forked from Minki/linux
befs: improve documentation in datastream.c
Convert function descriptions to kernel-doc style. Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com> Signed-off-by: Salah Triki <salah.triki@gmail.com>
This commit is contained in:
Luis de Bethencourt
parent
d327e612bd
commit
a20af5f9ea
@ -75,7 +75,13 @@ befs_read_datastream(struct super_block *sb, const befs_data_stream *ds,
|
||||
return bh;
|
||||
}
|
||||
|
||||
/*
|
||||
/**
|
||||
* befs_fblock2brun - give back block run for fblock
|
||||
* @sb: the superblock
|
||||
* @data: datastream to read from
|
||||
* @fblock: the blocknumber with the file position to find
|
||||
* @run: The found run is passed back through this pointer
|
||||
*
|
||||
* Takes a file position and gives back a brun who's starting block
|
||||
* is block number fblock of the file.
|
||||
*
|
||||
@ -212,36 +218,35 @@ befs_count_blocks(struct super_block *sb, const befs_data_stream *ds)
|
||||
return blocks;
|
||||
}
|
||||
|
||||
/*
|
||||
Finds the block run that starts at file block number blockno
|
||||
in the file represented by the datastream data, if that
|
||||
blockno is in the direct region of the datastream.
|
||||
|
||||
sb: the superblock
|
||||
data: the datastream
|
||||
blockno: the blocknumber to find
|
||||
run: The found run is passed back through this pointer
|
||||
|
||||
Return value is BEFS_OK if the blockrun is found, BEFS_ERR
|
||||
otherwise.
|
||||
|
||||
Algorithm:
|
||||
Linear search. Checks each element of array[] to see if it
|
||||
contains the blockno-th filesystem block. This is necessary
|
||||
because the block runs map variable amounts of data. Simply
|
||||
keeps a count of the number of blocks searched so far (sum),
|
||||
incrementing this by the length of each block run as we come
|
||||
across it. Adds sum to *count before returning (this is so
|
||||
you can search multiple arrays that are logicaly one array,
|
||||
as in the indirect region code).
|
||||
|
||||
When/if blockno is found, if blockno is inside of a block
|
||||
run as stored on disk, we offset the start and length members
|
||||
of the block run, so that blockno is the start and len is
|
||||
still valid (the run ends in the same place).
|
||||
|
||||
2001-11-15 Will Dyson
|
||||
*/
|
||||
/**
|
||||
* befs_find_brun_direct - find a direct block run in the datastream
|
||||
* @sb: the superblock
|
||||
* @data: the datastream
|
||||
* @blockno: the blocknumber to find
|
||||
* @run: The found run is passed back through this pointer
|
||||
*
|
||||
* Finds the block run that starts at file block number blockno
|
||||
* in the file represented by the datastream data, if that
|
||||
* blockno is in the direct region of the datastream.
|
||||
*
|
||||
* Return value is BEFS_OK if the blockrun is found, BEFS_ERR
|
||||
* otherwise.
|
||||
*
|
||||
* Algorithm:
|
||||
* Linear search. Checks each element of array[] to see if it
|
||||
* contains the blockno-th filesystem block. This is necessary
|
||||
* because the block runs map variable amounts of data. Simply
|
||||
* keeps a count of the number of blocks searched so far (sum),
|
||||
* incrementing this by the length of each block run as we come
|
||||
* across it. Adds sum to *count before returning (this is so
|
||||
* you can search multiple arrays that are logicaly one array,
|
||||
* as in the indirect region code).
|
||||
*
|
||||
* When/if blockno is found, if blockno is inside of a block
|
||||
* run as stored on disk, we offset the start and length members
|
||||
* of the block run, so that blockno is the start and len is
|
||||
* still valid (the run ends in the same place).
|
||||
*/
|
||||
static int
|
||||
befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data,
|
||||
befs_blocknr_t blockno, befs_block_run * run)
|
||||
@ -273,29 +278,28 @@ befs_find_brun_direct(struct super_block *sb, const befs_data_stream *data,
|
||||
return BEFS_ERR;
|
||||
}
|
||||
|
||||
/*
|
||||
Finds the block run that starts at file block number blockno
|
||||
in the file represented by the datastream data, if that
|
||||
blockno is in the indirect region of the datastream.
|
||||
|
||||
sb: the superblock
|
||||
data: the datastream
|
||||
blockno: the blocknumber to find
|
||||
run: The found run is passed back through this pointer
|
||||
|
||||
Return value is BEFS_OK if the blockrun is found, BEFS_ERR
|
||||
otherwise.
|
||||
|
||||
Algorithm:
|
||||
For each block in the indirect run of the datastream, read
|
||||
it in and search through it for search_blk.
|
||||
|
||||
XXX:
|
||||
Really should check to make sure blockno is inside indirect
|
||||
region.
|
||||
|
||||
2001-11-15 Will Dyson
|
||||
*/
|
||||
/**
|
||||
* befs_find_brun_indirect - find a block run in the datastream
|
||||
* @sb: the superblock
|
||||
* @data: the datastream
|
||||
* @blockno: the blocknumber to find
|
||||
* @run: The found run is passed back through this pointer
|
||||
*
|
||||
* Finds the block run that starts at file block number blockno
|
||||
* in the file represented by the datastream data, if that
|
||||
* blockno is in the indirect region of the datastream.
|
||||
*
|
||||
* Return value is BEFS_OK if the blockrun is found, BEFS_ERR
|
||||
* otherwise.
|
||||
*
|
||||
* Algorithm:
|
||||
* For each block in the indirect run of the datastream, read
|
||||
* it in and search through it for search_blk.
|
||||
*
|
||||
* XXX:
|
||||
* Really should check to make sure blockno is inside indirect
|
||||
* region.
|
||||
*/
|
||||
static int
|
||||
befs_find_brun_indirect(struct super_block *sb,
|
||||
const befs_data_stream *data,
|
||||
@ -365,47 +369,46 @@ befs_find_brun_indirect(struct super_block *sb,
|
||||
return BEFS_ERR;
|
||||
}
|
||||
|
||||
/*
|
||||
Finds the block run that starts at file block number blockno
|
||||
in the file represented by the datastream data, if that
|
||||
blockno is in the double-indirect region of the datastream.
|
||||
|
||||
sb: the superblock
|
||||
data: the datastream
|
||||
blockno: the blocknumber to find
|
||||
run: The found run is passed back through this pointer
|
||||
|
||||
Return value is BEFS_OK if the blockrun is found, BEFS_ERR
|
||||
otherwise.
|
||||
|
||||
Algorithm:
|
||||
The block runs in the double-indirect region are different.
|
||||
They are always allocated 4 fs blocks at a time, so each
|
||||
block run maps a constant amount of file data. This means
|
||||
that we can directly calculate how many block runs into the
|
||||
double-indirect region we need to go to get to the one that
|
||||
maps a particular filesystem block.
|
||||
|
||||
We do this in two stages. First we calculate which of the
|
||||
inode addresses in the double-indirect block will point us
|
||||
to the indirect block that contains the mapping for the data,
|
||||
then we calculate which of the inode addresses in that
|
||||
indirect block maps the data block we are after.
|
||||
|
||||
Oh, and once we've done that, we actually read in the blocks
|
||||
that contain the inode addresses we calculated above. Even
|
||||
though the double-indirect run may be several blocks long,
|
||||
we can calculate which of those blocks will contain the index
|
||||
we are after and only read that one. We then follow it to
|
||||
the indirect block and perform a similar process to find
|
||||
the actual block run that maps the data block we are interested
|
||||
in.
|
||||
|
||||
Then we offset the run as in befs_find_brun_array() and we are
|
||||
done.
|
||||
|
||||
2001-11-15 Will Dyson
|
||||
*/
|
||||
/**
|
||||
* befs_find_brun_dblindirect - find a block run in the datastream
|
||||
* @sb: the superblock
|
||||
* @data: the datastream
|
||||
* @blockno: the blocknumber to find
|
||||
* @run: The found run is passed back through this pointer
|
||||
*
|
||||
* Finds the block run that starts at file block number blockno
|
||||
* in the file represented by the datastream data, if that
|
||||
* blockno is in the double-indirect region of the datastream.
|
||||
*
|
||||
* Return value is BEFS_OK if the blockrun is found, BEFS_ERR
|
||||
* otherwise.
|
||||
*
|
||||
* Algorithm:
|
||||
* The block runs in the double-indirect region are different.
|
||||
* They are always allocated 4 fs blocks at a time, so each
|
||||
* block run maps a constant amount of file data. This means
|
||||
* that we can directly calculate how many block runs into the
|
||||
* double-indirect region we need to go to get to the one that
|
||||
* maps a particular filesystem block.
|
||||
*
|
||||
* We do this in two stages. First we calculate which of the
|
||||
* inode addresses in the double-indirect block will point us
|
||||
* to the indirect block that contains the mapping for the data,
|
||||
* then we calculate which of the inode addresses in that
|
||||
* indirect block maps the data block we are after.
|
||||
*
|
||||
* Oh, and once we've done that, we actually read in the blocks
|
||||
* that contain the inode addresses we calculated above. Even
|
||||
* though the double-indirect run may be several blocks long,
|
||||
* we can calculate which of those blocks will contain the index
|
||||
* we are after and only read that one. We then follow it to
|
||||
* the indirect block and perform a similar process to find
|
||||
* the actual block run that maps the data block we are interested
|
||||
* in.
|
||||
*
|
||||
* Then we offset the run as in befs_find_brun_array() and we are
|
||||
* done.
|
||||
*/
|
||||
static int
|
||||
befs_find_brun_dblindirect(struct super_block *sb,
|
||||
const befs_data_stream *data,
|
||||
|
||||
Loading…
Reference in New Issue
Block a user