fix race between fuse_iget() and fuse_reverse_inval_inode() #75
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This reverts commit fabde09.
There is a race condition where fuse_reverse_inval_inode() can be called while fuse_iget() is still initializing an inode. This can lead to the inode's attributes being invalidated before they are properly set up, causing inconsistent state. The race occurs when: 1. Thread A calls fuse_iget() and starts initializing an inode 2. Thread B calls fuse_reverse_inval_inode() for the same inode 3. Thread B updates attr_version, invalidating the inode 4. Thread A completes initialization with stale attributes This patch fixes the race by introducing a delayed invalidation mechanism: - Use attr_version == 1 as a sentinel value to indicate that an invalidation occurred during fuse_iget() initialization - In fuse_change_attributes_common(), skip updating attr_version if it equals 1, allowing fuse_iget() to detect the pending invalidation - In fuse_reverse_inval_inode_common(), if attr_version <= 1, set it to 1 and return early, deferring the invalidation - In fuse_iget(), after calling fuse_change_attributes(), check if attr_version == 1 and perform the delayed invalidation The function fuse_reverse_inval_inode() is refactored to extract the common invalidation logic into fuse_reverse_inval_inode_common() Since fc->attr_version is initialized to 1, normal inode attr_version values will be 0 (for new inodes before first update) or >= 2, making the value 1 safe to use as a sentinel. Signed-off-by: Guang Yuan Wu <gwu@ddn.com> Applied-by: Horst Birthelmer <hbirthelmer@ddn.com>
bsbernd
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Jan 14, 2026
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Sorry no, we cannot fix an issue between clients and cause another issue on the local client.
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