From 87d93731e7f60f71238ab3820f18ab1ee13c9ea0 Mon Sep 17 00:00:00 2001 From: George Amanakis Date: Thu, 17 Jun 2021 03:17:42 +0300 Subject: [PATCH] Avoid deadlock when removing L2ARC devices under I/O In case we have I/O and try to remove an L2ARC device a deadlock might occur. arc_read()->zio_read()->zfs_blkptr_verify() waits for SCL_VDEV to be dropped while holding the hash_lock. However, spa_l2cache_load() holds SCL_ALL and waits for the hash_lock in l2arc_evict(). Fix this by moving zfs_blkptr_verify() to the top top arc_read() before the hash_lock is taken. Verify the block pointer and return a checksum error if damaged rather than halting the system, by using BLK_VERIFY_LOG instead of BLK_VERIFY_HALT. Reviewed-by: Brian Behlendorf Reviewed-by: Mark Maybee Signed-off-by: George Amanakis Closes #12054 --- module/zfs/arc.c | 17 ++++++----------- module/zfs/zio.c | 3 --- 2 files changed, 6 insertions(+), 14 deletions(-) diff --git a/module/zfs/arc.c b/module/zfs/arc.c index b6b0f8587..e70b37d4b 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -5835,6 +5835,12 @@ top: * Embedded BP's have no DVA and require no I/O to "read". * Create an anonymous arc buf to back it. */ + if (!zfs_blkptr_verify(spa, bp, zio_flags & + ZIO_FLAG_CONFIG_WRITER, BLK_VERIFY_LOG)) { + rc = SET_ERROR(ECKSUM); + goto out; + } + hdr = buf_hash_find(guid, bp, &hash_lock); } @@ -6003,17 +6009,6 @@ top: goto out; } - /* - * Gracefully handle a damaged logical block size as a - * checksum error. - */ - if (lsize > spa_maxblocksize(spa)) { - rc = SET_ERROR(ECKSUM); - if (hash_lock != NULL) - mutex_exit(hash_lock); - goto out; - } - if (hdr == NULL) { /* * This block is not in the cache or it has diff --git a/module/zfs/zio.c b/module/zfs/zio.c index 05bc2d63a..dfc3c71c1 100644 --- a/module/zfs/zio.c +++ b/module/zfs/zio.c @@ -1106,9 +1106,6 @@ zio_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, { zio_t *zio; - (void) zfs_blkptr_verify(spa, bp, flags & ZIO_FLAG_CONFIG_WRITER, - BLK_VERIFY_HALT); - zio = zio_create(pio, spa, BP_PHYSICAL_BIRTH(bp), bp, data, size, size, done, private, ZIO_TYPE_READ, priority, flags, NULL, 0, zb, -- 2.30.2