| Message ID | 1445417149-804-2-git-send-email-anand.jain@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Anand Jain wrote on 2015/10/21 16:45 +0800: > mkfs from latest btrfs-progs will enable latest default features, > and if the kernel is down-rev and does not support a latest default > feature then mount fails, as expected. > > This patch disables default features based on the running kernel. > > Signed-off-by: Anand Jain <anand.jain@oracle.com> > --- > mkfs.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mkfs.c b/mkfs.c > index a5802f7..2b9d734 100644 > --- a/mkfs.c > +++ b/mkfs.c > @@ -1357,10 +1357,13 @@ int main(int ac, char **av) > int dev_cnt = 0; > int saved_optind; > char fs_uuid[BTRFS_UUID_UNPARSED_SIZE] = { 0 }; > - u64 features = BTRFS_MKFS_DEFAULT_FEATURES; > + u64 features; > struct mkfs_allocation allocation = { 0 }; > struct btrfs_mkfs_config mkfs_cfg; > > + features = btrfs_features_allowed_by_kernel(); > + features &= BTRFS_MKFS_DEFAULT_FEATURES; > + Despite the problem of btrfs_features_allowed_by_kernel() I mentioned in previous mail, the behavior is a little aggressive for me. So a user with old kernel won't be able to create a filesystem with newer feature forever. Maybe the user are just making btrfs for his or her newer kernel? IMHO, it's better to output a warning other than just change features without any information. Thanks, Qu > while(1) { > int c; > static const struct option long_options[] = { > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Thanks for the comments.. more below. On 10/21/2015 05:12 PM, Qu Wenruo wrote: > > > Anand Jain wrote on 2015/10/21 16:45 +0800: >> mkfs from latest btrfs-progs will enable latest default features, >> and if the kernel is down-rev and does not support a latest default >> feature then mount fails, as expected. >> >> This patch disables default features based on the running kernel. >> >> Signed-off-by: Anand Jain <anand.jain@oracle.com> >> --- >> mkfs.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/mkfs.c b/mkfs.c >> index a5802f7..2b9d734 100644 >> --- a/mkfs.c >> +++ b/mkfs.c >> @@ -1357,10 +1357,13 @@ int main(int ac, char **av) >> int dev_cnt = 0; >> int saved_optind; >> char fs_uuid[BTRFS_UUID_UNPARSED_SIZE] = { 0 }; >> - u64 features = BTRFS_MKFS_DEFAULT_FEATURES; >> + u64 features; >> struct mkfs_allocation allocation = { 0 }; >> struct btrfs_mkfs_config mkfs_cfg; >> >> + features = btrfs_features_allowed_by_kernel(); >> + features &= BTRFS_MKFS_DEFAULT_FEATURES; >> + > > Despite the problem of btrfs_features_allowed_by_kernel() I mentioned in > previous mail, > the behavior is a little aggressive for me. > > So a user with old kernel won't be able to create a filesystem with > newer feature forever. > Maybe the user are just making btrfs for his or her newer kernel? I am not understanding the complete picture here, is there any example that you can quote. ? Thanks, Anand > IMHO, it's better to output a warning other than just change features > without any information. > > Thanks, > Qu > >> while(1) { >> int c; >> static const struct option long_options[] = { >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
? 2015?10?21? 22:15, Anand Jain ??: > > Thanks for the comments.. more below. > > On 10/21/2015 05:12 PM, Qu Wenruo wrote: >> >> >> Anand Jain wrote on 2015/10/21 16:45 +0800: >>> mkfs from latest btrfs-progs will enable latest default features, >>> and if the kernel is down-rev and does not support a latest default >>> feature then mount fails, as expected. >>> >>> This patch disables default features based on the running kernel. >>> >>> Signed-off-by: Anand Jain <anand.jain@oracle.com> >>> --- >>> mkfs.c | 5 ++++- >>> 1 file changed, 4 insertions(+), 1 deletion(-) >>> >>> diff --git a/mkfs.c b/mkfs.c >>> index a5802f7..2b9d734 100644 >>> --- a/mkfs.c >>> +++ b/mkfs.c >>> @@ -1357,10 +1357,13 @@ int main(int ac, char **av) >>> int dev_cnt = 0; >>> int saved_optind; >>> char fs_uuid[BTRFS_UUID_UNPARSED_SIZE] = { 0 }; >>> - u64 features = BTRFS_MKFS_DEFAULT_FEATURES; >>> + u64 features; >>> struct mkfs_allocation allocation = { 0 }; >>> struct btrfs_mkfs_config mkfs_cfg; >>> >>> + features = btrfs_features_allowed_by_kernel(); >>> + features &= BTRFS_MKFS_DEFAULT_FEATURES; >>> + >> >> Despite the problem of btrfs_features_allowed_by_kernel() I mentioned in >> previous mail, >> the behavior is a little aggressive for me. >> >> So a user with old kernel won't be able to create a filesystem with >> newer feature forever. >> Maybe the user are just making btrfs for his or her newer kernel? > > I am not understanding the complete picture here, is there any > example that you can quote. ? > > Thanks, Anand > Sorry my fault. Your features are set before parse_fs_features() So it's just my misunderstanding. However, I still prefer warning other than just changing default features. Thanks, Qu >> IMHO, it's better to output a warning other than just change features >> without any information. >> >> Thanks, >> Qu >> >>> while(1) { >>> int c; >>> static const struct option long_options[] = { >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, more details about this RFC as below.. > So a user with old kernel won't be able to create a filesystem with > newer feature forever. Thats not true. Here below is an example of the problem and fix in action. > Maybe the user are just making btrfs for his or her newer kernel? Yes. Thats still possible as below. [[current problem]] I am on 3.8 kernel which does not support the skinny-metadata feature. --------- # uname -r 3.8.13-98.4.1.el6uek.x86_64 ------------- Lets say customer upgraded the latest btrfs-progs as they wanted better cli interface, reporting and document which is only available in the latest btrfs-progs. As btrfs-progs is backward kernel compatible, they don't have to upgrade the kernel. But as skinny-metadata is part of the "mkfs default feature", thats get enabled by default during mkfs. ---------- # mkfs.btrfs -f /dev/sdc btrfs-progs v4.2.2-7-g03cf344 See http://btrfs.wiki.kernel.org for more information. Label: (null) UUID: bb85b156-35eb-49a5-be5a-512fec1abab4 Node size: 16384 Sector size: 4096 Filesystem size: 3.00GiB Block group profiles: Data: single 8.00MiB Metadata: DUP 161.56MiB System: DUP 12.00MiB SSD detected: no Incompat features: extref, skinny-metadata <----- Number of devices: 1 Devices: ID SIZE PATH 1 3.00GiB /dev/sdc ------------------- mount on the running kernel 3.8 fails, as there is no kernel support for skinny-metadata ----------- # mount /dev/sdc /btrfs mount: wrong fs type, bad option, bad superblock on /dev/sdc, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so BTRFS: couldn't mount because of unsupported optional features (100). btrfs: open_ctree failed ---------- Customers need to upgrade the kernel also to mount this FS. [[current solution]] User must know that their running kernel does not support skinny metadata and disable features accordingly as below. ------------ # mkfs.btrfs -f -O ^skinny-metadata /dev/sdc > /dev/null && mount /dev/sdc /btrfs # echo $? 0 ------------ [[problem with the current solution]] btrfs-progs is backward kernel compatible. But the default feature as set during mkfs is very btrfs-progs centric, and is not in sync with the current running kernel. [[new proposed, with the patch]] - the default-features that are not supported by the running kernel are masked. So now the default mkfs.btrfs and mount works. As progs finds that kernel version is too old to support skinny-metadata and remotes is from the default feature list. ------------------- # uname -r 3.8.13-98.4.1.el6uek.x86_64 # mkfs.btrfs -f /dev/sdc btrfs-progs v4.2.2-7-g03cf344 See http://btrfs.wiki.kernel.org for more information. Label: (null) UUID: f2513ff0-6d94-4b6a-8bbf-ff53d343fa62 Node size: 16384 Sector size: 4096 Filesystem size: 3.00GiB Block group profiles: Data: single 8.00MiB Metadata: DUP 161.56MiB System: DUP 12.00MiB SSD detected: no Incompat features: extref <----- Number of devices: 1 Devices: ID SIZE PATH 1 3.00GiB /dev/sdc # mount /dev/sdc /btrfs ------------------- However as Qu pointed out if user wants to create FS with a feature that is not supported by running kernel. They still have the choice to enable it using -O option. as below. however they won't be able to mount it unless kernel is upgraded as well. ------- # mkfs.btrfs -f -O skinny-metadata /dev/sdc btrfs-progs v4.2.2-7-g03cf344 See http://btrfs.wiki.kernel.org for more information. Label: (null) UUID: 30c018ab-3d2a-4acc-8287-3f28c5324fca Node size: 16384 Sector size: 4096 Filesystem size: 3.00GiB Block group profiles: Data: single 8.00MiB Metadata: DUP 161.56MiB System: DUP 12.00MiB SSD detected: no Incompat features: extref, skinny-metadata <---- Number of devices: 1 Devices: ID SIZE PATH 1 3.00GiB /dev/sdc # mount /dev/sdc /btrfs mount: wrong fs type, bad option, bad superblock on /dev/sdc, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so # --------- In nut shell this patch makes _mkfs and btrfs-convert default features_ dynamically aligned with the running kernel. Thanks, Anand -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Anand Jain wrote on 2015/10/22 11:09 +0800: > > Hi, > > more details about this RFC as below.. > > >> So a user with old kernel won't be able to create a filesystem with >> newer feature forever. > > Thats not true. Here below is an example of the problem and fix > in action. > >> Maybe the user are just making btrfs for his or her newer kernel? > > Yes. Thats still possible as below. > > > > [[current problem]] > > I am on 3.8 kernel which does not support the skinny-metadata feature. > --------- > # uname -r > 3.8.13-98.4.1.el6uek.x86_64 > ------------- > > Lets say customer upgraded the latest btrfs-progs as they wanted better > cli interface, reporting and document which is only available in the > latest btrfs-progs. > > As btrfs-progs is backward kernel compatible, they don't have to > upgrade the kernel. > > But as skinny-metadata is part of the "mkfs default feature", thats get > enabled by default during mkfs. For real customer case, that's really a problem. Customer is god, right? But on the other hand, normally support team only provides support for their own product. Here "product" may be their distribution or other software, but never any software customer build from source by themselves. If customer want to upgrade btrfs-progs, they should use the repo from distribution, not compile by themselves. And it will be the responsibility of backport team to backport needed features for kernel/btrfs-progs or change default features. But unfortunately(or fortunately?), we are not backport team. > > ---------- > # mkfs.btrfs -f /dev/sdc > btrfs-progs v4.2.2-7-g03cf344 > See http://btrfs.wiki.kernel.org for more information. > > Label: (null) > UUID: bb85b156-35eb-49a5-be5a-512fec1abab4 > Node size: 16384 > Sector size: 4096 > Filesystem size: 3.00GiB > Block group profiles: > Data: single 8.00MiB > Metadata: DUP 161.56MiB > System: DUP 12.00MiB > SSD detected: no > Incompat features: extref, skinny-metadata <----- > Number of devices: 1 > Devices: > ID SIZE PATH > 1 3.00GiB /dev/sdc > ------------------- > > mount on the running kernel 3.8 fails, as there is no kernel support > for skinny-metadata > ----------- > # mount /dev/sdc /btrfs > mount: wrong fs type, bad option, bad superblock on /dev/sdc, > missing codepage or helper program, or other error > In some cases useful info is found in syslog - try > dmesg | tail or so > > BTRFS: couldn't mount because of unsupported optional features (100). > btrfs: open_ctree failed > ---------- > > Customers need to upgrade the kernel also to mount this FS. > > > [[current solution]] > > User must know that their running kernel does not support > skinny metadata and disable features accordingly as below. > > ------------ > # mkfs.btrfs -f -O ^skinny-metadata /dev/sdc > /dev/null && mount > /dev/sdc /btrfs > # echo $? > 0 > ------------ > > > [[problem with the current solution]] > > btrfs-progs is backward kernel compatible. > > But the default feature as set during mkfs is very btrfs-progs centric, > and is not in sync with the current running kernel. > > > [[new proposed, with the patch]] > > - the default-features that are not supported by the running kernel > are masked. > > So now the default mkfs.btrfs and mount works. As progs finds that > kernel version is too old to support skinny-metadata and remotes is > from the default feature list. > > ------------------- > # uname -r > 3.8.13-98.4.1.el6uek.x86_64 > > > # mkfs.btrfs -f /dev/sdc > btrfs-progs v4.2.2-7-g03cf344 > See http://btrfs.wiki.kernel.org for more information. > > Label: (null) > UUID: f2513ff0-6d94-4b6a-8bbf-ff53d343fa62 > Node size: 16384 > Sector size: 4096 > Filesystem size: 3.00GiB > Block group profiles: > Data: single 8.00MiB > Metadata: DUP 161.56MiB > System: DUP 12.00MiB > SSD detected: no > Incompat features: extref <----- > Number of devices: 1 > Devices: > ID SIZE PATH > 1 3.00GiB /dev/sdc > > # mount /dev/sdc /btrfs > ------------------- > > > However as Qu pointed out if user wants to create FS with a feature that > is not supported by running kernel. They still have the choice to enable > it using -O option. as below. however they won't be able to mount it > unless kernel is upgraded as well. > > ------- > # mkfs.btrfs -f -O skinny-metadata /dev/sdc > btrfs-progs v4.2.2-7-g03cf344 > See http://btrfs.wiki.kernel.org for more information. > > Label: (null) > UUID: 30c018ab-3d2a-4acc-8287-3f28c5324fca > Node size: 16384 > Sector size: 4096 > Filesystem size: 3.00GiB > Block group profiles: > Data: single 8.00MiB > Metadata: DUP 161.56MiB > System: DUP 12.00MiB > SSD detected: no > Incompat features: extref, skinny-metadata <---- > Number of devices: 1 > Devices: > ID SIZE PATH > 1 3.00GiB /dev/sdc > > # mount /dev/sdc /btrfs > mount: wrong fs type, bad option, bad superblock on /dev/sdc, > missing codepage or helper program, or other error > In some cases useful info is found in syslog - try > dmesg | tail or so > # > --------- > > In nut shell this patch makes _mkfs and btrfs-convert default features_ > dynamically aligned with the running kernel. Maybe just personal choice, I still prefer not to change default features, output warning should be good enough for such case, due to the unreliableness of version check. Thanks, Qu > > Thanks, Anand > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 10/21/15 4:45 AM, Anand Jain wrote: > mkfs from latest btrfs-progs will enable latest default features, > and if the kernel is down-rev and does not support a latest > default feature then mount fails, as expected. > > This patch disables default features based on the running kernel. I like the idea generally based on comments further in the thread, but what I don't like is: 1) It's silent. 2) There's no way to override it. If we're going to change the defaults at runtime, we should tell the user what has changed and why. Otherwise, an identical mkfs.btrfs binary will behave differently on different systems without feedback and that violates the principle of least surprise. If they want to do what Qu suggests later in the thread, where the device is being prepared for use on a newer kernel, it should be possible to force it. The normal -f should be fine there. - -Jeff > Signed-off-by: Anand Jain <anand.jain@oracle.com> --- mkfs.c | 5 > ++++- 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mkfs.c b/mkfs.c index a5802f7..2b9d734 100644 --- > a/mkfs.c +++ b/mkfs.c @@ -1357,10 +1357,13 @@ int main(int ac, char > **av) int dev_cnt = 0; int saved_optind; char > fs_uuid[BTRFS_UUID_UNPARSED_SIZE] = { 0 }; - u64 features = > BTRFS_MKFS_DEFAULT_FEATURES; + u64 features; struct mkfs_allocation > allocation = { 0 }; struct btrfs_mkfs_config mkfs_cfg; > > + features = btrfs_features_allowed_by_kernel(); + features &= > BTRFS_MKFS_DEFAULT_FEATURES; + while(1) { int c; static const > struct option long_options[] = { > - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.19 (Darwin) iQIcBAEBAgAGBQJWKlE/AAoJEB57S2MheeWy2mAP/33RvA9174u0PRmh+RBorZDC p3nDFFxS7pI5u7rSkFqUvbsKy9AoblUvgMYS8pDNkFokDML2hbH3HaYWFEmqvMch mp9DQ+wKz5hI5fYt/wgDdtVO6X0E3TCm2Cj1Uw4fl7E0bMzgNgio8tnOoGTrHGa5 YkZ96L9UWzEScv9EtesO3DLbUC+O3pokyHsHCdBRVgEwLcLB1AtmPrQmhc2a1+M4 sfzElmbo9Rld/xmtI4ecHl1sWbpfrYcKimzV32Jdv/SNhEyPuFOcN6/GUDOrGE7o Vs87+HtuXUr+CbFUM9r9wB1Nqj4yYJ78LnBfepBMjY9vWyAgPR49WFPRA/uhkvu/ uOd4DNgUbLktakztsMb1GRiS/6AEj6s8mHFzkOrS5b9E/RbwegWgcnpnWCveFcDO Nsfa6Mg99X7ojuXeMi8c00Jins70uSnh/dLOtP5JYkxTAf8v5znbouYYawBZLHAi P0KbIpQFmW+Qm9is1CDVZktnj79BFMcd+twMFQu/m9jhYdLUFqeEFCJ+sxCGcmoM n18ayAzbvCQCYz5dBOk2EQPgQoQKJGEOdc4IY0GdRcOwNcbw2hWbwbfGjLAKpLrA PVC8YmRsyT1CotXBXJEpn7jYFR2fnDOyO/5jq1JRDa6Mxeq3dECIRWof3pwQLnpI boQXIGHUlVWltF+hla3C =TG+F -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Thanks Jeff for the comments. On 10/23/2015 11:24 PM, Jeff Mahoney wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 10/21/15 4:45 AM, Anand Jain wrote: >> mkfs from latest btrfs-progs will enable latest default features, >> and if the kernel is down-rev and does not support a latest >> default feature then mount fails, as expected. >> >> This patch disables default features based on the running kernel. > > I like the idea generally based on comments further in the thread, but > what I don't like is: > > 1) It's silent. Will add warning. > 2) There's no way to override it. > If we're going to change the defaults at runtime, we should tell the > user what has changed and why. Otherwise, an identical mkfs.btrfs > binary will behave differently on different systems without feedback > and that violates the principle of least surprise. If they want to do > what Qu suggests later in the thread, where the device is being > prepared for use on a newer kernel, it should be possible to force it. > The normal -f should be fine there. Sill have no idea how to get this, trying. Thanks, Anand > - -Jeff > >> Signed-off-by: Anand Jain <anand.jain@oracle.com> --- mkfs.c | 5 >> ++++- 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/mkfs.c b/mkfs.c index a5802f7..2b9d734 100644 --- >> a/mkfs.c +++ b/mkfs.c @@ -1357,10 +1357,13 @@ int main(int ac, char >> **av) int dev_cnt = 0; int saved_optind; char >> fs_uuid[BTRFS_UUID_UNPARSED_SIZE] = { 0 }; - u64 features = >> BTRFS_MKFS_DEFAULT_FEATURES; + u64 features; struct mkfs_allocation >> allocation = { 0 }; struct btrfs_mkfs_config mkfs_cfg; >> >> + features = btrfs_features_allowed_by_kernel(); + features &= >> BTRFS_MKFS_DEFAULT_FEATURES; + while(1) { int c; static const >> struct option long_options[] = { >> > > > - -- > Jeff Mahoney > SUSE Labs > -----BEGIN PGP SIGNATURE----- > Version: GnuPG/MacGPG2 v2.0.19 (Darwin) > > iQIcBAEBAgAGBQJWKlE/AAoJEB57S2MheeWy2mAP/33RvA9174u0PRmh+RBorZDC > p3nDFFxS7pI5u7rSkFqUvbsKy9AoblUvgMYS8pDNkFokDML2hbH3HaYWFEmqvMch > mp9DQ+wKz5hI5fYt/wgDdtVO6X0E3TCm2Cj1Uw4fl7E0bMzgNgio8tnOoGTrHGa5 > YkZ96L9UWzEScv9EtesO3DLbUC+O3pokyHsHCdBRVgEwLcLB1AtmPrQmhc2a1+M4 > sfzElmbo9Rld/xmtI4ecHl1sWbpfrYcKimzV32Jdv/SNhEyPuFOcN6/GUDOrGE7o > Vs87+HtuXUr+CbFUM9r9wB1Nqj4yYJ78LnBfepBMjY9vWyAgPR49WFPRA/uhkvu/ > uOd4DNgUbLktakztsMb1GRiS/6AEj6s8mHFzkOrS5b9E/RbwegWgcnpnWCveFcDO > Nsfa6Mg99X7ojuXeMi8c00Jins70uSnh/dLOtP5JYkxTAf8v5znbouYYawBZLHAi > P0KbIpQFmW+Qm9is1CDVZktnj79BFMcd+twMFQu/m9jhYdLUFqeEFCJ+sxCGcmoM > n18ayAzbvCQCYz5dBOk2EQPgQoQKJGEOdc4IY0GdRcOwNcbw2hWbwbfGjLAKpLrA > PVC8YmRsyT1CotXBXJEpn7jYFR2fnDOyO/5jq1JRDa6Mxeq3dECIRWof3pwQLnpI > boQXIGHUlVWltF+hla3C > =TG+F > -----END PGP SIGNATURE----- > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/mkfs.c b/mkfs.c index a5802f7..2b9d734 100644 --- a/mkfs.c +++ b/mkfs.c @@ -1357,10 +1357,13 @@ int main(int ac, char **av) int dev_cnt = 0; int saved_optind; char fs_uuid[BTRFS_UUID_UNPARSED_SIZE] = { 0 }; - u64 features = BTRFS_MKFS_DEFAULT_FEATURES; + u64 features; struct mkfs_allocation allocation = { 0 }; struct btrfs_mkfs_config mkfs_cfg; + features = btrfs_features_allowed_by_kernel(); + features &= BTRFS_MKFS_DEFAULT_FEATURES; + while(1) { int c; static const struct option long_options[] = {
mkfs from latest btrfs-progs will enable latest default features, and if the kernel is down-rev and does not support a latest default feature then mount fails, as expected. This patch disables default features based on the running kernel. Signed-off-by: Anand Jain <anand.jain@oracle.com> --- mkfs.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)