aba392e630
- Remove redundant code. - Always wait for the initial reply from an asynchronous select request, even if the select has been satisfied on another file descriptor or was canceled due to a serious error. - Restart asynchronous selects if upon reply from the driver turns out that there are deferred operations (and do not forget we're still interested in the results of the deferred operations). - Do not hang a non-blocking select when another blocking select on the same filp is still blocking. - Split blocking operations in read, write, and exceptions (i.e., blocking on read does not imply the write will block as well). - Some loops would iterate over OPEN_MAX file descriptors instead of the "highest" file descriptor. - Use proper internal error return values. - A secondary reply from a synchronous driver is essentially the same as from an asynchronous driver (the only difference being how the answer is received). Merge. - Return proper error code after a driver failure. - Auto-detect whether a driver is synchronous or asynchronous. - Remove some code duplication. - Clean up code (coding style, add missing comments, put all select related code together).
46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
#ifndef __VFS_FILE_H__
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#define __VFS_FILE_H__
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/* This is the filp table. It is an intermediary between file descriptors and
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* inodes. A slot is free if filp_count == 0.
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*/
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EXTERN struct filp {
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mode_t filp_mode; /* RW bits, telling how file is opened */
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int filp_flags; /* flags from open and fcntl */
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int filp_state; /* state for crash recovery */
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int filp_count; /* how many file descriptors share this slot?*/
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struct vnode *filp_vno; /* vnode belonging to this file */
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u64_t filp_pos; /* file position */
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/* the following fields are for select() and are owned by the generic
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* select() code (i.e., fd-type-specific select() code can't touch these).
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*/
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int filp_selectors; /* select()ing processes blocking on this fd */
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int filp_select_ops; /* interested in these SEL_* operations */
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int filp_select_flags; /* Select flags for the filp */
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/* following are for fd-type-specific select() */
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int filp_pipe_select_ops;
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} filp[NR_FILPS];
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#define FILP_CLOSED 0 /* filp_mode: associated device closed */
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#define FS_NORMAL 0 /* file descriptor can be used normally */
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#define FS_NEEDS_REOPEN 1 /* file descriptor needs to be re-opened */
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#define FSF_UPDATE 001 /* The driver should be informed about new
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* state.
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*/
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#define FSF_BUSY 002 /* Select operation sent to driver but no
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* reply yet.
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*/
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#define FSF_RD_BLOCK 010 /* Read request is blocking, the driver should
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* keep state.
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*/
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#define FSF_WR_BLOCK 020 /* Write request is blocking */
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#define FSF_ERR_BLOCK 040 /* Exception request is blocking */
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#define FSF_BLOCKED 070
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#endif
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