*/
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static void prune_dcache(int count)
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{
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struct super_block *sb;
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struct super_block *sb, *n;
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int w_count;
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int unused = dentry_stat.nr_unused;
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int prune_ratio;
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@ -545,13 +545,12 @@ static void prune_dcache(int count)
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if (unused == 0 || count == 0)
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return;
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spin_lock(&dcache_lock);
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restart:
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if (count >= unused)
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prune_ratio = 1;
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else
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prune_ratio = unused / count;
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spin_lock(&sb_lock);
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list_for_each_entry(sb, &super_blocks, s_list) {
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list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
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if (list_empty(&sb->s_instances))
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continue;
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if (sb->s_nr_dentry_unused == 0)
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@ -592,14 +591,10 @@ static void prune_dcache(int count)
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}
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spin_lock(&sb_lock);
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count -= pruned;
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/*
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* restart only when sb is no longer on the list and
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* we have more work to do.
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*/
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if (__put_super_and_need_restart(sb) && count > 0) {
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spin_unlock(&sb_lock);
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goto restart;
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}
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__put_super(sb);
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/* more work left to do? */
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if (count <= 0)
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break;
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}
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spin_unlock(&sb_lock);
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spin_unlock(&dcache_lock);
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