From: Matthew Wilcox (Oracle) willy@infradead.org
[ Upstream commit 537e11cdc7a6b3ce94fa25ed41306193df9677b7 ]
As described in commit 02117b8ae9c0 ("f2fs: Set GF_NOFS in read_cache_page_gfp while doing f2fs_quota_read"), we must not enter filesystem reclaim while holding the dq_lock. Prevent this more generally by using memalloc_nofs_save() while holding the lock.
Link: https://lore.kernel.org/r/20220605143815.2330891-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- fs/quota/dquot.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index 09fb8459bb5c..65f123d5809b 100644 --- a/fs/quota/dquot.c +++ b/fs/quota/dquot.c @@ -79,6 +79,7 @@ #include <linux/capability.h> #include <linux/quotaops.h> #include <linux/blkdev.h> +#include <linux/sched/mm.h> #include "../internal.h" /* ugh */
#include <linux/uaccess.h> @@ -427,9 +428,11 @@ EXPORT_SYMBOL(mark_info_dirty); int dquot_acquire(struct dquot *dquot) { int ret = 0, ret2 = 0; + unsigned int memalloc; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
mutex_lock(&dquot->dq_lock); + memalloc = memalloc_nofs_save(); if (!test_bit(DQ_READ_B, &dquot->dq_flags)) { ret = dqopt->ops[dquot->dq_id.type]->read_dqblk(dquot); if (ret < 0) @@ -460,6 +463,7 @@ int dquot_acquire(struct dquot *dquot) smp_mb__before_atomic(); set_bit(DQ_ACTIVE_B, &dquot->dq_flags); out_iolock: + memalloc_nofs_restore(memalloc); mutex_unlock(&dquot->dq_lock); return ret; } @@ -471,9 +475,11 @@ EXPORT_SYMBOL(dquot_acquire); int dquot_commit(struct dquot *dquot) { int ret = 0; + unsigned int memalloc; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
mutex_lock(&dquot->dq_lock); + memalloc = memalloc_nofs_save(); if (!clear_dquot_dirty(dquot)) goto out_lock; /* Inactive dquot can be only if there was error during read/init @@ -483,6 +489,7 @@ int dquot_commit(struct dquot *dquot) else ret = -EIO; out_lock: + memalloc_nofs_restore(memalloc); mutex_unlock(&dquot->dq_lock); return ret; } @@ -494,9 +501,11 @@ EXPORT_SYMBOL(dquot_commit); int dquot_release(struct dquot *dquot) { int ret = 0, ret2 = 0; + unsigned int memalloc; struct quota_info *dqopt = sb_dqopt(dquot->dq_sb);
mutex_lock(&dquot->dq_lock); + memalloc = memalloc_nofs_save(); /* Check whether we are not racing with some other dqget() */ if (dquot_is_busy(dquot)) goto out_dqlock; @@ -512,6 +521,7 @@ int dquot_release(struct dquot *dquot) } clear_bit(DQ_ACTIVE_B, &dquot->dq_flags); out_dqlock: + memalloc_nofs_restore(memalloc); mutex_unlock(&dquot->dq_lock); return ret; }