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+--------+-------------------------+-------------------------+--------+--------+
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|00000520| 00 00 00 00 00 00 00 00 | 00 67 72 70 63 00 00 00 |........|.grpc...|
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|00000600| 25 20 2d 2a 2d 6c 61 74 | 65 78 2d 2a 2d 0a 25 0a |% -*-lat|ex-*-.%.|
|00000610| 25 0a 25 25 25 20 5c 64 | 6f 63 75 6d 65 6e 74 73 |%.%%% \d|ocuments|
|00000620| 74 79 6c 65 20 5b 31 31 | 70 74 2c 61 34 2c 65 70 |tyle [11|pt,a4,ep|
|00000630| 73 66 2c 72 63 6e 61 6d | 65 64 2c 72 65 6d 79 2c |sf,rcnam|ed,remy,|
|00000640| 74 77 6f 63 6f 6c 75 6d | 6e 5d 20 7b 61 72 74 69 |twocolum|n] {arti|
|00000650| 63 6c 65 7d 0a 5c 69 6e | 70 75 74 7b 65 78 74 32 |cle}.\in|put{ext2|
|00000660| 66 73 2f 72 65 6d 79 2e | 73 74 79 7d 0a 0a 5c 6e |fs/remy.|sty}..\n|
|00000670| 65 77 63 6f 6d 6d 61 6e | 64 20 7b 5c 6d 79 69 74 |ewcomman|d {\myit|
|00000680| 65 6d 7d 20 7b 5c 76 73 | 70 61 63 65 20 7b 2d 33 |em} {\vs|pace {-3|
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|000006a0| 62 65 67 69 6e 20 7b 64 | 6f 63 75 6d 65 6e 74 7d |begin {d|ocument}|
|000006b0| 0a 5c 63 68 61 70 74 65 | 72 7b 44 65 73 69 67 6e |.\chapte|r{Design|
|000006c0| 20 61 6e 64 20 49 6d 70 | 6c 65 6d 65 6e 74 61 74 | and Imp|lementat|
|000006d0| 69 6f 6e 20 6f 66 20 74 | 68 65 20 53 65 63 6f 6e |ion of t|he Secon|
|000006e0| 64 20 45 78 74 65 6e 64 | 65 64 20 46 69 6c 65 73 |d Extend|ed Files|
|000006f0| 79 73 74 65 6d 7d 0a 5c | 6c 61 62 65 6c 7b 63 68 |ystem}.\|label{ch|
|00000700| 61 70 3a 65 78 74 32 66 | 73 70 61 70 65 72 7d 0a |ap:ext2f|spaper}.|
|00000710| 0a 54 68 69 73 20 61 70 | 70 65 6e 64 69 78 20 69 |.This ap|pendix i|
|00000720| 73 20 61 20 70 61 70 65 | 72 20 77 72 69 74 74 65 |s a pape|r writte|
|00000730| 6e 20 62 79 20 52 5c 27 | 65 6d 79 20 43 61 72 64 |n by R\'|emy Card|
|00000740| 20 28 5c 74 65 78 74 74 | 74 7b 63 61 72 64 40 6d | (\textt|t{card@m|
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|00000760| 65 6f 64 6f 72 65 20 54 | 73 27 6f 20 28 5c 74 65 |eodore T|s'o (\te|
|00000770| 78 74 74 74 7b 74 79 74 | 73 6f 40 6d 69 74 2e 65 |xttt{tyt|so@mit.e|
|00000780| 64 75 7d 29 2c 20 61 6e | 64 20 53 74 65 70 68 65 |du}), an|d Stephe|
|00000790| 6e 20 54 77 65 65 64 69 | 65 0a 28 5c 74 65 78 74 |n Tweedi|e.(\text|
|000007a0| 74 74 7b 73 63 74 40 64 | 63 73 2e 65 64 2e 61 63 |tt{sct@d|cs.ed.ac|
|000007b0| 2e 75 6b 7d 29 2c 20 74 | 68 65 20 64 65 73 69 67 |.uk}), t|he desig|
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|00000800| 69 73 68 65 64 20 69 6e | 20 74 68 65 0a 50 72 6f |ished in| the.Pro|
|00000810| 63 65 65 64 69 6e 67 73 | 20 6f 66 20 74 68 65 20 |ceedings| of the |
|00000820| 46 69 72 73 74 20 44 75 | 74 63 68 20 49 6e 74 65 |First Du|tch Inte|
|00000830| 72 6e 61 74 69 6f 6e 61 | 6c 20 53 79 6d 70 6f 73 |rnationa|l Sympos|
|00000840| 69 75 6d 20 6f 6e 20 4c | 69 6e 75 78 2c 0a 49 53 |ium on L|inux,.IS|
|00000850| 42 4e 20 39 30 20 33 36 | 37 20 30 33 38 35 20 39 |BN 90 36|7 0385 9|
|00000860| 2e 0a 0a 25 25 25 20 5c | 74 69 74 6c 65 20 20 7b |...%%% \|title  {|
|00000870| 44 65 73 69 67 6e 20 61 | 6e 64 20 49 6d 70 6c 65 |Design a|nd Imple|
|00000880| 6d 65 6e 74 61 74 69 6f | 6e 20 6f 66 20 74 68 65 |mentatio|n of the|
|00000890| 20 53 65 63 6f 6e 64 20 | 45 78 74 65 6e 64 65 64 | Second |Extended|
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|000008b0| 20 5c 61 75 74 68 6f 72 | 20 7b 52 5c 27 65 6d 79 | \author| {R\'emy|
|000008c0| 20 43 61 72 64 5c 74 68 | 61 6e 6b 73 20 7b 4c 61 | Card\th|anks {La|
|000008d0| 62 6f 72 61 74 6f 69 72 | 65 20 4d 41 53 49 20 2d |boratoir|e MASI -|
|000008e0| 2d 2d 20 49 6e 73 74 69 | 74 75 74 20 42 6c 61 69 |-- Insti|tut Blai|
|000008f0| 73 65 20 50 61 73 63 61 | 6c 2c 0a 09 25 25 25 20 |se Pasca|l,..%%% |
|00000900| 45 2d 4d 61 69 6c 3a 20 | 63 61 72 64 40 6d 61 73 |E-Mail: |card@mas|
|00000910| 69 2e 69 62 70 2e 66 72 | 7d 20 5c 61 6e 64 0a 09 |i.ibp.fr|} \and..|
|00000920| 25 25 25 20 54 68 65 6f | 64 6f 72 65 20 54 73 27 |%%% Theo|dore Ts'|
|00000930| 6f 5c 74 68 61 6e 6b 73 | 20 7b 4d 61 73 73 61 63 |o\thanks| {Massac|
|00000940| 68 75 73 73 65 74 73 20 | 49 6e 73 74 69 74 75 74 |hussets |Institut|
|00000950| 65 20 6f 66 20 54 65 63 | 68 6e 6f 6c 6f 67 79 2c |e of Tec|hnology,|
|00000960| 0a 09 25 25 25 20 45 2d | 4d 61 69 6c 3a 20 74 79 |..%%% E-|Mail: ty|
|00000970| 74 73 6f 40 6d 69 74 2e | 65 64 75 7d 20 5c 61 6e |tso@mit.|edu} \an|
|00000980| 64 0a 09 25 25 25 20 53 | 74 65 70 68 65 6e 20 54 |d..%%% S|tephen T|
|00000990| 77 65 65 64 69 65 5c 74 | 68 61 6e 6b 73 20 7b 55 |weedie\t|hanks {U|
|000009a0| 6e 69 76 65 72 73 69 74 | 79 20 6f 66 20 45 64 69 |niversit|y of Edi|
|000009b0| 6e 62 75 72 67 68 2c 0a | 09 25 25 25 20 45 2d 4d |nburgh,.|.%%% E-M|
|000009c0| 61 69 6c 3a 20 73 63 74 | 40 64 63 73 2e 65 64 2e |ail: sct|@dcs.ed.|
|000009d0| 61 63 2e 75 6b 7d 0a 09 | 25 25 25 20 7d 0a 25 25 |ac.uk}..|%%% }.%%|
|000009e0| 25 20 5c 64 61 74 65 20 | 20 20 7b 7d 0a 0a 25 25 |% \date |  {}..%%|
|000009f0| 25 20 5c 6d 61 6b 65 74 | 69 74 6c 65 0a 0a 5c 72 |% \maket|itle..\r|
|00000a00| 61 67 67 65 64 62 6f 74 | 74 6f 6d 0a 0a 5c 73 65 |aggedbot|tom..\se|
|00000a10| 63 74 69 6f 6e 2a 20 7b | 49 6e 74 72 6f 64 75 63 |ction* {|Introduc|
|00000a20| 74 69 6f 6e 7d 0a 0a 09 | 4c 69 6e 75 78 20 69 73 |tion}...|Linux is|
|00000a30| 20 61 20 55 6e 69 78 2d | 6c 69 6b 65 20 6f 70 65 | a Unix-|like ope|
|00000a40| 72 61 74 69 6e 67 20 73 | 79 73 74 65 6d 2c 20 77 |rating s|ystem, w|
|00000a50| 68 69 63 68 20 72 75 6e | 73 20 6f 6e 20 50 43 2d |hich run|s on PC-|
|00000a60| 33 38 36 20 63 6f 6d 70 | 75 74 65 72 73 2e 0a 49 |386 comp|uters..I|
|00000a70| 74 20 77 61 73 20 69 6d | 70 6c 65 6d 65 6e 74 65 |t was im|plemente|
|00000a80| 64 20 66 69 72 73 74 20 | 61 73 20 65 78 74 65 6e |d first |as exten|
|00000a90| 73 69 6f 6e 20 74 6f 20 | 74 68 65 20 4d 69 6e 69 |sion to |the Mini|
|00000aa0| 78 20 6f 70 65 72 61 74 | 69 6e 67 20 73 79 73 74 |x operat|ing syst|
|00000ab0| 65 6d 0a 5c 63 69 74 65 | 20 7b 6d 69 6e 69 78 7d |em.\cite| {minix}|
|00000ac0| 20 61 6e 64 0a 69 74 73 | 20 66 69 72 73 74 20 76 | and.its| first v|
|00000ad0| 65 72 73 69 6f 6e 73 20 | 69 6e 63 6c 75 64 65 64 |ersions |included|
|00000ae0| 20 73 75 70 70 6f 72 74 | 20 66 6f 72 20 74 68 65 | support| for the|
|00000af0| 20 4d 69 6e 69 78 20 66 | 69 6c 65 73 79 73 74 65 | Minix f|ilesyste|
|00000b00| 6d 20 6f 6e 6c 79 2e 20 | 54 68 65 20 4d 69 6e 69 |m only. |The Mini|
|00000b10| 78 0a 66 69 6c 65 73 79 | 73 74 65 6d 20 63 6f 6e |x.filesy|stem con|
|00000b20| 74 61 69 6e 73 20 74 77 | 6f 20 73 65 72 69 6f 75 |tains tw|o seriou|
|00000b30| 73 20 6c 69 6d 69 74 61 | 74 69 6f 6e 73 3a 20 62 |s limita|tions: b|
|00000b40| 6c 6f 63 6b 20 61 64 64 | 72 65 73 73 65 73 20 61 |lock add|resses a|
|00000b50| 72 65 20 73 74 6f 72 65 | 64 20 69 6e 0a 31 36 20 |re store|d in.16 |
|00000b60| 62 69 74 20 69 6e 74 65 | 67 65 72 73 2c 20 74 68 |bit inte|gers, th|
|00000b70| 75 73 20 74 68 65 20 6d | 61 78 69 6d 61 6c 20 66 |us the m|aximal f|
|00000b80| 69 6c 65 73 79 73 74 65 | 6d 20 73 69 7a 65 20 69 |ilesyste|m size i|
|00000b90| 73 20 72 65 73 74 72 69 | 63 74 65 64 20 74 6f 20 |s restri|cted to |
|00000ba0| 36 34 20 6d 65 67 61 0a | 62 79 74 65 73 2c 20 61 |64 mega.|bytes, a|
|00000bb0| 6e 64 20 64 69 72 65 63 | 74 6f 72 69 65 73 20 63 |nd direc|tories c|
|00000bc0| 6f 6e 74 61 69 6e 20 66 | 69 78 65 64 2d 73 69 7a |ontain f|ixed-siz|
|00000bd0| 65 20 65 6e 74 72 69 65 | 73 20 61 6e 64 20 74 68 |e entrie|s and th|
|00000be0| 65 20 6d 61 78 69 6d 61 | 6c 20 66 69 6c 65 20 6e |e maxima|l file n|
|00000bf0| 61 6d 65 0a 69 73 20 31 | 34 20 63 68 61 72 61 63 |ame.is 1|4 charac|
|00000c00| 74 65 72 73 2e 0a 0a 09 | 57 65 20 68 61 76 65 20 |ters....|We have |
|00000c10| 64 65 73 69 67 6e 65 64 | 20 61 6e 64 20 69 6d 70 |designed| and imp|
|00000c20| 6c 65 6d 65 6e 74 65 64 | 20 74 77 6f 20 6e 65 77 |lemented| two new|
|00000c30| 20 66 69 6c 65 73 79 73 | 74 65 6d 73 20 74 68 61 | filesys|tems tha|
|00000c40| 74 20 61 72 65 0a 69 6e | 63 6c 75 64 65 64 20 69 |t are.in|cluded i|
|00000c50| 6e 20 74 68 65 20 73 74 | 61 6e 64 61 72 64 20 4c |n the st|andard L|
|00000c60| 69 6e 75 78 20 6b 65 72 | 6e 65 6c 2e 20 54 68 65 |inux ker|nel. The|
|00000c70| 73 65 0a 66 69 6c 65 73 | 79 73 74 65 6d 73 2c 20 |se.files|ystems, |
|00000c80| 63 61 6c 6c 65 64 20 60 | 60 45 78 74 65 6e 64 65 |called `|`Extende|
|00000c90| 64 20 46 69 6c 65 20 53 | 79 73 74 65 6d 27 27 20 |d File S|ystem'' |
|00000ca0| 28 45 78 74 20 66 73 29 | 20 61 6e 64 0a 60 60 53 |(Ext fs)| and.``S|
|00000cb0| 65 63 6f 6e 64 20 45 78 | 74 65 6e 64 65 64 20 46 |econd Ex|tended F|
|00000cc0| 69 6c 65 20 53 79 73 74 | 65 6d 27 27 20 28 45 78 |ile Syst|em'' (Ex|
|00000cd0| 74 32 20 66 73 29 20 72 | 61 69 73 65 20 74 68 65 |t2 fs) r|aise the|
|00000ce0| 20 6c 69 6d 69 74 61 74 | 69 6f 6e 73 0a 61 6e 64 | limitat|ions.and|
|00000cf0| 20 61 64 64 20 6e 65 77 | 20 66 65 61 74 75 72 65 | add new| feature|
|00000d00| 73 2e 0a 0a 09 49 6e 20 | 74 68 69 73 20 70 61 70 |s....In |this pap|
|00000d10| 65 72 2c 20 77 65 20 64 | 65 73 63 72 69 62 65 20 |er, we d|escribe |
|00000d20| 74 68 65 20 68 69 73 74 | 6f 72 79 20 6f 66 20 4c |the hist|ory of L|
|00000d30| 69 6e 75 78 20 66 69 6c | 65 73 79 73 74 65 6d 73 |inux fil|esystems|
|00000d40| 2e 20 57 65 0a 62 72 69 | 65 66 6c 79 20 69 6e 74 |. We.bri|efly int|
|00000d50| 72 6f 64 75 63 65 20 74 | 68 65 20 66 75 6e 64 61 |roduce t|he funda|
|00000d60| 6d 65 6e 74 61 6c 20 63 | 6f 6e 63 65 70 74 73 20 |mental c|oncepts |
|00000d70| 69 6d 70 6c 65 6d 65 6e | 74 65 64 20 69 6e 20 55 |implemen|ted in U|
|00000d80| 6e 69 78 20 66 69 6c 65 | 73 79 73 74 65 6d 73 2e |nix file|systems.|
|00000d90| 0a 57 65 20 70 72 65 73 | 65 6e 74 20 74 68 65 20 |.We pres|ent the |
|00000da0| 69 6d 70 6c 65 6d 65 6e | 74 61 74 69 6f 6e 20 6f |implemen|tation o|
|00000db0| 66 20 74 68 65 20 56 69 | 72 74 75 61 6c 20 46 69 |f the Vi|rtual Fi|
|00000dc0| 6c 65 20 53 79 73 74 65 | 6d 20 6c 61 79 65 72 20 |le Syste|m layer |
|00000dd0| 69 6e 20 4c 69 6e 75 78 | 20 61 6e 64 0a 77 65 20 |in Linux| and.we |
|00000de0| 64 65 74 61 69 6c 20 74 | 68 65 20 53 65 63 6f 6e |detail t|he Secon|
|00000df0| 64 20 45 78 74 65 6e 64 | 65 64 20 46 69 6c 65 20 |d Extend|ed File |
|00000e00| 53 79 73 74 65 6d 20 6b | 65 72 6e 65 6c 20 63 6f |System k|ernel co|
|00000e10| 64 65 20 61 6e 64 20 75 | 73 65 72 20 6d 6f 64 65 |de and u|ser mode|
|00000e20| 20 74 6f 6f 6c 73 2e 0a | 4c 61 73 74 2c 20 77 65 | tools..|Last, we|
|00000e30| 20 70 72 65 73 65 6e 74 | 20 70 65 72 66 6f 72 6d | present| perform|
|00000e40| 61 6e 63 65 20 6d 65 61 | 73 75 72 65 6d 65 6e 74 |ance mea|surement|
|00000e50| 73 20 6d 61 64 65 20 6f | 6e 20 4c 69 6e 75 78 20 |s made o|n Linux |
|00000e60| 61 6e 64 20 42 53 44 20 | 66 69 6c 65 73 79 73 74 |and BSD |filesyst|
|00000e70| 65 6d 73 0a 61 6e 64 20 | 77 65 20 63 6f 6e 63 6c |ems.and |we concl|
|00000e80| 75 64 65 20 77 69 74 68 | 20 74 68 65 20 63 75 72 |ude with| the cur|
|00000e90| 72 65 6e 74 20 73 74 61 | 74 75 73 20 6f 66 20 45 |rent sta|tus of E|
|00000ea0| 78 74 32 66 73 20 61 6e | 64 20 74 68 65 20 66 75 |xt2fs an|d the fu|
|00000eb0| 74 75 72 65 20 64 69 72 | 65 63 74 69 6f 6e 73 2e |ture dir|ections.|
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|00006250| 65 20 64 69 73 6b 20 68 | 65 61 64 20 73 65 65 6b |e disk h|ead seek|
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|00006300| 6b 2e 20 50 72 65 61 6c | 6c 6f 63 61 74 69 6f 6e |k. Preal|location|
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|00006320| 72 6f 75 6e 64 0a 37 35 | 5c 25 20 65 76 65 6e 20 |round.75|\% even |
|00006330| 6f 6e 20 76 65 72 79 20 | 66 75 6c 6c 20 66 69 6c |on very |full fil|
|00006340| 65 73 79 73 74 65 6d 73 | 2e 0a 54 68 69 73 20 70 |esystems|..This p|
|00006350| 72 65 61 6c 6c 6f 63 61 | 74 69 6f 6e 20 61 63 68 |realloca|tion ach|
|00006360| 69 65 76 65 73 20 67 6f | 6f 64 0a 77 72 69 74 65 |ieves go|od.write|
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|00006380| 64 65 72 20 68 65 61 76 | 79 20 6c 6f 61 64 2e 20 |der heav|y load. |
|00006390| 49 74 20 61 6c 73 6f 20 | 61 6c 6c 6f 77 73 20 63 |It also |allows c|
|000063a0| 6f 6e 74 69 67 75 6f 75 | 73 20 62 6c 6f 63 6b 73 |ontiguou|s blocks|
|000063b0| 20 74 6f 0a 62 65 20 61 | 6c 6c 6f 63 61 74 65 64 | to.be a|llocated|
|000063c0| 20 74 6f 20 66 69 6c 65 | 73 2c 20 74 68 75 73 20 | to file|s, thus |
|000063d0| 69 74 20 73 70 65 65 64 | 73 20 75 70 20 74 68 65 |it speed|s up the|
|000063e0| 20 66 75 74 75 72 65 20 | 73 65 71 75 65 6e 74 69 | future |sequenti|
|000063f0| 61 6c 20 72 65 61 64 73 | 2e 0a 0a 09 54 68 65 73 |al reads|....Thes|
+--------+-------------------------+-------------------------+--------+--------+