erofs: fix broken illustration in documentation

Illustration was broken after ReST conversion by accident.
(checked by 'make SPHINXDIRS="filesystems" htmldocs')

Link: https://lore.kernel.org/r/20210510162506.28637-1-xiang@kernel.org
Fixes: e66d8631dd ("docs: filesystems: convert erofs.txt to ReST")
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Gao Xiang <xiang@kernel.org>
This commit is contained in:
Gao Xiang 2021-05-11 00:25:05 +08:00
parent 6efb943b86
commit 1b55767dfd
1 changed files with 59 additions and 60 deletions

View File

@ -113,31 +113,31 @@ may not. All metadatas can be now observed in two different spaces (views):
::
|-> aligned with 8B
|-> followed closely
+ meta_blkaddr blocks |-> another slot
_____________________________________________________________________
| ... | inode | xattrs | extents | data inline | ... | inode ...
|________|_______|(optional)|(optional)|__(optional)_|_____|__________
|-> aligned with the inode slot size
. .
. .
. .
. .
. .
. .
.____________________________________________________|-> aligned with 4B
| xattr_ibody_header | shared xattrs | inline xattrs |
|____________________|_______________|_______________|
|-> 12 bytes <-|->x * 4 bytes<-| .
. . .
. . .
. . .
._______________________________.______________________.
| id | id | id | id | ... | id | ent | ... | ent| ... |
|____|____|____|____|______|____|_____|_____|____|_____|
|-> aligned with 4B
|-> aligned with 4B
|-> aligned with 8B
|-> followed closely
+ meta_blkaddr blocks |-> another slot
_____________________________________________________________________
| ... | inode | xattrs | extents | data inline | ... | inode ...
|________|_______|(optional)|(optional)|__(optional)_|_____|__________
|-> aligned with the inode slot size
. .
. .
. .
. .
. .
. .
.____________________________________________________|-> aligned with 4B
| xattr_ibody_header | shared xattrs | inline xattrs |
|____________________|_______________|_______________|
|-> 12 bytes <-|->x * 4 bytes<-| .
. . .
. . .
. . .
._______________________________.______________________.
| id | id | id | id | ... | id | ent | ... | ent| ... |
|____|____|____|____|______|____|_____|_____|____|_____|
|-> aligned with 4B
|-> aligned with 4B
Inode could be 32 or 64 bytes, which can be distinguished from a common
field which all inode versions have -- i_format::
@ -175,13 +175,13 @@ may not. All metadatas can be now observed in two different spaces (views):
Each share xattr can also be directly found by the following formula:
xattr offset = xattr_blkaddr * block_size + 4 * xattr_id
::
::
|-> aligned by 4 bytes
+ xattr_blkaddr blocks |-> aligned with 4 bytes
_________________________________________________________________________
| ... | xattr_entry | xattr data | ... | xattr_entry | xattr data ...
|________|_____________|_____________|_____|______________|_______________
|-> aligned by 4 bytes
+ xattr_blkaddr blocks |-> aligned with 4 bytes
_________________________________________________________________________
| ... | xattr_entry | xattr data | ... | xattr_entry | xattr data ...
|________|_____________|_____________|_____|______________|_______________
Directories
-----------
@ -193,19 +193,18 @@ algorithm (could refer to the related source code).
::
___________________________
/ |
/ ______________|________________
/ / | nameoff1 | nameoffN-1
____________.______________._______________v________________v__________
| dirent | dirent | ... | dirent | filename | filename | ... | filename |
|___.0___|____1___|_____|___N-1__|____0_____|____1_____|_____|___N-1____|
\ ^
\ | * could have
\ | trailing '\0'
\________________________| nameoff0
Directory block
___________________________
/ |
/ ______________|________________
/ / | nameoff1 | nameoffN-1
____________.______________._______________v________________v__________
| dirent | dirent | ... | dirent | filename | filename | ... | filename |
|___.0___|____1___|_____|___N-1__|____0_____|____1_____|_____|___N-1____|
\ ^
\ | * could have
\ | trailing '\0'
\________________________| nameoff0
Directory block
Note that apart from the offset of the first filename, nameoff0 also indicates
the total number of directory entries in this block since it is no need to
@ -216,22 +215,22 @@ Compression
Currently, EROFS supports 4KB fixed-sized output transparent file compression,
as illustrated below::
|---- Variant-Length Extent ----|-------- VLE --------|----- VLE -----
clusterofs clusterofs clusterofs
| | | logical data
_________v_______________________________v_____________________v_______________
... | . | | . | | . | ...
____|____.________|_____________|________.____|_____________|__.__________|____
|-> cluster <-|-> cluster <-|-> cluster <-|-> cluster <-|-> cluster <-|
size size size size size
. . . .
. . . .
. . . .
_______._____________._____________._____________._____________________
... | | | | ... physical data
_______|_____________|_____________|_____________|_____________________
|-> cluster <-|-> cluster <-|-> cluster <-|
size size size
|<- variable-sized extent ->|<- VLE ->|
clusterofs clusterofs clusterofs
| | |
_________v_________________________________v_______________________v________
... | . | | . | | . ...
____|____._________|______________|________.___ _|______________|__.________
|-> lcluster <-|-> lcluster <-|-> lcluster <-|-> lcluster <-|
size size size size . .
. . . .
. . . .
. . . .
_______.______________.______________.______________._________________
... | | | | ...
_______|______________|______________|______________|_________________
|-> pcluster <-|-> pcluster <-|-> pcluster <-|
size size size
Currently each on-disk physical cluster can contain 4KB (un)compressed data
at most. For each logical cluster, there is a corresponding on-disk index to