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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2022-06-05 15:38:13 +0100 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2022-06-06 10:08:10 +0200 |
| commit | 537e11cdc7a6b3ce94fa25ed41306193df9677b7 (patch) | |
| tree | f52707439580c1c059f989ab9f1823b7637bd161 /fs | |
| parent | 10e14073107dd0b6d97d9516a02845a8e501c2c9 (diff) | |
| download | linux-537e11cdc7a6b3ce94fa25ed41306193df9677b7.tar.bz2 | |
quota: Prevent memory allocation recursion while holding dq_lock
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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/quota/dquot.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c index a74aef99bd3d..09d1307959d0 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> @@ -425,9 +426,11 @@ 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) @@ -458,6 +461,7 @@ 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; } @@ -469,9 +473,11 @@ 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 @@ -481,6 +487,7 @@ int dquot_commit(struct dquot *dquot) else ret = -EIO; out_lock: + memalloc_nofs_restore(memalloc); mutex_unlock(&dquot->dq_lock); return ret; } @@ -492,9 +499,11 @@ 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; @@ -510,6 +519,7 @@ 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; } |