91 lines
5.1 KiB
Text
91 lines
5.1 KiB
Text
Changes from version 0.4a to version 0.4b
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=========================================
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- Copyrights changed to include the name of my laboratory.
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- Clean up of balloc.c and ialloc.c.
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- More consistency checks.
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- Block preallocation added by Stephen Tweedie.
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- Direct reads of directories disallowed.
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- Readahead implemented in readdir by Stephen Tweedie.
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- Bugs in block and inodes allocation fixed.
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- Readahead implemented in ext2_find_entry by Chip Salzenberg.
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- New mount options:
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`check=none|normal|strict'
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`debug'
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`errors=continue|remount-ro|panic'
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`grpid', `bsdgroups'
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`nocheck'
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`nogrpid', `sysvgroups'
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- truncate() now tries to deallocate contigous blocks in a single call
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to ext2_free_blocks().
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- lots of cosmetic changes.
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Changes from version 0.4 to version 0.4a
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========================================
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- the `sync' option support is now complete. Version 0.4 was not
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supporting it when truncating a file. I have tested the synchronous
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writes and they work but they make the system very slow :-( I have
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to work again on this to make it faster.
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- when detecting an error on a mounted filesystem, version 0.4 used
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to try to write a flag in the super block even if the filesystem had
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been mounted read-only. This is fixed.
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- the `sb=#' option now causes the kernel code to use the filesystem
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descriptors located at block #+1. Version 0.4 used the superblock
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backup located at block # but used the main copy of the descriptors.
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- a new file attribute `S' is supported. This attribute causes
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synchronous writes but is applied to a file not to the entire file
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system (thanks to Michael Kraehe <kraehe@bakunin.north.de> for
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suggesting it).
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- the directory cache is inhibited by default. The cache management
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code seems to be buggy and I have to look at it carefully before
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using it again.
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- deleting a file with the `s' attribute (secure deletion) causes its
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blocks to be overwritten with random values not with zeros (thanks to
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Michael A. Griffith <grif@cs.ucr.edu> for suggesting it).
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- lots of cosmetic changes have been made.
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Changes from version 0.3 to version 0.4
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=======================================
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- Three new mount options are supported: `check', `sync' and `sb=#'.
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`check' tells the kernel code to make more consistency checks
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when the file system is mounted. Currently, the kernel code checks
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that the blocks and inodes bitmaps are consistent with the free
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blocks and inodes counts. More checks will be added in future
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releases.
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`sync' tells the kernel code to use synchronous writes when updating
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an inode, a bitmap, a directory entry or an indirect block. This
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can make the file system much slower but can be a big win for files
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recovery in case of a crash (and we can now say to the BSD folks
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that Linux also supports synchronous updates :-).
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`sb=#' tells the kernel code to use an alternate super block instead
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of its master copy. `#' is the number of the block (counted in
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1024 bytes blocks) which contains the alternate super block.
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An ext2 file system typically contains backups of the super block
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at blocks 8193, 16385, and so on.
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- I have change the meaning of the valid flag used by e2fsck. it
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now contains the state of the file system. If the kernel code
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detects an inconsistency while the file system is mounted, it flags
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it as erroneous and e2fsck will detect that on next run.
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- The super block now contains a mount counter. This counter is
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incremented each time the file system is mounted read/write. When
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this counter becomes bigger than a maximal mount counts (also stored
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in the super block), e2fsck checks the file system, even if it had
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been unmounted cleany, and resets this counter to 0.
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- File attributes are now supported. One can associate a set of
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attributes to a file. Three attributes are defined:
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`c': the file is marked for automatic compression,
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`s': the file is marked for secure deletion: when the file is
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deleted, its blocks are zeroed and written back to the disk,
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`u': the file is marked for undeletion: when the file is deleted,
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its contents are saved to allow a future undeletion.
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Currently, only the `s' attribute is implemented in the kernel
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code. Support for the other attributes will be added in a future
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release.
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- a few bugs related to times updates have been fixed by Bruce
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Evans and me.
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- a bug related to the links count of deleted inodes has been fixed.
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Previous versions used to keep the links count set to 1 when a file
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was deleted. The new version now sets links_count to 0 when deleting
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the last link.
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- a race condition when deallocating an inode has been fixed by
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Stephen Tweedie.
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