Date: Sat, 16 Jun 2001 09:22:47 +0900 From: jdscol92@etri.re.kr To: phk@critter.freebsd.dk, jdscol92@etri.re.kr Cc: freebsd-fs@FreeBSD.ORG Subject: =?euc-kr?B?W8D8w7zIuL3FXSBSZTogJ2JfZGVwJyBpbiBidWZmZXIgc3RydWN0?= =?euc-kr?B?dXJlLi4uLj8/?= Message-ID: <766FA1FC5C2AD511B3C800D0B7A8AC4A391289@cms3.etri.re.kr>
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[-- Attachment #1 --] Thank you for being concerned about my qeuestions. the precise file + line number is as follows. The version of FreeBSD is 4.3 Release. >HI.. > >I have some question about the meaning of buffer flag, "b_dep" ... >There is a comment in source code(buf.h) as follows ... > >"List of filesystem dependencies" ==> /sys/sys/buf.h + 144 line (defined) > >1. In this comment, what does the 'filesystem dependencies' mean? > >2. In the code about buffer operations, you can see 'b_dep' flag marked NOT >NULL or NULL. ( b_dep!=NULL or b_dep==NULL).. > > What does the code, 'b_dep!=NULL or b_dep==NULL', mean? ==> /sys/kern/vfs_bio.c + 664, 733, 735, 1003, 1637 lines etc.... ==> /sys/ufs/ffs/ffs_softdep.c + 720, 724, 727, 1208 lines etc .... ==> /sys/ufs/ufs/ufs_readwrite.c + 323, 350, 502 lines etc .... ==> etc .... ==> I think that b_dep is not NULL if buffer is being used in a filesystem. ==> So, b_dep is checked if the buffer is being used now. Right?? > > What does the code, 'b_dep!=NULL or b_dep==NULL', mean? 3. Which routine is called when buffer's data is written to the disk( due to 'bwrite' or write back )?? I have found bwrite(), bdwrite(), bawrite() etc..routines, but I don't know which routine does actually write buffer's data to disk. Does 'softdep_disk_write_complete()' routine in 'bio_ops bioops' structure write buffer's data to disk ?? ==> /sys/ufs/ffs/ffs_softdep.c + 207 lines .. (defined in 'bio_ops_bioops' structure) ==> /sys/ufs/ffs/ffs_softdep.c + 3176 lines .. (softdep_disk_write_complete() implementation) Thank you.. Again. Good Day. p.s.) You might see this page with HTML type. If so, I'm sorry. I don't know the way that this page is sent without HTML type. ...... [-- Attachment #2 --] <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=euc-kr"> <META NAME="Generator" CONTENT="MS Exchange Server version 5.5.2653.12"> <TITLE>[Àüüȸ½Å] Re: 'b_dep' in buffer structure....??</TITLE> </HEAD> <BODY> <P><FONT SIZE=2>Thank you for being concerned about my qeuestions.</FONT> </P> <P><FONT SIZE=2>the precise file + line number is as follows.</FONT> <BR><FONT SIZE=2>The version of FreeBSD is 4.3 Release.</FONT> </P> <BR> <P><FONT SIZE=2>>HI.. </FONT> <BR><FONT SIZE=2>> </FONT> <BR><FONT SIZE=2>>I have some question about the meaning of buffer flag, "b_dep" ... </FONT> <BR><FONT SIZE=2>>There is a comment in source code(buf.h) as follows ... </FONT> <BR><FONT SIZE=2>> </FONT> <BR><FONT SIZE=2>>"List of filesystem dependencies" </FONT> </P> <P><FONT SIZE=2>==> /sys/sys/buf.h + 144 line (defined)</FONT> </P> <P><FONT SIZE=2>> </FONT> <BR><FONT SIZE=2>>1. In this comment, what does the 'filesystem dependencies' mean? </FONT> <BR><FONT SIZE=2>> </FONT> <BR><FONT SIZE=2>>2. In the code about buffer operations, you can see 'b_dep' flag marked NOT </FONT> <BR><FONT SIZE=2>>NULL or NULL. ( b_dep!=NULL or b_dep==NULL).. </FONT> <BR><FONT SIZE=2>> </FONT> <BR><FONT SIZE=2>> What does the code, 'b_dep!=NULL or b_dep==NULL', mean?</FONT> </P> <BR> <P><FONT SIZE=2>==> /sys/kern/vfs_bio.c + 664, 733, 735, 1003, 1637 lines etc....</FONT> <BR><FONT SIZE=2>==> /sys/ufs/ffs/ffs_softdep.c + 720, 724, 727, 1208 lines etc ....</FONT> <BR><FONT SIZE=2>==> /sys/ufs/ufs/ufs_readwrite.c + 323, 350, 502 lines etc ....</FONT> <BR><FONT SIZE=2>==> etc ....</FONT> </P> <P><FONT SIZE=2>==> I think that b_dep is not NULL if buffer is being used in a filesystem.</FONT> <BR><FONT SIZE=2>==> So, b_dep is checked if the buffer is being used now. Right??</FONT> </P> <P><FONT SIZE=2>> </FONT> <BR><FONT SIZE=2>> What does the code, 'b_dep!=NULL or b_dep==NULL', mean?</FONT> </P> <P><FONT SIZE=2>3. Which routine is called when buffer's data is written to the disk( due to 'bwrite' or write back )??</FONT> <BR><FONT SIZE=2>I have found bwrite(), bdwrite(), bawrite() etc..routines, but I don't know which routine does actually write buffer's data to disk.</FONT></P> <P><FONT SIZE=2>Does 'softdep_disk_write_complete()' routine in 'bio_ops bioops' structure write buffer's data to disk ??</FONT> </P> <P><FONT SIZE=2>==> /sys/ufs/ffs/ffs_softdep.c + 207 lines .. (defined in 'bio_ops_bioops' structure)</FONT> <BR><FONT SIZE=2>==> /sys/ufs/ffs/ffs_softdep.c + 3176 lines .. (softdep_disk_write_complete() implementation)</FONT> </P> <BR> <P><FONT SIZE=2>Thank you.. Again.</FONT> <BR><FONT SIZE=2>Good Day.</FONT> </P> <P><FONT SIZE=2>p.s.) </FONT> <BR><FONT SIZE=2>You might see this page with HTML type. If so, I'm sorry.</FONT> <BR><FONT SIZE=2>I don't know the way that this page is sent without HTML type.</FONT> <BR><FONT SIZE=2>......</FONT> </P> </BODY> </HTML>
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