* Why is the length of max mount option a page size??
@ 2018-05-21 17:39 Jungsub Shin
2018-05-25 10:42 ` J. R. Okajima
0 siblings, 1 reply; 8+ messages in thread
From: Jungsub Shin @ 2018-05-21 17:39 UTC (permalink / raw)
To: viro; +Cc: linux-fsdevel, linux-kernel
Hi, now i'm interested in mount lenght of max mount option.
I anaylsis ksys_mount() function in /fs/namespace.c. and find out
the length of max mount option is a page size (4096 bytes).
I know that almost mount option short and page size is enough to
contain almost mount options. but because of options for
unionfs(overlay, aufs), lenght of mount option could be exceed it
and cut.
I suffer this problem with aufs. aufs's branch option is cut and
fail to aufs mount. I know that aufs is not offical fs in linux,
but overlay fs now support multi layer mount option and could be
suffer the same problem.
I think the best is dynamic allocate mount option's kernel memory.
but I'm only have shallow knowlege of kernel, I can't guess it.
And I think If the length of mount option cannot exceed a page size,
kernel must leave warning messsage about lenght and return err.
copy_mount_options() function seems to done this.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Why is the length of max mount option a page size??
2018-05-21 17:39 Why is the length of max mount option a page size?? Jungsub Shin
@ 2018-05-25 10:42 ` J. R. Okajima
2018-05-29 0:24 ` Jungsub Shin
0 siblings, 1 reply; 8+ messages in thread
From: J. R. Okajima @ 2018-05-25 10:42 UTC (permalink / raw)
To: Jungsub Shin; +Cc: viro, linux-fsdevel, linux-kernel
Jungsub Shin:
> I know that almost mount option short and page size is enough to
> contain almost mount options. but because of options for
> unionfs(overlay, aufs), lenght of mount option could be exceed it
> and cut.
>
> I suffer this problem with aufs. aufs's branch option is cut and
> fail to aufs mount. I know that aufs is not offical fs in linux,
For aufs, it should not happen because of the module parameter 'brs.'
(from the aufs manual)
----------------------------------------------------------------------
.SH Module Parameters
.TP
.B brs=1 | 0
Specifies to use the branch path data file under sysfs or not.
If the number of your branches is large or their path is long
and you meet the limitation of mount(8) ro /etc/mtab, you need to
enable CONFIG_SYSFS and set aufs module parameter brs=1.
When this parameter is set as 1, aufs does not show `br:' (or dirs=)
mount option through /proc/mounts (and /etc/mtab). So you can
keep yourself from the page limitation of
mount(8) or /etc/mtab.
Aufs shows branch paths through <sysfs>/fs/aufs/si_XXX/brNNN.
Actually the file under sysfs has also a size limitation, but I don't
think it is harmful.
There is one more side effect in setting 1 to this parameter.
If you rename your branch, the branch path written in /etc/mtab will be
obsoleted and the future remount will meet some error due to the
unmatched parameters (Remember that mount(8) may take the options from
/etc/mtab and pass them to the systemcall).
If you set 1, /etc/mtab will not hold the branch path and you will not
meet such trouble. On the other hand, the entries for the
branch path under sysfs are generated dynamically. So it must not be obsoleted.
But I don't think users want to rename branches so often.
If CONFIG_SYSFS is disable, this parameter is always set to 0.
----------------------------------------------------------------------
If you post the details of your environment to aufs-users ML, then I
may be able to describe more.
J. R. Okajima
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Why is the length of max mount option a page size??
2018-05-25 10:42 ` J. R. Okajima
@ 2018-05-29 0:24 ` Jungsub Shin
2018-05-29 1:14 ` Al Viro
2018-05-29 1:14 ` J. R. Okajima
0 siblings, 2 replies; 8+ messages in thread
From: Jungsub Shin @ 2018-05-29 0:24 UTC (permalink / raw)
To: J. R. Okajima; +Cc: viro, linux-fsdevel, linux-kernel, aufs-users
On Fri, May 25, 2018 at 07:42:10PM +0900, J. R. Okajima wrote:
> Jungsub Shin:
> > I know that almost mount option short and page size is enough to
> > contain almost mount options. but because of options for
> > unionfs(overlay, aufs), lenght of mount option could be exceed it
> > and cut.
> >
> > I suffer this problem with aufs. aufs's branch option is cut and
> > fail to aufs mount. I know that aufs is not offical fs in linux,
>
> For aufs, it should not happen because of the module parameter 'brs.'
>
> (from the aufs manual)
> ----------------------------------------------------------------------
> .SH Module Parameters
> .TP
> .B brs=1 | 0
> Specifies to use the branch path data file under sysfs or not.
>
> If the number of your branches is large or their path is long
> and you meet the limitation of mount(8) ro /etc/mtab, you need to
> enable CONFIG_SYSFS and set aufs module parameter brs=1.
>
> When this parameter is set as 1, aufs does not show `br:' (or dirs=)
> mount option through /proc/mounts (and /etc/mtab). So you can
> keep yourself from the page limitation of
> mount(8) or /etc/mtab.
> Aufs shows branch paths through <sysfs>/fs/aufs/si_XXX/brNNN.
> Actually the file under sysfs has also a size limitation, but I don't
> think it is harmful.
>
> There is one more side effect in setting 1 to this parameter.
> If you rename your branch, the branch path written in /etc/mtab will be
> obsoleted and the future remount will meet some error due to the
> unmatched parameters (Remember that mount(8) may take the options from
> /etc/mtab and pass them to the systemcall).
> If you set 1, /etc/mtab will not hold the branch path and you will not
> meet such trouble. On the other hand, the entries for the
> branch path under sysfs are generated dynamically. So it must not be obsoleted.
> But I don't think users want to rename branches so often.
>
> If CONFIG_SYSFS is disable, this parameter is always set to 0.
> ----------------------------------------------------------------------
>
>
> If you post the details of your environment to aufs-users ML, then I
> may be able to describe more.
>
>
> J. R. Okajima
I think brs module option is irrelevant to this issue. brs module
option looks like that didn't affect passing option parameter with in
mount() system call.
I suffered this problem below environments.
------------------------------------------------------------------------
OS : Ubuntu 18.04 LTS / 4.15.0-20-generic / 64bit
AUFS module parameter : brs = 1 / allow_userns = N
Mount command : mount -t aufs -o br=~/tca_agent/container_rw_dir/51509032=rw:~/tca_agent/image_layer_dir/5a259d94211e449fd466d997b5b0b149cb2997a732fd3a838c14295e0eb93f92=ro+wh:~/tca_agent/image_layer_dir/faca908333f884648b75738571879df977339ee7615c65410c98001a463bcd00=ro+wh:~/tca_agent/image_layer_dir/67b50813aedeb67fd06b434163fa64d07fbd16f714196daea1cd139a0171b080=ro+wh:~/tca_agent/image_layer_dir/28b6f7699be037b7f80dd03b22830712aa75b88ddfbba0910dd059b522fbff20=ro+wh:~/tca_agent/image_layer_dir/c47c7125efa9172d262c5b3645594010704f67cf44005da9f6d7ea5a5d2a05db=ro+wh:~/tca_agent/image_layer_dir/b91ed1b448ac52d251c785f5cfc299ca3ba4cfd68d739832b766228afa84a651=ro+wh:~/tca_agent/image_layer_dir/0169cd8bc0bdbecedb30c7d995e69e832d7ccd5c435e72c40af6940db87851b7=ro+wh:~/tca_agent/image_layer_dir/e7ef7d443e31f8b3b8a0a002a6895746d3737289eb2eea18d669924c089279f2=ro+wh:~/tca_agent/image_layer_dir/31bfb0cd724fda09280305b8dc1c4b0587ca01f5dd503d28afa82cff4fa92475=ro+wh:~/tca_agent/image_layer_dir/74428f0d76521fa9b9b1189cb72d303e367003c113cc8a11db125e3f7df1daa1=ro+wh:~/tca_agent/image_layer_dir/b20a927da14045cac0cd6a745f67fdeb88ead6d85752c670ea2773b27387f6ae=ro+wh:~/tca_agent/image_layer_dir/7dee3bce119631e3c922d78860d6b0ae160e237b63bf19f43713a05d1086c72f=ro+wh:~/tca_agent/image_layer_dir/636bce8f18e8734cb98f170bdcf1fb9ae52f1b091bfadcb2bef378b0d829ceb6=ro+wh:~/tca_agent/image_layer_dir/9c6fde234e701cf7b61534ef3a23cc4e0cdb6d3ffc497feaa8fcddc52e8d1fda=ro+wh:~/tca_agent/image_layer_dir/83c2f1968a932e3e284ef20b10a4ef8a9cfc01589dacf2100fb9a78e88c3888e=ro+wh:~/tca_agent/image_layer_dir/ec096a351601040fcd37c31edccd2f68106438097e8adf7253539366b2232de5=ro+wh:~/tca_agent/image_layer_dir/6de889accecb819028355196bde150749598e982b5dfe556540e102c737bfc34=ro+wh:~/tca_agent/image_layer_dir/1042cb8f2263d1030fdb57e0ca671b34a2180bb35d9448737e4a03e4987cf942=ro+wh:~/tca_agent/image_layer_dir/4fab8c997a447af2375e325467661ca1d74bf62dc6d802426f20d0134c9c43bc=ro+wh:~/tca_agent/image_layer_dir/ca57efb1c28464fab46af1826243c02af0a0b6cfb90bf92b30110e79028c5e68=ro+wh:~/tca_agent/image_layer_dir/ad86d54176611b5117fc155e8dfbd0b59bc0abce4e2051baef12c2f1e152c92f=ro+wh:~/tca_agent/image_layer_dir/f323ae7b264dcc517876e7c722ac3369baaef1a7c18cc5aae5f43f440fd646c0=ro+wh:~/tca_agent/image_layer_dir/a7d1c89c8422563102bd353de46154191038f92c9ebde8b22a8b2749140029ec=ro+wh:~/tca_agent/image_layer_dir/104adb8634902678f87db6bdbdb12d43d5bd6db9909ae9b12e078286046a1298=ro+wh:~/tca_agent/image_layer_dir/00450b5308ac99846ae7e5fa47652952c4fbbe82882ac241d5153d630644f790=ro+wh:~/tca_agent/image_layer_dir/129675caf5fdc1616c619d5b5718417806a64f282d324a3a580d6df1269b4f3f=ro+wh:~/tca_agent/image_layer_dir/8ce8b37ab4829a1fd34fcd38842b912d46eb3f7511365ccec0399a06670ab2fc=ro+wh:~/tca_agent/image_layer_dir/57080e2e0baad381605079107f08435133d7829364a9c450fc08877f01e57601=ro+wh:~/tca_agent/image_layer_dir/9ca225075a8c2bfd27ef5084e41335d781d24e7be0cbf4575ec3d42de662c6ac=ro+wh:~/tca_agent/image_layer_dir/74ec3835691908f9e6e271797f373257de3f9cc4bb408fd66dd229537ea5fcc1=ro+wh:~/tca_agent/image_layer_dir/59aa8f04c38abaae9c0e430d7b1a91f6560641e429386ee2c4eec57f0af35c04=ro+wh:~/tca_agent/image_layer_dir/bc318ac48b4f7a9536b72e2b0f223726a5225e13ecc70eba4b7b00e2bf80081b=ro+wh:~/tca_agent/image_layer_dir/bbfb0e8818be82ca0f17f280f7ad89497fef6c92e2bb50c40b2bd17c79347425=ro+wh:~/tca_agent/image_layer_dir/f36b94436263ce21d885d2f3f94c7b307e966a989fcefd3027c039e987d7dc2b=ro+wh:~/tca_agent/image_layer_dir/9103dae307f5748103f89093273329a523300b4f103a1d397c44abd766fe0015=ro+wh:~/tca_agent/image_layer_dir/9bd48cc89c1fc083b0db7ed45e5d7e4fec277450b8b47f96884588930ce8c56f=ro+wh:~/tca_agent/image_layer_dir/47ba0411cc8344ab1895a6b8eb0878a9ffd34410170a140ad1f210f20eedcdce=ro+wh:~/tca_agent/image_layer_dir/42b317de582399eb395b2818b4d658fb0a5987e8df1163e49ac2d8bec95a078e=ro+wh:~/tca_agent/image_layer_dir/57bb07a87ab6c29b048638c65566febe800fe79672730f7bb9e70b8f2e677e5a=ro+wh:~/tca_agent/image_layer_dir/b89b49aa036df19c6a2e77cc4aaef707ab3fd916d2d936b9e5e160d448d96ab3=ro+wh:~/tca_agent/image_layer_dir/d7bf931f8235cc7cc68c223b2945f77e858eb8cff4c9cb8bd64bacfd29312672=ro+wh:~/tca_agent/image_layer_dir/49a8b40dbec97066dbad4fb14d1bf388102190442679527e112b030270426ccc=ro+wh:~/tca_agent/image_layer_dir/05f05d402ea8ee67da1af2c9e35d10b9619b0f0c14a56788a1a0b5eeb290d685=ro+wh:~/tca_agent/image_layer_dir/b05d3f32ac4ff52a542dfcf50dbf155d060d79bd23d0ebed1439a3c6b1120731=ro+wh:~/tca_agent/image_layer_dir/0d061258f32c904c95aa020a9f679790c5722c3017eef98e298d6e29b4f02089=ro+wh:~/tca_agent/image_layer_dir/1f9c07049bcd59c59413c1706d0402b04c96598174eb16ef3de25b4e47413ad2=ro+wh:~/tca_agent/image_layer_dir/a86578a8bff61017b80eb653705c3f41136efb9b88facd6a2c67e8b3426e47f9=ro+wh:~/tca_agent/image_layer_dir/c3fdf4a694f0cc03939ee2cfdd09fb623966c5bb193778eaaea317655773656e=ro+wh:~/tca_agent/image_layer_dir/1b8fcd446a37050b55f57687aaae1150d74cc7f4468bbd00942535bad5ab22fe=ro+wh:~/tca_agent/image_layer_dir/6624cfa732b528cf7c1996719e30d1525aa27af7584f61a149d4d386aa8cf301=ro+wh:~/tca_agent/image_layer_dir/5b57e87f9b5859d902c4338c7a7ce5996a51fb8226a8f11ab29e10af4af5f14f=ro+wh:~/tca_agent/image_layer_dir/0c65112ac5c572a950e2671f903ef11e918e6e3cdbf026edda90db6c7a9c6ef8=ro+wh:~/tca_agent/image_layer_dir/ce16b72d243b82ded684a547da1400b8f2d07ed7b36b114ae0cbe2f20c17b0bf=ro+wh:~/tca_agent/image_layer_dir/a3937b112d7dbedfe075162862e404b7b85803d880589eaf3ebad9855629bdd5=ro+wh:~/tca_agent/image_layer_dir/b486d646cd9f5b8151856133ea3e81d53c3664bb727a0a87d0197cbbae9211de=ro+wh:~/tca_agent/image_layer_dir/de1b712fcfedbc3f61248c1a5fb9cba5a5ab6c7415f2c71c7ea162fd7c738c6f=ro+wh:~/tca_agent/image_layer_dir/2958a858559d3091b8162c066cfe5e17012f2307772180e702ffbc89bcae8fc2=ro+wh:~/tca_agent/image_layer_dir/14eae848ef41eb275ad37cc9d12dc276d3f08beeb06e041407371b9489335ee1=ro+wh:~/tca_agent/image_layer_dir/d72e07c403501a4abefaa80f3b81121392c42f314fc14bbf1bb434dc84457dd5=ro+wh:~/tca_agent/image_layer_dir/ee0efde24e35b4e2f801ca25640169ca2f319f9b5d37dbb0917cfd43e818d1f4=ro+wh:~/tca_agent/image_layer_dir/67dfb4d7c7ce39829d36740e1ef5279e00320a0d2bfe06bb67b6571f1ff47627=ro+wh:~/tca_agent/image_layer_dir/b3a1a69310f719755232ed5f8509f11f549d620d723ea293f001e3d30795108b=ro+wh:~/tca_agent/image_layer_dir/a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4=ro+wh:~/tca_agent/image_layer_dir/e5ad7970bc69d2ba62d2bbb4b80627273350e1982ff43bc1ca04a3215bc6da5b=ro+wh none ~/tca_agent/container_root_dir/51509032
dmesg : [343090.744067] aufs opt_add:810:mount[30864]: lookup failed /root/tca_agent/image_layer_di (-2)
------------------------------------------------------------------------
br option is cut and aufs search cut directory. Length of mount option
is about 6400. So I tested again with reduced option to about 4000
characters (PAGE_SIZE 4096 in kernel) by reducing branches, AUFS works well.
So I looked copy_mount_options() function in the kernel. This function
copys mount option form user memory to kernel memory within PAGE_SIZE(4096).
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Why is the length of max mount option a page size??
2018-05-29 0:24 ` Jungsub Shin
@ 2018-05-29 1:14 ` Al Viro
2018-05-29 3:57 ` Jungsub Shin
2018-05-29 1:14 ` J. R. Okajima
1 sibling, 1 reply; 8+ messages in thread
From: Al Viro @ 2018-05-29 1:14 UTC (permalink / raw)
To: Jungsub Shin; +Cc: J. R. Okajima, linux-fsdevel, linux-kernel, aufs-users
On Tue, May 29, 2018 at 09:24:56AM +0900, Jungsub Shin wrote:
> Mount command : mount -t aufs -o
br=~/tca_agent/container_rw_dir/51509032=rw:~/tca_agent/image_layer_dir/5a259d94211e449fd466d997b5b0b149cb2997a732fd3a838c14295e0eb93f92=ro+wh:~/tca_agent/image_layer_dir/faca908333f884648b75738571879df977339ee7615c65410c98001a463bcd00=ro+wh:~/tca_agent/image_layer_dir/67b50813aedeb67fd06b434163fa64d07fbd16f714196daea1cd139a0171b080=ro+wh:~/tca_agent/image_layer_dir/28b6f7699be037b7f80dd03b22830712aa75b88ddfbba0910dd059b522fbff20=ro+wh:~/tca_agent/image_layer_dir/c47c7125efa9172d262c5b3645594010704f67cf44005da9f6d7ea5a5d2a05db=ro+wh:~/tca_agent/image_layer_dir/b91ed1b448ac52d251c785f5cfc299ca3ba4cfd68d739832b766228afa84a651=ro+wh:~/tca_agent/image_layer_dir/0169cd8bc0bdbecedb30c7d995e69e832d7ccd5c435e72c40af6940db87851b7=ro+wh:~/tca_agent/image_layer_dir/e7ef7d443e31f8b3b8a0a002a6895746d3737289eb2eea18d669924c089279f2=ro+wh:~/tca_agent/image_layer_dir/31bfb0cd724fda09280305b8dc1c4b0587ca01f5dd503d28afa82cff4fa92475=ro+wh:~/tca_agent/image_layer_dir/74428f0d76521fa9b9b1189cb72d303e367003c113cc8a11db125e3f7df1daa1=ro+wh:~/tca_agent/image_layer_dir/b20a927da14045cac0cd6a745f67fdeb88ead6d85752c670ea2773b27387f6ae=ro+wh:~/tca_agent/image_layer_dir/7dee3bce119631e3c922d78860d6b0ae160e237b63bf19f43713a05d1086c72f=ro+wh:~/tca_agent/image_layer_dir/636bce8f18e8734cb98f170bdcf1fb9ae52f1b091bfadcb2bef378b0d829ceb6=ro+wh:~/tca_agent/image_layer_dir/9c6fde234e701cf7b61534ef3a23cc4e0cdb6d3ffc497feaa8fcddc52e8d1fda=ro+wh:~/tca_agent/image_layer_dir/83c2f1968a932e3e284ef20b10a4ef8a9cfc01589dacf2100fb9a78e88c3888e=ro+wh:~/tca_agent/image_layer_dir/ec096a351601040fcd37c31edccd2f68106438097e8adf7253539366b2232de5=ro+wh:~/tca_agent/image_layer_dir/6de889accecb819028355196bde150749598e982b5dfe556540e102c737bfc34=ro+wh:~/tca_agent/image_layer_dir/1042cb8f2263d1030fdb57e0ca671b34a2180bb35d9448737e4a03e4987cf942=ro+wh:~/tca_agent/image_layer_dir/4fab8c997a447af2375e325467661ca1d74bf62dc6d802426f20d0134c9c43bc=ro+wh:~/tca_agent/image_layer_dir/ca57efb1c28464fab46af1826243c02af0a0b6cfb90bf92b30110e79028c5e68=ro+wh:~/tca_agent/image_layer
_dir/ad86d54176611b5117fc155e8dfbd0b59bc0abce4e2051baef12c2f1e152c92f=ro+wh:~/tca_agent/image_layer_dir/f323ae7b264dcc517876e7c722ac3369baaef1a7c18cc5aae5f43f440fd646c0=ro+wh:~/tca_agent/image_layer_dir/a7d1c89c8422563102bd353de46154191038f92c9ebde8b22a8b2749140029ec=ro+wh:~/tca_agent/image_layer_dir/104adb8634902678f87db6bdbdb12d43d5bd6db9909ae9b12e078286046a1298=ro+wh:~/tca_agent/image_layer_dir/00450b5308ac99846ae7e5fa47652952c4fbbe82882ac241d5153d630644f790=ro+wh:~/tca_agent/image_layer_dir/129675caf5fdc1616c619d5b5718417806a64f282d324a3a580d6df1269b4f3f=ro+wh:~/tca_agent/image_layer_dir/8ce8b37ab4829a1fd34fcd38842b912d46eb3f7511365ccec0399a06670ab2fc=ro+wh:~/tca_agent/image_layer_dir/57080e2e0baad381605079107f08435133d7829364a9c450fc08877f01e57601=ro+wh:~/tca_agent/image_layer_dir/9ca225075a8c2bfd27ef5084e41335d781d24e7be0cbf4575ec3d42de662c6ac=ro+wh:~/tca_agent/image_layer_dir/74ec3835691908f9e6e271797f373257de3f9cc4bb408fd66dd229537ea5fcc1=ro+wh:~/tca_agent/image_layer_dir/59aa8f04c38abaae9c0e430d7b1a91f6560641e429386ee2c4eec57f0af35c04=ro+wh:~/tca_agent/image_layer_dir/bc318ac48b4f7a9536b72e2b0f223726a5225e13ecc70eba4b7b00e2bf80081b=ro+wh:~/tca_agent/image_layer_dir/bbfb0e8818be82ca0f17f280f7ad89497fef6c92e2bb50c40b2bd17c79347425=ro+wh:~/tca_agent/image_layer_dir/f36b94436263ce21d885d2f3f94c7b307e966a989fcefd3027c039e987d7dc2b=ro+wh:~/tca_agent/image_layer_dir/9103dae307f5748103f89093273329a523300b4f103a1d397c44abd766fe0015=ro+wh:~/tca_agent/image_layer_dir/9bd48cc89c1fc083b0db7ed45e5d7e4fec277450b8b47f96884588930ce8c56f=ro+wh:~/tca_agent/image_layer_dir/47ba0411cc8344ab1895a6b8eb0878a9ffd34410170a140ad1f210f20eedcdce=ro+wh:~/tca_agent/image_layer_dir/42b317de582399eb395b2818b4d658fb0a5987e8df1163e49ac2d8bec95a078e=ro+wh:~/tca_agent/image_layer_dir/57bb07a87ab6c29b048638c65566febe800fe79672730f7bb9e70b8f2e677e5a=ro+wh:~/tca_agent/image_layer_dir/b89b49aa036df19c6a2e77cc4aaef707ab3fd916d2d936b9e5e160d448d96ab3=ro+wh:~/tca_agent/image_layer_dir/d7bf931f8235cc7cc68c223b2945f77e858eb8cff4c9cb8bd64bacfd293126
72=ro+wh:~/tca_agent/image_layer_dir/49a8b40dbec97066dbad4fb14d1bf388102190442679527e112b030270426ccc=ro+wh:~/tca_agent/image_layer_dir/05f05d402ea8ee67da1af2c9e35d10b9619b0f0c14a56788a1a0b5eeb290d685=ro+wh:~/tca_agent/image_layer_dir/b05d3f32ac4ff52a542dfcf50dbf155d060d79bd23d0ebed1439a3c6b1120731=ro+wh:~/tca_agent/image_layer_dir/0d061258f32c904c95aa020a9f679790c5722c3017eef98e298d6e29b4f02089=ro+wh:~/tca_agent/image_layer_dir/1f9c07049bcd59c59413c1706d0402b04c96598174eb16ef3de25b4e47413ad2=ro+wh:~/tca_agent/image_layer_dir/a86578a8bff61017b80eb653705c3f41136efb9b88facd6a2c67e8b3426e47f9=ro+wh:~/tca_agent/image_layer_dir/c3fdf4a694f0cc03939ee2cfdd09fb623966c5bb193778eaaea317655773656e=ro+wh:~/tca_agent/image_layer_dir/1b8fcd446a37050b55f57687aaae1150d74cc7f4468bbd00942535bad5ab22fe=ro+wh:~/tca_agent/image_layer_dir/6624cfa732b528cf7c1996719e30d1525aa27af7584f61a149d4d386aa8cf301=ro+wh:~/tca_agent/image_layer_dir/5b57e87f9b5859d902c4338c7a7ce5996a51fb8226a8f11ab29e10af4af5f14f=ro+wh:~/tca_agent/image_layer_dir/0c65112ac5c572a950e2671f903ef11e918e6e3cdbf026edda90db6c7a9c6ef8=ro+wh:~/tca_agent/image_layer_dir/ce16b72d243b82ded684a547da1400b8f2d07ed7b36b114ae0cbe2f20c17b0bf=ro+wh:~/tca_agent/image_layer_dir/a3937b112d7dbedfe075162862e404b7b85803d880589eaf3ebad9855629bdd5=ro+wh:~/tca_agent/image_layer_dir/b486d646cd9f5b8151856133ea3e81d53c3664bb727a0a87d0197cbbae9211de=ro+wh:~/tca_agent/image_layer_dir/de1b712fcfedbc3f61248c1a5fb9cba5a5ab6c7415f2c71c7ea162fd7c738c6f=ro+wh:~/tca_agent/image_layer_dir/2958a858559d3091b8162c066cfe5e17012f2307772180e702ffbc89bcae8fc2=ro+wh:~/tca_agent/image_layer_dir/14eae848ef41eb275ad37cc9d12dc276d3f08beeb06e041407371b9489335ee1=ro+wh:~/tca_agent/image_layer_dir/d72e07c403501a4abefaa80f3b81121392c42f314fc14bbf1bb434dc84457dd5=ro+wh:~/tca_agent/image_layer_dir/ee0efde24e35b4e2f801ca25640169ca2f319f9b5d37dbb0917cfd43e818d1f4=ro+wh:~/tca_agent/image_layer_dir/67dfb4d7c7ce39829d36740e1ef5279e00320a0d2bfe06bb67b6571f1ff47627=ro+wh:~/tca_agent/image_layer_dir/b3a1a69310f719755232ed5f8509f1
1f549d620d723ea293f001e3d30795108b=ro+wh:~/tca_agent/image_layer_dir/a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4=ro+wh:~/tca_agent/image_layer_dir/e5ad7970bc69d2ba62d2bbb4b80627273350e1982ff43bc1ca04a3215bc6da5b=ro+wh
none ~/tca_agent/container_root_dir/51509032
> dmesg : [343090.744067] aufs opt_add:810:mount[30864]: lookup failed /root/tca_agent/image_layer_di (-2)
> ------------------------------------------------------------------------
>
> br option is cut and aufs search cut directory. Length of mount option
> is about 6400.
The lack of planning on your part...
IOW, don't do it. Use of symlinks (or bindings) might alleviate the problem
if aufs interface is that nasty. And before you go "just read up to \0",
consider e.g. NFS flavours with binary data structure passed instead of
a string.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Why is the length of max mount option a page size??
2018-05-29 0:24 ` Jungsub Shin
2018-05-29 1:14 ` Al Viro
@ 2018-05-29 1:14 ` J. R. Okajima
1 sibling, 0 replies; 8+ messages in thread
From: J. R. Okajima @ 2018-05-29 1:14 UTC (permalink / raw)
To: Jungsub Shin; +Cc: viro, linux-fsdevel, linux-kernel
Jungsub Shin:
> I suffered this problem below environments.
> ------------------------------------------------------------------------
> OS : Ubuntu 18.04 LTS / 4.15.0-20-generic / 64bit
> AUFS module parameter : brs =3D 1 / allow_userns =3D N
> Mount command : mount -t aufs -o br=3D~/tca_agent/container_rw_dir/51509032=
:::
(very long command line)
For such long branches, try "remount,append" option.
# mount -t aufs -o br=br0:br1:br2...:brN none /mntpnt
# mount -o remount,append=brN+1 /mntpnt
# mount -o remount,append=brN+2 /mntpnt
:::
J. R. Okajima
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Why is the length of max mount option a page size??
2018-05-29 1:14 ` Al Viro
@ 2018-05-29 3:57 ` Jungsub Shin
2018-05-30 2:40 ` J. R. Okajima
0 siblings, 1 reply; 8+ messages in thread
From: Jungsub Shin @ 2018-05-29 3:57 UTC (permalink / raw)
To: Al Viro; +Cc: J. R. Okajima, linux-fsdevel, linux-kernel, aufs-users
On Tue, May 29, 2018 at 02:14:12AM +0100, Al Viro wrote:
> On Tue, May 29, 2018 at 09:24:56AM +0900, Jungsub Shin wrote:
> > Mount command : mount -t aufs -o br=~/tca_agent/container_rw_dir/51509032=rw:~/tca_agent/image_layer_dir/5a259d94211e449fd466d997b5b0b149cb2997a732fd3a838c14295e0eb93f92=ro+wh:~/tca_agent/image_layer_dir/faca908333f884648b75738571879df977339ee7615c65410c98001a463bcd00=ro+wh:~/tca_agent/image_layer_dir/67b50813aedeb67fd06b434163fa64d07fbd16f714196daea1cd139a0171b080=ro+wh:~/tca_agent/image_layer_dir/28b6f7699be037b7f80dd03b22830712aa75b88ddfbba0910dd059b522fbff20=ro+wh:~/tca_agent/image_layer_dir/c47c7125efa9172d262c5b3645594010704f67cf44005da9f6d7ea5a5d2a05db=ro+wh:~/tca_agent/image_layer_dir/b91ed1b448ac52d251c785f5cfc299ca3ba4cfd68d739832b766228afa84a651=ro+wh:~/tca_agent/image_layer_dir/0169cd8bc0bdbecedb30c7d995e69e832d7ccd5c435e72c40af6940db87851b7=ro+wh:~/tca_agent/image_layer_dir/e7ef7d443e31f8b3b8a0a002a6895746d3737289eb2eea18d669924c089279f2=ro+wh:~/tca_agent/image_layer_dir/31bfb0cd724fda09280305b8dc1c4b0587ca01f5dd503d28afa82cff4fa92475=ro+wh:~/tca_agent/image_layer_dir/74428f0d76521fa9b9b1189cb72d303e367003c113cc8a11db125e3f7df1daa1=ro+wh:~/tca_agent/image_layer_dir/b20a927da14045cac0cd6a745f67fdeb88ead6d85752c670ea2773b27387f6ae=ro+wh:~/tca_agent/image_layer_dir/7dee3bce119631e3c922d78860d6b0ae160e237b63bf19f43713a05d1086c72f=ro+wh:~/tca_agent/image_layer_dir/636bce8f18e8734cb98f170bdcf1fb9ae52f1b091bfadcb2bef378b0d829ceb6=ro+wh:~/tca_agent/image_layer_dir/9c6fde234e701cf7b61534ef3a23cc4e0cdb6d3ffc497feaa8fcddc52e8d1fda=ro+wh:~/tca_agent/image_layer_dir/83c2f1968a932e3e284ef20b10a4ef8a9cfc01589dacf2100fb9a78e88c3888e=ro+wh:~/tca_agent/image_layer_dir/ec096a351601040fcd37c31edccd2f68106438097e8adf7253539366b2232de5=ro+wh:~/tca_agent/image_layer_dir/6de889accecb819028355196bde150749598e982b5dfe556540e102c737bfc34=ro+wh:~/tca_agent/image_layer_dir/1042cb8f2263d1030fdb57e0ca671b34a2180bb35d9448737e4a03e4987cf942=ro+wh:~/tca_agent/image_layer_dir/4fab8c997a447af2375e325467661ca1d74bf62dc6d802426f20d0134c9c43bc=ro+wh:~/tca_agent/image_layer_dir/ca57efb1c28464fab46af1826243c02af0a0b6cfb90bf92b30110e79028c5e68=ro+wh:~/tca_agent/image_layer_dir/ad86d54176611b5117fc155e8dfbd0b59bc0abce4e2051baef12c2f1e152c92f=ro+wh:~/tca_agent/image_layer_dir/f323ae7b264dcc517876e7c722ac3369baaef1a7c18cc5aae5f43f440fd646c0=ro+wh:~/tca_agent/image_layer_dir/a7d1c89c8422563102bd353de46154191038f92c9ebde8b22a8b2749140029ec=ro+wh:~/tca_agent/image_layer_dir/104adb8634902678f87db6bdbdb12d43d5bd6db9909ae9b12e078286046a1298=ro+wh:~/tca_agent/image_layer_dir/00450b5308ac99846ae7e5fa47652952c4fbbe82882ac241d5153d630644f790=ro+wh:~/tca_agent/image_layer_dir/129675caf5fdc1616c619d5b5718417806a64f282d324a3a580d6df1269b4f3f=ro+wh:~/tca_agent/image_layer_dir/8ce8b37ab4829a1fd34fcd38842b912d46eb3f7511365ccec0399a06670ab2fc=ro+wh:~/tca_agent/image_layer_dir/57080e2e0baad381605079107f08435133d7829364a9c450fc08877f01e57601=ro+wh:~/tca_agent/image_layer_dir/9ca225075a8c2bfd27ef5084e41335d781d24e7be0cbf4575ec3d42de662c6ac=ro+wh:~/tca_agent/image_layer_dir/74ec3835691908f9e6e271797f373257de3f9cc4bb408fd66dd229537ea5fcc1=ro+wh:~/tca_agent/image_layer_dir/59aa8f04c38abaae9c0e430d7b1a91f6560641e429386ee2c4eec57f0af35c04=ro+wh:~/tca_agent/image_layer_dir/bc318ac48b4f7a9536b72e2b0f223726a5225e13ecc70eba4b7b00e2bf80081b=ro+wh:~/tca_agent/image_layer_dir/bbfb0e8818be82ca0f17f280f7ad89497fef6c92e2bb50c40b2bd17c79347425=ro+wh:~/tca_agent/image_layer_dir/f36b94436263ce21d885d2f3f94c7b307e966a989fcefd3027c039e987d7dc2b=ro+wh:~/tca_agent/image_layer_dir/9103dae307f5748103f89093273329a523300b4f103a1d397c44abd766fe0015=ro+wh:~/tca_agent/image_layer_dir/9bd48cc89c1fc083b0db7ed45e5d7e4fec277450b8b47f96884588930ce8c56f=ro+wh:~/tca_agent/image_layer_dir/47ba0411cc8344ab1895a6b8eb0878a9ffd34410170a140ad1f210f20eedcdce=ro+wh:~/tca_agent/image_layer_dir/42b317de582399eb395b2818b4d658fb0a5987e8df1163e49ac2d8bec95a078e=ro+wh:~/tca_agent/image_layer_dir/57bb07a87ab6c29b048638c65566febe800fe79672730f7bb9e70b8f2e677e5a=ro+wh:~/tca_agent/image_layer_dir/b89b49aa036df19c6a2e77cc4aaef707ab3fd916d2d936b9e5e160d448d96ab3=ro+wh:~/tca_agent/image_layer_dir/d7bf931f8235cc7cc68c223b2945f77e858eb8cff4c9cb8bd64bacfd29312672=ro+wh:~/tca_agent/image_layer_dir/49a8b40dbec97066dbad4fb14d1bf388102190442679527e112b030270426ccc=ro+wh:~/tca_agent/image_layer_dir/05f05d402ea8ee67da1af2c9e35d10b9619b0f0c14a56788a1a0b5eeb290d685=ro+wh:~/tca_agent/image_layer_dir/b05d3f32ac4ff52a542dfcf50dbf155d060d79bd23d0ebed1439a3c6b1120731=ro+wh:~/tca_agent/image_layer_dir/0d061258f32c904c95aa020a9f679790c5722c3017eef98e298d6e29b4f02089=ro+wh:~/tca_agent/image_layer_dir/1f9c07049bcd59c59413c1706d0402b04c96598174eb16ef3de25b4e47413ad2=ro+wh:~/tca_agent/image_layer_dir/a86578a8bff61017b80eb653705c3f41136efb9b88facd6a2c67e8b3426e47f9=ro+wh:~/tca_agent/image_layer_dir/c3fdf4a694f0cc03939ee2cfdd09fb623966c5bb193778eaaea317655773656e=ro+wh:~/tca_agent/image_layer_dir/1b8fcd446a37050b55f57687aaae1150d74cc7f4468bbd00942535bad5ab22fe=ro+wh:~/tca_agent/image_layer_dir/6624cfa732b528cf7c1996719e30d1525aa27af7584f61a149d4d386aa8cf301=ro+wh:~/tca_agent/image_layer_dir/5b57e87f9b5859d902c4338c7a7ce5996a51fb8226a8f11ab29e10af4af5f14f=ro+wh:~/tca_agent/image_layer_dir/0c65112ac5c572a950e2671f903ef11e918e6e3cdbf026edda90db6c7a9c6ef8=ro+wh:~/tca_agent/image_layer_dir/ce16b72d243b82ded684a547da1400b8f2d07ed7b36b114ae0cbe2f20c17b0bf=ro+wh:~/tca_agent/image_layer_dir/a3937b112d7dbedfe075162862e404b7b85803d880589eaf3ebad9855629bdd5=ro+wh:~/tca_agent/image_layer_dir/b486d646cd9f5b8151856133ea3e81d53c3664bb727a0a87d0197cbbae9211de=ro+wh:~/tca_agent/image_layer_dir/de1b712fcfedbc3f61248c1a5fb9cba5a5ab6c7415f2c71c7ea162fd7c738c6f=ro+wh:~/tca_agent/image_layer_dir/2958a858559d3091b8162c066cfe5e17012f2307772180e702ffbc89bcae8fc2=ro+wh:~/tca_agent/image_layer_dir/14eae848ef41eb275ad37cc9d12dc276d3f08beeb06e041407371b9489335ee1=ro+wh:~/tca_agent/image_layer_dir/d72e07c403501a4abefaa80f3b81121392c42f314fc14bbf1bb434dc84457dd5=ro+wh:~/tca_agent/image_layer_dir/ee0efde24e35b4e2f801ca25640169ca2f319f9b5d37dbb0917cfd43e818d1f4=ro+wh:~/tca_agent/image_layer_dir/67dfb4d7c7ce39829d36740e1ef5279e00320a0d2bfe06bb67b6571f1ff47627=ro+wh:~/tca_agent/image_layer_dir/b3a1a69310f719755232ed5f8509f11f549d620d723ea293f001e3d30795108b=ro+wh:~/tca_agent/image_layer_dir/a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4=ro+wh:~/tca_agent/image_layer_dir/e5ad7970bc69d2ba62d2bbb4b80627273350e1982ff43bc1ca04a3215bc6da5b=ro+wh none ~/tca_agent/container_root_dir/51509032
> > dmesg : [343090.744067] aufs opt_add:810:mount[30864]: lookup failed /root/tca_agent/image_layer_di (-2)
I think kernel at least must print warning message when mount option
overflow the PAGE_SIZE if length of mount option should be fixed.
When i encouter this problem, i found the reason hard because of
lack of kernel log and wrong infomation.
> > ------------------------------------------------------------------------
> >
> > br option is cut and aufs search cut directory. Length of mount option
> > is about 6400.
>
> The lack of planning on your part...
>
> IOW, don't do it. Use of symlinks (or bindings) might alleviate the problem
> if aufs interface is that nasty. And before you go "just read up to \0",
> consider e.g. NFS flavours with binary data structure passed instead of
> a string.
Do you mean using symlinks or bind mount to reduce length of mount
options?? I can remove "~/tca_agent/image_layer_dir" string. But the
other character means unique ID of layer and i can't compress it or
replace it to another string. This is not fundamental solution. Docker
use the same unique ID to manage layers.
As i said before overlayfs could suffer same problem because overlayfs
support multiple lowerdir options and there is no route to pass lower
dirs without mount option. So i think to support unionfs stably in
kernel, dynamic memory allocation for mount option is needed.
Thanks.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Why is the length of max mount option a page size??
2018-05-29 3:57 ` Jungsub Shin
@ 2018-05-30 2:40 ` J. R. Okajima
2018-05-30 23:51 ` Jungsub Shin
0 siblings, 1 reply; 8+ messages in thread
From: J. R. Okajima @ 2018-05-30 2:40 UTC (permalink / raw)
To: Jungsub Shin; +Cc: Al Viro, linux-fsdevel, linux-kernel
Jungsub Shin:
> Do you mean using symlinks or bind mount to reduce length of mount
> options?? I can remove "~/tca_agent/image_layer_dir" string. But the
> other character means unique ID of layer and i can't compress it or
> replace it to another string. This is not fundamental solution. Docker=20
Can't it be a solution?
# mount -o bind /long/path0 /br0
# mount -o bind /long/path1 /br1
:::
# mount -t aufs -o br=/br0:/br1:... none /mntpnt
or
# ln -s /long/path0 /br0
# ln -s /long/path1 /br1
:::
# mount -t aufs -o br=/br0:/br1:... none /mntpnt
J. R. Okajima
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: Why is the length of max mount option a page size??
2018-05-30 2:40 ` J. R. Okajima
@ 2018-05-30 23:51 ` Jungsub Shin
0 siblings, 0 replies; 8+ messages in thread
From: Jungsub Shin @ 2018-05-30 23:51 UTC (permalink / raw)
To: J. R. Okajima; +Cc: Al Viro, linux-fsdevel, linux-kernel
On Wed, May 30, 2018 at 11:40:27AM +0900, J. R. Okajima wrote:
> Jungsub Shin:
> > Do you mean using symlinks or bind mount to reduce length of mount
> > options?? I can remove "~/tca_agent/image_layer_dir" string. But the
> > other character means unique ID of layer and i can't compress it or
> > replace it to another string. This is not fundamental solution. Docker=20
>
> Can't it be a solution?
>
> # mount -o bind /long/path0 /br0
> # mount -o bind /long/path1 /br1
> :::
> # mount -t aufs -o br=/br0:/br1:... none /mntpnt
>
> or
>
> # ln -s /long/path0 /br0
> # ln -s /long/path1 /br1
> :::
> # mount -t aufs -o br=/br0:/br1:... none /mntpnt
>
>
> J. R. Okajima
I don't test them, but they will work well.
That's temporary solution. So i'm use remount,append option.
Thanks
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-05-31 0:02 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-05-21 17:39 Why is the length of max mount option a page size?? Jungsub Shin
2018-05-25 10:42 ` J. R. Okajima
2018-05-29 0:24 ` Jungsub Shin
2018-05-29 1:14 ` Al Viro
2018-05-29 3:57 ` Jungsub Shin
2018-05-30 2:40 ` J. R. Okajima
2018-05-30 23:51 ` Jungsub Shin
2018-05-29 1:14 ` J. R. Okajima
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