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/* Unlock pages prepared by reiserfs_prepare_file_region_for_write */ | /* Unlock pages prepared by reiserfs_prepare_file_region_for_write */ |
void reiserfs_unprepare_pages(struct page **prepared_pages, /* list of locked pages */ | void reiserfs_unprepare_pages(struct page **prepared_pages, /* list of locked pages */ |
int num_pages /* amount of pages */) { |
size_t num_pages /* amount of pages */) { |
int i; // loop counter | int i; // loop counter |
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for (i=0; i < num_pages ; i++) { | for (i=0; i < num_pages ; i++) { |
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int offset; // offset in page | int offset; // offset in page |
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for ( i = 0, offset = (pos & (PAGE_CACHE_SIZE-1)); i < num_pages ; i++,offset=0) { | for ( i = 0, offset = (pos & (PAGE_CACHE_SIZE-1)); i < num_pages ; i++,offset=0) { |
int count = min_t(int,PAGE_CACHE_SIZE-offset,write_bytes); // How much of bytes to write to this page |
size_t count = min_t(size_t,PAGE_CACHE_SIZE-offset,write_bytes); // How much of bytes to write to this page |
struct page *page=prepared_pages[i]; // Current page we process. | struct page *page=prepared_pages[i]; // Current page we process. |
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fault_in_pages_readable( buf, count); | fault_in_pages_readable( buf, count); |
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struct reiserfs_transaction_handle *th, | struct reiserfs_transaction_handle *th, |
struct inode *inode, | struct inode *inode, |
loff_t pos, /* Writing position offset */ | loff_t pos, /* Writing position offset */ |
int num_pages, /* Number of pages to write */ |
size_t num_pages, /* Number of pages to write */ |
int write_bytes, /* number of bytes to write */ |
size_t write_bytes, /* number of bytes to write */ |
struct page **prepared_pages /* list of pages */ | struct page **prepared_pages /* list of pages */ |
) | ) |
{ | { |
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static int reiserfs_prepare_file_region_for_write( | static int reiserfs_prepare_file_region_for_write( |
struct inode *inode /* Inode of the file */, | struct inode *inode /* Inode of the file */, |
loff_t pos, /* position in the file */ | loff_t pos, /* position in the file */ |
int num_pages, /* number of pages to |
size_t num_pages, /* number of pages to |
prepare */ | prepare */ |
int write_bytes, /* Amount of bytes to be |
size_t write_bytes, /* Amount of bytes to be |
overwritten from | overwritten from |
@pos */ | @pos */ |
struct page **prepared_pages /* pointer to array | struct page **prepared_pages /* pointer to array |
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while ( count > 0) { | while ( count > 0) { |
/* This is the main loop in which we running until some error occures | /* This is the main loop in which we running until some error occures |
or until we write all of the data. */ | or until we write all of the data. */ |
int num_pages;/* amount of pages we are going to write this iteration */ |
size_t num_pages;/* amount of pages we are going to write this iteration */ |
int write_bytes; /* amount of bytes to write during this iteration */ |
size_t write_bytes; /* amount of bytes to write during this iteration */ |
int blocks_to_allocate; /* how much blocks we need to allocate for |
size_t blocks_to_allocate; /* how much blocks we need to allocate for this iteration */ |
this iteration */ |
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/* (pos & (PAGE_CACHE_SIZE-1)) is an idiom for offset into a page of pos*/ | /* (pos & (PAGE_CACHE_SIZE-1)) is an idiom for offset into a page of pos*/ |
num_pages = !!((pos+count) & (PAGE_CACHE_SIZE - 1)) + /* round up partial | num_pages = !!((pos+count) & (PAGE_CACHE_SIZE - 1)) + /* round up partial |
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/* If we were asked to write more data than we want to or if there | /* If we were asked to write more data than we want to or if there |
is not that much space, then we shorten amount of data to write | is not that much space, then we shorten amount of data to write |
for this iteration. */ | for this iteration. */ |
num_pages = min_t(int, REISERFS_WRITE_PAGES_AT_A_TIME, reiserfs_can_fit_pages(inode->i_sb)); |
num_pages = min_t(size_t, REISERFS_WRITE_PAGES_AT_A_TIME, reiserfs_can_fit_pages(inode->i_sb)); |
/* Also we should not forget to set size in bytes accordingly */ | /* Also we should not forget to set size in bytes accordingly */ |
write_bytes = (num_pages << PAGE_CACHE_SHIFT) - | write_bytes = (num_pages << PAGE_CACHE_SHIFT) - |
(pos & (PAGE_CACHE_SIZE-1)); | (pos & (PAGE_CACHE_SIZE-1)); |
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// But overwriting files on absolutelly full volumes would not | // But overwriting files on absolutelly full volumes would not |
// be very efficient. Well, people are not supposed to fill | // be very efficient. Well, people are not supposed to fill |
// 100% of disk space anyway. | // 100% of disk space anyway. |
write_bytes = min_t(int, count, inode->i_sb->s_blocksize - (pos & (inode->i_sb->s_blocksize - 1))); |
write_bytes = min_t(size_t, count, inode->i_sb->s_blocksize - (pos & (inode->i_sb->s_blocksize - 1))); |
num_pages = 1; | num_pages = 1; |
// No blocks were claimed before, so do it now. | // No blocks were claimed before, so do it now. |
reiserfs_claim_blocks_to_be_allocated(inode->i_sb, 1 << (PAGE_CACHE_SHIFT - inode->i_blkbits)); | reiserfs_claim_blocks_to_be_allocated(inode->i_sb, 1 << (PAGE_CACHE_SHIFT - inode->i_blkbits)); |
