* Add SEEK_DATA/SEEK_HOLE support V2
@ 2011-09-28 6:32 Jeff Liu
2011-09-28 7:21 ` Yongqiang Yang
0 siblings, 1 reply; 7+ messages in thread
From: Jeff Liu @ 2011-09-28 6:32 UTC (permalink / raw)
To: linux-ext4; +Cc: Yongqiang Yang, Sunil Mushran
Hello all,
This is the V2 for add SEEK_DATA/SEEK_HOLE support to ext4.
In V1, I copied all the codes regarding fetching delayed-extents out to
my seek callback function, it's stupid to duplicate the code blocks.
Now the idea is, since the delayed-extents is the main concern to search
extents for both fiemap and seek, so IMHO, it's better to consolidate
this procedure into a new function(get_delayed_extent() in my patch),
and call it in fiemap and seek call-back functions if necessary. In
this way, when yongqiang's delayed-extents tree is ready, we only need
to modify the code block at get_delayed_extent() accordingly.
In addition, yongqiang has pointed out there might be a deadlock, but
per my understood, as the target inode already locked via i_mutex in
ext4_llseek() before, this lock can prevent any modification to the
file, and we call find_get_pages_tag() when trying to fetch the dirty
pages, this function using rcu read lock, it also safe to read. So I
have no idea what's wrong, could anyone please kindly point me out in
this case? I'm definitely a newbie to this list, sorry for my ignorant.
Anyway, I'd like to post the revised for your guys review first.
In have split the modification to two patches this time, since I hope to
make it looks more convenient for the review purpose.
The 1st patch, remove the delayed-extents fetching procedure to a
function named as get_delayed_extent(), and modify the
ext4_ext_fiemap_cb() accordingly.
The 2nd path add the ext4_ext_seek_cb() to implement the
SEEK_HOLE/SEEK_DATA stuff based on previous code change.
Testing:
========
In addition to the test cases mentioned in V1, I also done another tests
through sunil's seek test program, please refer to:
http://oss.oracle.com/~smushran/seek_data/seek_test.c
To ensure the 1st patch does not cause regression issue on fiemap, I
have done some tests via cp(1) with fiemap copy support, the sparse file
used for this test is produced by:
python -c "f=open('./sptest', 'w'); [(f.seek(x) or f.write(str(x))) for
x in range(1, 1000000000, 99999)]; f.close()
Any feedback are appreciated!
Thanks,
-Jeff
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: Add SEEK_DATA/SEEK_HOLE support V2 2011-09-28 6:32 Add SEEK_DATA/SEEK_HOLE support V2 Jeff Liu @ 2011-09-28 7:21 ` Yongqiang Yang 2011-09-28 8:02 ` Jeff Liu 0 siblings, 1 reply; 7+ messages in thread From: Yongqiang Yang @ 2011-09-28 7:21 UTC (permalink / raw) To: jeff.liu; +Cc: linux-ext4, Sunil Mushran On Wed, Sep 28, 2011 at 2:32 PM, Jeff Liu <jeff.liu@oracle.com> wrote: > Hello all, > > This is the V2 for add SEEK_DATA/SEEK_HOLE support to ext4. > In V1, I copied all the codes regarding fetching delayed-extents out to > my seek callback function, it's stupid to duplicate the code blocks. > > Now the idea is, since the delayed-extents is the main concern to search > extents for both fiemap and seek, so IMHO, it's better to consolidate > this procedure into a new function(get_delayed_extent() in my patch), > and call it in fiemap and seek call-back functions if necessary. In > this way, when yongqiang's delayed-extents tree is ready, we only need > to modify the code block at get_delayed_extent() accordingly. > > In addition, yongqiang has pointed out there might be a deadlock, but > per my understood, as the target inode already locked via i_mutex in > ext4_llseek() before, this lock can prevent any modification to the > file, and we call find_get_pages_tag() when trying to fetch the dirty > pages, this function using rcu read lock, it also safe to read. So I > have no idea what's wrong, could anyone please kindly point me out in > this case? I'm definitely a newbie to this list, sorry for my ignorant. Ok. There is no deadlock, fiemap releases i_data_sem before calling get_delayed_extent(). BTW: It seems that there is a bug in fiemap according to code, I am not sure which commit introduced it, delayed extents beyond last allocated block are ignored. Yongqiang. > > Anyway, I'd like to post the revised for your guys review first. > In have split the modification to two patches this time, since I hope to > make it looks more convenient for the review purpose. > > The 1st patch, remove the delayed-extents fetching procedure to a > function named as get_delayed_extent(), and modify the > ext4_ext_fiemap_cb() accordingly. > > The 2nd path add the ext4_ext_seek_cb() to implement the > SEEK_HOLE/SEEK_DATA stuff based on previous code change. > > Testing: > ======== > In addition to the test cases mentioned in V1, I also done another tests > through sunil's seek test program, please refer to: > http://oss.oracle.com/~smushran/seek_data/seek_test.c > > To ensure the 1st patch does not cause regression issue on fiemap, I > have done some tests via cp(1) with fiemap copy support, the sparse file > used for this test is produced by: > python -c "f=open('./sptest', 'w'); [(f.seek(x) or f.write(str(x))) for > x in range(1, 1000000000, 99999)]; f.close() > > > Any feedback are appreciated! > > > Thanks, > -Jeff > -- Best Wishes Yongqiang Yang -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Add SEEK_DATA/SEEK_HOLE support V2 2011-09-28 7:21 ` Yongqiang Yang @ 2011-09-28 8:02 ` Jeff Liu 2011-09-28 8:11 ` Yongqiang Yang 0 siblings, 1 reply; 7+ messages in thread From: Jeff Liu @ 2011-09-28 8:02 UTC (permalink / raw) To: Yongqiang Yang; +Cc: linux-ext4, Sunil Mushran On 09/28/2011 03:21 PM, Yongqiang Yang wrote: > On Wed, Sep 28, 2011 at 2:32 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >> Hello all, >> >> This is the V2 for add SEEK_DATA/SEEK_HOLE support to ext4. >> In V1, I copied all the codes regarding fetching delayed-extents out to >> my seek callback function, it's stupid to duplicate the code blocks. >> >> Now the idea is, since the delayed-extents is the main concern to search >> extents for both fiemap and seek, so IMHO, it's better to consolidate >> this procedure into a new function(get_delayed_extent() in my patch), >> and call it in fiemap and seek call-back functions if necessary. In >> this way, when yongqiang's delayed-extents tree is ready, we only need >> to modify the code block at get_delayed_extent() accordingly. >> >> In addition, yongqiang has pointed out there might be a deadlock, but >> per my understood, as the target inode already locked via i_mutex in >> ext4_llseek() before, this lock can prevent any modification to the >> file, and we call find_get_pages_tag() when trying to fetch the dirty >> pages, this function using rcu read lock, it also safe to read. So I >> have no idea what's wrong, could anyone please kindly point me out in >> this case? I'm definitely a newbie to this list, sorry for my ignorant. > Ok. There is no deadlock, fiemap releases i_data_sem before calling > get_delayed_extent(). > > BTW: It seems that there is a bug in fiemap according to code, I am > not sure which commit introduced it, delayed extents beyond last > allocated block are ignored. Hmm... could you show me a bit more detailed info with the test scenario if convenient? I can help testing, at least 3.1.0-rc2+ is works to me. Also, upstream coreutils-cp(1) has been well tested for ext4, it could be used for fiemap tests based on the extent_scan module: http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/extent-scan.c?h=next&id=b56b53bd70b1f8fa2b5a95d4569bb72a2419b5cd Thanks, -Jeff > > Yongqiang. >> >> Anyway, I'd like to post the revised for your guys review first. >> In have split the modification to two patches this time, since I hope to >> make it looks more convenient for the review purpose. >> >> The 1st patch, remove the delayed-extents fetching procedure to a >> function named as get_delayed_extent(), and modify the >> ext4_ext_fiemap_cb() accordingly. >> >> The 2nd path add the ext4_ext_seek_cb() to implement the >> SEEK_HOLE/SEEK_DATA stuff based on previous code change. >> >> Testing: >> ======== >> In addition to the test cases mentioned in V1, I also done another tests >> through sunil's seek test program, please refer to: >> http://oss.oracle.com/~smushran/seek_data/seek_test.c >> >> To ensure the 1st patch does not cause regression issue on fiemap, I >> have done some tests via cp(1) with fiemap copy support, the sparse file >> used for this test is produced by: >> python -c "f=open('./sptest', 'w'); [(f.seek(x) or f.write(str(x))) for >> x in range(1, 1000000000, 99999)]; f.close() >> >> >> Any feedback are appreciated! >> >> >> Thanks, >> -Jeff >> > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Add SEEK_DATA/SEEK_HOLE support V2 2011-09-28 8:02 ` Jeff Liu @ 2011-09-28 8:11 ` Yongqiang Yang 2011-09-28 8:40 ` Jeff Liu 0 siblings, 1 reply; 7+ messages in thread From: Yongqiang Yang @ 2011-09-28 8:11 UTC (permalink / raw) To: jeff.liu; +Cc: linux-ext4, Sunil Mushran On Wed, Sep 28, 2011 at 4:02 PM, Jeff Liu <jeff.liu@oracle.com> wrote: > On 09/28/2011 03:21 PM, Yongqiang Yang wrote: > >> On Wed, Sep 28, 2011 at 2:32 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >>> Hello all, >>> >>> This is the V2 for add SEEK_DATA/SEEK_HOLE support to ext4. >>> In V1, I copied all the codes regarding fetching delayed-extents out to >>> my seek callback function, it's stupid to duplicate the code blocks. >>> >>> Now the idea is, since the delayed-extents is the main concern to search >>> extents for both fiemap and seek, so IMHO, it's better to consolidate >>> this procedure into a new function(get_delayed_extent() in my patch), >>> and call it in fiemap and seek call-back functions if necessary. In >>> this way, when yongqiang's delayed-extents tree is ready, we only need >>> to modify the code block at get_delayed_extent() accordingly. >>> >>> In addition, yongqiang has pointed out there might be a deadlock, but >>> per my understood, as the target inode already locked via i_mutex in >>> ext4_llseek() before, this lock can prevent any modification to the >>> file, and we call find_get_pages_tag() when trying to fetch the dirty >>> pages, this function using rcu read lock, it also safe to read. So I >>> have no idea what's wrong, could anyone please kindly point me out in >>> this case? I'm definitely a newbie to this list, sorry for my ignorant. >> Ok. There is no deadlock, fiemap releases i_data_sem before calling >> get_delayed_extent(). >> >> BTW: It seems that there is a bug in fiemap according to code, I am >> not sure which commit introduced it, delayed extents beyond last >> allocated block are ignored. > > Hmm... could you show me a bit more detailed info with the test scenario > if convenient? I can help testing, at least 3.1.0-rc2+ is works to me. Could you test a file with map info like AAAADDDDDHHHHDDDD, A-allocated block, D-deayed block, H-hole. then filefrag -v and have a look if extent map info is right. Thanks, Yongqiang. > > Also, upstream coreutils-cp(1) has been well tested for ext4, it could > be used for fiemap tests based on the extent_scan module: > http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/extent-scan.c?h=next&id=b56b53bd70b1f8fa2b5a95d4569bb72a2419b5cd > > Thanks, > -Jeff > >> >> Yongqiang. >>> >>> Anyway, I'd like to post the revised for your guys review first. >>> In have split the modification to two patches this time, since I hope to >>> make it looks more convenient for the review purpose. >>> >>> The 1st patch, remove the delayed-extents fetching procedure to a >>> function named as get_delayed_extent(), and modify the >>> ext4_ext_fiemap_cb() accordingly. >>> >>> The 2nd path add the ext4_ext_seek_cb() to implement the >>> SEEK_HOLE/SEEK_DATA stuff based on previous code change. >>> >>> Testing: >>> ======== >>> In addition to the test cases mentioned in V1, I also done another tests >>> through sunil's seek test program, please refer to: >>> http://oss.oracle.com/~smushran/seek_data/seek_test.c >>> >>> To ensure the 1st patch does not cause regression issue on fiemap, I >>> have done some tests via cp(1) with fiemap copy support, the sparse file >>> used for this test is produced by: >>> python -c "f=open('./sptest', 'w'); [(f.seek(x) or f.write(str(x))) for >>> x in range(1, 1000000000, 99999)]; f.close() >>> >>> >>> Any feedback are appreciated! >>> >>> >>> Thanks, >>> -Jeff >>> >> >> >> > > > -- Best Wishes Yongqiang Yang -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Add SEEK_DATA/SEEK_HOLE support V2 2011-09-28 8:11 ` Yongqiang Yang @ 2011-09-28 8:40 ` Jeff Liu 2011-09-28 8:53 ` Yongqiang Yang 0 siblings, 1 reply; 7+ messages in thread From: Jeff Liu @ 2011-09-28 8:40 UTC (permalink / raw) To: Yongqiang Yang; +Cc: linux-ext4, Sunil Mushran On 09/28/2011 04:11 PM, Yongqiang Yang wrote: > On Wed, Sep 28, 2011 at 4:02 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >> On 09/28/2011 03:21 PM, Yongqiang Yang wrote: >> >>> On Wed, Sep 28, 2011 at 2:32 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >>>> Hello all, >>>> >>>> This is the V2 for add SEEK_DATA/SEEK_HOLE support to ext4. >>>> In V1, I copied all the codes regarding fetching delayed-extents out to >>>> my seek callback function, it's stupid to duplicate the code blocks. >>>> >>>> Now the idea is, since the delayed-extents is the main concern to search >>>> extents for both fiemap and seek, so IMHO, it's better to consolidate >>>> this procedure into a new function(get_delayed_extent() in my patch), >>>> and call it in fiemap and seek call-back functions if necessary. In >>>> this way, when yongqiang's delayed-extents tree is ready, we only need >>>> to modify the code block at get_delayed_extent() accordingly. >>>> >>>> In addition, yongqiang has pointed out there might be a deadlock, but >>>> per my understood, as the target inode already locked via i_mutex in >>>> ext4_llseek() before, this lock can prevent any modification to the >>>> file, and we call find_get_pages_tag() when trying to fetch the dirty >>>> pages, this function using rcu read lock, it also safe to read. So I >>>> have no idea what's wrong, could anyone please kindly point me out in >>>> this case? I'm definitely a newbie to this list, sorry for my ignorant. >>> Ok. There is no deadlock, fiemap releases i_data_sem before calling >>> get_delayed_extent(). >>> >>> BTW: It seems that there is a bug in fiemap according to code, I am >>> not sure which commit introduced it, delayed extents beyond last >>> allocated block are ignored. >> >> Hmm... could you show me a bit more detailed info with the test scenario >> if convenient? I can help testing, at least 3.1.0-rc2+ is works to me. > Could you test a file with map info like AAAADDDDDHHHHDDDD, > A-allocated block, D-deayed block, H-hole. then filefrag -v and have > a look if extent map info is right. Do you means, open a file, write something, fsync(), then write something, seek to some position and write something again? If so, looks the filefrag -v result is ok by waiting for a few seconds. Thanks, -Jeff > > Thanks, > Yongqiang. >> >> Also, upstream coreutils-cp(1) has been well tested for ext4, it could >> be used for fiemap tests based on the extent_scan module: >> http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/extent-scan.c?h=next&id=b56b53bd70b1f8fa2b5a95d4569bb72a2419b5cd >> >> Thanks, >> -Jeff >> >>> >>> Yongqiang. >>>> >>>> Anyway, I'd like to post the revised for your guys review first. >>>> In have split the modification to two patches this time, since I hope to >>>> make it looks more convenient for the review purpose. >>>> >>>> The 1st patch, remove the delayed-extents fetching procedure to a >>>> function named as get_delayed_extent(), and modify the >>>> ext4_ext_fiemap_cb() accordingly. >>>> >>>> The 2nd path add the ext4_ext_seek_cb() to implement the >>>> SEEK_HOLE/SEEK_DATA stuff based on previous code change. >>>> >>>> Testing: >>>> ======== >>>> In addition to the test cases mentioned in V1, I also done another tests >>>> through sunil's seek test program, please refer to: >>>> http://oss.oracle.com/~smushran/seek_data/seek_test.c >>>> >>>> To ensure the 1st patch does not cause regression issue on fiemap, I >>>> have done some tests via cp(1) with fiemap copy support, the sparse file >>>> used for this test is produced by: >>>> python -c "f=open('./sptest', 'w'); [(f.seek(x) or f.write(str(x))) for >>>> x in range(1, 1000000000, 99999)]; f.close() >>>> >>>> >>>> Any feedback are appreciated! >>>> >>>> >>>> Thanks, >>>> -Jeff >>>> >>> >>> >>> >> >> >> > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Add SEEK_DATA/SEEK_HOLE support V2 2011-09-28 8:40 ` Jeff Liu @ 2011-09-28 8:53 ` Yongqiang Yang 2011-09-28 9:06 ` Jeff Liu 0 siblings, 1 reply; 7+ messages in thread From: Yongqiang Yang @ 2011-09-28 8:53 UTC (permalink / raw) To: jeff.liu; +Cc: linux-ext4, Sunil Mushran On Wed, Sep 28, 2011 at 4:40 PM, Jeff Liu <jeff.liu@oracle.com> wrote: > On 09/28/2011 04:11 PM, Yongqiang Yang wrote: > >> On Wed, Sep 28, 2011 at 4:02 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >>> On 09/28/2011 03:21 PM, Yongqiang Yang wrote: >>> >>>> On Wed, Sep 28, 2011 at 2:32 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >>>>> Hello all, >>>>> >>>>> This is the V2 for add SEEK_DATA/SEEK_HOLE support to ext4. >>>>> In V1, I copied all the codes regarding fetching delayed-extents out to >>>>> my seek callback function, it's stupid to duplicate the code blocks. >>>>> >>>>> Now the idea is, since the delayed-extents is the main concern to search >>>>> extents for both fiemap and seek, so IMHO, it's better to consolidate >>>>> this procedure into a new function(get_delayed_extent() in my patch), >>>>> and call it in fiemap and seek call-back functions if necessary. In >>>>> this way, when yongqiang's delayed-extents tree is ready, we only need >>>>> to modify the code block at get_delayed_extent() accordingly. >>>>> >>>>> In addition, yongqiang has pointed out there might be a deadlock, but >>>>> per my understood, as the target inode already locked via i_mutex in >>>>> ext4_llseek() before, this lock can prevent any modification to the >>>>> file, and we call find_get_pages_tag() when trying to fetch the dirty >>>>> pages, this function using rcu read lock, it also safe to read. So I >>>>> have no idea what's wrong, could anyone please kindly point me out in >>>>> this case? I'm definitely a newbie to this list, sorry for my ignorant. >>>> Ok. There is no deadlock, fiemap releases i_data_sem before calling >>>> get_delayed_extent(). >>>> >>>> BTW: It seems that there is a bug in fiemap according to code, I am >>>> not sure which commit introduced it, delayed extents beyond last >>>> allocated block are ignored. >>> >>> Hmm... could you show me a bit more detailed info with the test scenario >>> if convenient? I can help testing, at least 3.1.0-rc2+ is works to me. >> Could you test a file with map info like AAAADDDDDHHHHDDDD, >> A-allocated block, D-deayed block, H-hole. then filefrag -v and have >> a look if extent map info is right. > > Do you means, open a file, write something, fsync(), then write > something, seek to some position and write something again? Yep. > If so, looks the filefrag -v result is ok by waiting for a few seconds. What do you mean waiting for a few seconds? Yongqiang. > > Thanks, > -Jeff > >> >> Thanks, >> Yongqiang. >>> >>> Also, upstream coreutils-cp(1) has been well tested for ext4, it could >>> be used for fiemap tests based on the extent_scan module: >>> http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/extent-scan.c?h=next&id=b56b53bd70b1f8fa2b5a95d4569bb72a2419b5cd >>> >>> Thanks, >>> -Jeff >>> >>>> >>>> Yongqiang. >>>>> >>>>> Anyway, I'd like to post the revised for your guys review first. >>>>> In have split the modification to two patches this time, since I hope to >>>>> make it looks more convenient for the review purpose. >>>>> >>>>> The 1st patch, remove the delayed-extents fetching procedure to a >>>>> function named as get_delayed_extent(), and modify the >>>>> ext4_ext_fiemap_cb() accordingly. >>>>> >>>>> The 2nd path add the ext4_ext_seek_cb() to implement the >>>>> SEEK_HOLE/SEEK_DATA stuff based on previous code change. >>>>> >>>>> Testing: >>>>> ======== >>>>> In addition to the test cases mentioned in V1, I also done another tests >>>>> through sunil's seek test program, please refer to: >>>>> http://oss.oracle.com/~smushran/seek_data/seek_test.c >>>>> >>>>> To ensure the 1st patch does not cause regression issue on fiemap, I >>>>> have done some tests via cp(1) with fiemap copy support, the sparse file >>>>> used for this test is produced by: >>>>> python -c "f=open('./sptest', 'w'); [(f.seek(x) or f.write(str(x))) for >>>>> x in range(1, 1000000000, 99999)]; f.close() >>>>> >>>>> >>>>> Any feedback are appreciated! >>>>> >>>>> >>>>> Thanks, >>>>> -Jeff >>>>> >>>> >>>> >>>> >>> >>> >>> >> >> >> > > > -- Best Wishes Yongqiang Yang -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: Add SEEK_DATA/SEEK_HOLE support V2 2011-09-28 8:53 ` Yongqiang Yang @ 2011-09-28 9:06 ` Jeff Liu 0 siblings, 0 replies; 7+ messages in thread From: Jeff Liu @ 2011-09-28 9:06 UTC (permalink / raw) To: Yongqiang Yang; +Cc: linux-ext4, Sunil Mushran On 09/28/2011 04:53 PM, Yongqiang Yang wrote: > On Wed, Sep 28, 2011 at 4:40 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >> On 09/28/2011 04:11 PM, Yongqiang Yang wrote: >> >>> On Wed, Sep 28, 2011 at 4:02 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >>>> On 09/28/2011 03:21 PM, Yongqiang Yang wrote: >>>> >>>>> On Wed, Sep 28, 2011 at 2:32 PM, Jeff Liu <jeff.liu@oracle.com> wrote: >>>>>> Hello all, >>>>>> >>>>>> This is the V2 for add SEEK_DATA/SEEK_HOLE support to ext4. >>>>>> In V1, I copied all the codes regarding fetching delayed-extents out to >>>>>> my seek callback function, it's stupid to duplicate the code blocks. >>>>>> >>>>>> Now the idea is, since the delayed-extents is the main concern to search >>>>>> extents for both fiemap and seek, so IMHO, it's better to consolidate >>>>>> this procedure into a new function(get_delayed_extent() in my patch), >>>>>> and call it in fiemap and seek call-back functions if necessary. In >>>>>> this way, when yongqiang's delayed-extents tree is ready, we only need >>>>>> to modify the code block at get_delayed_extent() accordingly. >>>>>> >>>>>> In addition, yongqiang has pointed out there might be a deadlock, but >>>>>> per my understood, as the target inode already locked via i_mutex in >>>>>> ext4_llseek() before, this lock can prevent any modification to the >>>>>> file, and we call find_get_pages_tag() when trying to fetch the dirty >>>>>> pages, this function using rcu read lock, it also safe to read. So I >>>>>> have no idea what's wrong, could anyone please kindly point me out in >>>>>> this case? I'm definitely a newbie to this list, sorry for my ignorant. >>>>> Ok. There is no deadlock, fiemap releases i_data_sem before calling >>>>> get_delayed_extent(). >>>>> >>>>> BTW: It seems that there is a bug in fiemap according to code, I am >>>>> not sure which commit introduced it, delayed extents beyond last >>>>> allocated block are ignored. >>>> >>>> Hmm... could you show me a bit more detailed info with the test scenario >>>> if convenient? I can help testing, at least 3.1.0-rc2+ is works to me. >>> Could you test a file with map info like AAAADDDDDHHHHDDDD, >>> A-allocated block, D-deayed block, H-hole. then filefrag -v and have >>> a look if extent map info is right. >> >> Do you means, open a file, write something, fsync(), then write >> something, seek to some position and write something again? > Yep. >> If so, looks the filefrag -v result is ok by waiting for a few seconds. > What do you mean waiting for a few seconds? If run filefrag -v immediately against a just created file, the delayed extents will not shown, we have to wait a little while until they are really allocated IMHO. Thanks, -Jeff > > > Yongqiang. >> >> Thanks, >> -Jeff >> >>> >>> Thanks, >>> Yongqiang. >>>> >>>> Also, upstream coreutils-cp(1) has been well tested for ext4, it could >>>> be used for fiemap tests based on the extent_scan module: >>>> http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/extent-scan.c?h=next&id=b56b53bd70b1f8fa2b5a95d4569bb72a2419b5cd >>>> >>>> Thanks, >>>> -Jeff >>>> >>>>> >>>>> Yongqiang. >>>>>> >>>>>> Anyway, I'd like to post the revised for your guys review first. >>>>>> In have split the modification to two patches this time, since I hope to >>>>>> make it looks more convenient for the review purpose. >>>>>> >>>>>> The 1st patch, remove the delayed-extents fetching procedure to a >>>>>> function named as get_delayed_extent(), and modify the >>>>>> ext4_ext_fiemap_cb() accordingly. >>>>>> >>>>>> The 2nd path add the ext4_ext_seek_cb() to implement the >>>>>> SEEK_HOLE/SEEK_DATA stuff based on previous code change. >>>>>> >>>>>> Testing: >>>>>> ======== >>>>>> In addition to the test cases mentioned in V1, I also done another tests >>>>>> through sunil's seek test program, please refer to: >>>>>> http://oss.oracle.com/~smushran/seek_data/seek_test.c >>>>>> >>>>>> To ensure the 1st patch does not cause regression issue on fiemap, I >>>>>> have done some tests via cp(1) with fiemap copy support, the sparse file >>>>>> used for this test is produced by: >>>>>> python -c "f=open('./sptest', 'w'); [(f.seek(x) or f.write(str(x))) for >>>>>> x in range(1, 1000000000, 99999)]; f.close() >>>>>> >>>>>> >>>>>> Any feedback are appreciated! >>>>>> >>>>>> >>>>>> Thanks, >>>>>> -Jeff >>>>>> >>>>> >>>>> >>>>> >>>> >>>> >>>> >>> >>> >>> >> >> >> > > > ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2011-09-28 9:06 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2011-09-28 6:32 Add SEEK_DATA/SEEK_HOLE support V2 Jeff Liu 2011-09-28 7:21 ` Yongqiang Yang 2011-09-28 8:02 ` Jeff Liu 2011-09-28 8:11 ` Yongqiang Yang 2011-09-28 8:40 ` Jeff Liu 2011-09-28 8:53 ` Yongqiang Yang 2011-09-28 9:06 ` Jeff Liu
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