Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 27 Jun 2023 01:08:38 +0200 | From | наб <> | Subject | [PATCH v2 0/3] fanotify accounting for fs/splice.c |
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"people just forget to add inotify hooks to their I/O routines as a rule"? Guess what I did, fully knowing that some are missing in this file :)
==> te.c <== #define _GNU_SOURCE #include <fcntl.h> #include <stdio.h> int main() { ssize_t rd, acc = 0; while ((rd = tee(0, 1, 128 * 1024 * 1024, 0)) > 0) acc += rd; fprintf(stderr, "te=%zd: %m\n", acc); }
==> vm.c <== #define _GNU_SOURCE #include <fcntl.h> #include <stdio.h> #include <string.h> static char sb[1024 * 1024]; int main() { memcpy(sb, "żupan", sizeof("żupan")); ssize_t rd = vmsplice(1, &(struct iovec){.iov_base = sb, .iov_len = sizeof(sb)}, 1, SPLICE_F_GIFT); fprintf(stderr, "vm=%zd: %m\n", rd); }
echo zupa | ./te > fifo tees a few times and then blocks when the pipe fills, at which point we get into the broken state.
Similarly, ./vm > fifo (with the default 64k F_GETPIPE_SZ) enters that same state instantly.
With 2/3 and 3/3, they instead do 1: mask=2, cook=0, len=0, name= rd=80 1: mask=2, cook=0, len=0, name= rd=80 ... in a loop, as-expected, and # ./vm > fifo vm=65200: Success 1: mask=2, cook=0, len=0, name= rd=65200
I took the liberty of marking 2/3 and 3/3 as Fixes: of the original fanotify-in-splice commit as well, I think they fit the bill.
Ahelenia Ziemiańska (3): splice: always fsnotify_access(in), fsnotify_modify(out) on success splice: fsnotify_modify(fd) in vmsplice splice: fsnotify_access(in), fsnotify_modify(out) on success in tee
fs/splice.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-)
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