From 642be6ec218b956fbae88304449720f76ba0d578 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Mon, 25 Feb 2008 17:20:46 -0500 Subject: Remove incorrect BKL comments in ext4 Signed-off-by: Andi Kleen Signed-off-by: "Theodore Ts'o" --- fs/ext4/inode.c | 1 - 1 file changed, 1 deletion(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 7dd9b50d5eb..d3c6f58a9de 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -768,7 +768,6 @@ err_out: * * `handle' can be NULL if create == 0. * - * The BKL may not be held on entry here. Be sure to take it early. * return > 0, # of blocks mapped or allocated. * return = 0, if plain lookup failed. * return < 0, error case. -- cgit v1.2.3-70-g09d2 From 74d3487fc8aa58cec16dff7239dea1ca59bdab0e Mon Sep 17 00:00:00 2001 From: Valerie Clement Date: Fri, 15 Feb 2008 13:43:07 -0500 Subject: ext4: modify block allocation algorithm for the last group When a directory inode is allocated in the last group and the last group contains less than s_blocks_per_group blocks, the initial block allocated for the directory is not always allocated in the same group as the directory inode, but in one of the first groups of the filesystem (group 1 for example). Depending on the current process's pid, ext4_find_near() and ext4_ext_find_goal() can return a block number greater than the maximum blocks count in the filesystem and in that case the block will be not allocated in the same group as the inode. The following patch fixes the problem. Should the modification also be done in ext2/3 code? Signed-off-by: Valerie Clement Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- fs/ext4/extents.c | 8 +++++++- fs/ext4/inode.c | 8 +++++++- 2 files changed, 14 insertions(+), 2 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index c4d6f19faf3..8a59f7ba30e 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -148,6 +148,7 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, { struct ext4_inode_info *ei = EXT4_I(inode); ext4_fsblk_t bg_start; + ext4_fsblk_t last_block; ext4_grpblk_t colour; int depth; @@ -169,8 +170,13 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode, /* OK. use inode's group */ bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) + le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block); - colour = (current->pid % 16) * + last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; + + if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) + colour = (current->pid % 16) * (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); + else + colour = (current->pid % 16) * ((last_block - bg_start) / 16); return bg_start + colour + block; } diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d3c6f58a9de..34f3eb615fd 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -403,6 +403,7 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind) __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data; __le32 *p; ext4_fsblk_t bg_start; + ext4_fsblk_t last_block; ext4_grpblk_t colour; /* Try to find previous block */ @@ -420,8 +421,13 @@ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind) * into the same cylinder group then. */ bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group); - colour = (current->pid % 16) * + last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; + + if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) + colour = (current->pid % 16) * (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); + else + colour = (current->pid % 16) * ((last_block - bg_start) / 16); return bg_start + colour; } -- cgit v1.2.3-70-g09d2 From f5ab0d1f8f7df937778c60c3da6f4ef939a54a7b Mon Sep 17 00:00:00 2001 From: Mingming Cao Date: Mon, 25 Feb 2008 15:29:55 -0500 Subject: ext4: Fix BUG when writing to an unitialized extent This patch fixes a bug when writing to preallocated but uninitialized blocks, which resulted in a BUG in fs/buffer.c saying that the buffer is not mapped. When writing to a file, ext4_get_block_wrap() is called with create=1 in order to request that blocks be allocated if necessary. It currently calls ext4_get_blocks() with create=0 in order to do a lookup first. If the inode contains an unitialized data block, the buffer head is left unampped, which ext4_get_blocks_wrap() returns, causing the BUG. We fix this by checking to see if the buffer head is unmapped, and if so, we make sure the the buffer head is mapped by calling ext4_ext_get_blocks with create=1. Signed-off-by: Mingming Cao Signed-off-by: "Theodore Ts'o" --- fs/ext4/extents.c | 13 +++++++++++++ fs/ext4/inode.c | 47 ++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 57 insertions(+), 3 deletions(-) (limited to 'fs/ext4/inode.c') diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 8a59f7ba30e..bcf5d040e32 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2287,9 +2287,22 @@ out: } /* + * Block allocation/map/preallocation routine for extents based files + * + * * Need to be called with * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) + * + * return > 0, number of of blocks already mapped/allocated + * if create == 0 and these are pre-allocated blocks + * buffer head is unmapped + * otherwise blocks are mapped + * + * return = 0, if plain look up failed (blocks have not been allocated) + * buffer head is unmapped + * + * return < 0, error case. */ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, ext4_lblk_t iblock, diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 34f3eb615fd..945cbf6cb1f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -908,11 +908,38 @@ out: */ #define DIO_CREDITS 25 + +/* + * + * + * ext4_ext4 get_block() wrapper function + * It will do a look up first, and returns if the blocks already mapped. + * Otherwise it takes the write lock of the i_data_sem and allocate blocks + * and store the allocated blocks in the result buffer head and mark it + * mapped. + * + * If file type is extents based, it will call ext4_ext_get_blocks(), + * Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping + * based files + * + * On success, it returns the number of blocks being mapped or allocate. + * if create==0 and the blocks are pre-allocated and uninitialized block, + * the result buffer head is unmapped. If the create ==1, it will make sure + * the buffer head is mapped. + * + * It returns 0 if plain look up failed (blocks have not been allocated), in + * that casem, buffer head is unmapped + * + * It returns the error in case of allocation failure. + */ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, unsigned long max_blocks, struct buffer_head *bh, int create, int extend_disksize) { int retval; + + clear_buffer_mapped(bh); + /* * Try to see if we can get the block without requesting * for new file system block. @@ -926,12 +953,26 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, inode, block, max_blocks, bh, 0, 0); } up_read((&EXT4_I(inode)->i_data_sem)); - if (!create || (retval > 0)) + + /* If it is only a block(s) look up */ + if (!create) + return retval; + + /* + * Returns if the blocks have already allocated + * + * Note that if blocks have been preallocated + * ext4_ext_get_block() returns th create = 0 + * with buffer head unmapped. + */ + if (retval > 0 && buffer_mapped(bh)) return retval; /* - * We need to allocate new blocks which will result - * in i_data update + * New blocks allocate and/or writing to uninitialized extent + * will possibly result in updating i_data, so we take + * the write lock of i_data_sem, and call get_blocks() + * with create == 1 flag. */ down_write((&EXT4_I(inode)->i_data_sem)); /* -- cgit v1.2.3-70-g09d2