我遇到了一個奇怪的問題，mkfs.ext4 無法在臨時檔案支援的循環裝置上工作。
tmp_file="$(mktemp)"
fallocate -l 8M "$tmp_file"
loop="$(losetup --show -f "$tmp_file")"
mkfs.ext4 "$loop"
我也嘗試dd if=/dev/zero過truncate。相同的結果。荒謬的是，故障不會傳播到應用程式層。 mkfs 程式以 0 退出，但輸出檔案系統基本上已損壞。這可能與緩衝/延遲 io 有關。
難道我不被允許這樣做嗎？或者這是一個錯誤？我可能可以透過閱讀內核程式碼來進一步調查，但我想先聽聽專家的意見。
更新 哎呀。對不起。核心版本：5.7.10-201.fc32.x86_64
內核訊息。
[ 3213.106709] blk_update_request: operation not supported error, dev loop6, sector 16256 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3213.107013] blk_update_request: operation not supported error, dev loop6, sector 196 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3213.108396] blk_update_request: operation not supported error, dev loop6, sector 708 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3213.110006] blk_update_request: operation not supported error, dev loop6, sector 160 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3213.110158] blk_update_request: operation not supported error, dev loop6, sector 166 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3213.110852] blk_update_request: operation not supported error, dev loop6, sector 710 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3223.152191] blk_update_request: operation not supported error, dev loop7, sector 16256 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3223.152619] blk_update_request: operation not supported error, dev loop7, sector 196 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3223.153694] blk_update_request: operation not supported error, dev loop7, sector 708 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3223.155495] blk_update_request: operation not supported error, dev loop7, sector 160 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3223.155670] blk_update_request: operation not supported error, dev loop7, sector 166 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3223.156233] blk_update_request: operation not supported error, dev loop7, sector 710 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3568.666245] blk_update_request: operation not supported error, dev loop6, sector 16256 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3568.666543] blk_update_request: operation not supported error, dev loop6, sector 196 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3568.667546] blk_update_request: operation not supported error, dev loop6, sector 708 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3568.669204] blk_update_request: operation not supported error, dev loop6, sector 160 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3568.669380] blk_update_request: operation not supported error, dev loop6, sector 166 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
[ 3568.669974] blk_update_request: operation not supported error, dev loop6, sector 710 op 0x9:(WRITE_ZEROES) flags 0x1000800 phys_seg 0 prio class 0
就像我說的，mkfs 應該會成功運行。錯誤是無聲的。
答案1
我剛剛遇到了我認為是同樣的問題。我懷疑您本身不是 mktemp，但您的 /tmp 是 tmpfs 檔案系統。顯然tmpfs 不支援FALLOC_FL_ZERO_RANGE。有趣的是，您可以在 tmpfs 掛載上的檔案上執行 mkfs.ext4 而不會出現問題。但是，當它是由同一 tmpfs 上的檔案支援的循環設備時，就會出現問題。
您應該能夠透過使用設定支援零範圍（大多數標準範圍）的檔案系統上的路徑的-p選項來解決此問題。mktempTMPDIR